Car can't drive when cold. only once warmed up. Misfiring when Warm....

[fiftytakedowns]

Sounds good. ill try that out

[twistednut]

Have you tried running the car without the TPS sensor plugged in? Disconnect the DME and let it reset. Disconnect the TPS and plug the DME back in. Start the car and see what happens. Just a suggestion.

[fiftytakedowns]

will do thanks!

[fiftytakedowns]

Alright, Ive got some plans for this coming weekend of tackling the problem, both the Cold start one, as well as the fuel cut once warm.


This thread gave me some Idea of possibility:

http://www.r3vlimited.com/board/show...light=Fuel+cut

what I am going to do Is jump the Fuel pump, becuase aparently I have been jumping the wrong one the entire time ? Is the fuel pump one the five pronged or the Four pronged? my 5 pronged relay looked beat to shit when I pulled it so I cleaned the terminals and re-installed. (that being said, Does it matter where I get the relays? napa auto or does it need to be OEM?)

Then I was going to Smoke test for Vacuum leaks again. because I am hearing a hissing and especially a whistling when I create more vacuum by covering the intake. Then I will replace the lower Intake mani gasket. and fuel injector o-rings.

My Boot Is cracked in a bunch of places but I dont think it's leaking any air as light doesnt shine through. or the vacuum gauge doesnt fluctuate as I move it around. Either way I will replace it once I can find this problem.

I also Have a vacuum gauge to help me diagnose. (however I should use it)

- Seafoam the Gas, Intake, and Oil.

-Test fuel pressure when missfiring or bogging is present.

- swap in third ECU and check for codes

- See if all plugs look lean. or if a pair etc etc.

- run car without TPS and comp reset

--> another thing I was wondering was I have been Testing my crank and cam position sensors. Does it matter If they Are cold or Warm or both? What values should I expect When I do that?

Although I highly doubt it's a wiring issue, because I dont see any corrosion Etc. around wires, Is it difficult to exchange the engine wiring harness?

(although a silly question) I want to retest the coils. but I am not sure What ohm setting to put onto the multi-meter, They are sparkin thats for sure, just wanted to be sure I was doing it right.

[fiftytakedowns]

I think I thought of a Janky solution so at least I can drive the car and move it from my girlfriends (temporary fix).

If there is a signal somewhere telling the car that it needs to cut the fuel therefore fuel pressure is dipping causing the jerking, i am thinking about eliminating an entire pathway of wires. and signals.

What I can do is attach a switch to have teh fuel pump running or not, so at least I can elimnate the COIL POsition sensor pathway as a posibility, and eliminate a chance that maybe the CPS is sending a bad signal for fuel, or maybe the DME is getting a bad signal etc. etc.

I could use this so atleast I can move the car and use it until I can find another solution. Does anyone see a problem with this?

[pharow]

I am having kinda the same problem. My car starts, idles, and runs fine until...It is warmed up to operating temp. If I try to put a major load on thee car, it stutters and misfires in the mid to upper rpm range.

I have since changed the O2 sensor, the afm, and the fpr.

I found out that the fuel press was staying around 100psi. Pump pres. on both sdes of the rail. I think I have tracked it down to a bad/clolgged return line in the fuel tank.

I don't know if that will help you out, but that is where I am with my problem. Does anyone know how far the return goes into the tank?

[Ryann]

If you think your fuel pressure is dipping hook up your fuel pressure gauge, masking tape it to your wiper arm and watch for it while you drive!

[fiftytakedowns]

so I just did a quick test right now to see if the crank position sensor was possibly sending a (bad) signal to turn off the fuel pump when the car is cold, thus causing some bogging, and agressive misfiring. (some popping in the exhaust as well)

I didnt hear any distinct noises signaling the pump was stopping it's action, suggesting that maybe it isnt the fuel pump, or the fuel pump relay, or maybe the CPS sending a bad signal.... just a thought.

Also Ryan was awesome enough to send me a spare (third ECU) to test my car with. NO luck with the DME but It did kick out a 1244 code which one of my other ones were kicking out as well.... that is the camshaft position sensor I believe.

is the 5 pronged relay on the harness the ECU relay? it was pretty old and the terminals looked burnt.

Something peculiar I discovered however was that when I was pushing and holding on the throttle and the car was misfiring was the ligghts were getting and flickering much brighter than normal, and the pump was also pumping a bit harder and louder.

[fiftytakedowns]

I have a little bit of an update:

I spent all day today fuxoring with the car and I took some steps forward and backward. I guess I am back to square one.

But here is some prequel.

I have Three ECU's

Two of em are spitting out 1244 (camshaft sensor) the other one is spitting out a 1271 (coil one) I even was running a different coil in 1271 today. (I had to modify the housing to get it to fit as you may know with the COP's)

one of the 1244's takes a long time for it to start misfiring. It will be running and driving great like nothing's up. then after cruising a little while at a consistent RPM.

I was curious about something, IF it is in Nuetral the Car will rev up like it aint no thing. once some load gets on it, it doesnt like to drive. for example it will do alright in first gear. and if it does misfire even without the load. If i let it chill in nuetral for a minute It's all good again.

I was definitley getting fuel pressure when I heard some bogging as well. I checked it out. IT would be fully bogging/missing while still getting some 45 PSI.

anyone have a PERFECTLY good set of COP coils to use to help me rule out the coils?

[Ryann]

I guess I am back to square one.

Do it. Yank the valve cover, verify cam timing. Verify even compression numbers. Locate any vacuum leaks and fix them. Verify good spark at every plug. Verify fuel pressure during the conditions of symtoms..

[fiftytakedowns]

Do it. Yank the valve cover, verify cam timing. Verify even compression numbers. Locate any vacuum leaks and fix them. Verify good spark at every plug. Verify fuel pressure during the conditions of symtoms..

Im seriously depressed about this. I have checked cam timing like 4 times, Fuel pressure stayed at 40 at idle 45 When It was revving.

Crank position sensor was at 650 Ohms
Cam Sensor was at like 1400 Ohms

and I have One more of each.

My TPS was showing 1.8 through 2.5 ohms at the connectors and. 1.8 ohms through 4.8 ohms at the sensor itself . (bentley instructed to check with the sensor harness connector off)
My Spare TPS showd 1.6-4.6 ohms .

I dont even know what to fucking do anymore. Im starting to lean towards the coils but I dont want to buy new ones

[trackjunkie21]

Did you check fuel pressure whilst you were driving? This sounds alot like a fuel pump running out of steam.

[b*saint]

BMW dealer could probably figure it out

[fiftytakedowns]

BMW dealer could probably figure it out

aren't they going to charge an arm and a leg? I hate to be frugal, but I have to pay next months rent.

[fiftytakedowns]

I thineqrera