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

[dkbmxer002]

mine is a little different where mine only shows up when flooring it or under a decent amount of load. but mine does it all the way through rpms.

i will check my relays too, i have tried swapping them around in the past to see if anything changes.

[fiftytakedowns]

what do you mean exactly when you say you cover the intake so you create a vacuum?

also how hard was it to replace the relay box? or do you mean you pulled one of the relays?

I pulled one of the Relays that sit next the fuse box. the three up top that are covered by the plastic harness cover.


I create a vacuum by putting my hand over the front of the AFM. then opening hte throttle with the other hand. you can see the intake bellow collapsing, and the noise of a leak near the intake. I cant find it.

Here are Some driving symptoms:

occasionally the stuttering will start occuring between 2-3K rpm, and when It does, here is wat the car does when that happens:
IF I floor it I can sort of stutter through the missfire until i get out of the zone, then past 3k rpm and then pulls hard to redline. If I pull off the gas, but downshift back into the zone without letting the car cruise at a lower rpm for a bit it will stutter if I get back into that zone.
If I put it in nuetral and let the car idle for a second, or two, I can slowly (without any load) accelerate through that zone, and then it goes away and I can drive normally until it shows up again, usually within 5 minutes.

the event only shows up UNDER LOAD! or cruising, USUALY cruising. Never at WOT, or SMashing through the gears.

[dkbmxer002]

what do you mean exactly when you say you cover the intake so you create a vacuum?

also how hard was it to replace the relay box? or do you mean you pulled one of the relays?

[fiftytakedowns]

I replaced one of the relay boxes, actually pulled it out by accident, and it seemed to fix my problem for the most part the hesitation comes and goes much less.. I did find a vacuum leak though, which I think is causing occasional missing, not sure
and I can not FIGURE OUT WHERE IT IS. If I cover the intake so I create a vacuum you can hear the whistle, sounds like its coming from lower intake rail.
I took it all apart, and to no avail not fixing it or aynthign. sprayed some WD poured water, nothing cant find the fucking leak.

[fiftytakedowns]

Will do, Thanks a bunch.

[Kershaw]

i had a problem very similar to this in my eta. it was my o2 sensor. (i know you just said you replaced yours.)

try unhooking your o2 sensor and driving around. does it change anything?

[fiftytakedowns]

Literally, I think I have gone over every sensor in this fucking car. I even put in new upgraded injectors a while back. including 02 sensor.

[Ryann]

I'm way behind you, aren't I?

WHAT ELSE IS LEFT?? Wiring..

[fiftytakedowns]

I had a couple of AFMS and tried swappin them a while back with no avail. I have a narrowband and can have someone swing the barn door and see if it is changing the AFR

[Ryann]

I'd say swap the AFM with known good unit. 2K-4.5K would be the most used/worn out range of the AFM contacts. Maybe the chipped DME is more sensitive to AFM input, idk.

If I were there I'd swap every damn component out of mine until we figured this out.

[fiftytakedowns]

New hint:

I have ECu1, and ECU2.
-Start with ECU1 drive car for about a mile, misfiring occurs, first with one like quick hesitation, then it progresses to get worse, and worse.
-Pull over. pull out ECU 1, put in ECU2, (ECU2 still displays the same problem right off the bat,), pull out ECU2, put in ECU1, problem goes away until about a mile of driving...
-repeat.

OTHER symptom that may tell a lot about the problem.
-> If I can luckily Downshift to get the engine to be past 4500RPM it will not occur up there. Only misfires between 2k-4500 RPMS. IF I decelerate under 4500 rPM it will still misfire.

RYAN: It idles PErfectly fine now, and Drives fine up to about 1700RPMS, then the problem occurs. also, see above post. if the car isnt fully warmed up It will just bogg down outright, once warmed up. this funky misfiring problem occurs.

[Ryann]

At idle? What happens to the needle when you squeeze the throttle?

This is fucked up! It really sounds like you've got a gaping hole in the intake somewhere on the head side of the TB.

[fiftytakedowns]

Insufficient fuel pressure could cause all of these symptoms.

45 PSI 55 PSI without the FPR

[Ryann]

The car literally can not drive when It has not fully warmed up. it will idle (HARDLY), and will immediately Cut out/ Die / BOG if you tap the gas. This problem gets increasingly worse the colder it is outside.

Insufficient fuel pressure could cause all of these symptoms.

[fiftytakedowns]

See what was really interesting was that I was not having any trouble getting good spark from the coils, whichever coil was hooked up to number one was having a weaker spark than the other three. I checked this by pulling out all four coils and attaching them to spark plug wires which were attached to the corresponding cylinders. then I would pull the plug wire from the coil, and observe the spark arching between the coil and the plug wire. It was clearly a weaker color on cyl #1 no matter which COIL was attached.

That being said, the connector was getting a sufficient 12V to both grounds.

-Im not sure I understand how I check coil connections to places that are vs arent spupposed to be grounded.

Im getting really upset/depressed/ and frustrated with this car, I put in another 14 hours today replacing the Temp sender, the Coolant temp ssender, soaking the injectors in carb cleaner, pulling all the wires, checking for fraying checking the box under the intake plenum. testing the resistances between the DME and the coils. I also attached a large cable between the head and the block. NO avail.

What is sounding like the car is getting No fuel at all, the narrowband starts showing it going lean. I dont know what is goin on.

It's been 2-3 years having this car. and after this timing chain rebuild I did It's not even driveable. and I even double checked the cam timing. What the fucking fuck Im about to just pull this engine and go 24V or Just part it out, or sell It. Im really really feeling down.

Anyone who finds out the problem Will get a VDO gauge set that I have. as incentive.