My 90 iroc when 1st cranks up it smokes blue 4 jst a little"also been having issues with vavle rattle uder heavy throttle? Timing is set at 6 degrees"but smetimes it rattles n smetimes it doesn't"smeone said a knock sensor doesn't make any sounds when it works I guess"ant ideas? Been having this trouble since I bout this car a mnth ago!prevoius owner said he replace injectors n fuel pump relay n some other things"so any help would b nice.I just dnt no were to begin!anyone have this problem?

If im not mistaken you are supposed to set the timing to 0* and let the pcm advance it. If it is pinging then you prob. have it too far advanced.

So I would need to disconnect ecm"wire and n set timing on 0 degrees? Are can u instruct me on how to do it cause I get ppl telling me to set it on 6 n sme say 8 n 10 lol"I have no idea!

You will need to do some reading or wait on some one els to chime in b/c im not sure what all is involved, sorry.

While the engine is off disconnect the est in the wire look bye the blower motor in the wiring loom it is a orange wire with black stripe and then set your base timing to 6 dbtdc. turn engine off and plug the est back in. the blue smoke might be your valve guide seals if its just on startup.

Ok done timing the way u said n yur post but still gotta vavle rattle every now n then?

you mean pinging? or tappet noise ?

Yes I guess"like the lifters making taping??

Does it sound like marbles bouncing around in a can?

Yep u got it"jst like that lol

Your timing (if TPI) should be 6*
What type of gas are you running?? cheap stuff ?
Whats your fuel PSI ???

Its 6"how do u check fuel pressure? N if the pressure not rite"wat could it be then?

no ,on a tpi car it is 6 degrees BTDC. On a Tbi it is 0 Degrees.

you may also need a distributor wrench to get to your distributor hold down bolt.

Marbles in a can is spark knock. Your fuel is exploding in the chamber independently from the spark plug igniting, it's brutal on moving parts and it can and will eventually blow holes in pistons, damage connecting rods, and damage bearings.

Now the question to me is why does it do this?

Try to run 93 octane fuel - that should help.

Double check the timing (disconnect the ESC, set to 6 degrees) and see if that's correct.

If those are right, I would start pulling spark plugs and look for any that are possibly damaged. This is a serious case, but it hasnt gone on too long because the plug is still recognizable as a spark plug. See if any have black spots in the white portion, like this:



Keep the plugs labelled and organized and compare them to each other. See if any look damaged or different than the rest. Im curious to see if this is a problem from one cylinder or all eight.

If perchance all the plugs look fine, then go do a wide open throttle run, and then shut it down immediately and pull all the plugs, and if you dont know waht you're looking for, take some really good pictures for the guys here to check them out.

As you were told yesterday when you asked the same question

https://www.thirdgen.org/forums/tech...ng-sensor.html

Wow kool ill check that"ill let ya know friend thks"u been real helpful

Wats the gap on the plugs suppose 2 b? By the way?

Valves do not make "pinging" noises when they're inside an engine. That misconception has been around since I was a little boy. All I can guess is that once upon a time, some person, with no understanding of the inner workings of an engine, picked up a valve, dropped it on the floor, noted that sound, and that's how it got started
I remember my dad talking about "valves rattling" when he would crawl over a hill in high gear at 15 mph with his foot to the floor....lol!

It's detonation/pre-ignition/spark-knock.

Have some respect for the people who are taking time out of their day to help you by making your posts easy to read. English, please. I know you are posting from a phone, that's no excuse. Take an extra couple of minutes and do everyone a favor because they're helping you.

TPI cars got a .035 gap for at least some time period.

aw *** awn, Infernal! y ju hav to go'n edit dat??
Let the Friday Funnies roll....lol!

Very sorry sir" will try again" but I mean if were talking bout sparkplugs then I would imagine when I say gap it means the gap with the sparkplugs the previous person was talking about! Go figure"and for as respect goes there a lot of people on here that have an attitude"when someone is trying to learn something"I'm new at this sports car world so have little patience with people who obviously are not as intellingent as you seem to be! But I am very thankful the help people are doing here on this site"much thanks!!

No one minds uninformed people with little experience. It's the inability to decipher what you're saying that frustrates people, or at least it frustrates me.

Go take care of your timing issue, Im eager to see what the problem is.

Okay got timing set earlier this am"no detation or vavle ping"and going to check sparkplugs for a problem but as of now running real nice"thks infernal vortex"will update !

Thanks now I know.

How far off was it? just curious