Major Problem

[maynevent619]

Unfortunately, I have had many issue concerning my spark.I replaced an injector and the engine ran worse after. I then discovered that the plenum gasket was bad, so i replace that also. Upon doing that the car no longer starts. I have checked for fuel and spark and i only have fuel. I have checked the resistance of each coil pack and also checked the voltage going to the coil packs, that all check out okay. I now am focused on the PTU, Ignition Coil Relay and the ECU codes. I have heard that the relays dont usally go bad and that the PTU (Power Transistor Unit) is a common issue. Tonight, I plan to check for engine codes and also the continuity on the PTU. But the main concern i have is replacing the PTU and it could only be a relay. Is it possible that the relay is the problem?

[freakonaleash1187]

Welcome to NICO!

The PTU was put on recall a while back, check to see if you have the old-style one or the new-style one. The old-style had silver "heat sinks" on it and the new-style is smooth.

[Zwicked]

Odd that the PTU would choose to fail once you replaced the plenum gasket, although as the other post says, there was a recall on the silver ones. You are talking about the main upper plenum gasket that mates to the lower plenum? Just wondering if you got it seated correctly as if it isn't it may not start f the leak to atmosphere is big enough.Also, check to ensure all vacuum lines were reinstalled correctly if you pulled the upper plenum as there is a lot of stuff that has to be correct when reassembled.Have you tested at the coil pack to see if you are getting spark? Seeing as you have tested voltages, that should tell you if the PTU is ok or not.I would first pull the plugs off the PTU and check that all the termials are free from corrosion, then one at a time pull each coil pack, insert and ground a spark plug to see if they are firing.Also recommend you check the PTU connector is seated right and all injectors for no corrosion. If the connector isn't on all the way it won't even fire.Running codes are helpful to a degree, but really only tell you if there is an open circuit or component failure, and not always even then but it's still worth doing.

[300zx22]

hey i dont know any thing of this nature but where abouts in central alberta do you live ???do you have a 300zx?

[Zwicked]

Yes, I have a 1990 tt and am located in Red Deer....and you?