S5_RX7_BRRRAP2

First off, I have 1990 Mazda RX-7 GTU (S5 NA). I have unfortunately a beast of a car that won't run. Spent over 10k on this car and can't seem to figure out why it won't run. So here is the run down.

Last summer I would be driving it. Some days it would randomly have issues starting and flood itself which later, I thought was compression. At first, my friend had issues with his FD with injectors and he couldn't find the problem and later found out injectors, so I got some new injectors from Banzai. Well, it never solved the issue. Eventually I had done the whole fuel system. Fuel pump (not the assembly, just a walboro 255), fuel pressure is fine, cleaned and replaced hoses on all of my fuel setup, tank is clean, new fuel filter, like everything has been done, even orings. Got a new TPS and tuned it. Nothing worked so we compression tested. But whenever it died, the car would run and drive just fine, like nothing was wrong for about 20 mins, then the car would run rough, and die. Any time I tore the intakes off to clean the injectors again and again, it would run for 20 more minutes and then do the same thing, up until one day, it drove barely up the road and died to never turn over again. After that I decided to take the motor to Banzai for a rebuild thinking it was going thanks to the compression test.

Banzai kindly rebuilt my motor. I got a streetport and turbo exhaust sleeves so it's hogged out, I got an oil pan brace, just the basic rebuild, polyurethane motor mounts, and more goodies. While it was down there getting worked on and when I was working on dropping the motor in I got all this done and bought/installed.

-BAC Delete
-ACV Delete
-Smog Pump Delete
-Emission Canister Delete
-Dual Alternator Pulley
-OMP Delete (still on the motor, plugged in, instead of banjo bolts I have tephlon tape and set screws)
(OMP was bolted to the fender at one point with a block off plate on the engine, *still left it plugged in*, was told that is a no no and set it back up to the engine how i have it now with a new oring.)
-ALL MY EMISSIONS ARE DELETED, NO RATS NEST, DOWN TO 3 VAC LINES. BLOCK OFF PLATES HAVE BLUE RTV TO SEAL.
-Koyo radiator dual pass
-AC Delete
-PS Pump Delete
-Notable MAF installed
-New RAM Air Filter
-New wiring on O2 sensor
-New Plugs
-New Wires
-Clutchless Radiator Fan
-I have spare coil packs, put spare trailing on.
-Ohmed out injectors to double check.
-New fuel pump resistor relay (behind passenger headlight)
-Fuel pump relay under dash has been ohmed and tested
-Checked wire harness for any snapped wires or exposed wires
-Checked all clips to see if secure and fastened
-All other Vacuum lines are plugged with rubber caps nice and tight, some zip tied.
Throttle body Cold Start Assist delete for faster throttle response. (have to hold idle with foot till warm, then idles by itself when running fine)
-All new intake gaskets (tack sprayed on)
-New battery connectors because old ones were soft and ruined and just loosely hung on.
-Sprayed the whole engine down with Ether looking for vacuum leaks when manually idling.
-I have a new thermostat BUT HAVE NOT installed it yet.
-New Headers/exhaust (Racing Beat)
-New gas as of 1 month ago

Back window has a bad seal and behind the carpets on the side in the back back, water leaks in, it now sits in my garage since last fall.

Explaining what the car is doing:

When the Car is "dead" (before and after rebuild) Cranks, can smell fuel like its rich af, it tries to kick over constantly and once it kicks over, it immediately dies. You can hold your foot on the gas at a very specific point and the car might stay on for 2-3 seconds but it'll bog out rich. The only way to get it to kick over is holding the key in start position ONLY. If you let it go to On, it kills itself. If you press the gas pedal down further or let off the specific point, it dies. If you do get it, it'll kill itself within 2-3 secs. This is how it was when it died, and still how it is now. (NOTE: this is the MAF connected)

With the MAF disconnected is a different story. It will start up and run. It may run really rough and sound like timing is way off, or really smooth like its tuned perfect. I got it warmed up and had my friend hold the idle at 900-1k rpm, it was running smooth, I grabbed my timing light an timed the leading 1 with the white dot on the pulley (yellow on others) and adjusted the set screw to adjust idle slightly (not the one you need a 4 inch crescent wrench to adjust). TPS was adjusted when not running with the little Banzai connector light. Anyway, it ran like it was fixed but still won't idle.

I wanted to see if i could get any hints to as what was wrong with it trying to drive it around the block. Started up, ran rough and then smoothed back out doing it bridgeport sounding lope, then smoothed out to its usual sound within a minute. Backed it out of the garage and drove down the road, everything felt fine. Made it up to third gear at about 2k rpm, just nice and easy. literally, not even 1/3 of the way around the block, it bogs out and gets silent. Okay, maybe it just stalled out. I put it in to neutral and start to pull over and as soon as I stuck it in neutral, the engine suddenly was on and I stuck it back into second and it went silent, back to neutral, came back on again and then it stalled out. I unflooded it with the usual pop and bang from load. Any time I got it going and put it in gear, it would die. So I pushed it back home, half way pushing it home myself, my dad and brother saw me pushing it and helped me push it back in the garage. I spent hours in the book and on rx7 forum at work, at home, countless amount of money on parts, solvents, theories and nothing works.

My friend with the FD was so stumped, he stopped helping me. AND he has been working on RX-7s for 15 years. I seriously need some ideas and help with this one. I do not have the money to take it to Banzai and get it looked over, and I don't want to take a huge loss and sell it. It could be something simple that I overlooked, or something i haven't test, or have tested. I'm out of ideas. Yes I run premix and yes, I know, sounds like a vacuum leak. Future thanks to future responses and future help!

S5_RX7_BRRRAP2

Also, I have a spare ECU I put in as well, thinking the ECU was messed up possibly.

XBLADE

I'd check all the coils for spark and that they are in the correct order. New plugs if they are old. Might be fuel related though. Maybe a leaky injector or the little rubber seal that they sit into might be bad. Maybe fuel pressure?

conerychen

double check your work. vacuum routing. idle adjust screw. plug wires. maybe something with heat, you said you were able to drive for abit. lead coil? bac?

WondrousBread

Have you tried jumping the yellow test connector near the MAF?

The MAF includes a feature whereby fuel will not pump unless the engine is running or key is in the START position. If this fails, it will start and then immediately die. The connector bypasses this feature. It's yellow, two prongs. Try jumping the connector, and see if it starts and idles. You may just need a new MAF.

S5_RX7_BRRRAP2

NCross

iTrader: (18)

S5_RX7_BRRRAP2

I have spark, when I have it running and my friend manually holds the idle while i spray the whole engine down with starting fluid, if i spray it directly in the intake, it bogs out and even shuts off. Almost like it has too much air, then other times you start it, it smells rich af and your eyes burn.

S5_RX7_BRRRAP2

S5_RX7_BRRRAP2

Gabriel82

iTrader: (8)

When you changed everything in the tank did you change out the fuel pump strainer? When you replaced the fuel filter did you make sure the lines are returning to the correct position?

S5_RX7_BRRRAP2

Yes, It has everything replaced on fuel and have quadruple checked it to make sure everything is right. The only thing that isn't new is the fuel pump assembly itself. Have a Walboro 255 fuel pump that came with a kit with all new everything that drops right in the assembly. Lines are new and done one at a time so they would not get mixed up. Fuel filter is new too. Injectors are rebuilt injectors that run about 510cc to 520cc. The stock for the car normally runs 460cc. That could be a major issue. Also when the MAF is unplugged, the car runs on base maps allowing it to run. The maf testing voltage solo and unplugged tested fine, but when plugged in, its like it doesn't open. My friend manually pushed the cone open with his hand while the maf was plugged in, and it ran like it did unplugged. The car will also not run under load. You drive it halfway up the street and it kills itself and you push it back, unflood it, then it starts up, but as soon as it is in gear, it dies. So it could be wiring related (a short or mice chewed through wires) that could be causing this. Or the wiring to the fuel pump is messed up on the assembly itself. Those are at least my thoughts on this one.