Enginie on a 1988 300zx jerks and turns off while warming up

[Guest robert300zx]

Hello I'm new to Hybrid z and this is my first post. I bought a 1988 300zx two weeks ago and since then I've been working on it. A problem that I'm having is that my enigne starts jerking and it eventually turns off while I'm warming up the car. But once the egnine is warm, the car runs good. Some things that I did to it that i thought woudl get ride of this problem were oil change, new sparkplugs, and i got the enigned timed. I searched other posts and i couldnt find anything regarding this problem. I really want to fix this but i truelly dont know what to do or what the problem is.

[Careless]

try another mass air flow sensor, or do a diagnostics run using the ECU's diagnostic screw.

 

buy a hanes manual for your car, it's pretty easy to do.

[evildky]

might want to take a look at the ficv, might be sticking, or just dirty

[TearingRaven]

The problem here is typically the cylinder head temperature sensor acting up. Its fairly common on Z31's. What you'll want to do is run your diagnostic codes on the ECU (procedures are listed in the Haynes Manual) and see what you come up with. I'm not going to lie, changing this sensor is a serious pain in the ass. It sits behind the left side cam sprocket. Get back to us on what you find.

[Careless]

actually, there are somewhat easier ways to remove the sensor that what the book tells you.

 

there is actually a video on youtube!

 

if you break the sensor that is in the head (the plastic end), and then use a 19mm socket to get it off with a u-joint socket adapter, and then use a 17mm 12 point socket on the plastic head of the new unit to install it (and don't over tighten!) it will be tight enough to get a good reading and will be done in half the time!

 

Raff

[TearingRaven]

actually, there are somewhat easier ways to remove the sensor that what the book tells you.

 

there is actually a video on youtube!

 

if you break the sensor that is in the head (the plastic end), and then use a 19mm socket to get it off with a u-joint socket adapter, and then use a 17mm 12 point socket on the plastic head of the new unit to install it (and don't over tighten!) it will be tight enough to get a good reading and will be done in half the time!

 

Raff

 

Yes, I suppose you could give that a try. However, I assume that if the CHTS is out, the timing belt probably needs to be changed as well.

[Guest robert300zx]

I actaully changed the pcv valve and the motor doesnt turn off anymore but the check engine light turned on for some reason. I was going to try to run a diagnostic but I couldnt find the ECU screw so I dont think my car has the screw but it does have the ECU box.

[TearingRaven]

I actaully changed the pcv valve and the motor doesnt turn off anymore but the check engine light turned on for some reason. I was going to try to run a diagnostic but I couldnt find the ECU screw so I dont think my car has the screw but it does have the ECU box.

 

You'll want to remove the ECU from the car to do the diagnostics. Leave it hooked up (obviously) and you should be able to see the screw. If I remember correctly its in the top.

[Guest robert300zx]

I took out the ECU and the screw was on top. I did the test and it gave me 23 which is the throttle valve switch. So I tested the TVS to see if it's working and it turns out that it is working it was just turned off. So i turned it on and install it back on and now the engine started stulling again. Not as much as before though but it still turns off when I stop at a stop light. So now I'm going to try to see if the cylinder head temperature sensor is the one causing the problem jsut like some off the members mentioned earlier.

[Comrade_Charlie]

I just put a good maf on my friends 86 and it fixed his problem. He would have to start his car about 10-15 times while it was warming up. And it didnt drive smooth. But now with this other maf it runs perfect. A maf is easy to change. They are easy to find where im at, I have a extra one in my room, and a the local junkyard has like 4 of them.

[Racinjitter]

There are online FSM's for the z31 now. Take a gander at this site http://xenonzcar.com/, and here is the direct link to the z31 FSM section http://www.xenonz31.com/reference.html. The FSM is a much better resource than the haynes manual.