Shuddering and Whitish Smoke.

[Elisha]

just got my ECU replaced 2 weeks ago. new spark plugs as well.got an oil change on friday to Mobil1 Synthetic.

today i went to get some gas and after that the car started shuddering at idle and even while driving. lots of smoke and gas smell.popped the hood but everything was fine. no leaks whatsoever.lots of whitish smoke from the exhaust and sounds like the card is skipping a beat.

what are the possibilities?

[driverdriver]

Can you smell any coolant?

[Elisha]

smells intoxicating. a little sweet but more like gas.

[DAEDALUS]

Almost certainly an injector leak with white smoke and gas smell in the exhaust. You won't see gas in the engine bay--it's leaking down past the injector into the intake.

[Elisha]

so what do i need to do?would that cause misfiring?cause the car is shuddering as well.

[DAEDALUS]

Absolutely it will cause misfiring. If there's too much gas it won't burn; you'll see problems at around 8:1 or 10:1 A/F ratio.

You need to isolate the cylinder first. Wish there was an easier way, but I'd probably pull the plugs and look/smell for clues. It's most likely the injector seal, and not the injector. Hopefully it's one of the ones in front.

[Elisha]

does this cost alot to repair?and am i safe driving the car?

[DominickJ30]

does this cost alot to repair?and am i safe driving the car?

Depends on which injector is at fault to talk about price. More than likely the shop will want to pull the intake rather than dremmel through it.

[Elisha]

damn so i'm looking at $500+?i just spent $900 on the car last month :-(

[DAEDALUS]

I'd be inclined to agree! Keep the reconstructive surgery to a minimum.

[Elisha]

am i safe driving it or do i keep it to a minimum?

[DAEDALUS]

I wouldn't drive it. I had the same thing once. I put less than 50 miles on the car before I fixed it, and now that cylinder's compression is notably lower than the other 7. Don't know what kind of damage I may have done to the cat (expensive) and also there's a risk of explosion if air creeps in there after you shut it down. Gas + air + 1400*F = not good.

[Elisha]

aw damn thats no good.did synthetic motor oil cause this to happen?

[DAEDALUS]

Not possible. Fuel rail/seals don't see motor oil at all. I'd be more concerned with clumsy techs doing the plug change, or did you do the plugs yourself? Could just be age and temperature fluctuations.

[Elisha]

it was done at Midas.could the plug change have caused the problems?

[DAEDALUS]

Not if it was done right. They'd have to be either clumsy or malicious. A strong jarring of the fuel rail could cause it. The seals get pretty brittle over time. They can seal just fine as long as they're not disturbed.

[Elisha]

well there goes another paycheck :-(

[maxnix]

it was done at Midas.

Ah, the Golden Touch. They like to touch your gold.

Try to at least find an independent Z shop. A Consult I is a good hint they are serious.

[Jesda]

If you cant find a cheap independent, any local shop that does racing and performance tuning on the side has better experience with high-end imports. You'll pay out the nose, but they're usually more dedicated and more knowledgeable.

[Elisha]

i'll check into it guys. for now i'll have to drive my woman's Cavalier.

[911/Q45]

That is a terrible fate!

[driverdriver]

Did you use OEM Nissan plugs? Any other brand of plugs cause nightmares in the J as J owners on this board know.

Try to find a Nissan ZX car club in NS or even NB. The club members will be able to point you in the direction of either a good ZX car tuning shop or independent mechanic. The J30 and 300ZX (90's model) have identical engines that are tuned differently.

[metaverse3]

smells intoxicating. a little sweet but more like gas.

Sweet smell = coolant.. Nothing else like it, period.makes you want to reach out and take an atmospheric lick (don't do it)

At this point, I can only speculate you have something going on in the manifold area..head gasket. Check the engine oil and see if it is milky..phillips milk of magnesia milky (you get the jist)

Leaky injectors will cause hard start condition..accumulation in cats leaking to premature destruction. Possible dribbing out the exhaust..no white smoke. Extreme backfiring..and a notable trait, puff-puff at the tail pipe.. Whitish smoke is burning oil reacting with coolant mix.. Whatever is going on , does not sound good... Get a pro to check it out and stop driving it.you will cause more damage.

[DAEDALUS]

Leaking fuel will indeed cause white smoke. A little rich is black and sooty but a stream will vaporize into a dense white cloud. Exactly what happened on my Q when the injector tip cracked. Differentiate with smell.

[Elisha]

i did use NGK OEM plugs like sated on the NGK website.could it be that i have too much motor oil?i heard that too much oils is just as bad as not enough oil?could that be what burning?

[Jesda]

The dipstick will tell you if you have too much oil.

[Elisha]

but

The dipstick will tell you if you have too much oil.

could that be a possibility of whats going on here?

[DAEDALUS]

No. Too much oil can burst seals and cause frothing. Nothing to explain white smoke.

[Elisha]

a full 4.4l went ito the engine eventho with a filter change the engine full capacity was 4.3l

if you guys haven't noticed i have no clue when it comes to car mechanics. i'm a computer person :-(this is my first car and it has only been trouble so far.

[911/Q45]

A 12 year old car probably isn't right if you're not a DIY kind of guy.