danman Posted August 9, 2004 Share Posted August 9, 2004 Sorry for long post, but I think background may help. Here's the story: My 1974 260Z with 1983ZXT motor was stumbling under boost. It would feel like fuel was cutting out. I put in fuel injector cleaner run her for awhile on freeway and put her into garage again. Read some posts saying that cleaning electrical connections might help. Clean connections this weekend and start her up. Car runs horribly. It sputters at about 600 RPM. Try to step on gas and raise RPMs car raises to about 1500 and then almost dies, let off gas and it still stumbles around 600 RPM. I let car warm up for awhile and then it all of the sudden it seems to switch to new idle mode around 1000 RPM like normal. (Car usually runs around 700 RPM till warm and then switches to 1000 RPM idle) Once car is at 1000 RPM idle runs great, take for drive. I baby it not going on boost around the block a few times, runs great. Park car and realize I forgot to clean connection to cold-start valve which I think is problem. Clean and restart car, this time I let warm up for many minutes. It never switches to nice 1000 RPM idle. Please help. Tried disconnecting cold-start sensor, did nothing. Should I bridge connection with wire to test? Does this sound like cold-start valve, coolant temp sensor? Any help would be greatly appreciated. Car not in drivable condition, will have to tow to mechanic if can't fix myself. More money floats away into the Nissan black hole. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 9, 2004 Share Posted August 9, 2004 Check the basics, plugs, wires, cap, rotor, compression, fuel pressure. Look for vacuum leaks, cracked/loose rubber intake boot after the AFM. Then get a multimeter and check the resistance and continuity of all the FI component sensors and compare them to the manual. Make sure the connections are clean and shiny...AFM, Temp sens., TPS, ECU, Fusible Links, fuel pump, distributor plug, ground cables, relays.....do it methodically. Good luck. Quote Link to comment Share on other sites More sharing options...
danman Posted August 11, 2004 Author Share Posted August 11, 2004 I will try those suggestions. Cleaned O2 sensor, it was filthy, but not the problem. Need to find new AFM connector, mine is pretty thrashed. Thanks again, will repost if all you wrote doesn't work. Quote Link to comment Share on other sites More sharing options...
danman Posted August 12, 2004 Author Share Posted August 12, 2004 Thinking about my problem it seems to me that my cold start idle was screwed up to begin with. Every other car I have owned rev's high when cold and then drops to normal idle. On my car cold idle is 700 RPM and then it raises to 1000 RPM. Right now the car is racing between 500 RPM and 800 RPM in pretty even quick cycles. Does this sound like familiar proiblem to anybody? So my question is which sensors are associated with this cold start idle or all??? My car has AFM from 300ZX I believe. One of the connectors on meter has been cut or chisled off (The one on far right when looking from connector side toward meter). Is this what is done when adapting 300ZX to 280ZXT? Quote Link to comment Share on other sites More sharing options...
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