Turbo Buick Forums banner
1 - 20 of 29 Posts

·
aka: mOtOrHeAd MiKe
Joined
·
6,603 Posts
Discussion Starter · #1 ·
I was driving home from the "street races" last night when I started to notice the car surging. This was at about 24-2500rpm. It was light lugging. Until I came up to the big hill on the HWY. Then it start to turn into a bog.

So in my infinite wisdom I decided to punch it and see what happens under full load. Nothing. The engine ran strong @ 20+psi. Bring her back down to a 2500rpm cruise... buck... stutter... bog.

I got on & off the highway trying to duplicate the scenario in 1st, 2nd, 3rd, & 4th. It only really occurs in 3rd & 4th.

However, on the way back to the house (for the last time) the engine actually started to "backfire" and "pop" back through the intake tract as I could here it causing compressor surge as the force was pushing back on the compressor wheel. The same "mutant pigeon" sound you get when you dump off the throttle under boost.

Note: It seems to be very throttle sensitive. And doesn't always occur. dunno

I was getting NO KNOCK according to TurboLink. I did have a continuous ESC Count of about 5-7 (that doesn't sound right). But, otherwise it was running as it should. No MALFs came up... but, I'll double check the *.ecm files and report back.

I do know that I have one MSD 8.5 SC wire that has about 50% more ohms resistance than the other 5 (this is on the #1 cylinder) I will swap this out for a good stocker. And I'll check the plugs (oh boy :rolleyes: ) for any signs of damage or fouling. Also, I can swap out the coil pack for another. And I should be able to get my hands on a known good ignition module.

Any other suggestions or procedures would be appreciated.

Thanks for reading this really long post. :)
 

·
Resident Idiot
Joined
·
11,462 Posts
My initial thought, TCC was stuck engaged.

Backfiring and popping though sounds like ignition or computer related. Try a new set of plug wires and coilpack/ignition module.

Continuous ESC counts makes no sense. Maybe you need a new ESC module (passenger fender). powersix
 

·
Registered
Joined
·
1,797 Posts
Pull the orange wire to the ECM to clear any false codes, and see if it still happens, if so... I'm thinking Maf on the way out or cam sensor.


Paul
72 Toyota Celica with an 87 GN drive train
 

·
Registered
Joined
·
10,284 Posts
Did you replace that bad #6 wire you had going on?
Remember,the one that was arcing to ground until you moved it?
 

·
aka: mOtOrHeAd MiKe
Joined
·
6,603 Posts
Discussion Starter · #5 ·
1) I changed out the higher resistance #1 wire for a different one (AC Delco 8mm). The car seems to idle smoother.
b) Radius, the wire has been insulated from the S/S AN fuel line. There is no more arcing. Stupid $20ea plug wires.

2) I checked the plugs and they seem fine.

3) Took of the cap to the cam sensor to check for wear/contact/play in the shaft. Nothing. I did shim the camsensor last year and the cap is only a few months old.

4) My TurboLink files are showing no codes or unusual activity (other than the ESC module, I gotta spare I'll put on).

5) The car was warmed up to operating temps and taken for a spin and tested in the same "conditions" as the event. Nothing. With either plug wire in place. I have the inclination to believe that it is the ignition module or coil pack becoming heat soaked at caRping out. The same thing happened with my SS and its HEI.

Bah!

<small>[ June 15, 2003, 03:32 PM: Message edited by: mOtOrHeAd MiKe ]</small>
 

·
aka: mOtOrHeAd MiKe
Joined
·
6,603 Posts
Discussion Starter · #7 ·
WOW! What an afternoon!

Went for another drive and finally got it to act up again. No SES light.

1) Tried unplugging the cam sensor to see if that was the issue. Nope. It actually ran even worse on the drive back with it disconnected. SES is on, duh.

2) Tried a "new" coil pack. No change. SES is still on. Hmmmm...

At this point I am stumped. So I reset the computer again. Still got the SES. Turn on TurboLink. Get codes 32 and 33. MAF HI & LOW.

4) Tried a "known-good" stock MAF. Reset ECM. Sputter goes away.

5) Try old MAF on "known-good" car, runs fine. No codes as per TLink.

6) Reinstall old MAF on my car. No sputter. No codes.

Baaaaaaaaaaah!

Any thoughts out there?!
 

·
Registered
Joined
·
1,797 Posts
Mike, I shouldn't have read your post :mad: This afternoon I'm getting on the highway and I start to merge and bang... I thought what the ??? SES light comes on and I get a code 42 (EST monitor.)
I pull over and open the hood and see that the up pipe got blown off. I clamp it back down, clear the ecm and start the car... SES light comes on again and DS says code 42 EST monitor.
I managed to limp home. Stalling, backfiring, etc
Do these just go bad ?
We may be in the same boat Mike, but the difference is I'm running the LT1 maf and Trans+.

Time to pull out the trouble shooting book. :(

Paul
 

·
Registered
Joined
·
1,797 Posts
Well Mike this is part of the definition.
Code 42 is set when the engine is running at greater than 600 rpm and there has been no pulse on the white wire from the ECM to the ignition module for more than 200 milliseconds.
Code 42 can also be set if the voltage on the tan and black wire remains low (near zero) or goes low while the car is being driven.The ignition module is designed to ground out the EST signal which travels down the white wire unless there is 5 volts on the tan and black wire. this locks the timing at a fixed position while the engine is being started.
Common causes of a code 42 include bad connections, frayed or broken wires and rubbed through insulation on either the tan and black, white or purple and white wires running between the ignition module and the ECM.

I still have to read the troubleshooting table.

The code 32/33 sounds vacuum related. Have you checked all your hoses and MAF pipe for leaks, and checked the EGR valve and vac hoses.

Paul
 

·
aka: mOtOrHeAd MiKe
Joined
·
6,603 Posts
Discussion Starter · #10 ·
Well.

Isn't this a perdicamentalsitumation.

Paul, if you need a ESC/EST to use lemme know 'cause I have an '86 unit which I don't think has failed. Even though I changed it out.

I have been out in the car cruising all night without so much as a hiccup. It is pulled hard. And is very steady at 2500rpm on the highway.

So at this point I dunno

If this is good enough to get it up North tomorrow... so be it. I want the SS back.

*I think these burps and farts might be from Dennis' cooking yesterday. yup *
 

·
Registered
Joined
·
1,797 Posts
Yeah, what ever you said silly
I'm hoping the car fairy fixes mine as I sleep tonight. wink

Paul
 

·
Registered
Joined
·
743 Posts
I've been struggling since last november with the same problem. Nice to know I'm not alone.
 

·
It's me, really
Joined
·
1,892 Posts
Well, I'm now a victim of this. On the highway this morning, steady cruise @ 60 on flat ground, starts stumbling and backfires twice through exhaust. I get out, reset ECM, starts right back up. Go 1/4 mile feathering it and it does it again. Pull ECM, reseat Calpak and chip, reset ECM, starts back up. I limp it home (and I think it tried to do it once more maybe). Checked crank sensor, no scraping and balancer is tight. Checked cam sensor, tab is engaged and no visual problems. Pulled coil pack/module, ohm'd 12.1, 12.2, 12.4 across the terminals. The module has a one "crater" in the goo by the 2/5 wire. Everything else looks normal. I think it is the module so I plan to replace that unless someone has solved the same problem otherwise. I do have a separate ground wire on the module base so I don't think that's it.

Oh, coilpack/module is 3 years old and are OEM GM parts.

<small>[ September 06, 2003, 10:26 AM: Message edited by: JohnLarkin ]</small>
 

·
Registered
Joined
·
1,797 Posts
John
FWIW Are you running the Trans+ ? If so double check your Spark signal (EST) connection, and try running in "bypass mode" with the pigtail installed.

Paul
 

·
It's me, really
Joined
·
1,892 Posts
Nah, all stock MAF. Thanks though. You think the EST on the fender would have something to do with it?

EDIT: I just tested something. The coilpack is on the bench and had time to cool from the engine. Now cold, it ohms out at 11.6, 11.8 & 12.0. A consistent .5 ohm drop. I heated it back up by wafting a propane torch over it and the ohms went right back up to the original levels. This thing must be breaking down from heat, has to be.
 

·
Registered
Joined
·
10,284 Posts
JohnLarkin:
The module has a one "crater" in the goo by the 2/5 wire. Everything else looks normal.
There's your clue,you found it.
 

·
It's me, really
Joined
·
1,892 Posts
Yeah, that's my only clue so far. After a few conversations, the module is the only thing that keeps coming up. I just hate taking an expensive educated guess but I'll cross my fingers. Thanks
 

·
Registered
Joined
·
10,284 Posts
JohnLarkin:
Yeah, that's my only clue so far. After a few conversations, the module is the only thing that keeps coming up. I just hate taking an expensive educated guess but I'll cross my fingers. Thanks
That was a clue,not an absolute.
It could be you've got a low resistance on the primary side of the 2-5 coil and it's drawing too much current when it gets triggered.
Check the coilpack *Primary to Secondary* resistance first and see if it varies between the 2-5 and the other two.
:)
 

·
Not a Selfproclaimed guru
Joined
·
420 Posts
I had the same problem all summer no matter what I tried.I finally cleaned and adjusted the IAC,TPS adjusted,put in a new set of CR43TS's @.30 and it acts totally different and has'nt stumbled once yet....knock on wood.I was amazed at how important those two sensors are to the part throttle and off idle.
 
1 - 20 of 29 Posts
Top