Dead Z
 

Good day,

i hope someone here is able to assist me, as i have a issue with my Z unknown to everyone that has seen it so far, no1 is currently able to diagnose this nor can the computer they hook it up to, first, a bit about the car.

580lb act racing clutch
act street light fly wheel
invidia cat deletion system
Injen cold air injection system
DC sport racing headers

the above was done to the car and all was running fine for a while, the first symptom started when id start the car and it fire up the rev would drop and it die, id have to start give it a bit of gas and it be fine, normal idle so forth, i took it to my guy who works on mustangs corvettes and numerous other high performance vehicles and he said it required a new throttle body, so, figured it was ok. a few months after that while stopped at a stop sign it developed a lumpy idle kinda like it had a blown head gasket, of course a dropped one in my pants, shut the car off started it back up and it seemed fine there after that, this happen 2 or 3 times there after, i checked the oil there was no water oil mix so know it was not the head gasket.

on the way home from work 2 weeks back i was say 20miles from the office and going up a hill, i dropped from 6th to 5th gave it some gas and it started back firing and not wanting to go, i was fortunate enough to free wheel into a garage after the engine had died on me, i tried to start it up it refused to start, i left it to cool down, cranked it again and it started but was all flat and spluttering, had to call a flat bed tow truck to get it to my guy.

since it has been with my guy we have done the following to it, replaced the throttle body, replaced cam sensors as well as the crank sensor. we hook it into the computer and crank it, you can see the motor is behaving and responding as it should, injectors opening and closing etc.but for the life of us we have no idea why there is no spark on 2 of the cylinders.

thanks in advance.

All that done to it without any DTCs showing?

Pull the codes.

And have you checked the coil packs and spark plugs since spark is your guess?

Velo, CK,

the performance upgrades were done by a performance shop, fitted with parts designed for the Z, so it had accommodation in the design to put the cat sensors in which alleviated the issue with regards to the check engine light. the gentleman that did the work owns a VQ35DE himself and tracks his and has done modifications to his without issue, he has even been so kind as to use his parts on my car to test and make sure everything is in good working condition, he has even tried his ECU to make sure my ECU was not going faulty.

there are no codes no check engine light... NOTHING. it is the strangest issue i have ever seen. not to sound like a cracked record, i have even gone as far as replacing both cam sensors and crank sensor. i called Ztech out in Florida yesterday, the gentleman i spoke to told me to check the radiator fans, as if a fan is broken or faulty it will shut the car down without any form of indication, when hooked up to the laptop you can see the injectors moving motor cranking yet there is just no spark, fuel pump primes and comes on as per usual.

maybe you have a point, if 1 of the cat sensors was acting up it should throw a code, i do not think it shut the spark down, as far as we know coil pack and plugs are good.:icon32:

Well just because someone has a good resume doesn’t mean nothing can go wrong. I’ve been working on cars for 15+ years professionally and personally. No 2 cars are ever the same.

And don’t rule anything out until you know for a fact. Test the coil packs and spark process. Clearly something in the spark isn’t working.. Even if there is no engine light codes can be pulled at times. And I have never heard of rad fans shutting a car down. Dead fans will just cause the car to over heat. I’ve know some people to actually drive with out fans even in the car for some time.

And again a blown cat or cat sensor aka a wideband shouldn’t and wouldn’t **** the car down. It would just throw false readings of AFR’s. For example I don’t have cats. My car runs fine. People have had fully dead cats, and have driven their cars for months before they fixed the issue.

You might want to get a second professional opinion because it seems some of the things you’ve been told aren’t remotely close into what will kill or disable a Z.

https://www.justanswer.com/nissan/8s...-no-spark.html

this guy has had the exact same problem i am having word for dam word, he said its a loose ground, does anyone here know where the grounding wires are on the Z ???? it would be greatly appreciated.

CK i do not doubt you here and actually agree with you, but i am out of options and sitting with a astronomical bill for a rental car for 2 weeks almost 1k on the Z for repairs and trouble shooting and still no car, i am at the point now that if some1 told me to stick my d*ck up the exhaust id try it.

I feel you man. Nothing worse than a grimlin problem you can’t track down. Especially electrical.

And good luck, these cars have a crap ton of grounds to the motor. Just getting into my timing cover I had to fight off 4 or 5 different grounding mounts. And that’s just in the front on the motor.