exhaust smells like fireworks cracker and it's tunning rich

[turbozilla]

hello all,

I apologize in advance if this has been already discussed, but I was not able to find anything related using search. now to the point - I have 1990 TT 2 seater imported from US. ever since i have bought this car after previous owner, it has very bad mileage - you guys in US use mpg, so after conversion from european standard it is about 12.5 miles per gallon. pretty low, isn't it? another thing I have noticed is that after spirited driving, the exhausts emit very strange smell on idle for a good while - it smells like sulfur, or fireworks type of smell. I had a HC and NO test performed, becuase I suspected this to be a blown head gasket, but the test was negative - no gas chemicals in the coolant. What could be causing this? I do not have anything to compare the power to, as this is the first Z I own, but the power seems to be fine, it pulls like mad even on stock engine ( compared to 200sx I used to have ). What i have already tried to swap is the air and fuel filter, ETC is on its way from CZP, and O2 sensors tested out well. I didn't measure the impedance on the injectors yet, so i don't know if some of them are be bad.

I think this is something of the following - clogged cats, bad injectors, bad ECT which I will replace soon, or bad O2 sensors even though ECU tested them good.

What do you guys think?

[BigTDogg (MA)]

Welcome to Nico!

What the hell is an ECT?

What country are you in and what type of fuel are you using?

Does the car run rough?

[turbozilla]

thanks for the welcome. by ECT I mean engine cool temperature sensor - the one on the upper aluminium hose that leads to the radiator, with yellow harness on it. from what I understand, z32's use thermistor type of sensor which is analog and not digital, and it may go bad over time providing incorrect readings to the ECU.

I live in Slovakia, that is in central Europe, and the gas we use here is 98 octane, but i know USA has different octane numbers for the same gas. I think ours 98 is roughly equivalent to your 95, but I am not sure, though.

the car runs as smooth as can be, in my opinion. I bought it from a car collector who bought a diablo and had to get rid off one of his cars, my Z was taken care of for all 21 years, and only has 40k miles on it. the only problem it has is this smell, gas mileage, and fluctuating idle from time to time. other that that, it is fine.

[BigTDogg (MA)]

Ah, the coolant temp sender. Yes, if that's bad it will cause the car to run rich, or not run at all. Also check the harness on it, as that tends to fail more than the sensor itself. If that's loose it will cause you issues.

US does (RON+MON)/2 for our octane numbers. You may need to get a tune specifically for your type of fuel in addition to checking the other issues, as 95 octane isn't available here.

Check your fuel pressure regulator to see if it's working properly. At idle, you can disconnect the vacuum hose connecting to it. If you have no change in idle, then your regulator is bad, which would make you run rich at idle, but lean in boost, which is really bad.