turbotim

I own a 85z31 turbo. It dies after idling for about 20 or 30 seconds! I watch the fuel pressure as it dies and the fuel cuts before the car dies. I did a self diagnostic test and it revealed code 13 chts after doing it about 6 times to make sure. It told me fuel pump code 22 the first diagnostic but that went away! Now if my chts has failed me, can I just unplug it? There will be 2 progs, Can I attach a jumper wire to these 2 prongs in the plug, and then start the car, to see if anything changes. Basically im asking if I can bypass the chts to make sure that's the problem. Or are you guys pretty confident its the chts. Also can a chts tell the computer to shut off the fuel if it goes out, I believe it can cause I looked at the diagram in my hanes! Thanks for you're help! And my main question is, can a failed chts cause the car to not stay running? Before this happened car ran perfect and it just died one day! I can also rev it above 2000 rpm for the 20 to 30 sec it runs!

rogerz

you can't bypass the chts. you could put a resistor across the wires . Look in the fsm for what the chts resistance should be when you test it cold. If your fuel pressure is dropping that is the reason the car dies not the chts. usually just runs rough at certain temps and really annoying. the codes are just about useless in my estimation. hot wire the fuel pump to run continuous and see if that cures the problem.

turbotim

Ok I think u mean run a ground wire from the pump, and another wire to a battery or the cars battery. Well I pulled up the carpet in her! But are those the wires to the fuel pump, that are coming out of the two holes on the circular disk? One is covered in black shrink wrap with a blue plug, and one is covered in white shrink wrap with a white and yellow plug! Are these my fuel pump wires or my level sending unit wires?

rogerz

yeah thats what hot wire means. download the fsm from xenon and figure it out. you need to do the work to find out what makes your car run I know what makes mine run. I'm not looking things up for people who are too lazy to make an effort.

rogerz

after a cooling beverage I'm feeling more charitable. ef ec 61 in fsm says the blue connector is the fuel pump. you still need to look at the schematic to see what is what or you can take the devil may care approach and just feed 12 volts to whatever looks good.

turbotim

Thanks for pointing me in the right direction! Have a good day!

turbotim

I found out that the fuel pump is good, so could it be the relay? Or could the bad chts tell the car to stop the pump? Im just worried it could be a 02 sensor! Maybe I should take that out and clean it!

FlyingT

When you say the fuel pressure dies and the fuel cuts before the car dies, explain that further. Where are you testing the F pressure? What do you mean the FP dies? Does it go to 0? Does the pump shut off? Have you changed the fuel filter?

A bad CHTS would make your car run rough, a bad O2 sensor would make your car run rich. Both don't kill an engine. If you absolutely know both are bad, replace them. But they probably are not causing your running problems.

I would look further at the fuel system and all relays in that system. If the fuel cuts off before the engine dies, there could be your problem. Figure out why the fuel is cutting off. Something is shutting off the fuel pump. Could be a relay, or something telling/causing the F pump to switch off. Take out your volt meter and FSM and poke around a little.

turbotim

Im reading fuel pressure with a gauge attached to a fuel regulator. It goes to zero before or while cars dieing. I can hear the fuel pump shut off before the car dies. One thing I noticed is when I pull the vacuum hose off the fuel pressure regulator I get no change in fuel pressure or idle! I will check the relay thanks for you're help, Just have to keep trying thanks.
When is idles after I start it my fuel is reading real rich on my afr gauge its not normal. That's why im leaning toward it being my o2 sensor!

turbotim

Well, I started looking at my car with a fine tooth comb. Well guess what I found, a weld that holds up my intercooler piping broke, and the intercooler piping fell down onto the air intake piping that holds the afm. And it seems like its totally disconnected! Now if it is, the car could be starting then the afm is seeing a crap load of air its not supposed to be seeing thus dumping fuel in the car an killing it! I don't have time to go under car and make sure, I have to go to work but will report back later. Man what if that's all it was.

turbotim

That wasn't it, guess ill have to figure out how to test the afm!

turbotim

Took off afm. Between c and d terminals I cant get a reading if anything! Says 0.00 and its supposed to go to .9 or so! Do u think this is my problem! And when I test for continuity between c and d it goes from 1 to 0.00.

turbotim

Afm tested good. So I learned how to use a multi meter. I started testing parts for continuity, and when I came to my egr control solenoid, I can't get the multi meter to read anything but (I). Sometimes I can get it to say 188 for a sec. but not really. I believe this solenoid is dead. When I stick it on my fpr solenoid it goes from (I) to 55etc. So because I can't get my egr to read anything this means that the wire that I can't see inside my egr solenoid is broken and cannot receive an electrical current. So I just wanted to make sure from what I have been reading, the egr solenoid is powered from the ecu, but before the solenoid the power is also ran through the fuel inj relay. So can a blown egr solenoid really tell the relay to shut down the fuel pump. From what I have learned is that the egr system is a very important part on these cars and if not functioning properly could cause detonation at full throttle. Do u guys think I found the problem?

NismoPick

I assume you are testing resistance and 188 & 55 are ohms???

The EGR is for emissions, it's not going to cut the fuel pump. You should be focusing on things that make the fuel pump turn on / off... like: The ecu, the relay, the ignition switch, etc.

The ecu controls the fuel pump relay ground... when the fuel pump shuts off, is the ecu cutting ground signal? Or is it something else? As Roger said last year... the FSM contains very detailed steps to diagnose these things.

turbotim

I am testing for continuity.

1.Red Wire, Goes to ECU pin 6, This controls the Relay


2.Black with Red trace, Power in to relay from Fusible Link. From Fusible Link changes to Red and then Meets up with Pin 114 at the ECU and splits going to each Injector


3.Black with White trace, Connects to Pin 35 on the ECU Also meets up with Green Wire on the Pressure Regulator Control Modulator and the Blue and Red wire on Pressure Regulator Control Solenoid. All this ends up as a power supply for all of the following sensors.
◦Crank Angle Sensor
◦Air Flow Meter
◦Pressure Regulator Control Modulator
◦Pressure Regulator Control Solenoid
◦EGR Control Solenoid
◦Idle Up Solenoid Valve
◦FICD Solenoid Valve


4.Black with Red trace, Power in to relay from Fusible Link. From Fusible Link changes to Red and then Meets up with Pin 114 at the ECU and splits going to each Injector

I think u may be wrong, the egr system is very important! And sure seems to be tied into the relay somehow. Its okay to remove it, but if it stays on the car it has to be working properly. Especially for a turbo car at full throttle! I think also on some cars even if it doesn't make the relay shutdown the fuel pump, if stuck open or always flowing, could cause a messed up afr at idle causing the car to die. Or even the ecu to cut fuel! Just a thought though. I could be wrong, I'm not the smartest pee in the pod!

turbotim

Do u remove the egr solenoid and unplug it, when u do the egr block off? And if I can blow through my fuel filter, it means it should be good? Does anybody's car run okay with the egr solenoid unplugged!

NismoPick

Ok. Well best of luck then.

turbotim

That's why I said I THINK u may be wrong! I didn't say u were wrong. Its okay if u don"t want to help me fix my car. I think ill be okay. By the way are u what they call and internet troll? And u could still be wrong, I have not replaced my dead egr solenoid yet!

turbotim

The eccs unit controls the amount of fuel that is injected, fuel pump operation and mixture feedback. The fuel system is interrelated with and works in conjunction with the emissions control and exhaust system. Sure the egr wont cut the fuel pump. But the messed up broken egr system messing with you're afr will make you're cars fuel pump shut off!

turbotim

Well, u are right nismo pick changed egr solenoid, didn't fix it. So I did another self diagnosis and now speed sensor circuit has been popping up! So I have been learning what it does, and it cuts the fuel at factory set top speed, but I heard if it goes bad it can cause fuel to shut off all the time! In the fsm it says to take it out the transmission and spin it while watching a multimeter bounce on the pins to it, at the ecu plug. If it bounces and u are getting code 14 it says to replace ecu. So I will be testing this circuit next! I hope its the problem. Thanks for you're help and sorry nismo!

turbotim

I took out the ecu. I took it apart to look inside and found an area that's burnt up! I wonder how that happened, from moisture, old age, or just bad luck? But just wanted to let people know I found the problem. And thanks for you're help everyone including nismo pick who said it could be the ecu, He was right!

turbotim

Installed used ecu. Car runs fine now!