Misfire issue

torch318 · Jun 21, 2018

Dealing with a misfire on cylinder #1 and a coolant loss issue. I did a compression test and it was normal and there is no bubbling in the reservoir when the car is running. I bought a harbor freight leak down tester but I don't have a large enough air supply to get an accurate reading with it. I did a radiator pressure test and it holds 15 lbs. I was wondering what your guys thoughts were, I am thinking I lifted the head or have an intake manifold gasket leak and just wondering what the best way to diagnose the problem would be.

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lwarrior1016 · Jun 22, 2018

Intake gasket leak would definitely cause the problem. Cylinder 1 is right there by a water port. The intake comes off pretty easy, I would pull it and see what the gasket looks like.

Silver95bird · Jun 22, 2018

Is the plug well filling with water?

torch318 · Jun 22, 2018

Silver95bird said:
Is the plug well filling with water?

No its dry.

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torch318 · Jun 22, 2018

lwarrior1016 said:
Intake gasket leak would definitely cause the problem. Cylinder 1 is right there by a water port. The intake comes off pretty easy, I would pull it and see what the gasket looks like.

I'll try that and see.

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NEURON · Jun 23, 2018

The coolant is just disappearing leaving no signs of where or why? How much is it loosing? Since the COPS are dry then it must be two separate problems. You could try swapping the COP around to see if it travels with the COP. System is holding pressure and no signs of leaks, I might suspect the pressure cap or leakage from the radiator at the plastic end caps/aluminum finning. Not to depress you but I have '99 ZX2 that has been loosing about a quart or so of coolant every few weeks since I bought it 3 years ago and have put 23K on it including three 1K plus trips, not sure how that can even be happening.

96blak54 · Jun 23, 2018

Pull the #1 cylinder plug and read it!

torch318 · Jun 23, 2018

NEURON said:
The coolant is just disappearing leaving no signs of where or why? How much is it loosing? Since the COPS are dry then it must be two separate problems. You could try swapping the COP around to see if it travels with the COP. System is holding pressure and no signs of leaks, I might suspect the pressure cap or leakage from the radiator at the plastic end caps/aluminum finning. Not to depress you but I have '99 ZX2 that has been loosing about a quart or so of coolant every few weeks since I bought it 3 years ago and have put 23K on it including three 1K plus trips, not sure how that can even be happening.

Ive changed plugs and moved the COPs and the misfire doesn't follow. On a 20 min drive keeping the car out of boost the reservoir will go from full to just about empty and the car will smoke excessively if I wot it. Using a radiator pressure tester it held 15 psi for about 10 mins with no signs of leaking.

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Silver95bird · Jun 23, 2018

How much boost does this engine max at? If it is burning coolant, you'll know because the O2s on that bank will fail and that side will run pig rich. What did the #1 plug look like before and now? Have you been checking the oil for signs of that oil/coolant milkshake?

torch318 · Jun 24, 2018

Silver95bird said:
How much boost does this engine max at? If it is burning coolant, you'll know because the O2s on that bank will fail and that side will run pig rich. What did the #1 plug look like before and now? Have you been checking the oil for signs of that oil/coolant milkshake?

The car makes 17psi max boost. I don't have the old plugs but here's a pic of 1 and 2, 1 has a whitish yellow look to while 2 looks normal to me but they only have about an hour of run time on them. The oil looks normal with no signs of coolant.

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NEURON · Jun 24, 2018

torch318 said:
Ive changed plugs and moved the COPs and the misfire doesn't follow. On a 20 min drive keeping the car out of boost the reservoir will go from full to just about empty and the car will smoke excessively if I wot it. Using a radiator pressure tester it held 15 psi for about 10 mins with no signs of leaking.

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Is the smoke whitish? Sounds like a head gasket but doesn't show any of the signs in your testing, weird.

torch318 · Jun 24, 2018

Yes the smoke is white.

NEURON said:
weird.

That's been every issue with this car since the motor build. Last issue I couldn't figure out, local shop couldn't figure out then I hauled the car back out to the tuner and it sat there for 9 months before he got it done...

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torch318 · Jun 26, 2018

Well I pulled the intake and I don't see any obvious signs of gasket damage to be the cause of the misfire.

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lwarrior1016 · Jun 26, 2018

Are your heads ported? [MENTION=20979]OLD H2S[/MENTION] found out the hard way that the wall on the ports will get thin and put coolant in the intake port after the head gets hot.

torch318 · Jun 26, 2018

I'm running trick flows

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lwarrior1016 · Jun 26, 2018

What intake are you running?

96blak54 · Jun 26, 2018

That does look like coolant residue on the ground strap. Scrap it with your finger nail?

Both plugs should look the same. The dirty ceramic is a clear indicator of a sparkplug not getting to self cleaning temperature but thats not saying the plug with coolant scabs is cleaning. Moisture in the cylinder will clean out the carbon. Take out all the plugs, keep the numbered to the cylinder. All plugs should look very similar.

A small coolant leak may only happen when into the rpm's causing the head to lift.

Might be improper deck surface roughness finish for the headgasket not letting the headgasket do its thing. Headgaskets require a certain roughness finish of both deck surfaces to maximize holding potential. A combination of headlift and gasket release lets water weep into the cylinder.