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gearheadE30
gearheadE30 Dork
12/1/23 11:08 p.m.

A wideband might be in my future...seems like I have some decisions to make.

  • Hot start issues are very common on 924s. Porsche struggled with it all throughout production. At first there was the "WOT crank" instructions in the owners manual. In 1979 only they added a solenoid valve in the intake. Starting in 1980 through the end of production, they had a valve in the control pressure line that dropped control pressure very low on warm-ish restarts. None of these things totally fix the issue, and any leakdown in the system makes it far worse. These cars have a fuel accumulator that maintains system pressure, knowing that there will be some leakage that a simple check valve like a modern system can't really handle. Mine is not working. I did check the injectors and they don't leak, so I probably have a leak in the WUR or in the regulator valve in the metering head. Both have a return to the tank. The issue is compounded by the fuel pump only running when ignition signal is seen. So there's no pre-crank priming pulse. Right now, I believe my most grassroots option is to add an intermittent switch that will allow me to trigger the fuel pump prior to starting so that I can purge any vapor locks without cranking a dozen times. Cold starts, on the other hand, are great.
  • One of the local auto parts stores had injector orings. I replaced them all. Massive improvement, it idles like it is supposed to now. Cheap and easy.
  • I figured out why it intermittenly runs like crap. Unfortunately, I don't have a fix for it. These cars, starting in 1980, have a lambda system that uses o2 sensor input to vary the duty cycle of a frequency valve, which modulates signal pressure from the WUR. It constantly operates, whenever the fuel pump relay is latched, and runs at a 60hz frequency. It's fairly loud, to the point which many CIS people seem to refer to it as "the chatter valve". Mine only chatters sometimes, and when it does, the car runs great. When it doesn't, it feels like it makes about 50 horsepower. I tried to clean the valve, but it seems like it's just weak or something. Cleaning didn't really seem to make a difference. The forums are littered with people with this problem, but none seem to have a fix. The advice they get from people who seem to be the resident experts goes completely against what I've read in the manual I have as well as what I have measured on my own car. The resulting poor information leads people in circles, and eventually the threads die.

Of course, the frequency valve is NLA. There are a few out there NOS in the ~$700 range, which is not something I am going to jump at unless there is really no other option.

My hope is that I can delete the frequency valve and basically make this thing think it is a 1979 model without the frequency control. But that will require more research, and possibly a different WUR.

When the valve is working right, the car runs pretty well. It's not fast, but it goes 75 down the highway just fine at ~3100 rpm just loafing along. I've just touched 5k rpm a few times, still waiting on that water pump so I can do the timing belt. It should be here either tomorrow or Monday. When the valve isn't working right, it is nearly undriveable.

gearheadE30
gearheadE30 Dork
12/3/23 11:56 a.m.

As it turns out, if you move the power mirror button with the ignition on and the engine off, it will generally trigger a priming pulse from the fuel pump. So for now, that's my hot start solution because I don't have to hack any wiring, and it does seem to help.

Good news on the frequency valve, possibly. I decided to check the electronics just to be safe, because I don't actually have a good way to measure the signal to the frequency valve. I do love things from the 80s - they are generally made to come apart just fine, and the lambda control module on this car is no exception. Two screws and we're in.

I found one burned solder joint that is underneath the transistor with the head sink. Suspicious. So I reflowed that one.

All of the dash grounds go to a common point under the cowl. There are two round ground points spot welded to the cowl with a bunch of spade terminals off of each one. This module is one of the devices that grounds at this point. For whatever reason, the ground to this module had a T added to it to ground another device to the same spade, even though there was an extra (but bent down) spade on the factory terminal ring. So I bent it back up and removed this little jumper just to be safe. None of it screamed "bad connection" but it certainly can't hurt.

And....after that fix, it survived a 3 hour round trip up to indy and back. Maybe a bit unnecessarily risky, but so glad that seems to have taken care of it.

That trip taught me a lot about the car. It is small, as we all know, but it's small even compared to an E30. Modern traffic dwarfs it.

It's very happy to cruise at 75 mph, just a tick over 3000 rpm. It has no power. If you want to accelerate, downshift. Maybe twice, but I haven't tried that yet since the timing belt is still ancient. Might get to that later today. The power delivery is odd, like airflow is badly choked. the first third of throttle is responsive at lower revs, but more throttle does nothing past that, like at that throttle opening it's already moving as much air through as it can. Need to play around more once the belt is done to see if it is that way at higher revs, but it seems pretty reminiscent of my 318is but less happy to rev.

The front struts are totally gone now. No more highway drives until those are replaced.

Temp gauge gets out of the "cold" zone but never gets up towards the middle. Electric fans work fine in traffic.

Lots of wind noise, not sure from where. Seemingly top of the windshield or the sunroof. Some from the hatch area, too.

Temp blend lever is stuck on hot. Very uncomfortable.

Strong exhaust/hot engine smell if you close the fresh air vent.

Aggressive high frequency vibrations around 3500 rpm.

Speedo reads a bit low. 70 on the gauge is actually 74 mph.

This thing gets a TON of looks and waves. Way more than I get in an E30.

Now that the fueling is better (if not correct) heel and toe is easy, and with the manifold vacuum limiter removed and vacuum leaks are fixed, it doesn't feel like it has a 100 lb flywheel anymore. Major, major improvement.

Steering wheel to shifter placement is wonderful. You sit super low and the transmission tunnel is quite high, which puts the shifter right up where you want it. The stock shifter is just the right amount of shift throw for the car and is fluid and accurate. It isn't a miata, but it isn't rubbery like an E30 can be either.

Steering is slow, but doesn't feel like a bus like a stock E30. I think the smaller steering wheel helps this.

E30 sport seats are way better than 924 seats. These are not sporty seats at all.

Suspension is sooooft. Front spring rates are okayish (160 lb/in I believe) but hard to tell with the blown struts. Rear doesn't have an anti roll bar and generally feels very soft. It has at least as much body roll as a stock E30, which makes the car feel oddly ponderous given its small size. We will see if struts and shocks help enough to satisfy me or if I'll need to do more.

I figured out why the tach orientation is goofy. The steering wheel blocks the first quadrant, and you can really only see the needle between 3000 rpm and redline. It's weird, but it makes sense now. It's even worse than the picture shows because of where your head sits.

porschenut
porschenut HalfDork
12/3/23 12:24 p.m.

Bosch had a generic book on CIS that was a big help.  Wish I still had it.  The other thing is a fuel pressure gage with 2 fittings, one for injector pressure and one for control pressure.  The warm up regulator varies that which changes amount of fuel going to the injectors.  I still have that, I think.  I also have the "L" bar for pulling injectors.  Will be happy to work out a deal for them, or maybe just sell me the car!  My bet on the hot start is either a WUR adjustment or weepy injectors, or maybe fual pressure is bleeding off.

And I disagree with Mike924, discs rear disks make a huge difference on the track.  My 79S had them and I can say track brake cones were ignored regularly.  My brake point was determined by the amount of butt pucker after the last cone and before the turn in.  It stopped so hard after a weekend the harness left bruises on my shoulders.

Another speed tip, there was a weber "big throat" throttle body that replaces the 2 barrel with one huge one.  I could be wrong on this one but the EFI 280Z may have a better TB that bolts on, or maybe they use the weber one.  

gearheadE30
gearheadE30 Dork
12/4/23 10:59 a.m.

In reply to porschenut :

I may be interested in the CIS bits, I still need to see if the setup I have will work or not. 

I did leak test the injectors and they are fine, but based on the condition of some of the other seals, I would guess the WUR and system pressure valve in the metering head both need new orings. The system almost immediately loses residual pressure, so that's definitely the cause of the hot restart problem. 

I'm not sure how long I'll keep the car with so many other projects...might be an opportunity there! 

Because street car, and because I don't think this is a "keep for the next 10 years" kind of car for me, the plan is stock brakes and 4 lug for now. If it worms its way into my heart as a keeper, then I might swap it. 

Isn't the 280z throttle an upgrade for the 924 turbo? The flange on the NA is a weird shape and would need a crazy adapter for a single plate throttle. Someone did some dyno testing that basically showed none of the usual bolt ons, including the TB, make any power difference until you fix the head flow and add a cam. For now I'm just going to optimize stock stuff and see where that gets me. This is another area where if this car ends up being a favorite, I may develop the engine some more. 

In the meantime, the timing belt swap has begun. After the 3 hour drive, all those seals that have been sitting for years have started leaking, so I did the cam and crank seals while it's apart. Reassembly should happen tonight. 

johndej
johndej SuperDork
12/4/23 11:47 a.m.

Rolling thought getting this thing refreshed! It seems the 924 is a bit of an aquired taste P-car world but seems like a fun one!

porschenut
porschenut HalfDork
12/4/23 2:23 p.m.

In reply to gearheadE30 :

You could always wire a momentary button to the fuel pump to get pressure up on restart.  The weber big throat was a bolt on.  Between that, a mild cam and a header I was getting a little over 120 mph on the track.

But overall I agree with your strategy to keep it stock and simple stuff.  It is an interesting car but not worth a lot of mods, as it will never be fast.

matthewmcl
matthewmcl Dork
12/4/23 2:44 p.m.

In reply to gearheadE30 :

I think I have the Weber and adapter being discussed. I think it was also used as an upgrade for the Rabbit. If you would like to try it, let me know.

In regards to the frequency valve, the WOT switch on the throttle should make the car ignore the O2 sensor and go open loop. If it bogs at idle when you do that, you are already too rich. You should be able to tap into the O2 signal to set mixture. I seem to recall 2/3 to 3/4 of a volt was about right.

I still have a couple of those control boards, but wiser men than me have pointed out that they never really fail.

Does the 924 have a 5th injector for cold start? I am trying to run through similarities to my 84 GTI.

gearheadE30
gearheadE30 Dork
12/4/23 5:52 p.m.

@johndej - trying to! This one is a bit more motivated than usual because it is fairly close to being "driver"-level of reliability. Once it's generally good to go, I can bring the 325es back into the garage as it needs quite a bit more work before it's ready for prime time. I find that the less I think about this as a P-car and the more I think about it as an '80s sportscar, the more I like it.

 

@porschenut - the momentary fuel pump button was my original plan. I may still do that, if replacing some orings doesn't fix the hot restart leakdown. Some people also rig up a button to trigger the cold start injector to dump a burst of fuel in, but that's kind of a problem because you can very easily flood the engine and it's not the real issue. The issue is after hot shutdown, the fuel in the lines between the metering head and the injectors boil, and you have to purge all of that fuel before the injectors actually work again. This is also the idea behind the hot start control pressure solenoid - it completely interrupts control pressure for a few seconds so that the metering valve opens a bit more and purges the lines faster. Combine this with priming the fuel pump either with the mirror switch or the jumper wire I carry with me, holding the gas pedal at WOT during cranking, and it starts okay.

I dug around more for pics of the big throat, it's got an adapter deal that makes it fit. I've got a saved search out on Ebay just in case one of those or an Audi 5000 throttle show up cheap.

 

@matthewmcl - yep, it would have also been around for K jet rabbits and cabrios. They use the same TB flange. What size is that throttle? I may interested in it, maybe get the differential pressure gauge out and see what difference it makes since the 924 world seems to be lacking data.

Yes, there is a WOT switch and an idle switch on my TB. The idle switch was disconnected when I got it. Both of them disable closed loop, and the manual makes reference to the lambda controller disabling closed loop over 3500 rpm also.

No bogging on mine. With the solder joint fixed, it actually runs pretty well with no major bogs or surging. I found another vacuum leak and won't be able to test it until after the timing belt stuff is done.

I need to measure frequency valve duty cycle with those switches triggered, and check the O2 signal like you mention. If the O2 sensor signal is lost, the frequency valve goes to 50% duty cycle according to the manual. It's unclear exactly how duty cycle impacts control pressure, that is something I intend to measure.

My problem was that the frequency valve was shutting off, which should never happen. With no power, bench testing suggests that it is closed, defaulting to near-zero control pressure and going extremely rich. The soot under the bumper of this car would seem to confirm that. I have no idea if those boards are failure prone or not - I have seen a lot of posts about people with intermittent frequency valves, but very few posts about how they fixed it. So they might be failing but rarely get diagnosed. It does seem like a lot of K-jet lambda cars get scrapped for fueling problems, and they were only on the market for a fairly narrow time period anyway.

Yes, the 924 does have the 5th injector. My understanding is the system is nearly identical to what VW was using in the Rabbit/GTI/Cabrio/etc.

matthewmcl
matthewmcl Dork
12/4/23 8:02 p.m.

In reply to gearheadE30 :

Sorry, I still have to read all the posts, perhaps I can pay penance with parts. Does the 924 have both a thermotime switch and a hot pulse relay? Thermotime runs the 5th injector when cold and only a few seconds. Hot pulse gives the 5th injector a pulse while trying to start, similar to pulsing an accelerator pump when starting.

Edit: Looks like you need the relay. I will see if I can dig up an old one. There are multiple "upgrades" that VW did that were done with fancy relays.

Edit No. 2: The TB is 60mm

nlevine
nlevine GRM+ Memberand Reader
12/4/23 11:37 p.m.
gearheadE30 said:
It is small, as we all know, but it's small even compared to an E30. Modern traffic dwarfs it.

I noticed that with my 924s as well, but you can still fit 2 baritone saxophones in one to get to a gig. It's a pretty practical toy, even if you do have to worry about getting run over by SUVs...

gearheadE30
gearheadE30 Dork
12/6/23 9:18 a.m.

@matthewmcl - yes on the thermo time switch, no on the hot pulse relay. It does have the hot start solenoid that is in line with the frequency valve and which I believe drops control pressure to nearly nothing, but I haven't done a lot of research on that one. Yeah, if there's a fancy relay update, I'd be all about that. Some people in the 924 world have added a momentary switch that allows them to manually pulse the cold start relay, but I would like to make this work "correctly" rather than rig up manual solutions if possible. 

Rough math on the throttles, using my 1980 car as a baseline for the percentages: 

  • My 36/46mm throttle: 2678mm^2
  • Early 924 25/46mm: 2152mm^2, 20% smaller than mine
  • Weber Big Throat 60mm: 2826mm^2, 6% larger than mine
  • Audi throttle 36/53mm: 3222mm^2, 20% larger than mine

@nlevine yes they are very practical, I've already had 4 E30 wheels with tires in the back which would never happen in most cars this small. 

 

gearheadE30
gearheadE30 Dork
12/10/23 1:04 p.m.

Many updates, still making progress and looking forward to driving again.

Interior stuff:

  • Fixed the parking brake. Took it out of the car and disassembled before realizing the problem was that the button had come unscrewed from the internal pushrod somehow. Screwed it back on and it works!
  • Heat stuck on - there's no blend door on these, just a cable-operated valve that restricts flow through the heater core. It was gummed up with ancient coolant shmoo and, after cleaning, works great.
  • Realized one of the front sunroof catches is broken. OEM Porsche part for $3? I'll take two, thanks.

Engine stuff:

  • Water pump finally showed up, new T belt, pump, and tensioner are installed. Bearings in the pump and tensioner didn't have any play but made tons of noise, like they were full of rust. New tensioner required a pin wrench and different hardware to install, fortunately had both on hand.
  • Found another vacuum leak - crank breather hose is rotten. NLA part, will have to find some 22mm ID hose and rig something up. For now, I capped off the connection to the intake and put a breather filter on the engine side. Interestingly, the OEM hose has a restrictor plate in it. Haven't seen that before. Roughly 1/4" ID.
  • Welded up new alternator mounts to replace my rigged up spacer deal
  • Replaced several hoses, half of which didn't fit. Very annoying, still waiting on another lower radiator hose. Fortunately the others were too long so I could cut them down to size.
  • There are two (NLA) engine mounts on these, plus a hydraulic damper deal on the passenger side. NAs had this "vibration damper" but turbo cars did not. Mine was bottomed out, suggesting I probably will need to find some solution for the NLA worn out engine mounts, and the stud was broken. That's going in the trash, and is probably responsible for a lot of the high frequency vibration I was feeling.

This is the remains of the alarm system:

Suspension:

  • New ball joints. It didn't need them, but I'm replacing everything else and replacements are cheap so I did them anyway.
  • Cleaned and painted the strut housings
  • Rebuilt the completely collapsed upper strut mounts. I really don't like the upper strut mount design on these cars. Plenty of isolation, but they allow a lot of movement and when the suspension is at full extension or is dynamically extending, the top out bumper on the mount will add a lot of drag to the steering. Had I understood how these worked, I may have tried to find an alternative, but regardless, it's still better than the collapsed ones that were in there. With manual steering, I expect steering effort to be much lower
  • Koni sport adjustable inserts. There's nothing on the market between these and cheapo replacements. Bilsteins appear to be NLA. I actually have a set of matching rears sitting around, so I guess it works out
  • Weltmeister SP250 progressive front springs, also just because I have them lying around.

The original guts on this car were shot. One strut was only about half full of oil, both were leaking, one was worn through the chrome on the shock shaft, etc. Should be a massive improvement.

This car is super soft. Lots of body roll, etc. The struts weren't helping, but even steady state cornering produced an alarming amount of body roll. I know it will be unbalanced until I do some matching work to the rear, but it's a step in the right direction. My E30 is on 350 lb front springs also on strut suspension, that's still comfortable to me so these progressive 250 lb springs should be fine.

My OEM springs are "green dot" springs. Allegedly this is for M404 or M471 cars. They became the standard springs in 1981. My car is definitely not M471 (disc brakes+sport pack) and I don't think it's M404 (front and rear anti roll bars - I only have a front) so that's a little odd. That said, there's not a huge variation in spring rate (allegedly) and all of them are around 160 lb/in stock.

New lower rad hose shows up Monday, so I should be able to fill the cooling system and start her up then.

 

nlevine
nlevine GRM+ Memberand Reader
12/10/23 1:46 p.m.

In reply to gearheadE30 :

I should have a set of engine mounts from my '79 924 hanging around - the car came to me not running (seized engine) after sitting outside for a decade, so I'm not sure of their condition. Send me a PM if you want them and I can ship them to you. 

gearheadE30
gearheadE30 Dork
12/10/23 7:35 p.m.

In reply to nlevine :

I am definitely interested! I sent you a note. Even if they aren't in great shape, I can use them as a model to fabricate another alternative without taking the car off the road.

gearheadE30
gearheadE30 Dork
12/12/23 12:08 a.m.

Drove the car a bit since the lower radiator hose showed up. The engine is SO much quieter now, but it has picked up a whine. The timing belt tension is set with the "turn 90 degrees" thing similar to a V belt, and the internet suggests the belt will whine if you have gotten it too tight. I always seem to overdo it on V belts, so....seems likely. 

At some point I'll also pull the accessory belt and see if it's the alternator. Hopefully it isn't the oil pump, which is a concentric gerotor on the front of the crank. I pulled the belt off of the AC since it doesn't work anyway, it isn't that. 

Only did a brief drive after filling it with coolant, but it's a completely different experience after the last round of repairs. The steering weight is much more linear now, I think because the spring hats aren't dragging on the strut bearing housings under load anymore. The handling is approaching "fun" with the new springs and shocks, not too stiff at all. The rear definitely feels soggy now though. Corner entry is good, corner exit is wallowy. In a way it makes the car feel like it has more power than it really does because it really hunkers down when you transition from brakes to throttle.

For my own reference, -1 degree camber, 0 to 1/16 toed in, half turn out on the shock adjusters seems like a good place to be. I had a bit of toe out on it but it's surprisingly dirty for some reason. Very stable with that dialed out. Seems more sensitive to toe than my e30s. 

Unfortunately the front sits almost an inch higher than before, which is roughly stock height. The upper strut mounts were completely collapsed which lowered the car quite a bit. These springs supposedly lower a 944 nearly an inch, but the 924 is much lighter plus the strut mounts are new. I hope it settles a bit.

With the new timing belt I did finally give her the beans. Definitely not a fast car. It actually sounds pretty decent, but timing and/or mixture feel like they need work still. Peak power is supposed to be 5800 rpm, but it doesn't feel like there is much point to going past 5500. With the long gearing, that's a bummer, but it feels like there is room for improvement. 

On the plus side, the shifter is great, the clutch is great, it's easy to heel-toe, and with the vacuum limiter valve removed and the vacuum leaks fixed, the revs finally fall quickly enough that lightweight flywheel is off of my desires list.

porschenut
porschenut HalfDork
12/12/23 8:25 a.m.

Don't go nuts getting the front as low as the rear.  Not a pretty stance but it will handle, my track car had the same issue with cut front springs it was still a little nose high.  And it would reach redline but wasn't worth the wait.  

porschenut
porschenut HalfDork
12/12/23 4:25 p.m.

If you want euro bumpers just drill out the shocks in the bumper mounts, collapse and weld.

Crenshaw
Crenshaw New Reader
12/12/23 9:00 p.m.

Love this!  My first car in 1999 was a silver '80 924, I thought it was cool as E36 M3 and it basically had every single problem that yours has.  The random restart issues were vexing- sometimes it would refuse to start after sitting for hours in a ski area parking lot if you didn't hold your tongue just right.  Then if you had patience to let it sit for another 20 minutes or so it would fire right up.   I never did sort that out before I sold it, but mostly learned to work around it.  I always wanted another one of those cars, and after a couple decades of a bunch of e30s and Toyotas and whatever, I picked up an  '85.5 944 like 5 years ago and have proceeded to just break it constantly.  I still love it. 

Anyway great thread, and always nice to see yet another person with a soft spot for some of the exact same chassis as myself and a few others.  Cheers!

 

 

I like e30s too

 

gearheadE30
gearheadE30 Dork
12/13/23 9:52 a.m.

@porschenut - yeah with the strut front end going low isn't great for geometry. Right now the control arms are parallel with the ground, previously they were just above parallel but not to the point where the arms and struts are 90 degrees to each other and you start to lose camber on compression. Raising the rear is also an option, I just want a touch of rake to get rid of the droopy butt look.

I have considered tucking the bumpers. Super common in the E30 world, looks like the same is possible here. That will wait until everything is running great though. I think I'd go slightly less aggressive than the example below.

Current ride height:

 

@crenshaw man I feel like I remember your name/vehicles possibly from the glory days of r3v. Your 944 looks excellent, I do love the wider fenders and those wheels are perfect. Very nice. and of course I'm always a sucker for E30s, good to see the iX in its natural habitat! I think there are a few of us here who are suckers for transaxle Porsches and E30s.

Fortunately my hot starting issue isn't completely unpredictable - I can now pretty much 100% predict when it will or will not be a problem. Cold starts are great, restarts after sitting several hours are fine if I prime the fuel pump and hold the throttle at WOT. It's the warm day hot restarts after 30 minutes to an hour that are the worst, but it still lights off after several crank attempts at WOT.

I did replace the small oring in the fuel pressure regulator last night, this regulator is a much simpler one than what I see pictures of online. Not sure why it is different, most seem to have more pieces. I haven't driven it enough to know if this has fixed anything, the oring in there was flattened but not hardened. (edit - this oring is 3mm ID 2mm cross section)

 

I did also weigh the car at work. Full tank of gas, subtracting my weight out of it - 2680 lbs. Honestly, a bit more than I expected. I always thought these were a few hundred pounds lighter than that.

The more I drive the car, the better it runs. It hasn't gotten any quicker, but it does somehow feel like fueling is cleaning up a bit at part throttle where it felt like it was surging or running lean previously.

gearheadE30
gearheadE30 Dork
12/15/23 6:37 p.m.

Just about put a full tank of gas through the car since that round of major updates 

Removing that vibration damper thing seems to have helped quite a bit in terms of vibration with no other ill effects. It still sounds like something somewhere is rubbing where it shouldn't though, and a heat shield somewhere is rattling. 

The car surges a bit when accelerating in closed loop. It's smooth in open loop, which is over 3500 revs or with the secondary throttle open.

Playing with timing, I've got it set to 10 degrees BTDC now. No knocking or pinging and feels much stronger, but it really is too much advance around town when combined with vacuum advance. Response feels sharp and unstable. Plan is to see what vacuum retard does for me, and if that's not enough, I'll attempt some DIY distributor recurving to let mechanical advance do a bit more. Won't have much time to mess with that for a bit though.

All the speakers are blown. Currently using a portable Bluetooth speaker for music. 

Driver's door brake is broken. That might get replaced this weekend. 

This is a good car, and if I can get the engine to be a bit less vibey and pull a bit better up to 6k or so instead of falling off, I think it would be genuinely fun. Right now it really feels more like a budget small GT car than a sports car, with engine character still being the biggest downfall.

It understeers a lot with the new front end bits and original rear stuff with no rear bar. Transitional understeers is particularly bad because the front shocks have so much more rebound damping. 

The brakes are very strong. The drums are almost too strong, they lock easily. The right rear especially. I'm not sure why that would be, will eventually pull the drum off and take a look. 

I didn't like the wheels, but I spent some quality time cleaning them and they are growing on me. 

Fuel pressure regulator does seem to have helped a lot with hot starts, but it tends to start on 2-3 cylinders when warm. WUR rebuild still in the plan, need to decide if I care enough to swap the stock one for a nicer load sensing unit. With the lambda frequency control, it seems like I may be able to dial in good acceleration mixture by adjusting control pressure and letting the frequency valve handle the cruising mixture.

irish44j (Forum Supporter)
irish44j (Forum Supporter) MegaDork
12/15/23 7:23 p.m.
gearheadE30 said: 

Lots of wind noise, not sure from where. Seemingly top of the windshield or the sunroof. Some from the hatch area, too.

 

 

most of my wind noise was from the seam on the side mirrors, where they fold in. I put some matching red electrical tape around the seam and reduced it by 90% - so you may want to check that as well.  

gearheadE30
gearheadE30 Dork
12/16/23 9:03 a.m.

In reply to irish44j (Forum Supporter) :

I will have to try that. I discovered the front sunroof latch on the passenger side is broken so the sunroof panel is lifting up at high speed, and the hatch seal has shrunken enough that I can actually see out a gap in it where the ends meet in the rear view mirror, so there's at least those two huge sources. 

Does your 924S have the nearly flush windshield glass that the later 944s got? This 924 has like a half inch step around the lock strip trim that's definitely not helping. 

gearheadE30
gearheadE30 Dork
12/22/23 10:11 a.m.

Lots of little stuff. 

  • New sunroof latch pivots showed up. That cured 75% of the wind noise, now I just need a new hatch seal. So, so much quieter. 
  • The muffler (Bosal OE replacement) has a chrome tip thing on it, and it's only welded up by the muffler so it was flopping against the tube inside of it. Wedged a small piece of stainless between the layers and the rattle disappeared.
  • Heat shield on the exhaust manifold was rattling. It was cracked out around 2 of the 3 nuts holding it on. Maybe this car does have 140k miles and not 40k miles, I wouldn't expect that to happen at such a low mileage and a few other things point that way too. 
  • New clip for the hood prop and new rubbers that sit on the fenders to support the hood, now the hood doesn't vibrate
  • up to 14 degrees BTDC on the distributor. Verified mechanical advance and both vacuum pots are working. vacuum retard is necessary - it's too much timing at idle. Weather is cold, will be paying attention to pinging as it warms up. Considering buying another distributor to recurve - it really needs more mechanical advance authority as the vacuum retard is just a bandaid. 
  • Front suspension is settling. I think I'm okay with the ride height after all. 
  • Oil fill cap started leaking massively. Temporarily stole one off of the 325ES's replacement engine, fits perfectly. 

I've put a couple hundred more miles on it, it's a good little car, with a few things that need addressed sooner rather than later. 

  • Handling is spooky at higher speed. The rear suspension is just so, so soft. Lift throttle oversteer is truly remarkable, but controllable at least. 
  • Vibrations. I think the engine mounts are just totally collapsed. I haven't figured out what is touching where, but it's pretty bad from 2750-3250 revs or so. It also gets worse with aggressive cornering. 
  • Intermittent rubbing noise. I'm not sure what this is, but it's at engine speed. Almost sounds like alternator or water pump bearings, but I've checked those. Need to pull the belt just to be sure. Comes and goes every few seconds. I was afraid it was the torque tube, but clutch/gear selection doesn't change it. It might be nothing to worry about, but noises I can't explain scare me.
  • WUR rebuild/control pressure check. It runs well, but it doesn't run super consistently. I want to nail this down and do some measurements on frequency valve command as it feels like there's some performance left on the table. On rare occasions it will feel 10% stronger than normal, and I don't know why. If I could get it to feel that way all the time I'd be thrilled - it also runs more smoothly when this happens. 
  • Valve clearance check. Waiting on a valve cover gasket. 

I don't know how much or how little power this car is making right now, but it's more than adequate for driving in traffic. For "fun" driving, I do wish it had 10-20 more horses up top. As I've said before, it just doesn't feel willing to rev right now, and that definitely detracts from the overall experience.

gearheadE30
gearheadE30 Dork
12/22/23 10:15 a.m.

I did drive the 325ES automatic to work this week. The Porsche definitely feels more special (low, long hood, seating position, etc) with much better steering. The E30 is much more stable, sounds much better, and is marginally quicker. E30 seats are so, so much better than the 924. 

And of course, a couple pics. 

gearheadE30
gearheadE30 Dork
1/6/24 6:45 p.m.

Slowly jumping back in after the holidays, found a bit of a mystery: there is only one spring in my distributor. I can't find any reference online saying if this should be the case, but most of the pictures I have seen show two springs. Strange. Anyone seen this before?

It seemed to work more or less as I would expect based on the timing light, so this really surprises me.

 

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