Ok, so im finishing my S5 TII swap into my 90 GTU and i'm having a problem, two weeks ago, i took it in to get an exhaust made and when i took it in, it ran. I took it to an exhaust shop and the mechanic that made the exhaust was going to testdrive it after he finished to make sure there was no problems with it hitting on anything, so he started it up and backed it out of the garage, drove up the street and when he shifted into 2nd it died, now heres the problem... We checked everything, put a new set of plugs in, made sure all connections where tight, replaced the fuel pump, and basically trouble shooted everything we could think of, finally we discovered that if we held the AFM (Air Flow Meter) open a little bit, it will run, if we open it the whole way, it stalls, and if we don't hold it open at all, it will start for 2-3 seconds and stall. I'm not sure if its the AFM or not and I don't know of anything else to check for. Where I live, no one knows anything about Rx-7s and i think im probably the only one to know anything about them around here. If anyone knows anything or could recommend something for me to do about it, please help! I'm going without a car right now and i've spent a ton of money and now i'm losing faith..

 

were you there when he went on the test drive? i personally would not let an exhaust guy drive my turbo. anyways you might try a fuel filter and maybe try to test another afm or get one.

 

I was there, i didnt go with him because there is only 1 seat in the car right now, but it has a brand new fuel filter on it also.. i can't find another AFM and they're too expensive to buy just to try it... I have spent a ton already

 

Well to me, all signs point to the AFM. Get it replaced, you can get a used one on here for around 75 bucks

 

If i hold the AFM open a little bit, it will start and idle, but if i let it close it will stall, and if i let it open on its own, it will stall. and if i don't hold it open, it will start for 2-3 seconds and stall out after

 

Check the duct hose from the afm to the turbo for any cracks/ air leaks. You may need to remove the duct completely to see any cracks. Make sure all hoses are connected and not cracked. Try to keep the engine running with propane (unlit torch aimed at the air inlet to the air filter). If you can keep it running with propane, there is a vacuum leak somewhere or possibly a fuel pressure problem.

 

I installed a front mount and hard (Polished Aluminum) piping from the turbo inlet to the AFM with a reducer from the back of the AFM to the hard piping, so i know that there is no leaks. Also, it will run if i hold the AFM open just a little bit, but if i let it close on its own, it stalls and if i rev it and let it suck it in on its own, it stalls.. any further suggestions?

 

the comp. sees more air in, it'll give more fuel, it may not be getting enough fuel as siguy2k may have been getting at with the fuel filter.... if there's no vac. leaks then maybe you can diagnose your fuel system.

 

try undoing your fpr vacuum line(it should make it run more fuel press.) and if it works maybe there is something there. It really doesn't sound like a bad maf it sounds more like a leak or some fuel problem.

I say rig up something to hold the maf cracked a little then spray all your hoses and connections on turbo piping and the intake manifold connections maybe you blew an intake gasket. just spray starter fluid and if there is a leak it will change the rpm,(depends on the type of starter fluid, some raise idle some bog it down)

 

Tried the unplug of the FPR and checked all vaccuum lines, i replaced all the Vac lines with new line before i installed the engine, it still does the same thing any more ideas from anyone out there? I ohmed the AFM and everything tested alright except the thermosensor part didn't have a reading but i'm going to try more tomorrow any more ideas please help

 

fuel safety switch in AFM. Jumper the fuel connector on the strut tower to get u going bu you need to fix or replace the AFM with a used one for safety issues.

 

I jumped the fuel pump with that jumper on the strut tower to make it run all time and it still does it, the only time it will run is when I hold the AFM open just a little bit and then start... where is the fuel safety switch located?

 

anyone else out there with recommendations?

 

could be a dumb question but this has happend, did you suck anything into the throttle body? i have seen it happen on a few cars, gets stuck and clogs air. thats another reason why i dont let anybody else but me do work on my car lol

 

Theres nothing in there, checked that already, it flows freely, and if i take the intercooler piping off of the throttle body it will do the same thing start and stall start and stall, i found that if i disconnect the AFM completely, the car will start and run extremly rough, and rich but won't stall right away

 

does anyone else think that the AFM is the cause? i just really don't want to waste more money and end up with parts that aren't the problem

 

Think u jumped wrong one. Does your fuel pump run the entire time now when the key is on?

 

yea i jumped the yellow plug on the passenger fenderwell by the shock tower, the fuel pump runs all time when key is on, still same problem

 

well i had the kind of the same problem. but mine is like this. i would get it to start and then would die off. But it would actually take a little bit of cranking to get it to start too because it was a rebuilt engine. Stepping on the gas peddle wont help so its not a vac leak because if its a vac leak then the gas peddle would help the car idle. So i got spark and fuel because if i dont have spark and fuel then it would never start and the die. so those are check off. So i'm left with the afm. Lucky Tekk88 have a parts car that has an AFM. so i barrow it to see if its the problem and lucky enough, for me its the afm. Also when i got the AFM i forgot to hook up the black hose that was part of the intake pipe near the throttle body. After i hook that up. Its good. That my story.

 

Did the exhaust shop do any arc welding or all gas welding? I have seen damaged control units on cars from improper arc welding, but mostly at body shops.

 

no, they had the battery disconnected.. but anyways, i tested my AFM and its showing a reading of 1.560 ohms on the Air intake thermosensor part, I need to know if anyone out there could ohm their AFM (N370) and tell me what kind of a readings they are getting on the Air Intake Thermosensor part of the AFM, the other two sides tested 300 plus ohms..

 

If someone could do this for me, it would be really appreciated, I need to know if my AFM is bad..