Misfire when warm

[Tori]

Hi guys,... looking for some advice on what else to look at with my misfire situation.

Just got the car to pass smog a few weeks ago, put all my perf. goodies back in place and have been driving the car a good bit since with no issues. Then about a week ago it started to randomly misfire. At first it was maybe only once during a 8 mile around town cruise. Just a big hic-cup, like the ignition shut off for a second then it would recover and be good for a while. It has gradually gotten worse, and now once warm it'll start misfiring and cutting out at around 2500 rpm. I does not do this when cold. Once it gets to about 130* i can make it misfire around 2500 rpm.

I've replaced the spark plugs, and wires with zero change.

Thinking of doing O2 sensor next. When cold its in closed loop right ? What comes into play after it starts to warm up. ? What else should i be considering ?

 

[626gn]

If you're still running the factory ignition system, I'd look at the coil pack and/or module as possible culprits. Ignition problems will often show itself after warming up a bit.

 

[Tori]

I should have mentioned the coil pack and module are both brand new. Module is a Delco unit.

 

[Chuck Leeper]

A SM is ok for some things.
A Powerlogger is for capturing events such as the one you are chasing.
Logging fuel psi is a necessity, also.
What do the plugs look like?

 

[Tori]

A SM is ok for some things.
A Powerlogger is for capturing events such as the one you are chasing.
Logging fuel psi is a necessity, also.
What do the plugs look like?

Google did me no good..... what's involved in adding a powerlogger ? Is this a Laptop thing ? How user friendly are they, and where do they interface the vehicle ?

 

[Chuck Leeper]

Bad Google, evidently!

Powerlogger for Buick turbo cars - Bing

Mit der intelligenten Bing-Suche können Sie die gewünschten Informationen schneller und einfacher finden und dabei Punkte sammeln.

www.bing.com

 

[Tori]

Bad Google, evidently!

Powerlogger for Buick turbo cars - Bing

Mit der intelligenten Bing-Suche können Sie die gewünschten Informationen schneller und einfacher finden und dabei Punkte sammeln.

www.bing.com

Thanks Chuck, now i understand. I'd really hate to have to go thru that expense, time and energy learning the PL and what im supposed to do with the info just to diagnose this issue. That's way outta my league to be honest. I can see it just being massive frustration making it with a laptop that i'd also have to buy.
How did the GM tech's diagnose these cars back in the day ?

 

[dynoman]

Tori , there is a powerlogger & computer for sale in the for sale section ....check it out .
The powerlogger is very easy to use , that's why I liked it and it WILL help diagnose your problem .

turbobuick.com/threads/price-slashed-powerlogger-6-1.484764/

 

[Tori]

Tori , there is a powerlogger & computer for sale in the for sale section ....check it out .
The powerlogger is very easy to use , that's why I liked it and it WILL help diagnose your problem .

turbobuick.com/threads/price-slashed-powerlogger-6-1.484764/

Thank you, but i really have not time to wire it up, learn it, plus id have to buy a laptop too.

Tried a different O2 sensor last nite, no change. What happened to the tech help we used to be able to get on this forum ?

 

[dynoman]

plus id have to buy a laptop too.

That set up came with the laptop and software loaded .
I would try a different ignition module because that is one of the symptoms of a bad module ...failing when up to temp . Was the old one bad or did you just change it out for new ?

 

[Tori]

That set up came with the laptop and software loaded .
I would try a different ignition module because that is one of the symptoms of a bad module ...failing when up to temp . Was the old one bad or did you just change it out for new ?

The old one was bad. Had the car down for 2 years after changing out everything else. I did blast the coil and module with the heat gun last night too, although i doubt i changed it's internal temp much.
Car runs fine till about 130* which only takes about 5 minutes. There's barely any heat at the intake (module area) at that point so i don't think it's a component getting warm issue.

 

[dynoman]

Pull it and check if the potting material underneath gooey . It is internal heat from components failing ( shorting ) not so much from engine heat . When the motor warms up that means the ignition module has been working electrically and has been warming up also to a point of failure . See if you can get a known good module .

 

[Tori]

I'm 99% sure it isn't the module. It was a brand new Delco unit, and literally has like 100 miles on it. I can put the old, bad one on it and will know in 5 minutes if that's the case. Totally different symptoms with the bad unit. I'll do it just because i am running out of options. I'm more leaning toward the chip or ECM. It's happening as soon as it comes out of open loop.

 

[Chuck Leeper]

 

[mrtris]

Tori , there is a powerlogger & computer for sale in the for sale section ....check it out .
The powerlogger is very easy to use , that's why I liked it and it WILL help diagnose your problem .

turbobuick.com/threads/price-slashed-powerlogger-6-1.484764/

I bought it.