Cuttuing in and out but not stalling...

[DiverDavies]

Started off 8 lbs of boost or so 1/2 throttle. car starts cutting in and out all of a sudden. Got a 34 code. Replaced the mass air flow senser w/ reman one from orilley. Cleared the computer. Started the car and iidleing is fine. Take it out and its still cutting in and out not as bad in the beginnig but after 10 miles or so it is hard to keep from stalling out all together.. no codes... Fuel pump, Ground, Bad new senser, I dont know????????? Please Give me some ideas to check Thanks I advance.

 

[turbojd]

Alot of those rebuilt stock mafs are terrible, most are not calibrated properly, roll the dice to get a decent one. I got sick of the rebuilt stock mafs and went the translator route.

 

[DiverDavies]

Alot of those rebuilt stock mafs are terrible, most are not calibrated properly, roll the dice to get a decent one. I got sick of the rebuilt stock mafs and went the translator route.

There is no 34 code w/ the new one. Is that possable?

 

[turbojd]

It's possible, do you have a scanmaster, what are your idle readings, what are your WOT readings.It's possible it might not be properly calibrated in certain ranges of the maf which will cause those symptoms. could be possible ignition module acting up when it gets hot, causing a sputter or miss.

 

[DiverDavies]

It's possible, do you have a scanmaster, what are your idle readings, what are your WOT readings.It's possible it might not be properly calibrated in certain ranges of the maf which will cause those symptoms. could be possible ignition module acting up when it gets hot, causing a sputter or miss.

iac= 19
tps=.43 4.22 wot

what others do i need to look at?

 

[turbojd]

iac= 19
tps=.43 4.22 wot

what others do i need to look at?

af readings at idle, and at WOT

 

[DiverDavies]

af readings at idle, and at WOT

Ill check it and report back tonight Thanks alot turbojd

 

[DiverDavies]

Ill check it and report back tonight Thanks alot turbojd

AF=04 after warm up driving around lil bit..
AF=255 wot

What does this tell you about what the motor is doing?

 

[#13TTA]

Started off 8 lbs of boost or so 1/2 throttle. car starts cutting in and out all of a sudden. Got a 34 code. Replaced the mass air flow senser w/ reman one from orilley. Cleared the computer. Started the car and iidleing is fine. Take it out and its still cutting in and out not as bad in the beginnig but after 10 miles or so it is hard to keep from stalling out all together.. no codes... Fuel pump, Ground, Bad new senser, I dont know????????? Please Give me some ideas to check Thanks I advance.

Dont know if this will help you or not. But if the MAF goes out then the car will not run. That is what I had happen to me one time. I also had the same problem you are talking about. check all vac. lines and intercooler tubes and TB tube ect.

 

[DiverDavies]

Dont know if this will help you or not. But if the MAF goes out then the car will not run. That is what I had happen to me one time. I also had the same problem you are talking about. check all vac. lines and intercooler tubes and TB tube ect.

Checked all of those All ok .. When it happened to you did it sputter but run or not run at all?

 

[turbojd]

AF=04 after warm up driving around lil bit..
AF=255 wot

What does this tell you about what the motor is doing?

I wanna see if the calibration is right for idle specs and WOT because alot of those rebuilt stock mafs are known to be off, and if their off can cause intermittent problems in certain rpm ranges.

 

[DiverDavies]

I wanna see if the calibration is right for idle specs and WOT because alot of those rebuilt stock mafs are known to be off, and if their off can cause intermittent problems in certain rpm ranges.

How do my #s look to you?

 

[turbojd]

How do my #s look to you?

Yours are right on! factory stock maf or rebuilt maf your running?

 

[TurboBuRick]

Unplug the cam sensor while the car is running. Check engine light will come on. Leave it unplugged and take it for a ride. Does it still miss?

Rick

 

[#13TTA]

Checked all of those All ok .. When it happened to you did it sputter but run or not run at all?

Yes and if I tried to stay on the gas it would slowly die. A friend of mine told me to check all of those things. At first I didnt find it but then he said to change all lines and tubes even if they looked good. I did that and it ran just fine. Plus in doing that gives you a good chance to do a real good inspection of everything.

 

[DiverDavies]

Yours are right on! factory stock maf or rebuilt maf your running?

It looks like the oem with the gm sym on it but its a remanufactured. Bought from a parts house local. So was the one that I took off when I got the 34 code, A reman. Any other #s I should check.. Is mine calibrated right?

 

[DiverDavies]

Yes and if I tried to stay on the gas it would slowly die. A friend of mine told me to check all of those things. At first I didnt find it but then he said to change all lines and tubes even if they looked good. I did that and it ran just fine. Plus in doing that gives you a good chance to do a real good inspection of everything.

I have replaced 90 % of the vac hoses And a local shop just replaced the head gaskets. and it was running great. Out of no where, bame chug ghug...
When It isnt cutting out it runs really well.. In an accelaration it chugs more at the start than at speed... Is this like what happend to you.

 

[DiverDavies]

Unplug the cam sensor while the car is running. Check engine light will come on. Leave it unplugged and take it for a ride. Does it still miss?

Rick

I havent tryed that.. Im new to TRs and am a lil scared to do much that I dont know about What will that do?

 

[bmackinnon]

I havent tryed that.. Im new to TRs and am a lil scared to do much that I dont know about What will that do?

Unplugging the cam sensor (while engine is running) will put the fuel injection system in 'batch' fire mode instead of the normal sequential mode.... and will, for the most part, verify the cam sensor is not part of the problem.... if it still runs like crap in batch fire.... and don't beat the crap out of it while in batch mode... just do what's necessary to verify the problem is or is not still present... and remember, the engine will not restart with the cam sensor unplugged if you shut it off.... :wink: FWIW, in my opinion, your problem doesn't 'feel' like a cam sensor problem to me.... I would start below first...

I haven't seen anywhere where you've verified the fuel pressure is responding correctly... should be 43 psi at idle (with the vac line to the regulator off and plugged) and, (reconnected) rise 1 lb for every pound of boost while driving. You MUST verify this (will rule out fuel pump/related issue), and if that checks out proper, then the next most likely culprits are:

1) Bad maf, as mentioned, remanned are hit and miss at best... also make POSITIVE the hose from the maf to the turbo is intact and leak tite...

2) Ignition module/coil pack weak/failing..... a VERY common malady for these cars as they age... you can check the coil pack by connecting an ohmeter between front and rear cooresponding coil towers on each pack and verifying the reading is between 11k and 13k ohms... this test will catch 'most' bad coil packs... no way to test the module without Casper's tester, so it would be nice to find a known good spare to swap it out with before you buy a new one, as it is fairly expensive for a OEM GM Delco module, which like the maf, is MUCH preferred over remanned...

HTH...

all of the above will cause the symptoms you describe....

.....And Welcome to the Darkside....

 

[DiverDavies]

Unplugging the cam sensor (while engine is running) will put the fuel injection system in 'batch' fire mode instead of the normal sequential mode.... and will, for the most part, verify the cam sensor is not part of the problem.... if it still runs like crap in batch fire.... and don't beat the crap out of it while in batch mode... just do what's necessary to verify the problem is or is not still present... and remember, the engine will not restart with the cam sensor unplugged if you shut it off.... :wink: FWIW, in my opinion, your problem doesn't 'feel' like a cam sensor problem to me.... I would start below first...

I haven't seen anywhere where you've verified the fuel pressure is responding correctly... should be 43 psi at idle (with the vac line to the regulator off and plugged) and, (reconnected) rise 1 lb for every pound of boost while driving. You MUST verify this (will rule out fuel pump/related issue), and if that checks out proper, then the next most likely culprits are:

1) Bad maf, as mentioned, remanned are hit and miss at best... also make POSITIVE the hose from the maf to the turbo is intact and leak tite...

2) Ignition module/coil pack weak/failing..... a VERY common malady for these cars as they age... you can check the coil pack by connecting an ohmeter between front and rear cooresponding coil towers on each pack and verifying the reading is between 11k and 13k ohms... this test will catch 'most' bad coil packs... no way to test the module without Casper's tester, so it would be nice to find a known good spare to swap it out with before you buy a new one, as it is fairly expensive for a OEM GM Delco module, which like the maf, is MUCH preferred over remanned...

HTH...

all of the above will cause the symptoms you describe....

.....And Welcome to the Darkside....

Thanks for your time and answers to my questions. I have a friend that has that casper tester for his TR and I can use it. I was thinking fuel pressure but I cant see what its doing while driving. What will happen if the fuel pump is going out.. Is it all or nothing, or go out slow over time?. It has a hot wire kit but I dont know what pump is on it... Thanks alot for the info...