So is it weird that my car (91 n/a with S4 TII conversion..S5 TII ECU..no emissions) will only start if I push my finger knuckle deep into the MAS, pushing the flapper almost all of the way in? Once it starts, it runs shitty until you find just the right spot on the flapper slide and it runs like a rocket. There are no vacuum leaks, and everthing else specs out correctly. I have had a couple very compitent people check it out to just scratch their heads. There was a guy on here recently that had a similar problem with his 1st gen TII convert. Big backfire and ran shitty. He replaced his ECU and fixed it for a bit, then back to bang bang. Compression is 115 front and rear. Pineapple built motor with 5K on it. Oh yeah..when I did the conversion, it ran for about 20 miles, then the saga began. Hmmmm. ****. It needs to be ready for PIR in March..HELP!!!

 

check for ecu error codes

 

if your using a S5 ecy, I would recomend using the S5 AFM, and not the S4 AFM. Just an idea, may or may not make a difference.

 

Believe it or not, the AFM is the same part in the 88 S4 and the 91 S5. My next step is to tow the car to Rob at Pineapple, but I'd like to fix it myself if possible. This is my mission! One thing that is different from the 20 mile stint is that the SAFC is disconnected now. When it ran for the 20 miles, it was hooked up. I drove it from my shop home and around, and back to the shop. I got in it to drive a freind and it wouldn't start. Same symptoms as now. If you push the pedal past 1/4 throttle it cuts out and pops. I disconnected the SAFC to see if the maps had been lost, but no. I have not checked for codes. Actaully do not have the equipment for that. Rob does however. Hmmmm

 

Is your TPS calibrated or working correctly? I would double check that. and the S5 AFM is the dynamic slider type, not a flapper door meter, i know people say they should be interchangable, but im not totally convinced of that. I think they may have a different calibration range.

CJG

 

The TPS is perfect..The S4 TII car that I robbed the drivetrain from had the same flapper style (black tube looking gizmo, not the bulky silver style) AFM and the part number on them match. Fuel pump readings correct in pressure and voltage. All other electronics seem to be ok and match.

 

I am the guy with the turbo fb. My problem ending up being a bad electric S-5 omp, which put my car in limp mode. Hence the backfiring if I reved it too quickly. So you may want to check that, You do have one hooked up to the ecu? I would start there, apparently its not that uncommon for them to quit. Good Luck

 

I'd guess the intake temp or coolant temp sensor is bad. The car refuses to run rich enough to keep itself running, so pressing in the maf flapper artificially enriches the fuel mixture.

 

I am going to head down to the shop this am and try those things..Rob had mentioned the coolant sensor and it did check out ok. I'll triple check that and look into the OMP..I did swap the S5 cover onto the S4 motor for the elec OMP. It came off of my running S5 n/a though..I can't imagine it would die after the swap but who knows..maybe the connection is bad. I'll see if that does the trick. Appreciate the help. Maybe I'll get back on this afternoon with good news..any other ideas?

 

Well dunno...checked the componites..are checking ok. What next? At this time it fires right up, revs to about 2.5k for about 2 seconds, then dies.

 

are you certain the TB endpoint is set right?

 

So I threw the car on a transport today and ran it over to Pineapple. Guess we'll see what was the problem soon enough..Probably next week

 

DUDE! I just did a S4/S5 block and intake in my FB with S3 fuel injection. ANYWAYS same symptoms startup then dyes. Could stick finger in flapper and would kinda work. I had a leak after the MAF. Somewhere at either the elbow from the tube to the MAF, the flange on the throttle body, the BACV bypass tube, or just a small slit in the rubber will do it!!!!!!! MAF are gay! any tiny minute leak will do this!!!!

By the way, did you possibly accidently adjust the bypass air screw on the MAF? That would do it.

Third, I was under the impression S4 uses the swinging door style MAF while the S5 uses a cone style that moves away from the front as air gets sucked inside. I know you said it has same part # but for sh*ts and giggles I would borrow someones S5 MAF.

 

yeah as far as I know, s4 and s5 AFM's are not interchangable, and they are deffinately NOT the same. If you have a s4 AFM on a s5 ecu... id fix that

 

you dont need any special sort of error code checker. Search the forum, but on second gens, you have to ground a wire, and then the check engine lite will display the error code in morris code

 

Hey guys. So I have a S5 MAF on the car. The ECU is S5 so that matches. I have a spare S5 MAF and it rubs the same with that in. Are you ready for this? So Rob called me yesterday. I am embarrassed to admit this, but if what he found is ALL that is wrong....faulty lower intake gasket down by the turbo. ****. How stupid. My little brain for some reason overlooked the lower gasket as a possible cause. Actually, it crossed my mind, but it's new adn was lovingly installed..how it got sucked in on a corner I don't know. I'll update this very soon with the verdict...Your Portland dumbass signing out~

 

yah, so at least it is gonna be a cheap fix!!

 

BAM! My resolution hit me too like a ton of bricks. Matt and Ryan were sure to make me feel stupid for my leak. Better cheap fix than another engine....

 

That better be it...

 

just takes another set of eyes sometimes. IM guilty of it too!

 

Yeah it better and you'll be.....

 

The saga continues! Hmmmm. little subtle issues that point nowhere. ****

 

wait..so they're stumped? or is it fixed?

 

FIXED IT!

Fuel pump was dead. Me and apex went and wrenched on it today in robs shop. Drove it away even .

YES!!!!!!

 

no way....hummm....good job! have fun!