2G Misfires and Idle surge. Tried everything.

Andrew_99_GST · Feb 8, 2015

Let's start with the first problem
Misfires-
I've had misfires ever since I got the car. I rarely get a code, but the 2 times I have, I got 0300 and 0302. I can feel it at idle and then when accelerating.
Idle Surge-
I had idle surge for quite a while. I don't remember what I did, but I tried a bunch of different stuff and got it fixed. I then was getting a surge under light throttle. Fixed that by simulating idle switch in dsmlink. Today, after rebuilding my throttle body and boost leak testing, I start it up, and it idled really high. The Idle kept climbing and climbing. I tapped the accelerator and the idle dropped down, and surged like crazy. The only other idle thing I did, was one of the valves on top of the throttle body was boost leaking. So I put a new cap on it and fixed the leak there.

What I've tried-
3 different spark plugs
New wires
New coil packs
Boost leak test (leak free)
Rebuilt Throttle Body since I had a leak there
New IAC
New BISS O RING

And here's a log from today after warming up-

Andrew_99_GST · Feb 13, 2015

Nick97dsm said:
maybe new wire are needed if there loose they are probably done.

These are new wires. I have replaced everything spark except power transistor. New fuel injectors, wires to the fuel injectors are good. ECU is good. No boost leaks.

tuurbo junkiiiee · Feb 13, 2015

Bad ground from the alternator can cause surging which could cause a backfire. Does your lights dim?

Andrew_99_GST · Feb 13, 2015

tuurbo junkiiiee said:
Bad ground from the alternator can cause surging which could cause a backfire. Does your lights dim?

My lights do dim...... where is it's ground?

T-Flexx · Feb 14, 2015

Did you properly adjust your biss after rebuilding your tb?

Andrew_99_GST · Feb 14, 2015

T-Flexx said:
Did you properly adjust your biss after rebuilding your tb?

Of course... My idle is pretty good except I think I'm getting some misfires and it's not completely steady (goes inbetween 680-820 with my target idle at 750)

Andrew_99_GST · Feb 17, 2015

Narrowed it down quite a bit.

I'm only getting 4v to the injectors. Tested the thing on the fire wall and it tested 6 ohms across the board - so it's good. A new power transistor will be here tomorrow. Hopefully that does it.

inthemidst · Feb 17, 2015

You went thru 3 different crank sensors to get one good one that's far fetched maybe theirs a problem with the cas harness I would highly recommend a continuity test for cas to ecu.

Andrew_99_GST · Feb 18, 2015

inthemidst said:
You went thru 3 different crank sensors to get one good one that's far fetched maybe theirs a problem with the cas harness I would highly recommend a continuity test for cas to ecu.

The new CAS tests good. The problem, was every single CAS I got, already had the bag opened (got at advanced auto). I assume people just swapped out their CAS and returned it back to the store.

I battled a no start for over 2 months with the bad CAS. If popping a new one in made it start right up, I'm pretty sure the others were bad (they all tested out bad anyway). I also tested the wire, and the wire was good.

Anyway, like I said, I narrowed it down to low volts to the fuel injector. Which makes me believe power transistor. It was suppose to be here today, but looks like it will be here tomorrow.

dgdsm · Feb 18, 2015

I'm not sure how a PTU can favor one injector over another. If it fixes the problem, that's great and all's good.

But here's a page from my manuals showing the electrical circuits in a 2g connecting PTU, ECU, and injectors. It shows the injector circuits going through a resistor. I'm actually not familiar with this part or where it is physically in the vehicle. But if you're not seeing enough volts going to the injectors, maybe this resistor is what's bad. As you can see the resistor also connects to the ISC circuit.

Andrew_99_GST · Feb 18, 2015

dgdsm said:
I'm not sure how a PTU can favor one injector over another. If it fixes the problem, that's great and all's good.

But here's a page from my manuals showing the electrical circuits in a 2g connecting PTU, ECU, and injectors. It shows the injector circuits going through a resistor. I'm actually not familiar with this part or where it is physically in the vehicle. But if you're not seeing enough volts going to the injectors, maybe this resistor is what's bad. As you can see the resistor also connects to the ISC circuit.

The resistor is on the fire wall, which is what I tested, all were 6 ohms which is within spec. All the the fuel injector wires were reading 4v while cranking, and from my understanding they're suppose to be 12v.

dgdsm · Feb 18, 2015

Alright, I see that. I guess you're thinking that it's a spark issue.
Seems like it might be worth checking that "red" wire, since it goes into the IAC motor and also MFI relay.

inthemidst · Feb 18, 2015

The injectors are ground controlled by the ecu I don't think the transistor has anything to do with injectors.

Chumpaumpalumpa · Feb 18, 2015

www.dsm.org/how-tos/tttt/tttt3.html

Andrew_99_GST · Feb 18, 2015

Chumpaumpalumpa said:
www.dsm.org/how-tos/tttt/tttt3.html

My idle surge is fixed. I forgot to plug in my IAC :banghead:

... Now my only idle problems are because I have 272/272 cams...

Chumpaumpalumpa · Feb 19, 2015

Andrew_99_GST said:
My idle surge is fixed. I forgot to plug in my IAC ... Now my only idle problems are because I have 272/272 cams...

haha good glad you got it fixed. We all have our moments like that. Just be glad it wasnt something expensive

Andrew_99_GST · Feb 20, 2015

Well misfires are still here with the new power transistor. I adjusted my deadtime, because I suspect it was really far off. it seemed to make the misfires go away at first. But today, they came back. I'm going to drop my gap on my spark plugs. I wonder if the gap is too big at 0.28 with a decent amount of mods (only running 14 psi, though).

Andrew_99_GST · Feb 26, 2015

Well smaller gap didn't work. Nor did changing over to speed density. Really lost now. Just as an update
Things replaced-
Fuel injectors
Power Transistor
Spark plugs
Coils
Wires
MAF
CAS
CPS
Things checked-
Fuel transistor
ECU
Wiring
Timing

Really running out of ideas here. I am most likely forgetting things I've replaced or checked.

snowborder714 · Feb 26, 2015

At this point, I'd just uncheck the misfire DTC box in link.

Andrew_99_GST · Feb 26, 2015

snowborder714 said:
At this point, I'd just uncheck the misfire DTC box in link.

I don't get the CEL for it. So it may not be misfires, but I get a really bad shudder. I always assumed it to be misfires, but it may not be. Could it possibly be clutch?

The car is very hard to drive more then 10 minutes like this. I don't get it until the car warms up, and then it's very intermittent.

Chumpaumpalumpa · Feb 26, 2015

Try fuel filter or check your re-wire.

Andrew_99_GST · Feb 26, 2015

Chumpaumpalumpa said:
Try fuel filter or check your re-wire.

Yup forgot to add that. Did the fuel filter. The fuel pump is kicking on correctly

Andrew_99_GST · Mar 16, 2015

Tried changing the fuel transistor. Not sure what my next step will be.

Andrew_99_GST · May 25, 2015

Just incase someone has this problem again, what fixed my problem was unchecking the "use non-95/96 cam angle sensor) box in ecmlink.

snowborder714 · May 26, 2015

So do you have a '97 ECU converted to EPROM? I seem to remember you saying you have a stock CAS, which I'm assuming is the 2gb version on the passenger end of the intake cam.

Andrew_99_GST · May 27, 2015

I'm pretty sure it's just a 95 EPROM ecu. And yes the stock CAS.

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