random/multiple cyl missfire

new symptom, took the car to the car wash (she was dirty) and was pretty careful not to get the engine bay wet. so i took it down a back road to dry the car off and it started missing (like it has been since it started after it sits for about 10-15 mins when its at operating temp) the difference this time is that my airbag light started blinking for about 10 second and shut off. could it be a short? and why would it only happen when its at operating temp and shut off for 10-15 mins?

[Pampered-Z]

How old are your wires and what brand? I don't see anyone mentioning replacing the wires other then the coil, which is a common problem with corrosion. I had a few cases of wires going bad, after markets that don't fit in the stock holders can easily be cut through trying to force then unti the holders or by the belt or pullies where they run behind the PS pump, or even just damaged from the headers. I chased a freaken problem with the car shuddering badly after it went into closed loop and the engine was up to operating temp. Chased it for weeks and found out the #6 wire burnt just slightly on the header and was arcing to the knock module and it never threw a code!

Make sure the wires are run so they aren't near anything or against each other.

Are you running the stock heat range on the plugs? If the car is that rich maybe the colder plugs are adding to the problem?

If you think it's injector related, I have a set of stock 24lbs you could borrow.

It's very, very rare on the newer cars, but on the 93-94s there were also some cases of the harness on the top of the engine being bad causing intermittent problems with injectors not firing - actually pairs of injectors not firing ( batch fire back then and wired in pairs). With your car running poke around at the wires, wiggle the harnesses and such and see if anything happens.

Moister may not be getting to the opti but maybe leaking or sitting back by the ECM harness? I would look at that wiring as well.

JB

Originally Posted by Pampered-Z

How old are your wires and what brand? I don't see anyone mentioning replacing the wires other then the coil, which is a common problem with corrosion. I had a few cases of wires going bad, after markets that don't fit in the stock holders can easily be cut through trying to force then unti the holders or by the belt or pullies where they run behind the PS pump, or even just damaged from the headers. I chased a freaken problem with the car shuddering badly after it went into closed loop and the engine was up to operating temp. Chased it for weeks and found out the #6 wire burnt just slightly on the header and was arcing to the knock module and it never threw a code!

Make sure the wires are run so they aren't near anything or against each other.

Are you running the stock heat range on the plugs? If the car is that rich maybe the colder plugs are adding to the problem?

If you think it's injector related, I have a set of stock 24lbs you could borrow.

It's very, very rare on the newer cars, but on the 93-94s there were also some cases of the harness on the top of the engine being bad causing intermittent problems with injectors not firing - actually pairs of injectors not firing ( batch fire back then and wired in pairs). with your car running poke around at the wires, wiggle the harnesses and such and see if anything happens.

Moister may not be getting to the opti but maybe leaking or sitting back by the ECM harness? I would look at that wiring as well.

JB

my wire are 7k miles old and about 4 months, theyre Taylor custom cut wires, theyre not run near theyre not running that close to anything and theyres no damage to any of them, i checked when it started doing it again, if it was plugs why would it be so intermittent? i would think it would do it all tthe time if it was that.

ill check out the harness near the ecm and also check the injectors, still kinda curious as to why my airbag light would go off....

[Pampered-Z]

Plug wires can do odd things once heat gets to them. If you had to cut them and put the clips on them you should double check them.

[98tadriver]

i figured out my mom's blazers misfire problem. time actually mightve helped me lol. it stopped saying random/multiple cylinder misfire and said cyl 5 misfire. i changed the plugs, cyl 5 looked crappy. after the plugs were installed, i put the wires back on. i used the cyl 5 wire for cyl 3 (i didnt cross them) and cleared the codes. cyl 3 misfire. ripped the wire out of there and sure enough, it was burnt! lol. so i bought new wires and its fine now

[oh one ls1 SS]

im going threw this **** right now man.. its sssoooo aannooyyinggg!!!!!!

yeah fortunatly my ignition system isnt all that expensive except for the opti which i have a plan for, im going to replace all of it and if that solves it ill switch to the Delteq system and i shouldnt really have to worry about my opti at that point.

seems like my problem is fixed, replaced the MAF and had Brian from PCM4less tune it as per Josh and its a totally different, now the only light thats on on my dash is the low traction light

[IROCdan330]

Originally Posted by 86Formula

seems like my problem is fixed, replaced the MAF and had Brian from PCM4less tune it as per Josh and its a totally different, now the only light thats on on my dash is the low traction light

Did he dyno tune it for you, or did you just go ahead with the mail order? I remember Josh saying something about Brian being in the area which is why i ask.

[JSPERFORMANCE]

Nah since Josh's car only has bolt on mods there was no need to strap it to the dyno. Brian has so much data on LT1s that there would only be a minimal difference.


Oh yeah Dan,,,,,,311rwhp for Dads ride..

oh and the car is fine even in the rain, and after sitting for 10 mins and firing it back up. seems like the problem is sloved.... still curious about that airbag light though

[98tadriver]

Originally Posted by 86Formula

oh and the car is fine even in the rain, and after sitting for 10 mins and firing it back up. seems like the problem is sloved.... still curious about that airbag light though

thats awesome to see that shes running great again!! as for the airbags, TAKE EM OUT!! lol or pull the fuse so they dont go off

back to the drawing board, no missfire code or anything and no check engine light, wont idle unless i blip the throttle then it will for a second and the idle starts getting choppy. wont maintain RPMs at anything below 3k. IAC or TPS?

[98tadriver]

hmmm thats what I would think, but im no LT1 expert lol. check vaccum lines and such?

car is being dropped off at JSPerformance today. while its still acting up. just dont have time to diagnose the problem

[98tadriver]

werd. i hear that dude!

[oh one ls1 SS]

ever find out what was wrong with it?

O2 extensions, water was getting in em. car is GREAT now thanks again to Josh lol