CHTS/CTS codes and fix? 84 50th Turbo

[jfleenor]

I'm sure I am committing a crime here, but I'm stumped. I've scoured the forum but still can't find a solution. Maybe someone can point me in the right direction.

My car is a 1984 Z31 50th Turbo. It runs good until it gets to operating temp, then it starts loading up, and dies at idle. It gives the code for the CHTS. I have replaced the sender behind the idler pully, along with the harness that attaches to it, and checked and cleaned all connections. I have a new cat, o2 sensor, new egr tubes, new plugs and wires, and I have 2 ecu's that work and have tried both of them and have the same results. No matter what I have tried, I still have the same problem. Is there another sensor temp sender somewhere? I am at a total loss at this point. Has anyone else had this problem? I see that some of you have had my problem in reverse, where the engine runs good at temp, but not when it's cold. Any help is much appreciated. Thanks.

[AZ-ZBum]

Check the EGR valve and PCV. Check the fuel pressure sending unit.

[jfleenor]

Thanks. Pretty sure the EGR is working, but I haven,t checked the fuel pressure unit. I'll give it a try.

[evildky]

Check the EGR valve and PCV. Check the fuel pressure sending unit.

Someone one is off his game, I'm pretty sure Z bum meant to sway fuel pressure regulator, as there is no such thing as a fuel pressure sending unit, at least not on any car I know of.

[jfleenor]

True, but I understood what he meant. :-) I'm probably just going to replace the EGR, PCV, and Fuel Regulator, just because. I'm really tired of screwing around with this thing. Just want it to run right. I've been doing cars almost my whole life (I'm old). I have built MGs, VWs, Corvettes, Camaros, Mustangs, Miatas, muscle cars, tuner cars, racing cars, etc, and haven't found anything that has frustrated me more than the Z31.

If anyone has any valuable info that I can live without, please feel free to post.

[evildky]

I'm a bit stuck on the chts code thing. if the ecu is triggering a code for the chts I'd ohm the sensor then I'd ohm the wires at the ecu to verify that the chts works and that the signal is making it through. it just doesn't make sense for the ecu to throw a chts code unless it isn't seeing the signal, and a bad or open chts can cause the car to run extremely rich to the point of flooding out. if the wiring checks otu i'd try testing with a third ecu or at least a known good one.

[BadQ45t]

The Z31 can be tricky sometimes to work on so don't give up. Depending on what city you live in there are some good mechanics that know these cars very well and can cut to the chase for you and fix it. Where are you located? maybe someone can help you find a shop. I have one in Los Angeles and he could probably find the issue in no time and save you the headache.

[AZ-ZBum]

Check the EGR valve and PCV. Check the fuel pressure sending unit.

Someone one is off his game, I'm pretty sure Z bum meant to sway fuel pressure regulator, as there is no such thing as a fuel pressure sending unit, at least not on any car I know of.

WOW! Where was my head? Yeah. FPR. Dur....