Backfires, Rough Idle, Missing.

[SHOspazz92]

For the track car...

First off, I have not ran the codes. However I was hoping a breif description could get the juices flowing....

The Plugs, wires, coilpack...etc all work fine. The Symptom does not chance if the MAF is plugged in or not.

What happens is the CE light will come on yet the car will drive fine. Then under load the car will start missing and surging. I have more then once tried turning off the engine while the car was rolling, then tried to restart it. What I get instead is the car not starting and a Massive backfire.

If your sitting at Idle, the car will start idling really rough (Imagin a .600 Lift Cam in a V8). The CE light will come on, the car will smooth out, then the CE light goes off. This will happen about 4 times until you let it run for a while and it smooths itself out.

If you while your sitting at idle and it starts go all crazy, the car will have big problems trying to restart. Generally the motor will just turn over via the start, a backfire or two then nothing. When it does eventually restart, there is NO tachometer and a CE light. 30 seconds or so later the tach will start to work.

The car had these issues not to long ago and I replaced the CAM sensor, this seemed to fix it. However, its back. FWIW, My cam seals are not leaking.

Any Ideas?

-Sam

 

[zach44102]

Back fire = unburned fuel. Have you changed the plugs? I know you said they are working properly but under load they could have a harder time burning the gas/air mixture.

 

[boat]

I say failed cam sensor. With all the weird idling, it sounds like it doesn't know how to time itself.

Maybe the cam sensor you replaced just failed, that is possible. Try replacing it with a known good one and see if that takes care of the issue.

 

[vortex2450]

It has to be a sensor, or somewhere in the process of events in the electronic timing system of the ECU circuitry.


-Josh

 

[zach44102]

IIRC he said he changed the cam sensor already. But that could be the problem.

 

[kevinspann]

Or the wiring to it...

Sam, got any codes?

 

[SHOspazz92]

I'll have to pull the codes. I don't have a code reader and I don't remember how to do it with a paper clip. SHO phoenix project is down as well.

-Sam

 

[kevinspann]

shotimes....

 

[SHOtimer]

I'll have to pull the codes. I don't have a code reader and I don't remember how to do it with a paper clip. SHO phoenix project is down as well.

-Sam

http://www.shotimes.com/php-bin/mod...le=article&mode=thread&order=0&thold=0&sid=83

:wave:

Doug

 

[SHOspazz92]

Thanks. I should also mention that I drove the car home from work today with absolutely no issues. Idled great, started easy, went to 8,000 RPM with no issues and I even sprayed a little Nitrous through it.

D'oh!

-Sam

 

[TimboSHO]

With the tach not working, it makes me lean towards cam sensor as well. The only SHO I've had backfire needed a crank sensor though..... Checking the codes should steer you in the right direction.

 

[SHOtimer]

With the tach not working, it makes me lean towards cam sensor as well. The only SHO I've had backfire needed a crank sensor though..... Checking the codes should steer you in the right direction.

I agree. Cam or crank.

The cam sensor in there, it is a Ford one, or aftermarket?

Doug

 

[SeanMc]

Check to see if the LPM is loose. Mine was doing something similar, even dying, and Marcel suggested this.

 

[typhoon5000]

The only time I've seen no tach is from a bad Cam sensor too...

 

[frosho]

I'm wondering if one of your DIS ground connections might be a little loose. Either that or the cam sensor wiring.

 

[SHOspazz92]

Meh, If somone would just buy the car I would be motiveated to fix it =).

I'll go through quite a few things when I find the time this weekend and report my findings.

-Sam

 

[msteiny]

Could be the cam sensor plug in on the wire side. Check the terminals to see if they are making contact with the cam sensor. I had to adjust the contacts on some of my connectors so they worked and some I had to de-pin and replace the whole connector. Got to love those little gremlins playing with the wires.

 

[oneqwicksho]

Had all the same problems is was the crank sensor. And is their any way water could have got in the plug wells?

 

[92inPA]

Sam,
First time I,ve been on the forum in months. Sad to hear you're having a problem with my old baby. Wish I could go for a ride in her again. As for your problem, it sure sounds like a crank sensor to me.

 

[SHOspazz92]

Sam,
First time I,ve been on the forum in months. Sad to hear you're having a problem with my old baby. Wish I could go for a ride in her again. As for your problem, it sure sounds like a crank sensor to me.

Bob, Its the only problem I've ever had with it. The car is still dead nuts reliable.

-Sam