Help! Car Running Crap At Idle After Trying New Spark Plugs

[Benzino33]

Ok,, I posted this in another thread related to this issue but have had no responses at all, so I thought I'd just make another thread. here's what I posted:

Hey guys, dont wanna start a new thread so thought i'd post here,no offence to the OP.

Anyways, my car was running alright yesterday, but its always had a slight miss at idle, one of my mechanic friends thought one of my spark plugs might hav been loose. Anyways, i have a spare set of ngk iridiums and thought i might as well change them all if i was gonna look at the loose one. Found number 5 was a bit loose so i replaced them all.

Now, i got a friend with an r33 as well, but he's got one of those blitz BOV's that come on the intake pipe, and he's been getting a boost leak for a while, so we thought we could try my intake pipe on his car for a bit to see if it actually was the problem, we took that off while i replaced the plugs on my car. ok,so found out his bov was the problem, put the pipe back on my car, checked everythin was on tight and good, and ran it... it ran absolutely sh*t, idle's lumpy and would miss under acceleration. i thought it was the plugs since they are not gapped. it got dark, so i waited till this morning to put my old plugs(that are gapped to 0.8) back in. did that, reset the ecu and went again,,went a bit better, but still had a bad miss.

after work i came back, checked everything i thought would cause a miss,,cleaned the afm, checked for boost leaks, took the intake pipe off and refitted it.. still idles crap.

I have brand new coil packs in my car (yellow jackets) only 2 weeks old, and they ran great. i took the plugs out again, make sure they were clean and all around the chamber was too, put the plugs back in and checked the coil springs were fine and all.

now i've run out of ideas. Which vacuum hoses should i look at because i think ive looked at all of them.

sorry for the long post,,im jus out of ideas,,

any help greaty appreciated.

cheers

Ben

*Update* ran it last night and it seemed a bit better, drives pretty normal, just has a heavy miss at idle, i tried taking out the plugs today, cleaning them and cleaning around where they go in, still had the same problem. The car was running perfect 2 days ago,,dunno what i did to make this happen

[Moodles2]

Spray some brake cleaner or aerostart around the inlet manifold, focus on the inlet manifold gasket areas and see if the engine responses. If you get a response you have a inlet manifold leak

[Benzino33]

Spray some brake cleaner or aerostart around the inlet manifold, focus on the inlet manifold gasket areas and see if the engine responses. If you get a response you have a inlet manifold leak

thanks for the reply,,alright i'll go to autobarns tomorro and get some brake cleaner.

so, if it is a manifold leak, does that mean i need a new gasket for it? and if so, is it costly?

*Edit* Does it have to brake cleaner? i got some carb cleaner lying around..does it make a difference?

[Moodles2]

carb cleaner works too, has alcohol in it.

genuine nissan paper gasket costs about the same as a aftermarket metal gasket, rb26 metal inlet manifold gasket are about $70-$90

[Benzino33]

carb cleaner works too, has alcohol in it.

genuine nissan paper gasket costs about the same as a aftermarket metal gasket, rb26 metal inlet manifold gasket are about $70-$90

sweet,i'll get onto it tomorro, thanks for the advice man.

should i just concentrate on the gasket areas or go over the throttlebody and vac lines as well jus in case?

[Moodles2]

yep cover the gasket areas, throttle body & vac lines and double check the lines to the carbon canister, ive found the hoses to mine have blown themselves off the canister

[Benzino33]

yep cover the gasket areas, throttle body & vac lines and double check the lines to the carbon canister, ive found the hoses to mine have blown themselves off the canister

sweet, thanks a lot man, i think u pointed me in the right direction,,i was driving home tonight and had my window down, coud clearly hear a hissing sound coming from the right side of the car..i'll diagnose tomorro and see if i need a new gasket,,

im jus confused tho,,dunno how the hell this happened, the car was fine 2 days ago,,but yeh,,wat can i do..i'll let u kno how i go,,cheers man

Ben

[_Ryan_]

If i gap my stagea down to low it miss's at idle, go back to 1.1 gap(BCPR7ES come gapped to this most of the time as bursons near me stocks the -11) , perfect idle

[payback21]

If there was a vacuum leak it would increase idle revs. My thoughts are....

Earth wire on the ignitor not earthed, same goes for the one on the coil pack wiring harness

Check intake pipe from air pod to to the front of turbo turbo. If its sucking air in, idle will be rough as because fuel/air mixture wouldnt be correct

Check throttle position sensor. May have come loose or got bumped and has moved.

Last thing and i know this is going to sound dumb, adjust CAS. I have found once before that my wifes 32 had a miss at idle i could never sort it untill i retarded the CAS one day coz it was pinging under load. It fixed the pinging and and the miss went away. The CAS was way to far advanced. I would say this was done by the last person who changed the timing belt.

Apart from that, theres not to much to mention as you have already tried them. Hope you have some luck.

[bloodsword27]

maybe plugs are too cold or not gapped right?

[Benzino33]

If there was a vacuum leak it would increase idle revs. My thoughts are....

Earth wire on the ignitor not earthed, same goes for the one on the coil pack wiring harness

Check intake pipe from air pod to to the front of turbo turbo. If its sucking air in, idle will be rough as because fuel/air mixture wouldnt be correct

Check throttle position sensor. May have come loose or got bumped and has moved.

Last thing and i know this is going to sound dumb, adjust CAS. I have found once before that my wifes 32 had a miss at idle i could never sort it untill i retarded the CAS one day coz it was pinging under load. It fixed the pinging and and the miss went away. The CAS was way to far advanced. I would say this was done by the last person who changed the timing belt.

Apart from that, theres not to much to mention as you have already tried them. Hope you have some luck.

Hey man, well i tried spraying carb cleaner all round but didnt make a difference,,i'll check the TPS out tonight. im pretty sure i earthed the earth wire on the harness, but i'll have a look to mke sure its done right. well i did take my CAS off a day before to take my cam cover off, coz it wasnt put on right and was touching a belt, causing a noise. anyway, fixed it and lined it up according to a line that was painted on it by the guys who did my belts,, well it ran fine after the adjusting, but i will look into it..

when it comes to advancing it, is it clockwise to advance and anti-clockwise to retard?

but yeh i wouldnt be surprised if my tps was moved a bit.. i'll let u kno how i go..

Bloodsword27, the plugs that are in there now are the same set that was in before i changed them,,they're gapped to 0.8mm

[MBS206]

Anti clock wise will advance, clock wise will retard.

[STATUS]

try stock coil-packs ive had a fair few of the newer released aftermarket coil packs dying .... LIKE 50% so we only install splitfires now.

[Benzino33]

Ok well, took it to the work shop, the vacuum tested for leaks, found one if my IC hoses was leaky, fixed that, i dnt hear the whistling sound anymore..

They thought it had to do with my timing, they also found that my crank pulley wasnt sitting properly on it's key, im getting that replaced or fixed this friday. the car ran a lot better, but the miss came back soon after. It hesitates at cold start as soon as i touch positive boost. Im gonna regap some plugs today or tomorro and see how they go in there.

when Im driving it will go alright, and for some time, hesitate off it's head wen i step on it or get on boost, it's also there at idle.

The workshop said my timing was off and im gonna fix that ASAP. could that be a possible cause? They did what they could with my CAS and its better than it was before. i noticed that wen the idle is higher e.g. cold start, it wont miss, but wen it gets to normal it will feel like a wrx.

So,,im trying the plugs in tomorrow, and fixing the balancer on friday, i might as well try my old coil packs to see if they do anything, the new ones got waranty, so if theyre the problem, im sending them back.

quite out of ideas, but i'll see how i go

[STATUS]

If i gap my stagea down to low it miss's at idle, go back to 1.1 gap(BCPR7ES come gapped to this most of the time as bursons near me stocks the -11) , perfect idle

BCPR7ES are pregapped to 0.8mm not 1.1mm (most RB's hate 1.1mm unless they have aftermarket CDI units)

Yours is an exception, we gap down about 6 or so skylines a week that have 1.1mm gaps.. that miss like crazy on the dyno.

[Benzino33]

hmm,,. ok, the car has still been missing, ive got a new coil loom comin tomorro, my old one's pretty crap anyway so was gonna change it, im getting my timing reset tomorro. but yeh, today my car suddenly started running much better ..i had very little petrol left, was with my friends and left them to go get some gas on the way home, i had a big backfire while changing one of the gears on the way.. anyway, i fill up with premium bp and now its stopped missing when i get onto boost. its still got the idle miss, but as far as driving it, it seems perfect..well anyway,put a smile on my face for now, i'll let u guys kno how i go tomorro

[steeldawg_69]

I had a similar problem with my car and it turned out to be loose ground to the igniter. Just throwing it out there.

[Sheriff Wan]

A few questions...

- Do you always use 98 Ron fuel - i.e BP Ultimate and the like?

- What was your base timing?

- What spark plugs did you put in?

[blind_elk]

Bloodsword27, the plugs that are in there now are the same set that was in before i changed them,,they're gapped to 0.8mm

But what fecken plugs are they? Manufacturer, Pt/Cu, heat range?

Have you diagnosed which cylinder has the miss? Older ignitors have a tendency to cause misfires when they get hot.

Unless you are running fairly serious boost, 0.8mm is probably too small. Try opening back out to around 1mm (regardless how it used to run with 0.8).

[Benzino33]

I had a similar problem with my car and it turned out to be loose ground to the igniter. Just throwing it out there.

yeah I thought that could be the case, but ive earthed it again properly, and doesnt make a difference,..im lening towards the timing and plugs

A few questions...

- Do you always use 98 Ron fuel - i.e BP Ultimate and the like?

- What was your base timing?

- What spark plugs did you put in?

Yeah i always put 98 RON in,never 95. I put bp ultimate in the other day and it ran a lot better and didnt hesitate on boost, the idle's still shit tho. my base timing was 15, but i think it's off at the moment, so im getting it reset first. couldnt get a chance last night, so gettin it done on monday.

But what fecken plugs are they? Manufacturer, Pt/Cu, heat range?

Have you diagnosed which cylinder has the miss? Older ignitors have a tendency to cause misfires when they get hot.

Unless you are running fairly serious boost, 0.8mm is probably too small. Try opening back out to around 1mm (regardless how it used to run with 0.8).

I think theyre jus normal copper ngk one, i got them from status tuning when my old ones kept breaking down on the dyno. Trent said they were gapped to 0.8 i think. I kno its cylinder 5, ive had problems with it before, its like i hear a tick and it misses as soon as i hear it fromn there.

Im only running 10.5 psi at the moment, so i'll look at opening them up, one of my friends has a feeler guage