An upstream filter is proving difficult. The good news is that that's not actually the only filter. There's a standard canister style that I'm currently halfway through replacing that's post-pump. However the line going from tank to pump is going to be basically impossible to filter any other way. It's primarily hard line, except for a small area of 1/2" soft line from the tank and another one at the pump. Both of which are small in length and to top it off, being 1/2" line there's basically no in-line filter I can easily find, let alone one that will fit in the small space. I'm starting to see why Mazda used this silly cone.
I think garage floor be damned and I'll be popping the drain plug today and hoping I have enough drain pan capacity for whatever comes out, but we'll see. For now it's more brainstorming during my lunch break
Well a few days later and I got some more time to work on the Mazda. First step is to drain the tank. This wasn't elegant with the tools I had on hand and the space I was working with, but was successful in dumping minimal stale fuel into the gravel floor of the garage
With the tank drained I could (surprisingly easily) drop the tank out and take a look at what horrors would face me.
Surprisingly, the horrors were limited. The tank had definitely been opened before.
The pickup tube was completely missing the mesh strainer that's supposed to be in-tank, so that explains why the tiny cone filter was clogging so quickly and easily.
Fortunately, the tank seems to be in astonishingly good shape inside, but the baffle was collecting plenty of bits of rust I suppose from sitting.
I tried calling a local radiator shop but they don't want to touch a baffled fuel tank to clean and coat it, so I think I'm on my own for it. My thought was to hit it with white vinegar and let it sit there for a day or so, then flip it upside down and do the same then wash it out. Not sure if I should throw nuts and bolts in like I have for motorcycle tanks as the baffle walls are pretty thin and I don't want to damage them.
I also need to figure out an in-tank filter option. Cruising the RX7club forums it seems some folks have put a cellulose filter in-tank from Aeromotive, and other folks have put a Jaguar in-tank mesh screen in. I'm leaning towards the latter as that's a more likely part to be order-able at a parts store, but I don't like either because they don't technically fit the pickup tube and need to have either JB weld or fuel hose clamped to the tube to actually fit the filter. Of course the Mazda part is NLA and the tiny cone filter that is torn I can't even find in a parts diagram, let alone find any sort of viable replacement, so I'm not fully convinced it's not a figment of my imagination.
I know plenty of folks here have run FBs so any insight from those with more experience would be very appreciated
Over the last few days I had a chance to clean out the tank post-work between other chores.
Well some good news and bad news come today. I got some time to work on the car and managed to find a 1/2" in-line filter locally and was able to find some space to splice it into the system, so I now have an effective pre-pump filter
After running that and buttoning everything back up, it was time to get some fresh premix, throw it in the tank, and fire it up:
Unfortunately the battery had run flat because the car was hard starting on warm starts (I think from flooding, but not 100% sure.) After hooking up my truck to jump it...nothing. Didn't even cough. I took my power probe and was able to hit the pump with power from inside the cabin and heard it. Don't have a fuel pressure gauge so I guess I can't be sure it's actually pumping. Maybe it lost its prime and isn't able to get fuel back? Not sure.
I did hit the intake with a bit of ether to confirm it wasn't engine related and the car "ran" almost immediately for a few seconds so seems like its fuel, but I don't know what on earth it could be. Lines don't appear kinked and the fuel pump was hardly touched. Factor that along with the fact that it's still making noise when power is applied and I wouldn't think it's that.
That's all I could get to for today, so I'll take tonight (and work tomorrow) to ponder and search forum archives, that said, anyone here have anything similar or ideas where to go looking?
Well I thought I had it figured out with a slightly kinked fuel hose. Shortened that so that it is no longer kinked, but the fuel pump still wasn't pumping at all. Honestly not sure why that would be as fuel is getting to the pump (I even siphoned the hose to make sure there was fuel right there).
I took the pump off to diagnose and sure enough off the car in a jug of fuel it pumps when power is applied, further causing confusion. However a wire with a cold solder joint from a prior owner repair had come undone, so I needed to resolver the wire to the pump...
Annnnnnd turns out I'm not good enough at soldering. Managed to get too much heat into it, desoldering the brush from the lug, melting the plastic so that it pushed out of the pump, and effectively rendered it useless. Extremely frustrated with myself for this.
so now I'm in a tough spot. Option 1 is to buy a pump assembly from someone who has them used. Mazda discontinued the part years ago and even if they hadn't $450 for a fuel pump hurts too much. Option 2 is a Walbro 190 which 1 guy seems to say works but I can't easily get with the right fittings. Option 3 (and where I'm leaning for now) is this pump which seems to be a clone of the stocker. This should *hopefully* get me on the road or at least diagnosing the next problem in the chain and buys me some time to shake down the car, even if it doesn't last too long
Finally, some good news again.
After some research I found that the NLA fuel pump is actually just the assembly, and the fuel pump itself is a fairly common one that is used across several 80s Japanese cars. Fortunately that means Carter had a nearly plug and play solution with their pump P70199. Unfortunately I didn't get any pictures of the install because I consistently forget to do that. That said, as penance for my sins, I present the first start:
With that new pump, a proper pre-pump filter installed, a new post-pump filter installed, and new fuel lines, it was time to button the car up and see how it drove:
Definitely pulling a bit harder than before. And more importantly, not clogging up and fuel starving after a couple dozen miles. Thank goodness, it seems that the fueling issue is (for now) fixed.
So with the car running well and cleaned up a bit it was time to turn my attention to shoes:
The stock wheels are a great look on these cars but with the T3 Micro Big Brake kit the PO needed to run spacers to clear in the front. I don't like spacers, especially not hub-centric spacers, and doubly especially stacked spacers. I'd been keeping an eye on marketplace and saved some cool old wheels but for the most part anything in 4x114.3 was far more than my meager budget could muster.
I helped a buddy pick up a Mk2 Triumph GT6+ last week (trying to get him to join the forum and start a thread!), and along the way we were trying to find wheels we could also pick up. Unfortunately, Facebook basically refused to even show me any wheels that weren't 4x100 so that was a bust, and in frustration I tried low-balling one of the sets of wheels I had saved. To my surprise, the guy bit and so for $600 I got some JDM goodness (albeit part of Nissan's history): The Hoshino Impul D-01 Silhouette:
These guys are 14x6 +17 so a good setup for the car, and within the happy range to run Falken RT615K+ tires in their only 14" size which was a major goal. Unforuntately the tires on there now are ridiculously small (155/55r14) so they look ridiculous on the car, but once I can get the 195/60r14 Falkens on there they should look really good I think. I likely won't be able to get tires on before the car goes away for the winter as things are cooling down here in NJ and I have plenty of stuff to do to prep the house that takes away tire fun money (ordering fuel oil and firewood this week, that's going to hurt). But for now the car can roll around on silly tires and great looking wheels (at least in my eyes).
In reply to Sk1dmark (Forum Supporter) :
That startup video has everything. Good music, succinct with no long winded intro, a victory fist pump. I'm digging the whole project.
I love how 7000rpm and a few gears and you are not quite speeding. One of my favorite cars was my 85 GS, one of the few car that I would just drive around for the fun of it. My RX was my winter beater because jeeps suck as winter cars, it was the best for under 3" of snow.
$600 for the Impuls is absolute theft, well-done. I got overly ambitious with my offsets and lip sizing when I rebuilt my SSRs so now the maximum tire I can run is maybe a 185/55r14 without rubbing the quarter panels, but to be safe I've been running a 165/55. I could use a bit more tire now that the car is a 13b bridgeport.
In reply to akylekoz :
My second car (and the one I owned longest in life) was an NA Miata and that was my favorite part about it. Wringing the car out and staying not just out of "lose your license" territory but out of speeding ticket territory made me totally fine with losing drag races to Priuses that didn't know they were in a race.
In reply to dannyp84 :
Thanks! Those SSRs are a dream wheel for me. Long term I' dlove to be on them or Equip 01s, but for now I'm thrilled with the Impuls. The bright side of poor offset is that nowadays it doesn't seem to matter! As I was learning when looking at performance tire options there doesn't seem to be many options left for 14s. My poor buddy with his new GT6 on 13s is going to be forced onto either trailer tires or Hoosier A7s.
That Bridgeport thread is one that I was watching closely, great build! I added you on instagram to see the video haha. Hopefully it's been driving well. I am knocking on wood that this car lasts a while in stock form and doesn't grenade the second I take it near an autocross (I think at stock power levels I probably shouldn't head to any track days as I think I'd be mostly in the way), but once that time inevitably comes I've been trying to soak up as much info as possible on just how usable day to day the different levels of bridgeport are to see if that may end up being the way I go instead of just a street port. If I actually could feasibly make 200ish whp out of this motor without a turbo that's extremely enticing, but if the power is overly peaky or the car just isn't fun to drive around not at 9/10 it doesn't seem like a worthy trade-off for what I want out of it.
So I was going through the FSM and using that to help set my idle. Quite a process on this thing. Between adjusting the TPS to read properly using 2 multimeters, and having to remove the gas cap, it was almost comically roundabout, but I got the idle seemingly good!
That was particularly good because spark timing is, at the moment, a best guess instead of properly set. I have a timing light, but the pulley no longer had any notable paint marking on it to reference against the pin. Not sure if there's any other way to set the timing on these motors if there's no mark. Either way, I got the dizzy where it seemed to play nicely with sound, went to re-tighten the hold down bolt and...
Berk. Only the second broken bolt so far, but definitely not in a great spot. After a curse-filled night removing the dizzy, drilling out the broken bolt, installing a helicoil, and getting everything buttoned back up though, all was right once again. And what a great day for it to be right again. Got to take the car out on a real drive today instead of 1 or 2 miles and it did flawlessly. The way it handles is perfect, the character of the engine and chassis are just a joy to be a part of.
The car still needs plenty of work. I have a decidedly noisy rear diff and transmission, I still need tires, the windows go up only with decisive assistance, and I have to fix the butchered wiring for the radio (and also diagnose my reverse lights not working). But for about 25 miles today that melted away and I felt like I did in high school driving my NA Miata around. What a blast this silly thing is.
Bigger update post tomorrow when I have more time, but anybody have any idea what may be happening here? Removed quite a bit of emissions stuff, blocked off the cold start and ACV, went to start the car and it all seemed okay at first, high idle but everything likely needed adjustment. Tons of white smoke out the tailpipe but after running a few seconds the car just dies like it's been shut off with the key. Except I didn't shut it off. Video below
I believe these have an MAF. That is classic Maf disconnected symptoms.
Are you sure it's white smoke? That usually only happens with water / coolant. Either from cold temperature outside and the hot exhaust, or consumption in the engine.
Do you have coolant in the system? Does the exhaust smell sweet?
Another thing that could stop it from running is if the fuel pump is priming during key at start and then shutting off. This is what happens when MAF is disconnected. It doesn't see airflow so it shuts off the fuel pump.
There are other reasons for the fuel pump not running as well. I'm just not familiar enough with the 1st gen fuel injection to be more specific.
Edit to add... why remove the emissions stuff? It doesn't affect power, but can cause driveability issues.
The high idle seems to be partly fixed by a missed vacuum line in the IACV, so that's progress. MAF could be shot but I'd be surprised as it was running well when pulled apart a few weeks ago. MAF was plugged in and when I unplugged it it did change running condition for the worse so seems to be functional.
as far as why to remove emissions equipment, I was trying to simplify the vacuum diagram of the car. There were so many little lines all of which were old and brittle. Apparently I've gone too far though as you're right, drivability certainly suffers when stuff doesn't run. I suppose I'll be adding stuff back in shortly
In reply to Sk1dmark (Forum Supporter) :
I wouldn't think the MAF failed. Just disconnected. Those are the floppy for type, right? I have also seen where the door is stuck for some reason and not opening.
Clogged exhaust can also cause the symptoms you are describing, but that would mean no exhaust out the tail pipe.
It might be time to try some actual testing.
You can hook up a fuel pressure gauge OR a voltmeter at the pump to see if it's dropping fuel flow.
You could hook up an inline spark tester to see if it's dropping spark.
If it's neither, it could be running way too rich or lean.
My current guess is that it's dropping the voltage at the fuel pump.
There should be a way to check the inputs and outputs at the ecu. I know 2nd gens have a chart in the fsm that shows what each wire value should be at the ecu. I have spent a great deal of time with a paperclip and a DMM figuring out what isn't happy. Usually, it was a broken wire from crumbling wiring, or a disconnected ground.
Speaking of disconnected grounds, the 2nd gens have a SOUPER important ground under the intake manifold. If it is not connected, or connected poorly, you can have either a no start or run E36 M3ty condition.
