Misfire and Lost Power Problem!

[Black92GST]

I was driving down the freeway, and all of sudden I didn't make any boost and It took a lot of throttle just to keep the car at a constant speed. I thought I blew an intercooler hose. So I pulled over.

As I was pulling over to a stop, the engine died. I tried to start it back up, but the idle was lower and the engine was rocking back and forth very roughly. (Made worse that the engine mounts are worn). I had it towed back to my house.

I started up the car again, and checked all the connections to see if anything was loose. I then pulled each plug wire to see which cylinder was misfiring (I don't know how professional it is to do this, but oh well.) Anyways, when I took out the plug wires for cylinder 1 and 4, the engine died. But when i took out 2 and 3, the engine stayed the same (idle speed and roughness). So the problem is somehting to do with these two cylinders.

Well, I noticed that both cylinders use the same coil pack. But I also got shocked when I took out the wires (worn insulation ) So it is getting spark. Maybe It wasn't enough spark? I never was hit by a coil like that, but it wasn't too bad.

Where to start? Maybe...

Check spark plugs?
Get new spark plug wires?
Check compression?
Check voltage (batt and alt)?
Connections to Cam and Crank Sensors?
Swap known good coil pack?

Please help, I'm gonna need it
Thanks

 

[grnchevyz]

check your coil packs resistance would be the first logical place to start. A dying coil pack will still jolt you but could not be providing enough to fully spark.

Sounds like you lost 2 cylinders for sure, I'd bet on a bad coil pack...

Edit: Oh and I mean check for coils 2-3 seeing as they did no change when pulled.

 

[heckles]

Im having similar problems, only its not constant. My problem is that an injector will suddenly stop working although its getting an injector pulse. then go back to working and running fine.

 

[MrCotinTail]

i agree with the coils suggestion i just fixed that same problem on my buddies car. he thought the turbo went up. i checked it out he was missing to cylinders, i took and old coil i had on hand raplce it and bam he was back in business

 

[Black92GST]

I'm back to working on my project car, so here it goes:

I checked both secondary resistance and primary resistance of the coil packs and they were both ok.

I also changed the spark plug wires to new ones.

But I still am missing two cylinders.

Where do I go next from here?

 

[94dsmgsx]

I just bought this 94 gsx completely stock and cylinders 1 and 2 are not running. I checked my ignition on those two cylinders and I'm getting a spark so I switched injectors from cylinder #3 to cylinder #1 and still no fuel coming out of the injector on #1. Please help I'm really confused.

 

[EagleTalon1993]

For Black 92GST, I had exactly the same issue with my Talon I pulled the coil pack out to do a visual inspection after all the tests came back fine for both primary and secondary resistance and BAM, in between the towers for #2 and #3 there was a huge charred area where there had obviously been some arcing. turns out the insulation on that side had worn out (tests will not show that kind of wear).

What caused the entire issue was a bad ground from the engine block to the frame, I had to replace the coil pack power transistor and I added an extra ground from the coil pack and power transistor to the firewal as well as replacing the ground strap to the frame from the engine block.

Sorry this is so long but I just went through that recently.

 

[EagleTalon1993]

For 94dsmgsx, I would say CAS (Cam angle sensor) or leaking caps on your ECU would be good places to start.

 

[Black92GST]

Thanks for the response eagletalon1993!

anyways, before I saw your post, I read other threads with similar problems as mine:

1. I checked the wires going from the coilpack to the PTM and they were fine

2. I tried a known good PTM and I still had the two cylinders problem

After reading your post, I checked the coil packs out of the car but there was no visible charring or damage. That being said, how did you add a ground to the packs and transister module?

Also, I think I have to maybe start looking back from the module to the ecu (I'm guessing thats where those 4 wires go) and check the ecu itself.

I also checked the black wire on the transister and it was a good ground.

 

[Black92GST]

Well, I was at it again today

1. took out the ecu to see if any problems like capacitors leaking - the ecu was fine

2. checked continuity in the yellow/red wire coming from the middle connector (supposedly, it goes to the transistor #2 and #3 coils) - and it was fine. .2 or something low ohms.

I'm pretty much stuck now. I'm just about to put everything back together and take it to a shop. unless someone can help.

 

[94dsmgsx]

Well, I was at it again today

1. took out the ecu to see if any problems like capacitors leaking - the ecu was fine

2. checked continuity in the yellow/red wire coming from the middle connector (supposedly, it goes to the transistor #2 and #3 coils) - and it was fine. .2 or something low ohms.

I'm pretty much stuck now. I'm just about to put everything back together and take it to a shop. unless someone can help.

Before you take it to the shop, this may be a fuel problem not a ignition related issue. I would test the CAS. Here is a link for you. when you spin the back side of the CAS by hand you will here the injectors clicking, which means they are firing.
http://www.dsmtuners.com/forums/problem-diagnosis/238267-cas-diagnosing-steps.html#post50470620

 

[Black92GST]

well i did more searching on this forum to see what other people did to solve their 2 cylinder issues

1. I wiggled connectors (especially PTM and coil connectors) with the car on - no help

2. I put the ecu off the bracket and not touching any other metal - no help

I also checked the spark again on cylinder 2 and 3, and it seems as if it's "not sparking fast enough". There is spark, but lets say:

600rpms = 10 sparks per second. but then again is it a waste spark system??????

so I should see 20 sparks a second?

but anyways, the actual is I see like 2 sparks a second ish. So it's not sparking enough for some reason.

I also used a long extention to see if i can hear the injectors pulsing and they are for all cylinders. so it should be getting fuel, just not sparking enough

so............

1. cam sensor?
2. crank sensor?
3. ecu?

 

[Black92GST]

actually, i read on chilton that the cam shaft position sensor (and crank probably as well) helps the computer decide when to fire the injectors.

so it has nothing to do with spark.

something that might have to do with it: The engine when starting turns over very slowly. as if i didnt have enough voltage for the starter. but unlike low batt voltage, the engine does start up everytime, and quickly. Does this have anything to do with grounding of wires?

EDIT: I found a thread on dsm talk and there was one guy who had the same problem, and he found out the ecu was bad even though there was no visible damage to the ecu. of all the people who had this 2 cylinder problem, this seems like its the same as mine

 

[Black92GST]

WHOOPS! I didint see 94dsmgsx 's post before mine!

I'm going to test the CAS tommorow

 

[Black92GST]

well I tested the CAS today:

1. I checked the red wire at the harness and it got 12v with the key "on"
2. The ground wire was good

3. I took the camshaft sensor out while connected and key "on" and turned it. For every half turn (180 degrees) of the sensor, I heard one click. I was turning it pretty slowly. So for every full turn of the camshaft, I heard two clicks.

is this correct? does it matter how fast I turn the CAS?

 

[94dsmgsx]

As far as I understand, You just have to make sure all four injector's are clicking. I'm not sure if it's within one turn or more.

 

[94dsmgsx]

By the way, like Steve had mentioned in the link I gave you above, If you have a multimeter the plug going to the CAS has four wires. One of them is power, one is ground, one is the input for the cam and one is for the tdc. You need to check the cam wire for four pulses for every one Revolution of the CAS.

 

[Black92GST]

here we go:

4 wires going to CAS

1. black (ground) - read 27.8 ohms - not that great of a ground
2. red (power) - 12V
3. black (input?) - did not read anything (0V) with one full revolution of the cam
4. white (tdc) - pulsed twice (5V) per cam revolution

according to the link 94dsmgsx gave, the guy said it was supposed to pulse 4 times per revolution on the black input wire?

by the way, I got the readings of #3 and #4 by back probing the harness side of the connector.

so the black input wire is not getting the right readings? which pin does this correspond to on the ECU? I found out that the white tdc is pin #22
http://www.dsmtalk.com/gallery/data/500/Drawing2_Model_1_.jpg

I know, that's from dsmtalk.com, but I found it by googling.

I need to know what pin it is so I can do a continuity test on it from the cas to ecu. then I can see If it is the cas's fault or something else.
also, the ground is not the greatest....

Edit: Since I back probed the connector, I guess the wire going to the ecu has nothing to do with it. If it is a "input" to the ecu, then I should get the value I need from just the CAS (since it gets power from the red wire).

so, the CAS is the problem. I think. I still kinda want to know where the black input wire goes - to the ecu? or somewhere else?

 

[Black92GST]

update:

1. swapped the CAS - didnt help

2. swapped ecu's - didnt help

so....

only other thing i can think of is the fix that 94dsmgsx had in his car - the fuel injector resistors. that silver metal bracket with 5 wires on the firewall left of the cruise control. except in his case, a the wires were chewed up by some animal. my wires look fine.

can these fuel injector resistors go bad on their own with age? has anyone else had this part go bad on them naturally?

still stuck...

 

[TSIMonsteR]

was this problem ever resolved?

 

[zack13277]

Did you ever get the problem fixed my car just started this same problem today

 

[primo513]

I had a problem when i first tried to tune my car. I had no idea what I was doing and I installed v3 in a 91 tsi awd. I started it up and had to keep giving it gas at idle just to keep the car from stalling. I took out v3 and put the stock ecu back in and car ran like hell. It would misfire over 2k rpms and had practically no power. found out I ended up blowing one of the injectors or something or fried one. I replaced the injectors and the car ran perfect again. Im not sure if you've checked anything to do with the injectors, but I had a heck of a time with a similar situation because one of my cylinders weren't firing. Could potentially be a similar problem with the injectors. At least something to look into.

 

[zack13277]

Yeah I'll try to check my injectors, I think I'm getting spark because when I pulled off the spark plug wires individually it ran equally as bad on all of them. I'm going to try replacing the fuel filter also.

 

[primo513]

Yeah, the injector I had was pretty much stuck shut so it was misfiring extremely bad

 

[zack13277]

How can you tell if its stuck shut? I don't have DSM Link, is there anything visual? Fuel filter didn't help at all and all the injectors ohmed out at 2.5 ohms.