Bucking and surging all of a sudden?!

[dsapper]

Had the car dialed in... finally. Set at 22pis and ran amazing. Alky installed, all the sensors were set etc etc..

Drove it today and it was driving amazing. Stopped at a car show of all places and on the drive home I noticed a weird hickup in 6th gear, would be chugging along fine at 2000 ish rpm then bog and return.. thought it might be my tranny setup since Ive been tuning it. But it got worse and worse and worse until it started stumbling in all gears, worst off idle. It even does it when in neutral.

Fuel pressure is right, all the readings on the scanmaster are correct, o2's are good, seems like the maf is good (85mm z06 with translator). No hoses I can see disconnected under the hood, no check engine light or mal codes on the scan master.

Any ideas? I'd guess fuel pump or something but the fuel pressure wasn't moving even when it stumbled

 

[buickGN3:16]

possibly check the connection of the chip, pop it out & back in to be sure.


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[dsapper]

ok I'll do that, chips just pop out though?

 

[buickGN3:16]

yep, kinda pry it up from one end, gently


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[dsapper]

Thanks, but that didn't do it

 

[buickGN3:16]

ok id try unplugging 1 injector at a time with car idling & see if the engine changes as u unplug 1 injector @ a time.. Just incase.. possibly 1 stuck open or not opening causing a stumble


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[dsapper]

ok I will. Also the idle is hovering at 1000rpm for some reason

 

[buickGN3:16]

yea thats a tad high, mine idles at 825 or so.


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[we4Mateo]

What ignition system do you run?

 

[dsapper]

Stock system. New coil pack, new plugs, new wires, ignition coil, camshaft sensor, crankshaft sensor. Replaced them 3 weeks ago when I was chaseing a no-start issue, turned out to be the camshaft sensor.

I do have a powerlogger with wideband but I don't have my laptop here, I left it at work

 

[we4Mateo]

Hmmm, hard to tell without logs while it's doing it. Sorry. Sounds like everything is new at least but that doesn't mean it couldn't have gone bad still.

 

[dsapper]

Yeah, new parts being bad is a common theme with me these days it seems... Hope thats not it. Any what to test out the iac and maf with a multimeter or something?

 

[we4Mateo]

Yeah, new parts being bad is a common theme with me these days it seems... Hope thats not it. Any what to test out the iac and maf with a multimeter or something?

The log should show if any sensors are dipping out while it's doing it. I have ignition problems a lot it seems so I gravitate there first but each of these bastards is different. I even blew a coil on my new TR6 setup already!

 

[dsapper]

hmm ill get a log tomorrow then. Better than guessing.

 

[dsapper]

ok, here are the two logs. The first is me in neutral hitting the gas, it does it there as well. The second I drove down the street upto about 25mph and flipped around and came back... doing it horribly. Looking at the logs my wideband looks like its having a heart attack

 

[dsapper]

anyone? Trying to figure this out today if its something simple

 

[buickGN3:16]

Sorry man, outta my league with files. id just be guessing!


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[2QUICK2B6]

sounds like cam sensor could be going out ... loose vac hose ... or coil pac or moduel

 

[dsapper]

Well all three of those are brand new and the hoses look fine. That's why I was hoping someone could look at the log

 

[2QUICK2B6]

cam sensor adj proplerly ? new parts can be bad or defected ..... ill never buy a rem mass air flow metter