Major electrical issues, S5 TII conversion.
 

Im working on a 91 FC3S. I have performed a complete turbo TII swap from an 1988 10AE. For a week the car ran perfectly until one evening. The owner pulled the car into the garage and shut it off, only for it to not want to start.

Specifications:
1991 NA body
1988 13bt Pinapple 2mm rebuild
1988 5psd manual tranny, rebuilt by pinapple.
1988 LSD Rear diff, pinapple rebuilt
S4 intake manifolds
S4 Turbo charger
3" exhaust
SAFCII
1991 NA ECU and NA wiring harness, modifyied for S4 Turbo motor
S4 high imp 550 primaries
S4/S5 high impedance 750 RC engineering secondary injectors
S5 radiator
S4 topmount for now
FD fuel pump.
S5 throttle body and TPS sensor
S4 Pressure sensor, S4 FCD
S5 NA AFM

NO emissions. No rats nest. No solinoids.
3" CS exhaust
Boost controller
Mazdaspeed seats
Full roll cage
Sparco 5pt harness


I have tested every sensor, it has fuel, spark, compression. Double checked everything, removed the SAFCII, tried a different ECU or 2 and have a turbo one that will be going in the car.
Fuel lines are in the right places. I am worried one of the injector clips broke, so I will check that first thing monday.
Everything worked wonderfully for a week.
The car will run, if the SAFCII is connected and I hold the AFM sensor open. If you give it gas, it will choke and die. It will only run above 3500 rpms, which also leads me to believe its a primary injector problem.

I see no mention of the S5 OMP

Motor has a S5 front cover with S5 OMP fully functional and installed.

I would start by looking for vacuum leaks

Been over it a dozen times. Every vacume line is accounted for. All new hose clamps.

I will however check again tommorow when I check the primary injectors.

It only runs above 3500 rpms and dies if it goes below i issume. But i believe that only the primarys are used to start the car. If that is true, then the primarys must be working enough to start the car, but cuts off once the car is running. Have you check the ecu and made sure that is ok? Also have you check your timing?

Timing is good, and like I said, I have tried several ecu's. They all work fine in my 91 VERT too.

There is a possibility that either one of the primary injectors came un hooked, blew, or are reversed. I am going to check that out right now.

Injectors are fine. Clips are fine. Clips are on the correct injectors.
We used a S5 primary fuel rail and a S4 secondary and the fuel lines were switched. How could it have ran for a week like this? Switched them back and now the car will rev above 1500 rpms. Crapy like. But do you think the regulator is shot? Could that cause horrible reving and fuel suppply problems. The car does not like a load.

Believe it or not.. I had a car that had VERY similar symptoms.. and swapping in my 10mm NGK wires fixed everything.
With bad spark, the fuel doesn't combust as well and the car will dislke loads. Somethign to keep in mind.

I'd wager compression or a vacuum leak.

Has a set of magnacor 10mm wires, which worked fine on the car before.

Has good compression (115+ on all faces)

No vacume leaks. Checked by 2 other people then myself and confirmed. Carb cleaner shows no leaks either.

Guys I have tried everything I can think of. Any ideas, at all? I am days away from saying screw it and buying a wolf 3D or a haltech....

:(

You say you modified a S5 N/A ECU to run the S4 TII motor? But then you swapped out the ECU several times? So have all of the different ECU's been "modified" or whatever?

Have you tried swapping the AFM?

Make sure you've got those weird fuel 'diffusers' installed in the irons and the the injectors have the right sized O-rings to get a good seal.

Also, have you checked to make sure your coils/wires are still good?

Coils have been tested to spec, CAS has been tested to spec, injectors have been tested to spec, TPS has been tested to spec.

The NA ecu does not need to be modifyied.
I have swaped CAS, wires, AFM with known good working ones.

test the whole circuit, if you still have the UIM off then remove the primary injectors and tie them to the rail, pull the CAS and hook it up to the harness, turn the ignition on and spin the CAS and you can watch the spray patterns from the primaries. if there is no spray pattern then you have either a bad common wire to both injectors of which i can't remember which is cycled power or ground but i would suspect the single common non trigger wire. either that or the CAS wiring to the ECU is faulty or grounded/shorted somewhere.

if the injectors pulse with the CAS then i would suspect another issue like compression or a major vacuum leak. you did swap the MAF just for the hell of it right?

There is a spray pattern, already did that.

In the rare case that the FPD did die, I am taking a whole new set of spare fuel rails over now.

I had a similar problem and it was the brake booster hose.

Brake booster hose is clamped on tight, both ends.

Replaced the FPD and primary rail with a S4. Tested injectors again and everything looks good.
I have a dead battery now, but I will try to start it next time I can get into the shop.