85 300zx need help

[alan1970]

i just bought the car with the heater core busted and it was bypassed. runs fine like that but no heat. so i decided to replace it, got that done and hooked up the hoses and the car idles fine but when i give it gas it starts jumping around. passed 2200 rpms it drops back to 8000 rpms and back. acts like you are reving the engine but holding the pedal still as if you were trying to drive. then found out that the water c*** was missing. gat one and put it on. still did the same thing. went back to the bypass method runs fine. i found 2 free vaccum hoses, a white one and a blue one, no clue where they go. i put an advanced auto parts replacement heater core in it. the qestion is, is there anything that might still be missing from the heater system that could cause this problem and where do these vaccum hases go?

[evildky]

air in the cooling system can cause the idle to jump around as the air hits the water pump, as for your vacum hoses there should be at least one taht goes inside the cabin that supplies vacume to the dashpots that activate the dampers in the HVAC system, you might want to keep an eye on ebay for a fsm I believe they have a vac system map

[DustinZ]

White goe to inside the cabin, blue goes to heater valve, and red goes to the intake manifold (very back on top and on the pass side.) I believe that is correct. There is a vacume canister on the front pass side of the engine bay (by the head light) that all three lines go to. Hope that helps.

DustinZ

[evildky]

well there you have it, nice reply DustinZ

[alan1970]

thank you all for the help i shall try everything you suggested. its just hard to believe that a car 21 years old was thought to be unfixable because the heater core blew up. the motor does not knock, valves do not rattle, and does not smoke. the man went to the point of changing the timing belt and the injectors and thought the heater core did the car in.

[BadQ45t]

What a dolt, I cannot believe the heater core lasted that long anyways. I had mine replaced in 1992 or 3 on my 84', pretty simple (for me at least) and it has never failed since, but not a death blow. Pretty much the only death blow is the timing belt.

[evildky]

his loss your gain, my brother had a corsica hat killed heater cores for some reason, I think he put 3 of them in in 3 years, and for a corsica he shoudl have cut his osses

[alan1970]

just added water to it and it ran great. thanks for the help. now its time to recharge the air conditioning and see what needs attention there before i start on the minor body work (front passenger fender looks like he hit a curb, and a paint job). thanks again for the help.

[DustinZ]

If you need any other help email me at [email protected]

Keep the Z's on the roadDustinZ

[nsrZ32]

Glad you got it all fixed up

I got rid of my heater core a few years ago, not cause it didn't work but because I don't drive it when its cold and I eliminated everything