S52 obd1 swap - High Idle, 1 cyl. too lean??

[drez14]

Hi Yall,

Finally making more progress on my swap. Got my exhaust installed today and i have a couple of issues i would like to be reassured on.

1) My Idle seems high in closed loop. After the engine is warmed up, my idles seems to stick solid at around 1k. I bought the engine setup from a guy who had it on his track car. I am assuming he had a lightweight fly on it and had the chip coded for it BUT On a couple of occasions i would rev the motor from idle, and RPMS would float back down slower than usual. Any insight on that? Maybe vacume leak? ICV?

2) After i had my car idling for a little while, my exhaust guy noticed that one of the tubes on my header had turned more blue than the others. Could this be a sign of something? Maybe not enough fuel to that cylinder causing it to run lean? I am assuming that the temp is higher due to the blueing of the the ss header tube, but i will double check it when i get home with a laser temp gauge.

3) I am running the stock 325i O2 sensor. Is that fine?

Thanks in advance.

[drez14]

So i have pretty much figured out the problems i listed in my first post. But i still dont think that my s52 is running right.

Im pretty certain that there is a vacuum leak somewhere. I have removed pretty much all the intake hoses and tested them for rips or leaks. Nothing.

here is a video of what my tach/efficiency gauge does when i rev the motor (listen to the engine sounds too):

http://youtu.be/4geApvJLiso?hd=1

When i rev the engine, then let go of the gas pedal, the rpms will slowly go down, then at a certain point it will go down fast for about 1k rpms and there is a different engine/exhaust note. during the time the rpms are coming down at a different rate, the efficiency gauge gives a different reading. WTF?


Also, when i punch the gas from idle, the check engine light will come on. Whats odd about this is that the only code that comes up is 1281. This code is "Control Unit Memory Supply". I think i am getting this code because i disconnect the battery to clear the code. but why would it come on when i punch the gas?

Tomorrow im going to order some intake manifold gaskets, and a new gas cap.

Anyone want to take a stab at it?

[328ijunkie]

Dont bother with the gas cap

Try pushing your TB closed all the way.

[howelll]

probably the intake manifold gasket has a leak, you can spray a little carb cleaner along where the manifold meets the head to see if the idle changes any. as a saftey discloser i would have to say have a fire extinguisher bla bla bla.

[jaywood]

Try spraying carb cleaner. That's how I found my vac leak.

[drez14]

Thanks for the tips I will try carb cleaner tonight. Would starting fluid work, or should it be carb cleaning fluid? I cleaned the icv last night also but it didnt fix anything.

Also, i want to confirm that i have my line from my brake booster to my intake manifold correct. I currently have a line from the booster to the intake manifold with a check valve between the two. I bought the check valve from kragen and is not a bmw part. When i was hooking and unhooking things yesterday i pulled the hose from the intake maniford and tested by sucking then blowing. The valve would not let any air though. Then i pulled the the check valve from the booster and i heard air rushing past the gasket.(either air was going in or out of the brake booster) Is that normal? The valve should be letting vac from the booster to the intake manifold right?

Lastly, is there a particular direction the fuel evap valve should be hooked up? or is it just a 2 way valve?

thanks.

[Beej '86 325es]

Lastly, is there a particular direction the fuel evap valve should be hooked up? or is it just a 2 way valve?

Are you talking about the purge valve connected between the TB and charcoal canister?
If so, it will be obvious because one end matches the diameter of the TB connection, and the other matches the diameter of the charcoal cannister connection. They're like 1-2mm different.

[drez14]

Yep, the purge valve. Your right, it only will go one way. Thanks for the tip


During my ongoing quest to solve my problems i decided to pull the plugs. They were black. Does this add to the vacuume leak theory? Maybe the ecu senses too much fuel and it add fuel to compensate?

I have some new intake manifold gaskets on the way from Pelican parts that will be here tomorrow. Lets hope thats it. Im skeptical because i did the carb cleaner test and got nothing. If these new gaskets dont fix it, i dont know what to try next.


What else can cause this.. FPR?

[drez14]

I cant believe im asking this also, but which side of the fuel rail is the high pressure side? If i hooked it up backwards, would it be a cause for my problems?

the reason i ask is because i unhooked the fuel rail to test the injectors for clogs and there was no residual pressure in the rail.

[treff-7]

if you're using an obd1 fuel rail then the one on the FPR side is the return line.

http://realoem.com/bmw/showparts.do?model=BF32&mospid=47430&btnr=13_0369&hg=13&fg=15

note the arrows on fuel lines

[drez14]

Thanks treff- That was my original reference so now i know i did that right.

Last night i did some digging, So far i have:

Replaced intake manifold gaskets
replaced fuel pressure regulator
replaced o2 sensor
replaced brake booster check valve
cleaned ICV
Cleaned MAF sensor,
Cleaned the injectors
Replaced and gapped the spark plugs
New gas cap
New Fuel Pump
New Fuel Filter
Checked all rubber for cracks, all are new with no leaks

Double checked my wiring. (turns out i didnt have the heater relay wire hooked up the whole time.I then hooked it up but no change)

Honestly, i cant tell if things are better.. I looked up some 24v videos on youtube of the engine revving, and in all of them the efficiency gauge fluctuates. Can anyone confirm that this is normal?

Idle is a solid 1k, but doesnt change or kick down at any point.

Check engine light is off at start and idle and if i slowly rev. When i punch the gas, the light will come on. The code thrown is 1281, DME memory. Im thinking that code has to be from be having the battery disconnected to clear codes. My battery is new, bought it nov of last year, but when i first bought it i left it connected with my car in "on" so i drained it. I then left it uncharged for a good 2-3 months since i didnt need it charged. ( used a jump box to start the car when i needed to) 3 days ago i bought a battery charger to charge this battery. It was at 12.25 last night, but this morning it was at 9.5. Maybe the battery is bad since i left it uncharged for so long?

After clearing codes, i did let the car idle for 5 minutes, but i am not able to drive the car (except up and down my cul de sac) since the car does not have windows or a license plate. Maybe the DME just need to be driven to learn itself?

Im stumped.

I am going to try a new battery tonight, to try and rule that out.

Any other suggestions are welcomed ;-)

[treff-7]

9.5v is definitely low. imo this can easily cause the fault code you keep getting. most likely that battery is ruined but trying an other one is a good idea to rule out the possibility of a short somewhere.

what you said about the exhaust manifold keeps me thinking. have you done a compression test?

[drez14]

Yah, i took the battery into Pepboys and they replaced it for me. It was down to 7.6 at their test bench which is weird since it sat in the back floorboard of my car all day.

In regards to the exhaust manifold. Here is my theory. On Supersprint reps, the tube on the second cylinder from the firewall goes over the tube of the first cylinder with very minimal space between the two. I think because the two tubes are so close, the temps are higher there. I took IR temp readings about an inch off the block and all the cylinders were within 10 deg. Celsius from each other. I have not done compression tests, im still leaning towards an intake problem. Im hoping its not the MAF because those are a pretty penny.

I hooked up the new battery and let it idle until the motor warmed up. Then i drove up and down my street 3-4 times. This seems to have smooth things out, but when i punch the throttle, i still get a 1281 CEL light. I think the next step is to get it road worthy and do more DME learning.

Crossing my fingers.

[nebulous123]

Fixed

[drez14]

Quick update. After some learning, the CEL threw a 1266, Vanos. After further inspection i found out my VANOS solenoid was bad which would explain my suspicion of running rich. Got a new one from dr vanos today and so far, everything is good. Power is smooth and strong. My MPG guage still does funny stuff when i let off the gas, but maybe thats normal. I bought this non running so i dont even know what the m20 would have been like.

Thanks for your help guys.