Guest Anonymous Posted December 18, 2002 Share Posted December 18, 2002 Well now, this is certainly interesting. The power brake booster had no effect on how the car ran. I can pretty much assure you the car runs perfect when it's cold, like when you first start it up.. so I started messing around with the connectors on the thermostat housing. Sure enough, when I moved the smaller one, the one closer to the drivers side of the car, it affected how the car ran. I further inspected the connector (didn't take it off though, too hot, would burn my hand) and it looks pretty old and battered. So, I started the car back up and began moving the wire. I moved it in a position where the idle smoothed out even more, and I revved it.. it revved fine! This has to be the problem, this is the only thing I have found, other than the AFM, that makes my car run good. Now, the question is, is that smaller one, closer to the drivers side, the coolant temperature sensor? Can I get a connector for that? What are your thoughts? Chris Quote Link to comment Share on other sites More sharing options...
David K Posted December 18, 2002 Share Posted December 18, 2002 Unplug the connector you did not touch. Warm up the engine. Now go inside the car and look at the coolant temp guage. If it is all the way to the left, then the plug you took off was the coolant temp sensor. The one you did not take off, send the signal to the ecu. The connector you were playing with must be replaced. Go to a junkyard and cut the fuel injector connectors off an 84-89 300zx. Take them home and replace your old connectors by soldering them on. Make sure you connect the correct wires together. While you are at it, you may as well grab enough connectors from a 300zx at the junkyard to do all your injectors, and the other connectors throughout the engine. I used 300zx connector plugs. No complaints here, and they will never get brittle and break. They are grey, with a orange plug on top of them. Here you go. Good luck. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 18, 2002 Share Posted December 18, 2002 Does this seem logical to you? Would that sensor/connector cause me to have a lean condition when the car is warm rather than cold? Me fiddling with it makes me thing the connector is bad. Chris Quote Link to comment Share on other sites More sharing options...
David K Posted December 18, 2002 Share Posted December 18, 2002 One of those temp sensors DIRECTLY sends a signal to the ECU what the temperature the engine is running. The ECU then controls fuel that is injected into the engine from the fuel injectors. So yes, if there is anything obstructing the signal's path to the ECU, the engine will run very incorrect. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 18, 2002 Share Posted December 18, 2002 My guess is the loose wire is cause the engine to run too rich when the engine is warm. When the car is cold the computer "puts on the choke", i.e. makes the mixture richer to burn better. Car gets warm, the computer needs to take the choke off. But with a bad connection, the computer may think the car is still cold so it keeps the mixture too rich. Sooo when the car is cold, it doesn't matter what the temperature sender is reading. The computer correctly enriches the mixture. But when the car is warm moving the wire disrupts the temp signal causing the computer to think it is cold. BTW, I am now sure about your Z but many cars use 2 temperature senders, one for the gage and the other for the computer. so your gage reading right may not tell you anything about the signal getting to the computer. Quote Link to comment Share on other sites More sharing options...
David K Posted December 18, 2002 Share Posted December 18, 2002 Originally posted by Jim Powers:My guess is the loose wire is cause the engine to run too rich when the engine is warm....................................................................................so your gage reading right may not tell you anything about the signal getting to the computer. In other words, what I said. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 18, 2002 Share Posted December 18, 2002 The engine is not running rich when it's warm, it's running lean.. backfiring through the intake, not revving.. unless I wiggle that wire in the right position. Edit: If anything, it's running rich when it's cold. When it's cold I don't get the backfiring through the intake and bad revs, I can even drive it for the short period of time when it's cold. Chris Quote Link to comment Share on other sites More sharing options...
David K Posted December 18, 2002 Share Posted December 18, 2002 Chris. There is a device called the Air Flow Regulator. Pinch the incoming air tube on the AFR with a pair of vice grips. The AFR may be stuck open, allowing a little more air to enter the engine while at normal temps. The Air Flow Regulator maintains a steady idle during warmup. Also, you may be confusing yourself. The engine can also pop through the intake while running rich. Fix that connector and pinch off the AFR. You will have to find the location of the Air Flow Reg by looking in a manual. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 18, 2002 Share Posted December 18, 2002 David Karey wrote In other words, what I said. Yeah, looking back I guess you did. Sorry, slow day. Just trying to fill in a little more detail. Wanted to point out that a bad temp sensor could affect the car when warm but maybe not as much when cold. Either way, fix the connector. Quote Link to comment Share on other sites More sharing options...
David K Posted December 18, 2002 Share Posted December 18, 2002 Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2002 Share Posted December 19, 2002 I know you're trying to help but I have stated in previous posts that I had to set my AFM to run way rich, by 16 notches on the loose side, to get it to run good. That would indicate a lean condition. I am going to pull the connector off tommorw, clean it, and try sticking it back on and see if this has any affect. The connector could be totally shot too. Screwing with that connector has been the second thing that has had a positive affect on how the car runs, the other one was indeed setting the AFM to way rich (that was causing me to fail emissions). Chris Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 19, 2002 Share Posted December 19, 2002 Originally posted by David Karey:Chris. There is a device called the Air Flow Regulator. Pinch the incoming air tube on the AFR with a pair of vice grips. The AFR may be stuck open, allowing a little more air to enter the engine while at normal temps. The Air Flow Regulator maintains a steady idle during warmup. Also, you may be confusing yourself. The engine can also pop through the intake while running rich. Fix that connector and pinch off the AFR. You will have to find the location of the Air Flow Reg by looking in a manual. David - the air regulator cannot affect the fuel mixture, as all the air that it passes is already metered. All it does is bypass the throttle plate to provide the higher idle when cold. Maybe if it is leaking to atmosphere... Quote Link to comment Share on other sites More sharing options...
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