Massive misfires and smoke

[Kroegarn]

I have on a few occasions noticed some slight misfires since the latest trackday. But today it gradually was getting worse until it completely went belly up. At WOT the engine barely manage to reach 1500rpm and the exhausts are heavily smoked.

I have changed the POS and the coil packs as I have two complete kits of these parts, but no change with the misfires. Also sprayed "start gas" around the inlet to see if there was any leaks but it did not seem like it.

The fuel filter is really old, but since the car is so "smokey" with sooty spark plugs, it feels more like something with the ignition?? Worn out spark plugs??

Any other ideas?

Was planning to sell the car as the driveway have been "upgraded" with an old classic - a Datsun 240Z, so it perhaps is resisting these ideas of mine

[UrS4boy]

Did you pull the codes yet?

[Rusty]

Boost look. You need to pressurise the system to over 1 bar with no leaks.

[simon20vq]

What colour was the smoke?

[Cymru1]

Off topic.

240z ! Nice, love those ....pic ?

[Kroegarn]

What colour was the smoke?

The smoke is black... and smells of petrol, so alot of unburnt fuel.

Off topic.

240z ! Nice, love those ....pic ?

Pics of the "da monstah" http://www.garaget.org/?car=335170
A few things to sort out, revert to manual gearbox, restore some of the missing interior parts and give it a proper paint and a whole bunch of various minor fixes

[sidrick]

I'd question if the timing had jumped.

[UrS4boy]

I have on a few occasions noticed some slight misfires since the latest trackday. But today it gradually was getting worse until it completely went belly up. At WOT the engine barely manage to reach 1500rpm and the exhausts are heavily smoked. I have changed the POS and the coil packs as I have two complete kits of these parts, but no change with the misfires. ...Any other ideas?

Black smoke obviously = unburnt fuel. Either because the ignition system has a problem OR there is an air/fuel mixture issue, i.e. too much fuel or not enough air.\

You tell us that it's not the POSs or the OE coils. Not sure if I would rule them out yet.

You need to check your spark plugs. The tracking might have killed them (whatever they are).

You should probably check and/or clean the MAF, and check the six pin (only 5 wire) MAF connector to see if the pins are mating properly (sometimes the female pins in the harness connector get pushed back and away from the MAF male pins.

IF the ignition is fine and the spark plugs are fine and your injectors aren't leaking massive amounts of fuel and aren't stuck open, then you are missing air, i.e. boost leak.

1. Check and/or replace the spark plugs.
2. Check MAF
3. Boost leak check.

[prj]

Wrong order.
1. Boost leak test.

[simon20vq]

I would check o2 sensor after boost leak test

[prj]

o2 sensor is not active on WOT.

[simon20vq]

Ok learnt something new again! Thanks

[Kroegarn]

Wrong order.
1. Boost leak test.

This is what I will check first.. which would make sense since I have seen a minor loss of boost after the trackday, from 1.6 bar to around 1,4. But I was thinking that is was the dump valve/blow off valve that did'nt cope to hold tight.

Tnx for all the hints!

[UrS4boy]

This is what I will check first.. which would make sense since I have seen a minor loss of boost after the trackday, from 1.6 bar to around 1,4. ...Tnx for all the hints!

Please report your findings back here since those of us who try to remotetly diagnose issues like yours need feed back to archive for the future when somebody else comes to the forum with a similar problem.

[Kroegarn]

Defects detected

The first defects have been detected. The blow off valve was completely destroyed and basically wide open. Replaced that one and did another check for leaks. Could then hear a hissing noice from around the back short side of the engine. Took a while but I then found a cracked T-shaped crank house hose (that sounds weird almost like something else ) That small and strange piece of hose was nothing that I had on the shelf to will have to sort that from the dealer or if elsewhere. I do not know if I´m, well the car, is through the "woods" yet, but it feels like at least.

The evidence: