Rugh Idle and miss

[copo]

I found my problem that was causing my miss, rough cold idle and boost gauge to jump around then the car was cold if I stomped on the gas.

Well, after testing my spark plug wires with a Delco wire checker I found #6 wire that had the centre conductor broken where it bends over the insulator but still stuck on the insulator from the crimp. #6 cyl is a bitch to get the boot off even after using dielectric grease. There's no room there.

I installed one of the 2 long factory boots I kept from the factory wires and used it for a tool to start the plugs into the head because they are 1" longer than the boots that GM calls for the '87 GN today. That way I'll have a better grip next time. Why can't they make longer boots?

 

[darkred87T]

Mee too! I swapped out my plug wires for some old ones I had laying around and no more "stumble start." Thanks for the input.

However, I still have the idle dip after I let off the gas pedal. At least now though, my IAC counts are up around 10 in park.

 

[copo]

darkred87T, have you changed your PCV lately?

 

[darkred87T]

Yup, new PCV, line and grommet.

 

[darkred87T]

Where should my fuel pressure be at idle with the vacume line plugged in? (Stock injectors)

 

[copo]

After Sat and Sun getting misses at high rpms on Monday am on the way to work I hammered it and it missed near boost redline and I hit it again after a few secs and the car lost all power and was idling rough. When I floored it after that I was only able to get 2 yellow lights lit up on the stock boost gauge. And I smelled something sort of electrical.

The fix was a coil pack and module.

More $$$ spent. I guess it's better than a turbo failing.

 

[darkred87T]

Every so often, at WOT, my engine will cut out for a split second, the car bucks and and when it comes to, I get a "Servcice Engine Soon" light with a list of codes indicating the engine shut off. When I restart, the light goes out. It's only on a rare occasion. Other than that, it runs awesome under WOT.

 

[copo]

Mine was missing 99% of the time at WOT near redline. My friends '87 does the same as yours but without the serv engine light coming on . I told him I would suspect the coil pack/module could be going. But we're going to do the spring cleaning thing on his.

 

[darkred87T]

CoilPack/Module is probably a good guess. I don't get a chance to do alot of WOT where I live so I'll have to wait until track season to further diagnose.

 

[darkred87T]

Just thought I might try to pick you brains a little more here. My car is obviously running really rich. I have small drops all over the back of the car from the tail pipes and it smells rich. Sometimes, the idle drops to the point where it stalls. I'm tired of chasing my own tail looking for a vacume leak. What else might cause my BLM's to be so high and the car run so rich. Everything seems to point to a vacume leak but the intake is air tight. IAC counts seem to hold at 25.

 

[copo]

I've never had a rich condition. Sorry.

 

[turbov6ta]

Yeah, I upgraded to an LS1 MAF and translator and it still runs the same. Next chance I get, I'll post numbers. I might try a new TPS.

I see you have a LS1 MAS did you install it? If not could you recommend someone

Thanks

TurboV6T/A

 

[darkred87T]

It's an LS1 MAF (Mass Air Flow-I'm not sure what the difference is from a MAS). Anyhow, my translator came with all of the adaptors and plugs to install it and it's cake. You might need to get a reuducer for the turbo intake pipe because the diameter of the LS1 MAF is bigger than your stock pipe. You can also do what I did and just stick a K&N filter on the other end the the MAF. I believe I got mine from www.fullthrottlespeed.com.

 

[copo]

My coil pack and module crapped out finally about 3 months ago.

 

[darkred87T]

I know the last post was over a year ago but I don't want to start a new thread. Same problem, still trying to figure it out.

Anyhow, here's a video of my off idle hesitation. I ran around to the car so you could here the hesitation from inside the car. However, you can see the delay from under the hood when I pull the throttle back to when the engine responds.

YouTube - 87 Buick Regal T-type off idle hesitatiion

 

[copo]

Have you tried adding a can of fuel injector cleaner into the gas tank. I smelt a rich condition a couple of times and fixed it with a bottle of STP FI cleaner.
BTW, cheap gas stations (no name) do not have the cleaners in them.

 

[darkred87T]

Have you tried adding a can of fuel injector cleaner into the gas tank. I smelt a rich condition a couple of times and fixed it with a bottle of STP FI cleaner.
BTW, cheap gas stations (no name) do not have the cleaners in them.

Nah, I guess I could try it but I did change the injectors to #60's. However, when I increase the fuel pressure, it shortens the hesitation.

Also, when I start it cold the RPMs go way up. When I put it in and out of gear I have to keep a heavy foot on the brake so as not to lunge forward and hit my garage, Lol. It's almost like the throttle is cracked open but the TPS and IAC are within correct parameters. Then after about a minute it settles down, the idle kind of loses it's umph and it smells like fuel. I guess it's adding fuel to compensate for a lean condition.

BTW, thanks for sticking with my thread and trying to help. When I get it figured out, I'll try to get a sticky thread so others can learn from it.

 

[copo]

No problem. I have an automatic email whenever a post of mine is answered.

Also, when I start it cold the RPMs go way up. When I put it in and out of gear I have to keep a heavy foot on the brake so as not to lunge forward and hit my garage, Lol. Then after about a minute it settles down, .

This is normal for all GN when cold.

 

[darkred87T]

Eh, it's not normal and there's definitly a hesitation.The only thing I never replaced was the crank sensor. I can't see how it could be this (maybe timing is out of wack?) but I guess it can't hurt to try it. I know a local guy that works on them also. I might start bugging him again to take a look at it.

I guess I shouldn't complain too much it doesn't effect the top end. I can take it to the track and run 12 seconds flat with it all day long.

 

[copo]

The cold start idling high is normal for a couple of min.