hornbm

Well Guys, heres an update on my ongoing idle problem of my new S5 N/A swap.

I got my fuel injectors cleaned and blalanced. It turns out that one of them was really out of spec. I replaced the injector. So now the injectors are new or cleaned and blalanced. It didnt seem to make a big difference at all.

Next I was getting a pressure sensor error from the ECU. This effects the air/fuel ratio and timing. I was sure that that would fix the problem. I got the sensor in the mail yesterday, and threw it on, and the error went away, and the car ran a little better. However it still was running pretty bad.

Now, I know my timing is set right, I had a rotary shop do it. I couldnt find any vacuum leaks, and neither could the shop. However we both agreed that the motor seems to be running very rich. Just reving it in in neutral, the engine will make a small backfire on deacceleration.

The engine runs really well above 2000RPM, but pretty poor below. I've treid the air adjustment screw and it didnt help any. I'm beginning to wonder if its the BAC valve. I tried unplugging it, and the engine runs the same.

Doesn't this thing allways supply the engine with air below 2000RPM ish? I'm starting to think that this could be my problem. There really is only 3 possibilities left. The BAC, could be stuck, the ECU could be bad, or there could be something seriously wrong with the rebuild. The rebuild was done with used housings and only has about 150 miles on it, which probably isnt helping.

Tell me what you guys think.

hornbm

bump

hornbm

Ok heres an update. I cleaned out the BAC valve, and the engine did run differently. It shot up to like 2000RPM then died. I could keep it going if I have it gas. It seemed to run alot smother at around 1500 than it did before.

However, I am experiencing the same problems I have been having. I tightened up the throttle cable, so I could fake an idle and got it around 1100RPm or so. It was running rough as hell but it was running.

However after about 20 minutes of lettling the thing run, it died. I tried to restart it and it would not restart no matter what I did.

I came back an hour later, and tried to start it, and she started! SO I let her run for a while, and about in 15 minutes, the car died again! And this time as well it would not restart!

When it was running the second time I noticed that my secondary injectors were running. Are they supposed to be running at 1100 rpm? Or is it a matter of where the throttle is?

Last but not least, I checked ECU codes. And it gave me a pressure sensor error!!!!! I just replaced the pressure sensor, and the error code went away. Why on earth could it be back again?

ilike2eatricers

well I would think that maybe the problem is caused by a bad o2 sensor or maybe even a defective AFM. Not sure why the pressure sensor error would go off again unless perhaps there is a faulty connection. Have you tried grounding?

hornbm

yeah I checked the wires.... thats why I'm really stumped. I might have a bad ECU, or it might even be cracked wires or something in the harness. I'd hate to have to say it, but I think I'm gonna ditch the EFI and go carb.

trainwreck517

iTrader: (1)

Did you reset the ecu after you replaced the presure sensor. Disconnect the the neg battery terminal for about 15-30 sec. Connect it.. run the car and check and see if it comes up again.


Also check TPS and see if you have intake leak? But I am sure you done that already.

hypntyz7

Don't take this the wrong, way, you have done a great job getting this setup to work in your car. But this kind of thing is why, day in and day out, I preach on this board about the complexity of engine swaps, hacking, and other assorted riggery. IT can be done, and made to run, but it will never be what it is supposed to be, or what you really want it to be, and in the end both you and your car are unhappy.

I suggest you go carb as well. You will make better power, for less money, in the long run, but you will sacrifice some mileage and driveability (smoothness). Or, well, nevermind...had your car run properly to begin with, you would have sacrificed those things.

hornbm

You are exactly right. This project was a fantastic learning experience. The ammount of knowlege and experience from attempting this swap I have gained is amazing.

However, carb seems like my simple choice. I know its not exactly what I want, but it'll get a little worse milage and take a little longer to warm up in the morning. I can live with that.

MaxRX7

I can sympathize with you, I have VERY similiar idle problems. I know I am close to getting it to wrong correctly.