Hey guys, so as the title says my z has been running like crap after I replaced my stock turbos with T25's because one of the stock turbos (passenger) blew.

Since then it has had a rough idle and much longer turbo lag and a different sound from the exhaust (hard to describe, but kind of sounds like a piece of is fabric over the exhaust with a hole in it flapping around while I accelerate)

One day I was driving it and it stopped accelerating at about 40, then the engine shut off and I coasted to a stop and it wouldnt start.

I had a diagnostic done and was told that the 6th cylinder is "reporting as a dead cylinder" and that all they had to do to get it to start was unplug/replug the wiring harness connectors which are pretty beat up, the plastic connectors are missing bits of the plastic around the connector, but the metal "pins" look ok. The wiring harness has a few spots that are electrical taped (was like that when I bought it and it was running ok).

I've been told that this is most likely an issue with the wiring harness or a bad fuel injector.

Would it be better for me to purchase new connectors ($60 total) or to have the wiring harness soldered to the coil ($240)?

Is soldering the harness to the coils something I could do my self? Would it even help?

 

Or would it be better for me to just replace the whole wiring harness ($400 + labor)

 

I don't really know specifically for this case, but if there's a non-permanent connection I think it should stay non-permanent. That way when all your stuff gets messed up, it can easily be replaced! Sounds like your harness is pretty messed up, so if you've got the cash/time/whatever I'd say replace it even if the issue is the fuel injector alone.

 

Thank you for the quick response Rupe.

I agree with you, the soldering would probably be a waste of money and cause more issues than it solves.

I'm going to try replacing the connectors since its cheap and may just fix the issue, if that doesnt resolve the issue I will replace the entire wiring harness.

I did a compression test and all cylinders are in the correct ranges so I dont think there is any engine damage from the stock turbo blowing...

From the symptoms I described what else could cause this type of behavior?

 

No problemo, glad to help.

Not sure man, maybe someone around here will have an idea though.

 

Before I go Band-Aiding this harness.. I'd look for more serious issues..

Do a Compression Check.. as a 'Blown' turbo can be anything from bad seals to bits and pieces injested to the motor..

If the Exhaust is not sounding good.. something is up..

I'm not a turbo guy.. so I can't tell you squat about the unit's you put in the car.. but if you paid money to have this done, and your not happy with the result.. you need to talk to the guy that did the work..

If it was my Car..

Do a Compression Check..
Check Fuel Pressure..
Check the Plugs..

Cap

 

Did a compression test and all cylinders are in the appropriate range. The spark plug on cylinder 6 had wet fuel on it so my stepdad that is a master technician thinks it is a bad fuel injector.

Going to replace the following -
coilpack on cylinder 6 $25
coilpack connectors (6) $30
fuel injector $200
spark plugs (6) $55 (it has upgraded ecu from z1 motorsports and I will be getting the NGK PFR6B-11B plugs they recommend)
balance tube o-ring set $10 (driver side was damaged)
intake gasket $30-75

 

I had an issue like this a few weeks back actually, it turned out to be the plug connecting to the coil. Mine were all chipped up too, so i replaced the plastic, threw on some die-electric grease and still had the same problem till i grabbed the wires and sort of jammed them further into the coil. This was a really annoying problem, had a hard time getting to city speeds and i was afraid to boost, I could really feel the bad balance in the engine. Try pulling the coil pack wires when its running, if the idle doesn't change that may be your culprit, then jam them into place till they work! and replace them if necessary.