Possible ignition break up issue?

IndigoMKII

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May 9, 2011
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Okay so here goes.

New 7mgte crate engine, new spark plugs bcrp6es gapped @ .025, new ngk wires and properly timed @ 10 degrees with t1/e1 jumped.

Here's the weird part, I've got a very very common misfire at idle(650 rpms). I've grounded my igniter per the screw inside it to a body ground(I used the battery ground). I made a new wire for the coil pack to head ground. My coils are receiving good battery voltage and are at .7 ohms on all the coils but spec is .3 to .5 so this may not be helping.

I can't seem to find the misfire problem. It's just a misfire every 15 or so seconds, sometimes it'll misfire back to back for a few seconds then run fine. I decided to double check my timing so while I had the timing light on I rev'd the engine a little bit and that degree marker went on the other side of the timing cover which I guess is around 25 degrees. Holy hell? Is this common to be under no load and barely rev'd up?

While I was looking around the engine bay I put my hand on the alternator which is INSANELY hot then made the mistake of putting my hand on the igniter, which was also insanely hot.

To add to all of this I have what seems to be bad ignition break up at 4k to 4.5k. If I try to WOT I can go all the way through 1st and 2nd and sometimes 3rd but if I'm in 3rd then go WOT it'll break up in 3rd as well, so 4th and 5th it breaks up. The car feels as if it's slowing down around 3.5k rpms in every gear. I can back off the throttle to about half throttle and it will go beyond 4.5k rpms but I don't want to even get near 3k now as this problem has me worried.

So I've got a bad misfire at idle and a 3.5k to 4.5k ignition break up issue. Help?
 

IBoughtASupra

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Mar 10, 2009
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Ignition break up issue is very common on the JZ's and their problem are the cracked coils after such a long time of use.

You cannot really tell the strength of a coil using its OHM reading. Do they have any cracks? I have seen this issue, not the break up, but the missing at idle problem on many 7M's and after all of them did Toowik's retrofit of the 2JZ-GE VVT-i coils, it went away.

Is .025 the correct gap for a stock motor? Look up what the TSRM says, I am not sure what it is either for a 7M.
 

IndigoMKII

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May 9, 2011
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The correct gap for a stock 7m is .032 but since I'm running a ct2657 I closed the gap to .028 when I installed them. I closed it a bit further hoping it would help with ignition break up and it didn't. The plugs also look like they're burning good. A bit black soot on the outer ring but the center electrode is a nice tan color. #1 plug had a little bit of 'white flakes' around the top of the spark plug, above the metal piece.

The coils look visually to be in good condition, no cracks or visual damage.

Doubt this will help but it's only got custom hardpipe with a ct26 57 trim on WG pressure(6-8psi) and a borla catback.
 

Supracentral

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Mar 30, 2005
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IBoughtASupra;1808322 said:
Is .025 the correct gap for a stock motor? Look up what the TSRM says, I am not sure what it is either for a 7M.

Stock gap is 0.031 for the 7M-GTE

OP -- 0.025 is a very tight gap. How much boost are you running to require that tight of a gap?
 

IndigoMKII

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Supracentral;1808327 said:
Stock gap is 0.031 for the 7M-GTE

OP -- 0.025 is a very tight gap. How much boost are you running to require that tight of a gap?

Its 6-8 psi, only reason I closed them that far is to see if it would help.
 

IBoughtASupra

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Don't close the gap, it's not needed. If you were getting blowout, okay, but not at that boost level.

You should try another set of coil packs or have you already?
 

IndigoMKII

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I'll have to borrow a set from a friend and let you know.

If this isn't the problem, what else could it be? Should I open the gap back up? Could it hurt anything if I leave it at .025?
 

Supracentral

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IndigoMKII;1808363 said:
Could it hurt anything if I leave it at .025?

Poor fuel economy, poor throttle response, incompletely burned mixture, possible catalytic converter damage (due to rich exhaust), reduced power, misfires, etc...
 

IndigoMKII

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Supracentral;1808398 said:
Poor fuel economy, poor throttle response, incompletely burned mixture, possible catalytic converter damage (due to rich exhaust), reduced power, misfires, etc...

So what could I do about the ignition break up at 4k rpm then?
 

Supracentral

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IndigoMKII;1808424 said:
So what could I do about the ignition break up at 4k rpm then?

Could be a lot of things. Coils, igniter, bad ground, bad plugs, air leaks, weak electrical (alternator/battery) etc...

Best bet is to follow the EFI diagnostics procedures in the TSRM that start on page FI-49
 

IndigoMKII

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Battery is brand new. Alternator is within spec and charging within spec. Switched out my igniter with a good one and same problem still. Next I'll swap coils with known good coils to see if that fixes it. Might as well buy new plugs as they're cheap and I'm getting ready to change my oil anyways. Just ran new grounds from igniter to body ground, coil pack to head and head to body ground. Boost leak didn't show any vacuum leaks and smoke test didn't either. I know my accordian pipe has a crack in it near the turbo so I'll be buying a new one next month.

Something I did notice though when it starts to break up if I back off the throttle slightly it'll keep climbing in rpm then pick back up. This worries me because it sounds like an injector dropping at high demand.

I can get 550's and do the lex afm/550 mod but I'd prefer to get this fixed first.
 

arpus89

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Jan 27, 2012
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How did your issue turn out??

I'm currently experiencing the same thing with my 2jzge-t using the 7m electronics. I had the 7m in and running 23 lb of boost with no problems till the oil pump quit. Now I'm having breakup at 14 lb with the 2jz???
 

IndigoMKII

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May 9, 2011
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Madison, Virginia
My issue was a mix between a walbro 255 with no afpr along with cracked ignition coils. With my base fuel pressure set to 36 psi and new coils/plugs gapped at .028 she runs all the way to redline with no complaining.