blackeg

so, after my car comes up to temperature it seems to hesitate and be very sluggish from 2000-3000 rpms. it used to do it all the time, then i replaced the fuel filter now it only happens after the car has been on for like 20 minutes.


the motor is a bone stock y8 with 143k miles. ive so far replaced wires, cap ,rotor, plugs, fuel injectors, o2 sensor, fuel filter, as well as doing the timing belt and checking ignition and mechanical timing.


really out of ideas, except maybe a coil issue once it gets hot....

EJ1_CRIS_909

BUMP. havin the same problem but aint the dizzy... Hope you get an answer!

mechanix619

Did you replace all those parts because they were bad or because you were trying to solve this current issue? I firmly believe in pinpointing the root cause of an issue before spending money on parts. But to answer your question, check out this youtube video.

http://www.youtube.com/watch?v=9K78XIhhjAQ

fcm

Have you checked fuel pressure?

Have you checked ECT sensor?

Both the coil and ICM, [igniter] are susceptible to heat induced failure.

I agree with mechanix619, replacing parts to diagnose a problem is an expensive way to troubleshoot, not a biggy if the parts you replace are due to be replaced anyway 94

blackeg

the cap was nasty where the rotor contacts it. plugs are 2 bucks each, i had the fuel injectors in my shed in another motor, cat and o2 came from a low miles car i bought wrecked and parted out.... most of the stuff i was going to do anyway, basic tune up ****. im only in about 150 bucks into it trying to solve this issue.

i know that some of the z6's had issues with the distributor getting hot and not running well, i had it happen to me years ago.

i didnt check the ect sensor, i know it runs normal on the dash gauge. the coolant maintains its level and is clean with no signs of mixing or burning it. i wish i had an obd2b obd1 harness lying around i would hook it to my neptune and do some logging/monitoring.


i honestly thought the issue was in the ignition, which is what i did first. then it came to be noticed the plugs were showing different fuel per cylinder, which is why i replaced the injectors and fuel filter...

fcm

Different plug color can also be a sign of poor or inconsistent spark, [coil or ICM].

I would still want to know what fuel pressure is and if it is consistent, fuel pumps are also susceptible to heat failure. 94

blackeg

yes very true, especially if the car is always run low on gas, as they can use the gas itself to help dissipate the heat. ill have to find a way to throw the fuel pressure gauge from my other car in this for a little while.