Bucking and Snorting

[JeffW]

My Gn has been running great for a long time now, but this morning on the drive in to work I had a problem. I had driven about half of the 15 miles to work with no problems. Then as I'm going down the road, the car starts bucking and snorting at around 2500 to 3000 rpm. Sitting at the next light, it idles smooth as silk. Problem only seems to be in that rpm range. I pulled over and put it in park, revved it to 2500 or so, and it did the same thing while in park. Any ideas ? BTW, I did fill up yesterday afternoon just before I got home. Bad gas maybe ?

Thanks,
Jeff

 

[8587GN]

IC hose loose?,coil pack?

Keith

 

[NTMD8ER]

MAF, My car did the same thing, I kept getting a code 34 on the scanmaster, I ordered I new MAF it should be here today, we'll see if it fixes the problem..

Brad

 

[JeffW]

I'll check some things out when I'm able to get the car home. Stuck at work now, so can't check too many things. I will check the IC hose and make sure no vacuum lines or plug wires, etc. are loose. Sure hope it's not the MAF sensor. If so, guess I'll go the LS1/translator route. Unfortunately, my scanmaster just died a few weeks ago, so no scan tool. Thanks for the help and keep the ideas coming. Crank sensor ? Fuel Filter ?

 

[arista5]

does it do it all the time or only when the car is hot? mine was a cam sensor (started the car) disconnected it it ran like a champ.. so i changed it and it runs great

 

[JeffW]

Just went outside and checked some things out. It does it whether or not the car is hot. Unplugged MAF...car died. That may rule out a bad MAF. Fuel pressure is spot on. No loose hoses, etc. that I could see. Earlier I said it hesitated whether I was in drive or in park just revving. Wrong. It does not hesitate in park, only in drive with a load on the motor. I'm beginning to think it's either the cam sensor or the coil pack. I'll check coil to coil voltage when I get home. I've never had to mess with the cam sensor. Can someone give me a heads up how to unhook it ? I presume it's sitting right in front of the cam (duh !) ? Do I just unplug a connector to it ?

 

[Steve Wood]

1. Send your SM into Bob Bailey and get it repaired.

2. The cam sensor is on the front of the engine, on top of the front cover, just to the driver's side of the tb. It points straight up with a round cap on it. Just find the wiring coming out of it and unplug the connector while the engine is running and see if it runs okay. If you are running a Thrasher chip, this may not work.

Remember that it has to be plugged back in before the engine will restart once turned off.

3. Normally the car will idle fine with the maf unplugged altho you get a ses lite.

 

[JeffW]

Thanks Steve,
Actually, when I unplugged MAF sensor, it idled ok. It died when I put it in reverse and backed up a couple of feet. I did get the SES light when idling on no MAF sensor. Pardon my ignorance, but by SM do you mean sensor mechanism ? How can I contact Bob Bailey ? I'll test the cam sensor per your detailed (and very helpful) instructions. Thanks again for everyone's help. This just makes a very bad week even worse. We had to put one of our beloved cats to sleep this past Saturday. One day after her 13th birthday. She'd been with us since the day she was born. Then my wife had a wreck Monday morning. $3200 damage to her PT Cruiser. She got the ticket, and the worst part, she's got neck and back injuries along with some internal bleeding. She's recovering nicely though. Now I'm having to borrow a 2000 Mustang GT until I get the GN fixed....ouch. Sorry to rant, just makes me feel better.

 

[Carolinaturbot6]

Jeff, I believe Steve meant your Scanmaster (SM). I think Bob Bailey invented the scanmaster. See this link:http://www.turbobuick.com/forums/showthread.php?s=&threadid=35901&highlight=Bob+Bailey

There's some info here & you should be able to contact him through his e-mail in his sig. HTH

 

[azgn]

sniff, and just what is wrong with 2000 Mustang GT's?? Happens to be my daily driver......

before you go crazy replacing the cam sensor, take the cover off and make sure the reluctor (interrupter) ring is tight and in the slot

you can get the cap off without pulling the sensor itself...there are two small screws that hold it on...loosen them and pull the cap off with the screws still in it (or keep a retriever handy)....you'll see the ring...if it is loose, you found your problem...it locks into a slot and then tighten the screw holding it in place (it is prolly still in the slot or your car wouldn't start....)

 

[JeffW]

Ahhh,, SM = scanmaster . azgn. Actually, the mustang I'm borrowing used to be my wife's, but we sold it to my nephew when she got tired of shifting gears. I really do like the GT, it's just a bit slower than my daily driver, 2001 Lightning chip n filtered, and MUCH slower than the GN. Still fun to drive though.
I'll also check out that reluctor ring. I talked to the mechanic at Jack Cotton's, and he thinks it may be bad gas. I did just fill it up before the problem started. I'll probably replace the fuel filter too. It's due anyway. Thanks again guys.

 

[Ormand]

SM?

SM? S&M? Steve, this is family board! Or sort of, anyway. I have Turbolink, my wife wouldn't allow S&M. Well, not unless I wear the handcuffs, and I can't drive like that.

 

[NTMD8ER]

well I got the new MAF, replaced it, Car is back up and running like a champ again, My car was doing just what yours was, above 2500 RPM's it would buck and snort and chug and everything else that is not fun, now I'm back to just burning rubber. Ifyou can get a hold of one to just check, it will be an easy fix. It seems I only get about six months out of a MAF Lucky for me the Tomco unit has a one year warrenty.

Brad

 

[JeffW]

Latest tests update

Well, I tried testing several more things this morning and still have not uncovered the problem. Here's what I tried:

- cam sensor - First I unplugged the connector and drove the car for a few minutes. Same result. Big time stumble between 2000 and 3000 rpm. Turned off car and tried to restart to confirm that I had unplugged the correct sensor. No start. Reconnected sensor.
Then I removed the cap and checked the reluctor ring. It was tight and seemed to be in the slot. Should the notch on the reluctor ring be pointed in the direction of the firewall ? After this I don't think the cam sensor is the culprit.

- MAF - started with a tap test. No change in the idle characteristics. Next, removed connector to MAF sensor. Still had smooth idle with no change. I guess this MAY mean the MAF unit is ok ? Still need to switch out with a known good one for further testing.

I really don't know what could be wrong at this point, but I have a couple of other things I suspect.

- Bad gas - I had just filled the car up within 20 miles of the problem starting. Stopped at a gas station I don't normally use.

- Fuel Filter - overdue for replacement. I will change this out within the next few days to see it makes any difference. I doubt this would cause the symptoms I am seeing.

- Bad coil pack - Still need to check voltage across the towers. I know this isn't a sure thing test, but if I don't see the right numbers, could be the problem. I don't have a Casper style tester for a real test.

Any other ideas ?

I live in Memphis, so when everyone gets home from the NATS, I will probably be giving Greg Friend a call for help. Greg, you out there ? He's been a big help to me in the past, and is a MUCH better mechanic than me.

 

[GNSS]

Have you checked your TPS sensor? Put a digital meter on it and slowly crank open the arm on it and make sure the voltage is linear. I had a bad spot on mine at around 4.1 volts it would lose the voltage and pick back up again.

Jeff

 

[azgn]

I guess I would swap the MAF & coilpack/module with known good ones.....sometimes "testing" doesn't tell the tale...make sure crank sensor is tight and not rubbing

 

[MeanBuicks]

Yikes!

You had quite a week! Perhaps we can get together this weekend & troubleshoot your GN. I'll e-mail ya.