1gn Neon SRT-4 Swap for RallyX

No time and no rush to get the new tires mounted, but I piddled around a bit the last couple days and got some things done.

After a little searching and trimming, I was able to fashion a section of the aforementioned PT Cruiser silicone charge piping to run between the intercooler and the throttle body. I got the IAT sensor installed in it and the fit is pretty nice. There's going to be a much cleaner look in there now with a little more room.

The rest of my time was spent working on the throttle cable bracket. After spending about 45 minutes cleaning out a space to work, I got this grafted together:

It took a little adjustment with my 5 pound sledge, but I put a nice bend in it and the throttle travel seems to be about perfect.

I put a couple coats of paint on one side tonight and I'll do the other side tomorrow. It doesn't really need to be SUPER pretty, but I want it to look a little bit nice!

I checked out the closing RadioShack near me and they had a few things that are nice to keep on the shelf, but they lacked any 2N2222A transistors that I need for the tach output circuit. I ordered a hundred of them from eBay (because it was way cheaper to order 100 than 1...) so when that gets in it will be time to open up the MegaSquirt again and add the tach output, fan control, IAC control, and knock input.

Knurled wrote: SG1?

Those are MaxSport RBF1's

wae, hopefully those hold up better for you than I experienced on my SRT4. After 4 events, we were ripping the big outside lugs off the tires. They did fine on soft ground, but hard, dry clay destroyed them.

FooBag wrote:

Knurled wrote: SG1?

Those are MaxSport RBF1's wae, hopefully those hold up better for you than I experienced on my SRT4. After 4 events, we were ripping the big outside lugs off the tires. They did fine on soft ground, but hard, dry clay destroyed them.

I'm a little concerned about that -- they're really built for much less powerful cars -- but our surfaces usually stay fairly soft in most places so I'm hopeful. Only one way to find out!

Okay, so Megasquirt is hard when you're using a 16 year old PCB...

I was hoping to add in a knock input and outputs for tach, PWM IAC, and fan control, plus an input for launch control/flat shifting. It looks like I get 5 pins I can use, X11, X12, X13, and X14 plus pin 36 on the DB37. 11 and 12 are already in use for ignition control, so I'm going to put knock on X13 and tach on X14. Pin 36 is orphaned, so if I want to use that I just need to wire directly to the pin. Pins 1-19 are all wired directly to ground.

Not ideal, but I think I can make it work. I did swap out Q5 last night for the PWM-capable transistor. Knock input looks pretty simple - if I connect a jumper from X13 to X6 on the 2.2 PCB, that should put knock input on what MS2 calls JS4.

The tach circuit still perplexes me due to a lack of any specific direction. I have a bunch of the 2N2222A transistors (cheaper to buy 20 than to buy 1...) so I believe that I can use JS5 by wiring to X7 on the 2.2 PCB. That should mean that the right lead of the transistor should go to ground, the center lead wires to a 1k resistor and then to X7, and the left lead wires to a 10k resistor and a jumper wire. The 10k resistor goes to a 12V source and the jumper wire goes to X14. I don't really understand that, but let's see if it works.

That will mean that on my harness, the 2A wire (green/white) should be knock input from KnockSense and the 2B wire (green/red) should be tach out.

So I did all that wiring stuff, but it doesn't seem to work. I suspect that I've failed in picking up the +12V and the ground properly, but anything is possible.

I wired up the IAC and the tach connection to the megasquirt harness so I could wrap up the wiring. It's looking a lot cleaner than before and it should be less prone to any kind of breakage or rubbing:

The throttle cable bracket is installed and the vacuum lines are all hooked up as well.

Next, I need to figure out what went wrong with Megasquirt and then see how my mods work. The knock sensor is still not hooked up - I need to run it back into the cabin of the car because the knock sensor controller isn't weathertight. I'm thinking that I'll use the wire that is for the knock input pin to run from the sensor into the cabin, then snip the wire near the MS box and use the part wire that goes back to the DB37 as the knocksense output connection. Then I should just need to find switched +12V and a ground inside.

Well, there was a minor setback tonight. When I wired up the new PWM transistor in place of the old FIDLE transistor on the 2.2 board, I think I literally had my wires crossed. Uncrossing them got it working a bit, but in an attempt to troubleshoot, I cut out the tach output circuit and tried reloading the firmware. On the stimulator it acts fine but it always wants to keep the fuel pump relay turned on, even when it's reading 0 RPM. I've ordered up a new Q3 transistor for the fuel pump circuit so I'll see if that clears the problem up.

If that works, then I'll go ahead and rebuild the tach output circuit. I'll also need to find some place under the hood to pick up +12V when the ignition is on, but that shouldn't be too tough. Initially, I wired the IAC to the fuel pump relay control, but that's all ground not +12V so I undid that. I'm not doing anything else, though, until I know if I've fried the MS box entirely. If I can't get this squared away in short order, I'll just have to order up a new kit. And then I'll have to see how much I want to gamble -- do I hope that my MSII daughterboard is okay and just buy the MS1 3.0 kit and use my current proc, or do I spend the extra 60 or 70 bucks and get the MS2 3.0 kit?

And here things were running so well before I just had to make them better....

Fun fact.

I'm retarded.

All that stuff I posted before - just ignore it.

The real problem is that I blew a fuse that feeds MegaSquirt and it was getting backfed from a sensor somewhere so it was acting like it had power but wasn't working properly. It's all good now.

Tonight, I went ahead and re-did all the stuff I undid last night. I gave it a test fire and it started right up! Sort of. It won't stay running because the idle valve is closed and I need to find +12V for that. That's a job for tomorrow night. For now, it starts! And the tach works! So I will celebrate with hard root beer and Buffalo Creek Bourbon Cream!

More progress.

Fans are wired up and installed on the radiator with zip ties. I put a new hole in the core support so I could position the radiator forward a bit. They actually seem to blow a ton of air, so I'm cautiously optimistic.

Megasquirt is working okay. The car will start and idle but the IAC is not working so in order to start, the throttle has to be slightly pressed. The tach gets a signal but it is really jumpy. The IAC makes clicking sounds when I hook it straight to 12v, but MS isn't sending any signal down the FIDLE wire. I did have the TIP 120 transistor miswired at one point so I'm going to try replacing that.

Okay, well trying a new TIP120 resulted in acrid smoke, so I don't have the slightest clue what's going on with this stupid thing.

And I've cooked yet another TIP120. With the output connected to absolutely nothing and the FIDLE setting set to "Off". Something is wrong on the input side of the equation.

The next attempt was to remove the TIP120 completely. No smoke, but the dash tach was very jumpy.

Next test was to remove the jumper wire that sent the +12V to the CPU stepper chip. The instructions don't say that you NEED that wire if you're not using a stepper, just that you "should". With that wire removed, the tach isn't perfect but it's pretty close.

The coolant is pretty low from pulling the intake manifold and all that, so I need to top that off, but otherwise, I think it's ready for a test drive!

This whole idle valve thing has got me pretty bummed out. Same with the tach out. It's gone back to being super jumpy again, so basically worthless, and the IAC is completely non-functional. I suspect that there is something that isn't wired correctly, but of course the assembly manual for the 2.2 PCB with MS2Extra is no longer in existence, having been purged from the msextra.com site. Sure, they've got a link that says it leads to the manual archive with the older 2.2 manuals, but it's a dirty lie. I get that it's an old board, but why eliminate all traces of the old manual?

Anyway, the car starts and runs without idle air, but it does require holding the throttle down a little for a few seconds before the idle settles down to around 600 RPM. I'll take a drive tomorrow and see what it's like with the new intake.

Oh, and I found this sitting next to the car:

Stock ECU is out of the car! There's plenty of wiring that needs to be removed and cleaned up as a result, but at least I know that full standalone is functional now.

Holy E36 M3.

It's raining today and the car is basically undrivable. The slightest blip of the throttle in gears 1-3 breaks the tires free and gets the car bouncing off the rev limiter. Boost comes on much faster and holds at 15-16psi. Cruising in fifth at 65mph rockets to 80+ with no hesitation when I push the accelerator about half-way. This thing is fast.

Cooling seems okay, but it's hard to tell on a cool and rainy day. Sitting in the garage, idling after running for 30 minutes, I put the fans on and it did drop the temps pretty steadily, so I'm hopeful.

I'm starting to get a little nervous about the cooling. It's definitely creeping up higher when sitting in traffic than it did with the original(ish) fans. To be fair, its the digital water temp gauge that's creeping up, not the dash gauge, and I didn't have the laptop hooked up, so I couldn't see what MS was seeing. But, I may need to budget some time to deal with that between PE1 and PE2.

After adding some advance in part of the low end of the table, some of the missing at cruise seems to have gone away, but there's still a little bit of that going on at what I think is a different part of the table. I've given that other part a little advance and I've fiddled with the over-run settings a bit to keep the car from cutting fuel during a shift. The TPSdot settings didn't appear to be working right and I think it's because the threshold was set to a value that was higher than the first few buckets in my table. I lowered that threshold -- my TPS signal is pretty rock-solid at cruise -- so maybe some of the hesitation on light throttle events will go away. Or, you know, just get way worse.

Update from AMR Engineering is that springs should come in this week and he should be shipping my suspension out next Monday. I'm not 100% confident that target will be hit, but I am cautiously optimistic that I'll have the new setup for PE1.

Fiddled with the advance and the VE table a bit so it's now idling right around 900 RPM, nice and smooth. As a bonus, it returns to idle without stalling now when the clutch is put in.

I think there's something mechanically wrong, though. While adding advance seems to have helped the miss or sputtering at light throttle cruise, it does sometimes happen still. The weird part is that it's happening at the exact kPa and RPM and TPS % and TPSdot values as when it isn't happening. Since it seems to only happen after the car's been running for a while, I'm wondering if the coil might be faulty. I may dig out an OEM coil from my stash and swap it in to see if that changes anything.

Just read through this thread. I used to work at a dodge dealer and sell neons, this build is great. Keep it up.

In regards to the cooling...are you running an airdam? Mine did fine without it with the 2.0, but when I upsized to the 2.4, I had tons of issues until I found out the car came from the factory with an airdam. I may even have a stock one laying around somewhere. The stock one is small enough it might even survive rallycross.

I had bad luck with fans like that, my overheating issues went away when I put the stock fans back on.

Actually I noticed today that while my digital gauge with the sender on the upper rad hose is showing 200+, Megasquirt using the stock temp sender in the stock location is showing 178. So, my problems might be more gauge than actual cooling problems.

I will probably get some aluminum sheet and try to build a shroud, but the stock fans just aren't going to fit in that spot.

For taking a couple on-line tests, I got $75 worth of Amazon gift cards at work today and that was the motivation I needed to order up the next round of stuff for the car.

Ordered up a new wideband sensor tonight. I'll keep the AEM in the gauge pod and the new LC-2 will just feed Megasquirt. The AEM's voltage output is basically random, so Megasquirt never actually knows what the real AFR is. Once I have that installed, I'm going to look into taking the car for some dyno tuning.

In the same order, I've got a hub adapter, quick release, and a steering wheel coming. I'm tired of looking at the gaping hole where the airbag used to be.

I got the steering wheel and all that installed last night. There are pictures around here somewhere that I'll add later. Pretty straightforward setup that only took about 30 minutes -- most of that was making sure everything was lined up properly!

Another side benefit of the quick release is that when I'm working on things under and behind the dash, taking the steering wheel off gives me so much more room to maneuver! Downside, though, is that with the smaller wheel I can't really see the gauge cluster that well. Between that and the lower-ratio steering rack, it's very responsive and turns quickly plus the wheel is much more comfortable to hold. Couple hundred bucks well spent!

While I was at it, I also put in the Innovate LC-2. Here's some weird stuff for you: I pulled in +12V off of the knock sensor (which is off of the same source as Megasquirt) and I pulled in my ground from one of the ground wires on the Megasquirt harness. My thought was that I'd pull power from the same sources to get a more reliable reading, right? The tach was a little jumpy before and now it's all over the place! I'm going to try to re-ground the wideband and see if that fixes it, but something is really weird.

The other thing I noticed is that between the new LC-2 and the old AEM, (at least) one of them is making stuff up. I left the AEM installed and put the LC-2 into its own bung and its own power. Now, the LC-2 is brand new with a brand new sensor that I did the free air calibration on. The AEM was bought used with a used sensor, and I don't even know how to calibrate it. I set up MS to use it as a generic linear WB signal and put in the 0.0 volt and the 5.0 volt AFR values as stated in the Innovate manual. The two widebands are nowhere near each other and I don't know who's lying to me.

The whole missing at cruise problem is totally fixed, though. The reason that it wasn't happening when I first start out is because the CLT value wasn't high enough to engage closed-loop mode, so the VE table was ruling the roost. Once CLT got high enough, EGO correction was taking over and trimming me down to meet the AFR target table. I scaled the cruise section of the AFR table down about 10% (i.e. made it richer) and it's buttery now. The VE table could use some work because it's trimming like crazy with EGO correction, but the AFR targets are keeping it mostly in line.

An email came from AMR Engineering - They've sent me a tracking number for the new struts, but it's still showing as not picked up by UPS yet. I'm feeling pretty good though that I'll have the new suspension in time for the season opener on the 29th. There's also a chance that I might get super ambitious and order up a pair of Corbeau Forza Sport seats and try to install those as well. About $640 for the pair and they've got FIA homologation numbers. Alternately, I might just do the regular Forza seats which would be about $480 - I'm not sure if having the FIA number is worth the extra $160. For Rallycross I don't need any certification but would a track day require an FIA or SFI seat? Is the seat itself built to be any safer or is it just the cost of the cert process?

If you get Corbeau seats, budget some time to rework the seat bracket. Mine was so high my helmet rubbed the headliner. It was pretty easy to cut it down and reweld, though.

In reply to eastsidemav:

That actually is the main thing holding me back: I have no idea how to best mount seats like that. There are some "direct-fit" brackets that may or may not work, based on what you're saying. I've seen people use bar stock to make an adapter that bolts to the factory sliders and then to the bottom of the seat. And I've seen "universal" kits that take some cutting and welding.

Do your seats side mount or bottom mount?

In reply to wae:

The Forza I use for the drivers seat is bottom mount, I think.

LC1/LC2 should be existing options in the firmware.

In reply to Knurled:

Yeah, I tried that as well and the numbers are still wonky. Like the AEM says I'm super rich at idle and the LC-2 says 17.something. I'm doing something wrong here that probably has something to do with grounds.