Intermittent cut out with check engine light

M

meanchicken

gallo vicioso
Joined
Oct 6, 2007
OK...this is on my nerves. I need to solve it before the 31st because I'm going to the track to finally find out what kind of reaction, 60, 1/8, 1/4, mph I can eek out.
I've also been smack talking a couple Camaro buddies so I have to be there to put up or shut up.

When the engine is good and warmed up (180-210) this gremlin occasionally shows up.
The car runs, drives and idles normally, but as I lightly accelerate under part throttle and light boost (approx 5lbs) the engine will cut out real quick....sometimes one...sometimes 2-3 times back to back, and the check engine light will blip for as long as the cuttin out takes place. If I continue driving, the problem will come back and go away....it might be gone for a couple weeks, a couple days....or do it the next day....

At WOT it pulls good, but if it catches me going to WOT (rolling into it) and does the cut-out, I'll get a slight pop outa the intake. It did that today, so now I'm writing.
It seems to be igition related.

02's are good, fuel pressure is good, TPS is good, IAC is good (at keast at idle it is), volts ar about 13.2 with the headlights on and 13.4 without, new plugs, new wires, what else can I tell ya.
Help please!

Coil pack?
Ignition module?
ECM?
Alternator?

Thanks!
Tim
 
sounds like an intermitent short...I had a similar scenario occur when my TPS/5v source was being shorted....
 
Check the main power mine would do the same thing with the check light blinking it turns out that my poitive from the battary to starter was pinching when I would transition to wot
 
Check the orange wire going from battery to ECM to make sure the connector has a good, tight connection. Check to make sure there's no burnt/melted wiring under the hood. Also be sure to check all your grounds. Check around your headers and downpipe to make sure that as the engine moves nothing is shorting out against them. Do you have any malfunction codes? Also might be worth it to try monitoring different things on the Scanmaster (as opposed to O2s and KR all the time for example) to see if anything looks abnormal while the car is acting up and post it here to help us out.
 
dank GN said:
Check the main power mine would do the same thing with the check light blinking it turns out that my poitive from the battary to starter was pinching when I would transition to wot
Click to expand...

This is a possibility.
I just replaced a busted motor mount ....engine was wobbling all over the place....maybe my batt cable got killed before the motor mount was fixed....

I'll have to climb under there and check things out.
 
JST A 6 said:
Check the orange wire going from battery to ECM to make sure the connector has a good, tight connection. Check to make sure there's no burnt/melted wiring under the hood. Also be sure to check all your grounds. Check around your headers and downpipe to make sure that as the engine moves nothing is shorting out against them. Do you have any malfunction codes? Also might be worth it to try monitoring different things on the Scanmaster (as opposed to O2s and KR all the time for example) to see if anything looks abnormal while the car is acting up and post it here to help us out.
Click to expand...

No mal codes. It happens too fast for them to register.
Orange ECM wire seems OK
No apparent burnt wiring.....
 
Another couple of things I just thought of--check the wiring harness along the side of the driver's side valve cover. There's 2 wires hanging loose from it, one for the fuel pump and the other for a tach signal. At one time my tach wire hung down and was touching the driver's side header and it melted through the insulation and the bare wire was touching the header intermittently which was causing a problem. The other thing is if you still have your EGR valve on the engine, if the #1 and #3 fuel injector wiring isn't tied up away from it it could short on the hot EGR valve. This normally just causes one of those cylinders to go lean due to the injector not getting a proper signal but you never know if it could affect the ECM in other ways.
 
JST A 6 said:
Another couple of things I just thought of--check the wiring harness along the side of the driver's side valve cover. There's 2 wires hanging loose from it, one for the fuel pump and the other for a tach signal. At one time my tach wire hung down and was touching the driver's side header and it melted through the insulation and the bare wire was touching the header intermittently which was causing a problem. The other thing is if you still have your EGR valve on the engine, if the #1 and #3 fuel injector wiring isn't tied up away from it it could short on the hot EGR valve. This normally just causes one of those cylinders to go lean due to the injector not getting a proper signal but you never know if it could affect the ECM in other ways.
Click to expand...

Thanks!
I appreciate the extra thoughts.
I'll check this out also.
 
hey chicken. I had a similar issue, but yours may be something harder to figure out. My coil pack nuts (the 3 little ones underneath) were loose. When I would hit the gas, the coil pack rocked just enough to not make a good ground (grounds to the bracket and plate its on) and would cause the car to jerk/cut out/check engine light blinking. I tightened them up, along with running an extra ground strap directly to the bracket. Good luck, and kick some Gaymaro A##!
 
Could be an intermittent open circuit in the ecm
 
MC,

If the ce light flickers, I would look at ecm and chip connections. Cycle the plugs in and out the ecm a few times. Remove the chip and clean the leads. Use a pin to slightly pry the ecm prongs out so they make a tighter connection.

If the problem still persists, try a different chip.
 
Few more things to check.

- Main wiring harness grounds on the back of the passengers side cylinder head. Make sure they are not loose or broken.

- Alternator charging wire that runs from back of alternator under front of motor, up to the battery. Check the wire underneath the motor for signs of oil soaked delamination of the wire and possible grounding out on crossmember.

- Main wiring harness that routes behind the drivers side head. Make sure that it's not rubbing on the course thread bolt that sticks out into the engine bay. Been there, done that, blown fuses 4 days in a row. Sigh....

- If you car is a T-Top or Moonroof car, you could possibly have water leaking into the car, down onto your ECM. Disconnect orange ECM power wire at battery, pull out the ECM from passengers side kick panel pod. Carefully disconnect each wiring harness plug from the ecm, checking for signs of corrosion on the pins and connectors. If all dry and no corrosion, and all pins are there, you're good.

- With you saying you just went through a motor mount fiasco, check your battery cable that runs down to your starter. Look for signs of cable rubbing on header and or downpipe.

- With regards to your TPS possibly wiggin out, if you have a scanmaster, put it up on your dash, turn it around so you can see it while under the hood. Key on, car off, put Scanmaster on TPS. Now, by hand try to duplicate your operating condition when the miss/hickup happens. While watching your TPS numbers, rotate the throttle at different speeds. The numbers should be rock steady and not fluctuate. Meaning, they should steadily increase the more you crack the throttle and stop when you stop. If you stop and the numbers start dancing, R&R the TPS sensor.

- Grounds, grounds and more grounds. Check them all. With these cars being 23 years old, all of the underhood wiring has taken a real beating with our underhood temps and heat soaking. Wires become brittle and eventually break. With you having a motor mount go kaput on ya, I would suspect a loose wire somewhere that only shows up once underhood temps heat up, and the harness loosens up.

With what you are describing, it definitely sounds like an electrical gremlin happening. Over the years, I've had to deal with all of these above issues/checks on not only my personal cars, but friends cars, and I know how frustrating issues like this can be to diagnose and trouble shoot. Hang in there, you will find it.

The last thing I would check, would be the cam sensor cap.

- Check the 3 wires on the cam sensor cap for signs of cuts, fraying, or breaks. If good, pop the cap off the housing. (Two small phillips head screws) Inspect the magnet underneath the cap for signs of cracks or looseness with your finger. Don't break it tho. If it's cracked, you will be able to move it very easily with your fingertip. If cap checks good, check the interupter ring on the cam sensor body itself. Make sure the screw is there and tight. If that's good, then it checks fine.

Give us a run down on what sensors and electrical components you have replaced within the last year.
Hope some of this helps a little.

Patrick
 
Already stated but I'll state it again... Check the ECU wires...

Also, pull the connector that attaches to the Ignition module under the coil pack. Pull away some of the tape/wrap and check the condition of the wires. Some time ago I had an issue like you describe and when I pulled the tape back, I discovered that a few of the wires has stripped insulation. Don't ask me how but, it was causing a short. I fixed it and never had an issue again.

Good Luck.
 
i know this one. my car was doing the EXACT same thing. the battery cable was rubbing on the exhaust.
 
I've been there....... as mentioned above.....check the positive battery cable out going to the starter......under acceleration...the engine rocks over.... and if the cable is too close.....the header will burn through the insulation and short out.......once it shorts......the engine bucks....and rocks back the other way......unshorting it........ my DS log (18 frames per second) would only catch maybe 2-3 frames of "0" voltage......then it was all back to normal.........
 
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