Engine cutting out around 4100 rpm. Need help

flat tapet, or roller lifters? If flat tapets, they may not have liked the spring pressure from the new heads. Do you have a magnetic oil drain plug? If so, check it to see if it's covered with metal. If it's clean, then your cam should be good to go.
 
Huh, ask Eric if he sets up the chips differently for the Chevy maf's 3", 3.5" etc.
BLM's look low and maybe there's something there also with the IAC in the 10's at idle.

Might need to see if there's a # on the chip and contact Eric for his info on it.
 
Spoolfool2, I have flat tappet lifters, from GM. Don't have a mag drain plug, will dump the oil if nessesary.

GNVYUS 1, I put the chips and 60# motrons in about 3 weeks ago. Before that I had 42# injectors and a red Armstrong 93 chip. Had this combo when the car ran good for the 100 miles after I replaced the MAF. I thought If I upgraded the chip/injectors my problem would go away, I bought them used form a good source.

I'll get in contact with Eric. The chip has an orange sticker, says Don's Alky, 23. Given the chip doesn't say TT or anything, maybe the chip is unknown, and maybe I should just order a new one, set for my combo.
 
Positive battery cable going to the starter looks fine, not touching anything else. Tension er feels fine, moves a little at higher RPM's, normal looking.

I registered at turbo tweaks (Eric's)web site, haven't received the e-mail saying it's o.k. to post, been 3 hrs.
Injector PN is 4199002643 Morton's

Jacked up the front end, checked my torque converter bolts, were tight. Look around the underside, everything looked (and felt) tight.

Dropped the oil, looked okay, no amount of metal found, even ran a magnet through the drained oil, haven't cut the oil filter yet.
If it was a failing cam, wouldn't the problem be consistent at higher rpms? Re-guardless of the ramp up?
I did find out today, when the engine stumbles (in park at 4100 rmp), the boost gauge will jump up to 7-8 psi, maybe this is normal with this problem?
Get no boost pressure when engine is ran up to 5000 rpms, which I think is normal.

Any replies/advice are welcome.
 
Does your car just fall on its face? Does it pop or sputter? I'm going to assume that it's not just a bad vibration from something being out of balance. What kind of data recorder do you have? Does it go rich or lean when it does this? Just for the heck of it, make sure that you don't have a broken motor mount that's causing the engine to move and ground something out.

Not saying that I have the answer. Just trying to help.

Mike B.
 
Will the engine rev past 4100 at all??

I would check spark plugs, spark plug wires/grounding out, MAF in backwards, try another chip if you have.

Good luck,
Jerry
 
What is fuel pressure set at.
I know KevinB had a similar problem in Bowling Green this year.
I think it turned out it was too much fuel pressure.
Do you have an adjustable regulator on it.
Check fuel pressure with the line off.
Maybe KevinB will chime in???
It could also be a chip or ecm problem???
Good luck!
Jason
AffordableGN
 
Spoolfool2, the engine tries to rev up, but the sputtering won't allow it.
Doesn't kill the engine, engine will idle back down when I let off the throttle.

Just have a scan master, ver.2.1

Duplicating the problem in park, with a quick "stab" to the gas:
02-varies, 200-700 (when stumbling) KR-2-7 (when stumbling) will climb if I don't let off
AF-140
Lb-200
Bat-13.5
Int-128
Bl-124
Mph-00
Clt-168
Ats-136
Rpm-4250
Tps-3.64
Iac-53
CC-16- will climb
Mal-00

I have good motor mounts, both are H&R parts, in great shape.
Thanks spoolfool2

HellonWheels, car will redline (only in park) if I rev it a little slower then a "stab" I can bring it up to 5000rpm, and hold it there all day long with no problem or KR, but if under a load or I "stab" the trottle it will stubble around 4000 rpm in park. Going down the road under load it will start to stumble maybe at 3500rpm.

Have done all the things you listed, even have the extra gound going too fender, bell housing, a-arm bolt. Tried all the little things I can think of, but still have open ears for suggestions. Thanks

Affordablegn, fuel pressure has been all over the place, down to around 30# upto 50# and everywhere in between with line off, doesn't fix or make the problem worse.

I'm going to order a new chip from TT very soon, still I had this problem with the 42# and reds chip, then switched to 60# and a TT chip, thinking that will cure my problem, but it didn't. Thanks Jason.
 
b_rich, I haven't got this fixed yet. Haven't had the time in the last few days. Hopefully today I'll be able to do something, not sure what to do.

Anyone have any advice?
 
Head gasket

I have tiny air bubbles flowing in my radiator. Must be a head gasket.
I didn't see the bubbles before when this problem first occured, (and I looked for them) and with the solid compression check i dissmissed the head gasket.

Looks like I have a big job ahead of me.

thanks for the troubleshooting everyone.
 
The chip that I had was an older chip set up for when pump gas had higher octane than what is available now. So whenever I would get on the throttle the car would rev to so much and then fall on its face and the car would not accelerate any more. A ricer could have taken me out! The problem was the timing on the chip was too high for todays pump gas so the car was detonating and the computer was pulling back on the timing. It could be what you are experiencing and why you might have to replace your head gaskets due to detonation.
 
Not my thread but.....

I've had a popping (not detonation) in the intake everytime the boost would hit 10-14#'s-even with the alky going. Changed plug gaps, plugs, wires, ground wires, played with fuel and timing (T+, plus TT chip), new PCV valve, vacuum leak, all to no avail, then I removed the oil seperator that I had installed and bingo!! no more popping!


FWIW,
Jerry
 
Maybe I'm wrong???

Had my neighbor stop over to get a second opinion on the head gasket.
He brought with a test gauge to put on the radiator. Gauge went to about 9psi, (with engine warm) and fluctuated to about 5 psi. Took the gauge off didn't see any bubbles, except when engine is idles a little higher, which he said is normal. Bottom line, he thinks the head gaskets are fine.
I respect his opinion, he's been working on cars for 30+ years, although not turbo Buicks.

I will order a new chip from TT, if that doesn't fix the problem I don't know what to do.:confused:
 
I checked the head gaskets again, this time with an combustion gas tester.
Nifty little kit. Test was good, (ran the test three times). I'm now confident the head gaskets are fine.

I haven't seen the chip from TT yet, ordered Monday, don't know if it will help or not, at least I'll have a chip programmed to my car.

Don't know what to do next, suppose I'll double check the cam sensor for proper timing.

Anyone have any suggestions?

And to think I sold my 62 Impala SS convertible with a duel quad 409-4 speed, to fund the restoration of this car......OPPS! Guess I really (use to) like my Buick.
 
brent8487 -

I wish I could post up a suggestion or solution, but the symptoms you describe sound VERY similar (maybe identical) to what I've been trying to sort out on my GN off and on for 3 YEARS! I've researched these symptoms extensively on this and other turbo Buick boards. I've read numerous threads where similar symptoms were caused by all kinds of different problems. As for my car, the symptoms are completely intermittant and unpredictable. At times it runs abvolutely perfectly all the way through the powerband, then out of nowhere, it's starts the stumbling and "popping".

At this point I have literally replaced every fuel and ignition system component except the injectors and the main wiring harness. My next step is to do what I *should* have done a long time ago and get a good diagnostic tool other than the ScanMaster, which I already have. I'm planning to buy a PowerLogger soon and hopefully that will at least graphically show whats going on when the car acts up.

Good luck in diagnosing the problem with your car. I'd suggest some kind of diagnostic tool, like a PowerLogger or DirectScan.

Rob
 
cam sensor cup wheel

brent8487

Did you check the cam sensor cup wheel to make sure is has not moved or has broken the alignment leg off?

See if you can spin it with your fingers. I have had this happen twice , drove me nuts and it was a simple fix.

Den
 
Also check your tps. The number you gave on the stab was 3.6 something. I don't know if you matted the pedal when you stabbed it but it should show over 4.20 at wot to go into fuel enrichment. Also check to make sure that the voltage ramps up smoothly when the throttle is opened. May be running it lean.
 
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