Bucking and surging all of a sudden?!

[TURBOTIMMER]

Take your serp belt off and check your harmonic balancer. That big ass bolt that holds it to the crank has a way off working itself loose. If it starts walking out, your crank sensor will loose its signal, causing all kinds of misfires.

 

[TURBOTIMMER]

double post

 

[Scott Atk]

Can someone post a screenshot of the log please? I haven't been able to get my Powerlogger to work on my new computer yet. Thanks, Scott

 

[dsapper]

Harmonic balancer bolt was checked and crank and cam sensor were changed a couple weeks ago, was driving great after that.

Funny thing scott, right after I told you it was running great at the show it started doing this lol...

This is the screen shot of when I drove it up and down the block at 25mph or so, the wideband is crazy on it, afr is jumping from 9ish to 16ish very quickly

 

[dsapper]

Harmonic balancer bolt was checked and crank and cam sensor were changed a couple weeks ago, was driving great after that.

Funny thing scott, right after I told you it was running great at the show it started doing this lol...

This is the screen shot of when I drove it up and down the block at 25mph or so, the wideband is crazy on it, afr is jumping from 9ish to 16ish very quickly

Here is the two back screens when its at 9afr and 16 afr

 

[StageII86]

Have you re-checked the crank and cam sensors since this happened? When it is a control issue this large with no code that's usually where I'd start. Other than that, is it possible anything could be intermittently grounding out? Also maybe try seeing what happens in batch fire?

Slit in a I/C hose, cracked I/C, etc... are other things I've personally experienced that can sometimes hide but cause similar issues on a MAF car.

 

[dsapper]

I pulled the intercooler hoses all off and reattached them earlier. Cracked I/C I'd hate to think about.... How do you actually check a crank and cam sensor without just putting in a new one?

 

[StageII86]

First just making sure both are snug and the cam sensor hasn't moved or anything. Crank sensor has proper clearance to ring, etc... For an intermittent problem like you're having, my guess would be to try another crank sensor. But if visually all looks okay then I'd wait to actually do that. If it's on properly, my experience has been they work or they don't. I just thought it might be good to check since it was worked on recently.

Had an i/c crack at the seam between core and tank once and couldn't see it on the car... Didn't find it till I "pressure" checked the boost side of everything.

 

[earlbrown]

To check the cam sensor, start the car then unplug it. That way if it's acting like a douche while driving, with it unplugged it can't mess with you.

 

[dsapper]

Just did that. Still does it with the cam sensor unplugged

 

[Mike Licht]

try a fresh set of spark plugs, that fixes lots of little problems like this

 

[Scott Atk]

Verify all your grounds on the back of the passenger side cyl head, or did you relocate those? don't remember. Also check the pos batt cable, you've put just enough miles on the car that if it was run too close to the header it would just now start to show itself.

 

[dsapper]

Verified them Scott, all ohm out good. BUT I go through the trouble to change out the spark plugs (whoever put that heater box there should be dragged into the street and shot), started it up and now throwing a code 41 for a cam sensor... wtf. That thing is like 3-4 weeks old

I think I have another one at hackers or at my business but I pulled the cam sensor plug off after it started and it still runs like crap... now I'm getting confused.

 

[dsapper]

Ok put in a working coil pack and ignition module and a working cam sensor... same issue

 

[Scott Atk]

How are you setting the cam sensor?

 

[dsapper]

Setting it? I didn't even know you could set it?!? I just changed the cap, could the whole distributor part be bad?

 

[TurboBuRick]

Pull cap off the cam sensor and check the wheel. It's keyed to the shaft by a small tab and should not have any slop.

What brand cam sensor cap did you use to replace original?

Rick

 

[dsapper]

Fixed it! You were right TurboBuRick. The camshaft sensor and cap were fine but the wheel that the sensor reads off of was loose and sloppy. Few turns of a screwdriver and she is back to normal.

Thanks for everyones help, was getting very annoyed

Observation though. It was suggested here, and I've read elsewhere, that if you disconnect the cam sensor thats a way of seeing if its defective. Even after I unplugged it and it was loose it still ran horrible... Maybe that advice isn't sound in all cases

 

[whitehot1]

Glad you got it fixed.

I think i will check mine before i go out driving again.

 

[Franks86gn]

The cam sensor is only used on startup to fire the injectors. So it wouldn't matter if it was unplugged after you start the car. If I'm wrong, someone say so.