Right now i got a 87 camaro iroc z and I have a problem.
It´s about the temperature of the engine.
First time I start the engine the idle is running ok, but at the time the temperature is increasing it starts to stop without any reason. Once the engine is warm the idle is running ok again. I´m thinking about hte coolant temperaure sensor. Any of you can give any clue? Anyone has a list about the volts that the sensor has to have?

I forgot to mention that the engine is a 350 TPI, and there are not any code memoriced in the ecm.

 

well, I was taken the volts reading output in the cts, and I found this:
- with cold engine, the reading was 2.35 volts
- with the engine about 100 ºF reading 3,8 volts
- and with the engine warm (about 170 ºF) reading 2,05 volts.

I don't understand this, but I think that anything is wrong, but....

I said that when is warm the idle is ok, this is right, but I didn't see that if I put the transmision in any gear (automatic) the engine stop. Sound as the idle es without enough power to maintain the the engine running.

I checked the tps, timing, IAC (I prove an IAC from other running trans am and the problem continue), all vacuum lines appear to be good, I am crazy.

When I set the tps I notice that if I drop the idle below 800 rpm. its die, when in the trans am the idle is at 600 or less without problem.

Any help will be apreciate.

 

sounds like its having a problem when the motor makes it into closed loop.

does it smell like its running very rich?
and does the motor die when you put it into gear when the motor is still cold?

 

No, when is cold not die, but the idle is too high, about 1400 rpm. i thought that is for that. Only smell a bit rich when I crack it after it dies when fail, but only a few seconds.

 

have you made a custom tune for the car? or is it the stock prom

what have you done to the 350? is it stock?

 

The CTS wouldn't stall your engine but if you want to make sure it's good, here is a list of resistance values that you can use to check it.
Don't measure voltage on it. Disconnect the wire and measure the resistance on the sensor. (btw,the IAT sensor has the same electrical characteristics so you can measure it too)

Hope this helps.
Lou

 

I just bought the iroc in Germany about a month ago. All I know of the car is all I just can see. Previous owner said me that the engine has about 70.000 milles after was rebuilt, but appear to be all stock, exhaust manifolds, air pump (without belt), air filters...... are stock, but I don't know if the cam, or prom has been changed. In the engine bay I only had seen a custom setup for the dual fans, they start about only 180 ºF, both at same time.

 

well if it comes down to the point where you cant figure anything out, buy a fuel pressure regulator to turn the fuel pressure down from like 40psi to 8psi, swap the dizzy and put a carburator and carbed manifold on there.... itll gain a bunch of hp and you wont have to worry about the pain the the butt tpi

 

For carbureted I have a 73 Camaro with a mild 400 sbc, I am not a drastic purist, but as I will never fit an injection system in my 73, i will never fit a carburetor in this 87, or my daily 91 TA. I will follow breaking my head to find the fail.

 

so have you figured anything else out yet?

 

I am waiting for a scan tool to continue with the job, but thinking that could be a vacuum leak anywhere in the intake, plenum....

 

replace all the rubber hoses that connect to the intake plenum, and check all the vacuum lines.

if you think theres a vacuum leak, get a can of carb cleaner and spray it on the manifold where you think the leak is, it should change the idle of the car if there is any sort of significant intake leak.

 

Finaly is not a vacuum leak. I check with the scan tool and I find that the timing is set at about 27-29º at idle, first dont take a lot of value to this, but when I check the timing advance in my other 91TA, I see the advance at idle set at 16º.

Then I check the advance with the timing light and the check wire disconected in the Iroc, and it is where it must be, at 6º, and advanced untill 14º the engine never stall, even with gear, lights, fan..... After set again at initial 6º and Checked with the timing light and the wire reconected it is nearly 30º.

Conclusion: The problem is reduced to the timing advance system.
-The electronic spark timing (EST) is good. I also prove the EST from the TA and the problem persist.
-The distributor advance work properly, as the timing advance about another 18º when I raise the revolutions, until about 44º total.

Now my dudes is reduced to a pair of components, and now is when I need the opinion of any ignition guru

I doubt about the electronic spark control (ESC) or the knock sensor.
What do you think about?

Here there are not any more cars to swap these sensors and prove

 

Solved.

Thanks for all your help.

 

fran_astur, glad to hear you solved your problem. please share what it was!

 

That and people who post a long detailed problem then edit the post with "Nevermind, I fixed it!!" annoy the hell out of me. Someone else probably has your problem, post the solution.

 

After a lot off test on all sensor that could affect the injection, and the idle, finaly I could see that when I disconect the test wire to set the ignition the idle was very fine. I take attention to this,and figure that the problem was not any sensor, the problem was any ignition component. At least I could get a esc modul, and another ecm off of a running car, and prove it to eliminate posibilities.

The electronic spark timing also was verified and was ok. Now only can be one thing.

I buy a new coil pick up of $13 to inside the distributor and when I cranck the iroc the problem was solved, and I was very happy

The scanner was a great help, becouse I could see that all the main sensors was working correctly, temp sensors, maf, O2 sensor...... and with this I become to looking for another area.

This was the culprit:

 

I dont recall what this is....so, what is it?? I ask because I have close to the same problem.

 

The distributor pick-up coil for the ESC. It's not an expensive part but it takes some time to get to it.

Lou