7mgte missing/popping at idle

[suprra_girl]

Heya guys, I'm posting this mainly due to curiosity sake, there's no actual problems I can detect in the car.

Cold start.. 1kish rpm
Warm idle, pops around like it's missing but as soon as any power applied it's perfect, runs fine, boosts fine, revs fine everything. The popping at idle is driving me mad however, anyone would think I have a lumpy cam

I'm thinking not really ignition related as it would be more pronounced under load and it's fine under load :/

Discussion welcome

Tia xD

Oh, forgot all the important stuff >.<

Stock ecu + Fcon running 550cc injectors, custom 1j ffim, 1uz throttle body, 3sge tps, stock afm, stock coils, stock ignitor, zt2, boost/vacuum gauge, smexy engine and so forth xD

oh and for the 7m haters... no bhg

edit: oh yeah a buddy of mine reminded me that recently I pissed around with the cps timing and I haven't had a chance to pop a light on it yet.

 

[7M4EVR]

+1 for cps issue

 

[24vtoy]

when last did you do a plugs change ?

 

[suprra_girl]

oh hmm, when i first got it running Probly uhh, 4 years ago.. xD

However it's not done too many kms, possible fouling I guess, gonna do them along with timing, just using stocker plugs atm.

I'll put that on my to do checklist lol

Just spent the day fixing my mum's supra, lower right control arm uber fukaroo'd xD

 

[24vtoy]

 

[Insidious Surmiser]

uhm... I thought this was pretty normal for these engines :-/

I know some people have gotten rid of the issue by cleaning/re-routing grounds. My previous 89 turbo always had a slight miss/pop @ idle and I thought nothing of it... the 89 I have now runs smooth with no miss... I did add an extra igniter ground for good measure though

 

[suprra_girl]

I'm not sure if the exhaust is just pronouncing it more but it seems to be more poppy than what I'd expect heh, and yeah I grounded my ignitor too quite a while back and my grounds last I checked were supremely fantastically uber

 

[Insidious Surmiser]

hm... sounds like your car is in good shape... there are a few possibilities, but there's not loss of power or miss under load, right?

I'd check all the ignition wires for the coils and the injectors, I've seen cases where spark will jump and ground irregularly across the coils... I think at this point though, it's a matter of checking over as much as you can think of... if it's not causing any driveability issues, though, I'd probly ignore it... but I know all about OCD

 

[MK3Powah!]

I have the same issue but I thought it was because I had a KS light on.

 

[suprajztwenty]

same issue here, grounded ignitor, new-used coils, 8mm plug wires, 4 different brand plugs. i have full 3" and i think it just makes it louder and thats why i hear it and bugs me so bad. ive learned to deal with it but if anyone finds a solution ill be the next one out there turning wrenches!

 

[IndigoMKII]

My car does it too, normally grounding the igniter helps with it but doesn't always fully remove the miss at idle.

 

[SUPRASTEVE]

Reviving an old thread. My first motor which was stock with 317k on it. NGK wires, copper plugs and an intake and exhaust ran smooth at idle. Then my second motor would pop and miss at idle but ran fine. I noticed when the guys did the install that the coil pack didn't have its ground. How do you ground the igniter?

 

[suprra_girl]

http://www.supramania.com/forums/showthread.php?52217-IGNITER-GROUND...-crispics

There's a really nice writeup on it

 

[suprra_girl]

+1 for cps issue

looks like thats quite the possibility, did some checks over my ignition system today and cps is 186ohm on each pickup, I checked over all my others and picked the lowest one which was 156 (have 8 spares LOL) and air gap is good, so I'm going to flick that in and set my timing.
Coils & leads checked out fine although one of my leads is going suspect as it has higher resistance than #5 or #6 and it's #4 i think lol, still within spec technically heh

I can't do the battery check for the igniter in the tsrm as I don't have one so I just tested continuity of the wires to coils etc and those check out

I'll pinch my mums igniter off her car if I still have issues

 

[suprra_girl]

Roight, so I put in a spare cps and found it was missing still a bit like before but not as badly, got the timing light on it.. 25 deg advanced LOL So judging from the similar idle from the last cps I'd say it was advanced quite some then too, taking it to 10 appears to have smoothed out the idle extremely and now I just have the normal 7m random pop.

Hopefully that's it fixed but I'll update in the next couple of days just for reference for future readers