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vr4stealthrt
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Discussion Starter · #1 ·
Okay i just got my engine rebuilt, i got aam pistons 20 over sized...... and now when i drive the car my car stuters.. it drives perfect if i dont WOT it.. but if i WOT it like after it reaces abot 12-14 psi it starts to break up.... and i changed the spark plugs and wires ngks... still does it.. and i notice that it smokes a lil bit of blue oil sometimes just a lil bit... but the point is if i press the gas like 60% down the car pull slike crazy without breaking up.. if i try to floor it it just starts to break up... like after it goes to like 12-14 psi.. i have gt pro 368 sx turbos.. i though it was tuning but the guy from the awd dyno told me its ignition problems and do my heads because i never did my heads.... but i did the wires and plugs but still breaks up... th eonly thing i notice was.. when i got the car back my friend never did the timing on it cuz he did not have the gun but then when i floor it and it stuter i calle dhim and he said oh i never did the timing.. so then i put the timing all the way down and one time comming from the mall did not stuter at all... then... i never tightned th ebolt it got loose again... and it stuters again.. so now i went to his house and he did the timing for me but it still stuters if if i only floor it.... but doesnt stuter as much.. could this be to do with my timing .. please someone help me.. or can this be a bad engine???? feels normal to me but my car does tick alil my valves... cuz i never did the heads but i heard our cars tick .... someone have any ideas???? thanks....


~Marco
 

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#1. typing class
#2. check out the timing again. It sounds like it is out of timing and firing when it does not need to fire.
 

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It is too bad you didn't freshen the heads when they were off anyway while doing the pistons. It doesn't sound like a head problem - which would be poor compression - if it really pulls strong with 60% acceleration. I think your timing is off, either the timing belt (doubt it, again it wouldn't pull well) or the distributor is not working correctly. It might be a sensor isn't reading right. Cars under load react a lot differently than at idle or revving while sitting still. It might even be fuel delivery problem.. work on the distributor timing first since you have had problems with it from the beginning. good luck
 

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Member #140 Aug, 1998
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Try listing your mods. what size injectors, what pump, etc. No one can diagnose without all the info. Set timing back to zero? And how did you do that? timing is set by the ECU. Was the timing belt put in correctly? That is where timing starts off. Did you check the timing with a timing light? Usually if timing is off it won't run / start very good. Need more input here.
 

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vr4stealthrt
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Discussion Starter · #7 ·
Ok before i did my motor i had burnt rings but my engine did not stuter... and i did PISTONS JE pistons from AAM 20 over size.

here is my mods

gt pro 368sx turbos
450cc injectors
denso fuel pump
turbo back exahust
k & n intake
greddy type s bov
afc
hks evc4 boost controller
and boost gauge, egt gauge, air fuel gauge


i took the car to the dyno to make sure if it was the tuning or something else.. and it was something else.. my car made 268whp b4 it started to break up... @ 3000rpms. so then he tuned it its rich enough so i dont have to worry to damage the engine until i fix the problem. He also told me that it feels like ignition problems, like wires r spark plugs r something else.. but i changed the spark plugs and put ngk wires still the same. This only happened after i put 20 over sized pistons... Im going to have the timing checked again.
 

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Sure sounds like spark blowout.. what plugs / gap are you running.

What was your compression before/after rebuild. Perhaps before rebuild you had pretty lousy compression (as evidenced by the burnt rings cause by blowby gasses) and now that you have good compression you are getting spark blowout.

Try lowering boost to 10 PSI and see if you still get hesitation at WOT.



Clint
 

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vr4stealthrt
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Discussion Starter · #9 ·
OK IM GOING TO TURN DOWN THE BOOST TO 10PSI!!! BUT ABOUT THE COMPRESSION Y EAH I HAD LOW COMPRESSION B4 WHEN I HAD BAD RINGS I DONT REMEBER EXACTLY THE NUMBERS BUT IT WAS PRETTY BAD... NOW I DONT KNOW MY COMPRESSION... IM GOING TO CHECK I TOUT BUT I NEVER DID MY HEADS I THINK I SHOULD DO MY HEADS FIRST ... BUT THE SPARK PLUGS THAT I GOT ARE STOCK ONES BUT ITS THE 4 SPOKE ONES THAT DONT NEED GAPPING ANDI HEARD THEY SUCK....????? IF TURNING DOWN THE BOOST TO 10LBS DOES NOT MAKE IT STUTER AND BREAK UP... WHAT DOES THAT MEAN? THANKS FOR YOUR HELP? AND MY HAVING HIGHER COMPRESSION CUZ I GOT 20 OVER SIZE PISTONS DOES THAT MEAN I NEED MORE SPARK?? GAP IT DIFFERENTLY ?? BUT THE SPARK PLUGS I GOT I CANT GAP IT BECAUSE ITS THOSE THAT U DONT GAP THE 4 SPOKE PLUGS THE STOCK ONES.. U GET FROM R & S STRAUS!!!
 

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Member #140 Aug, 1998
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vr4stealthrt said:
OK IM GOING TO TURN DOWN THE BOOST TO 10PSI!!! BUT ABOUT THE COMPRESSION Y EAH I HAD LOW COMPRESSION B4 WHEN I HAD BAD RINGS I DONT REMEBER EXACTLY THE NUMBERS BUT IT WAS PRETTY BAD... NOW I DONT KNOW MY COMPRESSION... IM GOING TO CHECK I TOUT BUT I NEVER DID MY HEADS I THINK I SHOULD DO MY HEADS FIRST ... BUT THE SPARK PLUGS THAT I GOT ARE STOCK ONES BUT ITS THE 4 SPOKE ONES THAT DONT NEED GAPPING ANDI HEARD THEY SUCK....????? IF TURNING DOWN THE BOOST TO 10LBS DOES NOT MAKE IT STUTER AND BREAK UP... WHAT DOES THAT MEAN? THANKS FOR YOUR HELP? AND MY HAVING HIGHER COMPRESSION CUZ I GOT 20 OVER SIZE PISTONS DOES THAT MEAN I NEED MORE SPARK?? GAP IT DIFFERENTLY ?? BUT THE SPARK PLUGS I GOT I CANT GAP IT BECAUSE ITS THOSE THAT U DONT GAP THE 4 SPOKE PLUGS THE STOCK ONES.. U GET FROM R & S STRAUS!!!
Put in the stock NGK plugs and gap them to .035 and see if that solves your problem
 

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Toss the BOSH P.O.S. plugs....Nothing "stock" about the BOSH plugs. I tried them and replaced them within 100 miles.

Lots of opinions about the "ideal" plug but I have not found much wrong with the NGK platinum plugs (although I am runnning stock turbo)

With lousy compression, even at high boost, your spark was not blowing out. With better compression, your spark is blowing out at high boost.

Advise

1. Get some better plugs and look around the board for advise on proper gapping to eliminate blowout.

2. Check your compression periodically - it's easy to do and a pretty good indication of piston / ring health



Clint
 

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After checking the timing I suggest the ACCEL Coil upgrade and 720cc injectors to support the 368s. 450cc Injectors are marginal if you start to up the boost with 368s!
 

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vr4stealthrt said:
OK IM GOING TO TURN DOWN THE BOOST TO 10PSI!!! BUT ABOUT THE COMPRESSION Y EAH I HAD LOW COMPRESSION B4 WHEN I HAD BAD RINGS I DONT REMEBER EXACTLY THE NUMBERS BUT IT WAS PRETTY BAD... NOW I DONT KNOW MY COMPRESSION... IM GOING TO CHECK I TOUT BUT I NEVER DID MY HEADS I THINK I SHOULD DO MY HEADS FIRST ... BUT THE SPARK PLUGS THAT I GOT ARE STOCK ONES BUT ITS THE 4 SPOKE ONES THAT DONT NEED GAPPING ANDI HEARD THEY SUCK....????? IF TURNING DOWN THE BOOST TO 10LBS DOES NOT MAKE IT STUTER AND BREAK UP... WHAT DOES THAT MEAN? THANKS FOR YOUR HELP? AND MY HAVING HIGHER COMPRESSION CUZ I GOT 20 OVER SIZE PISTONS DOES THAT MEAN I NEED MORE SPARK?? GAP IT DIFFERENTLY ?? BUT THE SPARK PLUGS I GOT I CANT GAP IT BECAUSE ITS THOSE THAT U DONT GAP THE 4 SPOKE PLUGS THE STOCK ONES.. U GET FROM R & S STRAUS!!!

If by 4 spoke plugs you mean something like the Bosch +4 then 99% that's your problem right there. Get some NGK Plats and gap 'em .032. If that doesn't fix it then post again when that is done. The 4-spoke plugs are supposed to cause serious blow-out in TT's. So I've heard anyway.
 

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NGK is what you want. There doesn't seem to be anything an aftermarket plug can offer that it does not. Nothing else seems to work as consistantly (except the $25/ea denso iridium which don't seem to be worth it IMHO).
 
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