Heres a good one... Im stumped?

[gndoug]

Hopped in the buick to go for a drive. Everything was fine, car was running great. Went to hop on the freeway... It pulled fine onto the freeway, but when I was merging I had to let off the gas to slip inbetween cars. I went to pass the car infront of me and.......
put put put... fart... put put. faaaaaaarrrrrrrrrtttttttt

I took the next exit, barly able to keep 60 mph.... and limped it back to the shop. It bucks, and farts under load and no load. Sounds like ignition is cutting out. Here are all the things I have tried.

Unplugged and Drove:
Cam sensor
Air flow
Coolant
Egr Solenoid
All at once

Same thing every time.

44 psi fuel at idle.

Swapped ignition module and coils with another good (actually... great) running car. - Same thing

Swapped ECM's - same thing

Swapped with same chip off another ECM- same thing

The thing runs PIG rich, and when I whomp on it, and it bucks, it shoots fire out the tail pipes... kinda cool, but not really.

I guess tomorrow at work Ill hook the crank sensor up to the lab scope and check it out. But it seriously just happened all at once. One second everything was running tits... the next....

If anyone can think of ANYTHING else, input is greatly appreciated. But im kinda figuring its going to be the crank sensor. I figure even if that is what it is, mabye this post will help someone else in the future to figure out the problem their car is having.... I guess we'll see.....

 

[Blown&Injected]

All that stuff you did and the first two things that poped into my mind you did not check - and it is easier stuff to do too.

1) Maybe you popped off an intercooler hose.

2) MAF sensor

I have never had much luck with the tap test on the MAF, and when I have unplugged the MAF to see if there was a difference the car drove different even though the MAF was bad - seems like the scan tool was showing some reasonable gps numbers too even though the MAF was bad.

 

[Rodney87GN]

MAF sensor....try swapping it with a known good one.

Your symptoms sounded just like mine when my stock MAF died, plus I could verify it with Directscan. I could watch the LV8 and MAF max out at 255 and injector duty cycle went from 3% to 25% as soon as it started bucking and stuttering....this is while doing 30 mph and no boost!

Installed an LS1 MAF and Translator...works great now.

 

[turbobose13]

I agree with jolly, sound's like the Maf, and never tap the Maf with a screwdriver or for that matter anything. Good Luck.

 

[49-blues]

How about bad gas or water in fuel?

 

[Brer Rabbit]

Sounds like headgasket season

Similar thing happened to me yesterday. Maybe its the weather that makes it easier for these things to happen. Hope its something simple. Im checkin mine out in a few hours.

 

[1BUICKGN]

You also might want to check your alternator voltage to make sure it is working.

 

[mikestertwo]

Sounds like MAF. That's usually when they go, letting go of the throttle real quick under boost. The air inversion (reverse flow through the MAF) will ruin a stock style MAF pretty quick.

 

[rodman99999]

If it's not your MAF: Try another chip. I had one go bad in my '85, and it ran as you describe in the "limp" mode.

 

[notacarlo]

I second and third the MAF. - I can quite clearly picture exactly what happened to you cuz it happened to me many times.

Pig rich is an understatement.

 

[gndoug]

right on everybody. I didnt get a chance to check out my car today, but tomorrow I'll try swapping out the MAF. I tried driving it with it unplugged, and it still ran like poop, but stranger things have happened. I tried another chip, and another computer, and another computer with another chip.... so ive pretty much ruled out that its a computer problem. Plus swapping the maf is easier than swapping out the cps.

 

[URSPANKED]

Don't forget to check those intercooler hoses, too. They will bite ya.

 

[TurboTnZ06]

This happened to me recently, In fact I have to tear the timing cover and oil pan off to fix it. Pull the cam sensor out and see if the gear has fallen off because the shear pin is broken. I go the loud backfiring too. Only way the car would run was idle and full throttle. Also, the oil pumo is driven off this gear, so I also drove with no oil pressure. Guess that means my idiot oil light doesn't work either

 

[DonnieShort]

Don't forget to check those intercooler hoses, too. They will bite ya.

I agree, the step down hose from the turbo to intercooler is notorious for splitting in the middle of the step down part. Happened to me a few times in the past and will do exactly what you are describing.

One thing I haven't seen you say is has it thrown a code?

 

[87we410877]

Also, check your O2 sensor. I had a similar problem, running pig rich and like a 383 with a hairy cam. O2 sensor was bad. I have a wideband heated O2 and a fast, but you may have the same problem. Who knows. Love your sig. by the way. LMAO. !!!

 

[VadersV6]

Sounds like MAF. That's usually when they go, letting go of the throttle real quick under boost. The air inversion (reverse flow through the MAF) will ruin a stock style MAF pretty quick.

How would reversion hurt the MAF? In the case of a stock TR MAF that uses a strain gauge to measure airflow (the technology world has just gotten on board with strain gauges for precision measurement in the past 8 years or so...GM was using this over 20 years ago)..anyway, if you clean the MAF and push on the strain gauge, wrinkling it or stretchin it in ANY way, it will never be right again. Ive looked at my stock MAF, and the strain gauge is totally wrinkled up. It should be perfectly flat and stiff. About 8 years ago we designed and I built a little portable robotic strain gauge calibration machine, that would use an ultra fine lap compound to polish the strain gauge thinner...an order of microns. Polish it slightly thinner and the readings will totally change.
As for air blowing across it in the opposite direction, it will in NO way damage it. All it can do is throw off readings a bit. Ford MAF's are designed to only allow air to flow in 1 direction across the MAF thermode.

 

[SPOOLFOOL2]

How old is your timeing chain? I wonder if it sliped a tooth or more. Let us know what you find out.

Good luck

 

[gndoug]

I still havent worked on my car.... hahah.. But its not setting any hard codes, and timing chain is about 5k miles old. I figure its not a mechanical problem... About 5k ago I did a valve job, lt1 springs, cam, lifters, timing chain, high volume oil pump... and a few other things. Basically the spring cleaning....

 

[mikestertwo]

How would reversion hurt the MAF

Try putting a stock MAF in backwards, start the engine, and then put it in correctly and try running the engine again. Guaranteed, the MAF will be toast!

 

[Quick6'n'-K.C.]

Try putting a stock MAF in backwards, start the engine, and then put it in correctly and try running the engine again. Guaranteed, the MAF will be toast!

I know what this does, it will make the car run extreeeeemly rich at idle and blow black smoke out the tailpipe.

It happened to me one time...

The maf wasnt hurt one bit, actually still has 99,939 miles on it.

Why would you post this, and the other post???? Heck my stock setup has at least 1,000,000 reverse air thru the maf and running fine.

Not trying to be rude, just wondering where you got your facts from?
BW