Still missing and bucking

[Sleeper-6]

This can't be good. I was all happy, I got my new coilpack/module today. I went right home to put it in. I finish up, glad to finally have it in there only to find out that my prob is not fixed. My car still misses and bucks real bad, weather it's in gear or park. This only happens at light throttle. If I put my foot down it'll only miss for a sec the take off happily smoking the rear tires down the block. It's has gotten to the point that I can't really drive anywhere. It began as a problem only when the car was cold but has progressively gotten worse to the point that it does it all the time. So far, I've tried new plugs, wires, coilpack and module. TPS and IAC are adjusted to spec. I'm going to pull the plug on the cam sensor and check the grounds. After that I'm stumped on what to try next. Any suggestions would be greatly appreciated ! Thanks.

 

[GNSS]

Start the car and unplug the cam sensor and go for a drive.

I vote on the cam sensor cap.

Jeff

 

[NTMD8ER]

That sounds close to the problem I had. I replaced and checked everything then remembered I checked and adjusted my fuel pressure, then the problem started. All I did was raise my fuel pressure up to 50 psi Line off. Problem went away, then started lowering the pressure down till my O2's where around 780-800. Car runs great I suspect my Regulator or Gauge is shot. Now I'm tuning fuel pressure buy the O2's not the gauge and she is great.

below is the link for my problem.


http://www.turbobuick.com/forums/showthread.php?threadid=58780&goto=newpost

Good luck
Brad

 

[Russ Merritt]

Did you take out your MAF screens? What happens if you reset the computer, and immediately start and drive it? I vote for a bad MAF or post MAF leak. Hang in there, you'll find it! Just a minor glitch in the system.

 

[Sleeper-6]

GNSS : I'm hoping that's it, It's one thing i haven't tried yet. tomorrow I'll give it a shot, rain or not.

NTMD8ER : I haven't touched my fuel system, but thast doesen't mean that something hasn't gone south on it's own. I'll have the stuff to hook up my FP gauge sometime this week so I will be able to check that out.

Russ : I haven't touched the MAF at all either, but I'll double check the hoses and clamps for leaks just in case. I'll try resetting the ECM to see if it goes away, I think I've reset it since this started. I'll try again anyway.

Keep 'em Comming guys! Thanks

 

[Russ Merritt]

Try what I said first, unplug the computer, plug it back in and start the car and drive it! See if it is the computer compensating for a problem, if it does it right from the get go you know it's not a computer forced problem. The cam sensor, maybe but you say when you floor it it flies so I'm not convinced it's that. In park you could unplug the MAF and see if it still runs, if so rev it and see if it's better.

 

[Sleeper-6]

I may be on to something here

Ok I was out putsing today with my car. I tried resetting the ECM first since that was the easiest thing to do. That diddn't do it still bucked and missed real bad around 2000 rpm. next was the cam sensor. I unpluged it and the car still had a slight miss that was barely noticeable, Maybe due to being in batch fire? But overall Greatly improved and 100 % driveable. Pluged it and and the miss came back. I tried again but by then the car had been running for a while and as usual when everything gets hot the prob dissappeared. i coulden't get it to do it again. I'll give it another shot tonight when I get home from work after it gets good and cold to make sure that it's definately the prob. Now how do I know what to replace? I have seen the cam sensor sold two different ways, One is just the cap and the other is two pieces. What usually goes bad in a case like this? Were getting there guys, Thanks!

 

[Russ Merritt]

It might just need to be adjusted. 25 degrees ATDC on the compression stroke of #1 cyl.

 

[Sleeper-6]

I'll definately try that before I go replaceing anything. What's the procedure for doing this? I've gotta run to work now, but I'll check back later. Thanks !

 

[Russ Merritt]

If you look at the timing mark on the damper, 25 degrees is about 1 5/8 " counter clockwise on the damper looking from the front, draw a line on the damper. Do you have a cam sensor setting tool? If not loosen the hold down bolt and with the engine running turn the sensor clockwise till it dies. Then turn it back, start it up and keep turning counter clockwise till it dies. Then split the differance. That should get it close if you don't have a cam sensor setting tool. If you do have the tool, put the 1 5/8" mark on zero of the plastic timing scale, turn on the tool, and turn the sensor clockwise till the light goes out. Then turn it back till the light just turns on, then lock it. Good luck!

 

[Red Regal T]

Hey Chas, a friend of mine had a similar problem and found some wires had been worn bare around the back of the engine. Don't know where exactly but take a look back there and at least move the harness around some. Maybe you'll get lucky. He did.

 

[GNSS]

sensor cap

My problem was similar to yours.
Crusing down the road and give it light throttle and the car would buck and jerk violently. I could give it more gas and it responded fine. Light throttle and bucking bronto again. It only did it sometimes. I replaced the complete sensor although I'm sure it was only the cap.

Jeff

 

[Sleeper-6]

Yup, just confirmed it. Went out side when I got home and tried it out. It's about 45 degrees outside so I know everything's good and cold. I tried it 3 times just to be sure. Unplug the sensor and it's all good, plug it in and it goes to $h!t. I bet my neighbors really love me now. Tomorrow I'll try setting it. I do not have the proper setting tool, but I'll try the spliting the difference method. Like you said, should get me close enough to tell if the sensor cap is shot or just a little out of wack. Thanks anyway for the quick service on the coilpack/module John, between my and my friends car I'm sure a spare set will come in handy sooner than we hope. Thanks again guys!

 

[Sleeper-6]

Problem Solved

Well, I tried the cam sensor ajustment, I think that did the trick. She's back to normal. It looks like it's in about the same place at it was before I started, but it definately works alot better now. I no longer have to let the car run for 15 minuets just to dirve down the block without embaressing myself. Now I'm off to hook up my FP gauge and put the Thrasher in that's been sitting on my kitchen table. Thanks again all!

 

[rcparks1]

Buck, Snort, Stumble, Stall

My 87 Tr was acting the same way, but turned out to be a different problem. Start the car, open the passenger side door. Take your hand and tap the ECM housing, located below the glove box to the right, on the kickpanel. If the car hesitates, stalls or stumbles, the chip is not making good electrical contact. The chip needs to be reseated, and possibly the contacts adjusted. Sounds simple and stupid, but is more common than you might think. Good Luck!