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

[Ryann]

Wonder if you've got a wiring issue? Grounds at the DME connector are pins 34 and 6. Google says the other end of one of those is in the group of grounds behind the RH strut tower. Also, pin 3 is batt+ from the main relay.

[fiftytakedowns]

I was getting a consistent 45 PSI at one of the fuel lines and 55 if I disconnect the FPR . I only tested one, but I figured the return line wouldnt have 45 PSI anyway.

I replaced the ground strap that goes from the Frame to the like engine mount arm thing. I have another ground strap that I attached from the shock tower to the intake throttle body( I figured it would get to the head?). There Is a third ground wire that appears to be coming from the Firewall where the battery would be, and it's grounded at a spot right there (clean contact)

I have a spare stock set of injectors, if all else fails I'll swap them in. as well as the TPS that is on that spare throttle body.

Is it possible that the coils are grounding out to the COP bracket? I cant quitte understand why its throwing a COIL #1 code in one of the DME's and the other DME is throwing a Camshaft Sensor Code.

I also did a smoke test and found NO vacuum leaks or any smoke protruding.


The car did sit for about a month while I did the Timing chain job.I just filled up the tank yesterday. But what Is extremely weird Is why would the problem go away temporarily If I unplug the DME and plug it back in again?

[fiftytakedowns]

mechanic says its a misfire, where should I check next?

BTW i unplugged the camshaft sensor and it changed nothin, same synptoms.

[fiftytakedowns]

Good news: its not the coils.
got some new ones, and they didnt change anything.
I put some plug wires in, and then had the coils on separate, and then I disconnected the plugs wires, and there was still spark jumpin between the coil pack and the plug wires.

what Is really odd is how if I disconnect the DME and plug it back in again, the problem goes away temporarily.

[fiftytakedowns]

Did some sensor Testing:

Coil 1: WAs Sparatically Changing Ohm Levels:
from .03 to .05
Coil 2: .015
Coil 3: .015
Coil 4: .015

These were the coils Off of a Coil on Plug conversion, not sure if that makes a difference.

AFM:
got a consistent reading between pins 3 & 4 to 3.94V through -.06V
Between pins 1 & 2 : 3.8 V

TPS:
At idle between Pins 1 & 2 4.3V
Full throttle: .96V

Between pins 1 & 3 5v
Between pins 2&3 at Idle .62 V
full throttle: 4.0V

[fiftytakedowns]

Do you have another spare DME to swap in? If you don't I would seriously be happy to mail you mine.

As I think you said earlier Google finds threads with these same codes and symtoms. Weird.

NEW UPDATE:

So I do have a SPARE DME.

and its been even more frustrating now, as I am leaning towards fuel problem now.

I'll be driving, the car will be going fine, and after 30 seconds of driving, it will do agressive sputtering, and nearly impossible to drive. my narrowband gauge is going all over the place, but moving to the lean area. I think... But If I take out the ECU and put it back in, it resets and goes back to normal. until 30 seconds are over.

Gets worse with the chipped ECU.

[Ryann]

Do you have another spare DME to swap in? If you don't I would seriously be happy to mail you mine.

As I think you said earlier Google finds threads with these same codes and symtoms. Weird.

[immajackuup]

sucks to be in your shoes.

[fiftytakedowns]

I made some headway today.

the sensors Checked out pretty good CPS had a like 650 ohm reading while the camshaft sensor was like 1300 ohm.

I think it's a spark issue becuase now it's acting like it's hitting a REv limiter. Im hoping there isnt some fucked Wiring somewhere. and I added and extra ground between the shock tower and the intake plenum.

Any Ideas?

I am getting two different ECU readings

Of my MARK D chip ECU the engine wont rev past 2K rpms and its spitting out a 1271 code

off the stock ECU no chip Im getting a 1244 code and it's revving up to 3.5K rpm before it does the misfire/sputtering now..


EDIT:

I thought I would mention that When the car was warmed up this misfiring, sputtering jerking Etc. WAs intermittent and would show up randomly. I also tried wrapping the coil wires separately too see if there was a noise issue etc... but to no avail.

[Ryann]

A cold engine needs a richer mixture. Even a small intake leak will lean out the mixture enough to cause problems.

I would eliminate the possibility of vacuum leaks first, particularly since someone else has been under your intake before.

I would tend to doubt AFM problems simply because you aren't getting a CEL, although I've seen certain modes of failure for MAF's and AFM's fly under the radar on earlier systems.

[dkbmxer002]

yup. my guess was going to be either failed temp sensor or the maf was bad. haven't had time or money to replace either of them yet.

[fiftytakedowns]

lol. don't commit suicide yet. Maybe try checking the ohms on the DME temp sensor? unplug the ICV? Have you thought about posting this on m42club.com?

they already gave up on it, I had a multiple page thread goin. I know multiple people are having this problem too.

[fiftytakedowns]

why would such a aggressive fall on it's face occut during this situation, at the same RPM?
the RPM threshhold RAISES as it gets warmer as well.

[dkbmxer002]

but then wouldn't it have the same issues any time it goes into open loop mode..

[jlevie]

why would leaks cause issues only when cold though...?

A cold engine needs a richer mixture. Even a small intake leak will lean out the mixture enough to cause problems. Since the DME is running in open loop mode while the engine is cold it can't compensate for the leak. Once the engine comes up to temperature the DME shifts to closed loop mode and uses data from the O2 sensor to increase/decrease fuel trim to achieve stoic conditions.