S52 OBDII swap problems (E3 and E4 Peake codes)

[drulle]

I just finished s52 OBDII swap and it has this idling issue:
- when I start it up, engine idles somewhat rough for about 10 seconds (1300-1500rpm) and then goes to smooth idle (~700rpm). It does this every cold start, but if the car is warm, it doesn't do this.
- Also, when acceleraring gradually, engine performs normal, but if I rev it up fast or try to accelerate quickly, it bogs down and looses power.

So far I've checked for vacuum leaks and couldn't find any loose fittings or cracked hoses. I did check all hoses when assembling the motor as well.

My car is 1989 325is with S52 OBDII with OBDI intake manifold conversion. Harness was done by RobertK and Dave did the DME flash. My next step is to replace fuel filter, and check spark plugs.

Any help and suggestions are appreciated.

Thanks

EDIT: there's no Check Engine light, if I do diagnostics, will it show any codes?

[MyE30]

Make sure your IACV is completely clean and moves like butter. If you have done this, have you spoke to Dave yet? Could be related to your flash.

[drulle]

Make sure your IACV is completely clean and moves like butter. If you have done this, have you spoke to Dave yet? Could be related to your flash.

Thanks, I did clean the ICV when converting to OBDI manifold, and it wasn't sticking or anything. I will check it again if I run out of ideas but it will be a tough one to get too...

I will contact Dave, maybe he knows what could be causing this.

[DesertBMW]

my bet is on OBD1 manifold conversion was not done right

[drulle]

^^^ Do you mean it was hooked up wrong?
A few DIY's that I found on Bimmerforums were used, as well as single piece silicone hose and throttle body seal needed for M50 manifold conversion. I will go over it again to make sure though. Thank you.

[drulle]

Checked all hoses and M50 manifold conversion for air leaks, all seems good.
Replaced fuel filter.
Also verified MAF, works fine.

Still have the same issue :(

[DesertBMW]

what fault codes are you getting? Read BMW factory codes

[328ijunkie]

Check ST and LTFT with any OBD2 scanner... Im betting youre having a fuel pressure delivery issue....

[drulle]

what fault codes are you getting? Read BMW factory codes

Check ST and LTFT with any OBD2 scanner... Im betting youre having a fuel pressure delivery issue....

I will read codes and report back... btw, what's ST and LTFT?
Thanks guys.

[328ijunkie]

Long term and short term fuel trims

[drulle]

Finally had some time to work on my car and also got a Peake scanner to pull codes.
I got:

Table 11
E3 02 sensor adaption limit Cylinder #1-3
E4 02 sensor adaption limit Cylinder #4-6

Searching for these codes I got:

Vacuum leaks - checked and rechecked. All seems good.
Maf sensor - cleaned with CRC and tested on my friends e36. Works great.
CCV - not really sure how to check it's functionality.

Also wanted to check LT and ST fuel trims as Dave suggested. But Peake scanner is no good for that. Trip to the dealer?

[328ijunkie]

You have the O2 sensors plugged into the right ports 1-3 is rear plug 4-6 is front plgu

[drulle]

You have the O2 sensors plugged into the right ports 1-3 is rear plug 4-6 is front plgu

Good point... I didn't even know there is a difference.
Just checked O2 sensors and they are hooked up correctly.
The sensor closest to the front of the car is for Bank 2 (cylinders 4, 5, 6, or the rear-most three cylinders) while the other is naturally for Bank 1 (cylinders 1, 2, 3)

Thanks Dave. I will read fuel trims tomorrow hopefully and report back.

[328ijunkie]

Get an advance auto parts OBD2 reader that will output data to see what your fuel trims acutally are. Without that youre guessing whether its lean or rich...

[drulle]

Ok. Here it is.

P1188 Fuel Control (Bank 1, Sensor 1)
P1189 Fuel Control (Bank 2, Sensor 1)

Freeze Frame Data
Fuel System 1
Closed loop
Fuel System 2
Closed loop
Calculated Load 25.8%
STFT Bank 1 21.0%
LTFT Bank 1 5.4%
STFT Bank 2 17.9%
LTFT Bank 2 8.5%