misfire? boost leak? vacuum leak? arrgghh NOW WITH VIDS! Options

[brianforster]

ok so today was the first road trip to be taken in my car, but i made it like 20 miles and it started feeling like it was misfiring.

the other day i spoke to art about this problem, he said it was probably the same boost leak that causes my car to stall out when i shift to nuetral after my blow off valve goes off.

well i found this hose that was loose and replaced it and the problem went away (i said it felt like the car was missing, but i wasnt sure and he said boost leak) then i took off the hose and the car acted the same, little stumbly, and at idle it does a little "pop pop pop pop pop pop" thing.

today that problem came back 20 miles into my trip, but worse, i could definitly diagnose this as a misfire, the car was very hesistant when the gas was pressed and even trying to maintain 65mph i got some misfire-esque symptoms.

im gonna look in the bgb on how to test the continuity of my plug wires because i really dont wanna replace them if its not necessary, money is really tight ATM.

i just replaced the plugs with ngkr7e's gapped at .028 or .28 im not sure which, i used one of those round spark plug gapper thigns to do this.

yesterday i ran the boost leak tester idea that art had and found one, my throttle body was leaking, but that didnt fix any problems, i could not find any more but it had been a long day and since i couldnt hear loud hissing anymore i gave up, im gonna do it again soon with the soapy water bit.

does anyone have any ideas as to what my problem is? can a vacuum leak cause me to misfire?

could bad plug wires cause me to misfire only sometimes, not 100% of the time?

This post has been edited by brianforster: Jun 6, 2006 - 7:37 PM

[Supersprynt]

Misfiring can be a host of different problems. Your ignition system (coil, ignitor, dist. cap & rotor, plugs, wires) could have a problem.

Make sure you have proper grounds. ie make sure theres no paint where you have things grounded, this can cause some issues.

What kind of intercooler are you using? You sure your cars not pulling timing because of poor cooling?

Have you checked your timing?

This post has been edited by Supersprynt: Jun 2, 2006 - 3:17 PM

[BBoYRuGGeD]

yah bad sparkplug wires will cause hesitation. if they havent been replaced i'd replace 'em first along with new cap & rotor. i had the smae prob u had and it turned out to be the wires. btw just as a tip when u buy sparkplug wires go with TOYOTA oem ones...i've had the worst luck ever imaginable with after-market oe replacement wires. i'v got my toyota oem ones now am very happy

bboy

[brianforster]

i was gonna order them from toyota today but he said the part number is different for 91-92 ones and 92-95 ones, does anyone know why, and how i can check to see which engine i have? i think mines a 93 but im not 100% sure..

right now i have some red ones on there, i forget who makes them, ngk i think, they came with the engine, so i guess getting oem ones will give me piece of mind..

i have a precision turbo FMIC, but my engine bay gets HOT i mean like you cant even touch anything near my manifold, turbo, or even like the throttle body

right now my IC piping runs right over my manifold and i have no heat shield.. so that pipe gets untouchably hot, and its sposed to be cold side, i have a stock manifold and heat shield coming in the mail, so that should cut down on heat issues

it does seem to happen only when the car is warm, and if i turn the car off and say go into a store or something and come back out it wont do it right away.. hmm

edit: i checked timing when my car wouldnt idle and it was fine, but i havent checked it since then, i guess it wouldnt hurt to check it again

This post has been edited by brianforster: Jun 2, 2006 - 3:24 PM

[burneeed]

I would replace the entire ignition. When I first swapped I replaced everything. Went MSD And never had a problem. Your problem sounds like its a missfire I would replace everything with ethier oem parts or msd ignition.

[BBoYRuGGeD]

if you have 7 bolts on your exhaust manifold your 3SGTE is a 90-91 and if its got 9 bolts its a 92-93. this is what i gathered from the alltrac.net forums. also, i've heard some of the ignition stuff on the alltrac 3sgte got bigger on late model '93s. im not 100% sure on this tho but i've read that on alltrac.net somewhere.

bboy

[brianforster]

i really dont have money to replace the entire ignition.. so if the consensus is that my issue is a misfire because of bad ignition components i will work my way up the ladder, next will be wires.


what i am basically trying to find out is if there is any way to A) test spark plug wires and B) if the spark plug wires are good then is it possible i am getting a misfire from some kind of vacuum leak

[brianforster]

well mark just told me that the plug wires, dist cap, rotor, are all new when he got the motor rebuilt.. so now im suspecting some kind of vacuum leak or perhaps the ecu pulling timing due to heat?

This post has been edited by brianforster: Jun 2, 2006 - 4:51 PM

[lagos]

you can test the cap and wires with a multimeter. the details are in the bgb.


take off the cap .... look inside and visually inspect everything. maybe your dist is leaking oil into the cap or some other issue going on.

the main problem is the the car runs crappy and not smooth. that could be caused by a number of things, but something important to remeber is that your car is also stalling out. i think the 2 problems are related. stall outs are normally cause by some type of vac or boost leak.

[presure2]

ahh the joys of swapping..
the 3sgte is very sensitive to crappy ignition components.
go OEM under 400whp you will not find better parts.
i wouldnt be suprized to find it was "both" things, worn ignition, and boost leaks.
good luck

[brianforster]

the problems have just started though, i just checked codes and got a code 21 which is oxygen sensor, i unbolted oxygen sensor and found the bolts, bung, and o2 sensor completely caked in black (running rich?)

could running rich cause me to misfire? it would explain why at WOT (open loop) the car did not misfire, just when i was trying to cruise or acellerate slowly.

i have another o2 sensor laying around so i suppose i will put that one on and see if it fixes it

[toyotacrazy]

You should check the wires by pulling the tubes out one by one with the car running. But wear rubber gloves. If you see them arching anywhere but from the end, they are bad. Also spray them down and the cap with water. The mis should get worse. Let me know how this goes then I can give you more suggestions.

[brianforster]

i got rid of my code 21 but it still does it its about to thunderstorm here so i suppose the rest will wait for tomorrow

[jgreening]

ahh the joys of swapping..
the 3sgte is very sensitive to crappy ignition components.
go OEM under 400whp you will not find better parts.
i wouldnt be suprized to find it was "both" things, worn ignition, and boost leaks.
good luck

Wisdom.

I suggest you make a cheap boost leak tester and rule that out before you buy anything else. Also, boost leaks occur from time to time on these cars so having one around is a good idea.

I have posted a how-to make a boost leak tester link before. Just search using my name as the poster and the word "leak" and I am sure you will find it.

[brianforster]

i made a boost leak tester already, i just ran out of time diagnosing leaks, i had thought i fixed them all but apparently not, so tomorrow i will be checking for more boost leaks

now that i know all of my ignition components have less than a thousand miles on them i am pretty sure it is a boost leak

[brianforster]

guys im pretty sure i am running ultra rich and hopefully i can figure out why soon.

so far i know that my ignition components are less than 1000 miles old, and my spark plugs are like 100 miles old, they are one step colder and i am only running wastegate pressure at the moment (could this be harmful?)

im going to test for boost leaks tomorrow, and i will be determined to make sure that i have none, and i hope this will fix my problem but something tells me it wont..

i am paranoid now thinking maybe i hooked something up wrong, or something major is about to go wrong, and its freaking me out, if you ask art youll know that i am paranoid about my swap and i ask him 1000 questions a day.

i got 22mpg on my last tank of gas, this was with not going over 4k rpms and also only boosting 7psi, if that will tell you if im running rich or not..

like i said earlier i took off my o2 sensor and the sensor, bolts, and o2 bung were completely covered in black, and right now since i am running no exhaust the exit of my downpipe is also caked in it.

this all means im running rich but what i want to know is if this is beyond the stock rich conditions, and what might be causing this.

[Rjb23]

A boost leak will cause you to run rich, because your ECU thinks you are supplying this much air but some of it is leacking out causing you to run rich.

[brianforster]

well im not getting any more obvious boost leaks so i think i am doing something wrong, i fixed one in the pcv system and the car runs better but its hardly what it used to be, the driver over to my friends house was TERRIBLE, like flooring it would give me like no power and it was very hard to drive.

now whenever i get over 3k rpms teh car starts backfiring like hell, and it does not feel good at all, so im confused as to what to do.


arrghhhh

[Kadett]

This is the same problem a fellow dutch celica owner had. He swapped the 2nd gen in his ST, made a FMIC and car wasn't driveable, above 3000 rpm it would stutter etc so he went back to TMIC and never had any problems since.

[lagos]

now whenever i get over 3k rpms teh car starts backfiring like hell, and it does not feel good at all, so im confused as to what to do.

sounds to me like a bad cap and rotor