spark blowout, plug gap Q's

[darshy523]

hey guys, i was having a spark blowout issue after installing my new exhaust and DDP (all stock except for exhaust and modified stock air box). i fixed a coil pack ground and regapped the plugs to .029", seemed to clear up the problem when pushing 8psi. recently got my HKS EVC 3 setup so it matches my boost gauge and put it up to 10psi boost, pulls great thru 1st and 2nd gear, 3rd gear around 4500 is when the sputters and pops start. since the stock plug gap is .031" i gapped them down an extra .002" for the little extra power i was pushing, i didnt think i would have to worry about blowout again till i upped the boost level to 15-20psi or so. im going to go thru and do the igniter ground mod and connect the coilpack ground to the battery as some preventative, although im not expecting that to fix my issue. tested my coil packs today and everything was within specs also.

any insight would be appreciated, not sure if i should gap my plugs a little lower or if something else is the issue, but im going to go tinker around for a while, ill be back later tonight to see if i get any feedback. thanks in advance for any advice, have a good day all!

-Ryan

 

[hvyman]

What brand and kind of plugs are you using?

 

[darshy523]

im running a practically brand new set of NGK iridium 5690's

 

[hvyman]

Iridiums are a pain to gap. And expensive.

You can try gapping them farther to like 25 and see if that helps. But you shouldn't be seeing spark blow out at such low boost level esp with a stock turbo.

Stock is platinum. Coppers also work very well but don't last as long.

I run coppers and change them every 10k with my oil.

 

[morganson]

I had that problem with ngk. I got a set of mk4 denso plugs and it fixed the problem. Sounds weird I know but it worked.

 

[darshy523]

ya I would rather not regap the iridiums again, heard the coppers are pretty good besides the short lifespan. i might pick up a set of coppers and try it out since they are cheap.

whats the part number on the denso plugs? also how much boost are you pushing on them?

im going to do some digging to see what the stock 440 injectors max out at also, not sure if the issue could be related to fuel but it would be worth looking into. thanks for the help guys

 

[hvyman]

350 is about where you want to stop with the 440. Copper can last like 10-15k and at 1.60$ each doesn't really matter.

 

[super51fan]

Have you tried new plug wires?

 

[morganson]

Ive been running 14psi on 550cc inj. If you are still on 440s your not gonna get much better than 11psi unless of course you are already running a maft or something. Denso part number is 4504 gap to .032

 

[Aleo24]

You may find you damaged the plug the first time you regapped them. Iridium is hard but brittle and NGK specifically say not to regap iridium plugs. I tend to use copper plugs pregapped to 0.8mm and change/inspect every service, tells you alot about how your engine is running.

 

[darshy523]

i was very careful regapping the iridiums, i did read that alot of people said not to regap them, but then i read this...

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqpregap.asp?mode=nml

anyways i was very careful not to pry on the center electrode, looked fine when i pulled them out, except #3 cylinder plug was pretty blistered. got the coppers installed, gapped at .028" and when i got off work i turned the boost back to 10 pounds. funny story tho, first pull down the highway it got all the way up to redline no problems, sweet! then my brake, rear light, and battery lights all came on.. this one threw me off, they all stay on until i get it over 3,000 rpm's. doing a little research people say thats the alternator going bad, another problem to fix lol, anyways ill test it tomorrow at work and then back to tweaking my car to perfection lol

 

[hvyman]

Well that's good.

For the alternator it's prolly the brushes. There about 10$ from Toyota and pretty easy to replace. Much better than buying a junk alternator from the parts store.

If make sure all grounds and battery are good and tight first. And the little wire on the postive terminal.

 

[darshy523]

still want to know why all those lights come on, thats weird.. i have never seen that before. i want to say that i read somewhere that somebody mentioned that if one or more of the diodes goes bad then it can cause the lights to come on because they are all grounded to the same spot, and that the current will flow backwards through the grounds.. correct me if im wrong, but that seems like a reasonable explanation. well thanks for the info, ill have to call up toyota and see what i can get my hand on and for how much $$$.

 

[hvyman]

The lights come on because there is low voltage.

 

[super51fan]

I don't see how you can have spark "blow out" with your set up. Stock turbo? correct. How old are your coils, plug wires? Resistance testing cannot tell if the insulation is up to par. Is it worse on damp days?

 

[darshy523]

ya stock turbo, the coppers gapped at .028" are running 10psi just fine. coils tested fine, plug wires need changing though. everything is probably pretty old, got the car about 3 months ago completely stock

 

[super51fan]

Toyota Wires have a date on them. Buy new plug wires , Most basic overlooked item in ignition system.