HAALP! Car Shaking, Engine check light on.

[Ricardosaurusrex]

Yesterday Morning as i got up to go to work, I turned on my car and the Engine check light comes on. I notice the car is shaking/ vibrating more than usual. The car still moves and drives around (though i didnt drive it to work, took my 85 magna to work that day) but i am concerned for the shaking.

I am convinced that i may be running on 5 cylinders, however, i was told that a coilpack going bad would not get the check engine light to come on. I also recently replaced my fuel injectors (new style injector upgrade kit by Z1) so i dont think it could be the injectors.

I was also told it could be the PTU? or the subharness? however i am not sure how likely this could be. if anyone could give me a hand with this i would appreciate it. I found the link to get the ECU codes but will not be able to do that until the weekend.

however any and all advice is completely welcome.


Thank you in advanced

[solaire]

Check for codes first. That'll give you a good place to start. Going to need to know what code it is to know where to start looking. It can be quite a few different things

[t.mcginley.jr]

With all the shaking/vibrating is the idle all over the place too?

[Ricardosaurusrex]

no, the idle drops sometimes but thats about it. This morning i went to go check what type of ptu i had, turned the car on, pulled it out of my car, moved the harness aside a bit, saw it was the new style ptu and was content.

then i go back inside my car and try to start it.... and now it wont start. it will turn over but doesnt seem to want to start up.

would it be safe to assume at this point its the sub-harness or the ptu? i know that without the ecu codes i wont know for sure, but after doing this, is it a safer bet that this is whats wrong?

[Ricardosaurusrex]

no, the idle drops sometimes but thats about it. This morning i went to go check what type of ptu i had, turned the car on, pulled it out of my car, moved the harness aside a bit, saw it was the new style ptu and was content.

then i go back inside my car and try to start it.... and now it wont start. it will turn over but doesnt seem to want to start up.

would it be safe to assume at this point its the sub-harness or the ptu? i know that without the ecu codes i wont know for sure, but after doing this, is it a safer bet that this is whats wrong?

sorry, meant to say pulled the car out of my GARAGE not the ptu.

[solaire]

Moving the harness caused the car to not start? Sounds like you've got a corroded PTU harness connector. Take the 2 old style harness connectors off. I would bet one of them is heavily corroded.

[ThisIsSparTTa]

Can't remember if I said it in your other thread. The PTU subharness being bad can definitely cause a no-start. Crunch it around some more, and if you can start again, there's your problem. Most people will cut this connector out and solder everything together so there's no more connector there. Just do it 1 wire at a time, and you'll be fine.

[Ricardosaurusrex]

So i went ahead and cleaned up my PTU subharness.... car started right back up. however..... the car still shakes. i did the diagnostics test and it threw a 51 code (injector circuit) which makes sense since i have just done the injector upgrade (new style injectors and connectors). i only used crimp connectors so now im going to try soldering them.

what type of solder should i look for? i know to use rosin flux as its non corrosive (been soldering for a while now) however as for the solder type im unsure.

[ThisIsSparTTa]

Whatever solder they're using now should work fine. You shouldn't be getting that code 51, it probably means you have a short somewhere in your circuit. I'd look more up on that code, and review the schematics either from the FSM, or search google for a 300zx color ecu diagram.

[Ricardosaurusrex]

sorry i didnt update this sooner. i figured out what was wrong. i got cheap heat shrink and it melted away enough so the places where i crimped were touching. got high temp heat shrink, wrapped them twice and that did it, no more CEL. thanks again for all your help guys!!!