89 cutty stalling

[red93z34]

My 89 Olds cutty with the 3.1 and auto trans runs for about 30-45 mins and then shuts off and won't start back up right away. If I wait 10-15 minutes it will start back up and do the same thing, runs a few mins and then shuts off. Any ideas on whats wrong? Thanks in advance

[Robby1870]

check the engine codes, but it sounds like it could be the MAP sensor going out. I broke the vacuum line to the MAP when doing my plug wires, and it did that same thing, cuz it only starts to work when the motor hits like 170-175*

 

Robby

[red93z34]

we already tried to check codes but it wasnt sending any out, the Service Engine Soon light doesn't even come on.

[Robby1870]

check for a vacuum leak. Sometimes, vacuum lines will be cracked enough where the SES light wont come on, but it will affect the car

 

Robby

[Slade901]

You might be experiencing a "heat soaked engine".

 

I did experience a similar problem with my car. Got my car to a repair shop and told me that it needed a block-off plate. Total charge $250 parts/labor.

 

I still did not know what they did to my car about that block-off plate because they won't tell me. The car was running ok after they did that.

 

I have researched and researched until I finally found what that block-off plate does. It was for the EGR block-off plate. As you know the EGR would re-circulate unburned gas back into the intake for emission purposes.

The problem with that is if the EGR is defective, then the EGR would just re-circulate the unburned gases back into the intake. Normal EGR would open/close at a proper time but bad EGR would just open and let all the hot gases cycle through.

This gases are hot and would cause some problems with your intake manifold and would cause one of those "heat soaked engine" problem.

 

So, I checked my EGR and sure enough the mechanic just placed a block-off plate on the EGR so that it won't recycle the unburned gases. I said to my self, I could have done it myself but I did not know it at the time.

 

I have the removed the block-off plate and fixed the EGR and cleaned the passage way. To keep my air intake cool, I have removed my stock air cleaner assembly and put an after market cone filter instead. I will also going to bypass the throttle body heater since its purpose is get the throttle body some heat during cold cold winter months.

You just disconnect the two inlet hoses from the throttle body and connect them together with an L shape hose and 2 clamp hose. GM has part # 10115742. I know it is for a 3.1L engine but it might be the same for other engine with a throttle body heater.

[GnatGoSplat]

A bad fuel pump can do that too. Unfortunately, I don't know how you can rule that out without a fuel pressure gauge.

[red93z34]

we already replaced the fuel pump, that was what we thought it was at first. Also replaced the ignition module and put in a new computer because it was throwing an invalid prom code which it doesn't do anymore with the new computer.

[red93z34]

well I replaced the map sensor and the car is still doing the same thing. After it runs for about 20-30mins, it starts to stumble a little bit then it shuts off and it won't start back up untill it cools off a bit. The fuel pump has also been replaced. The cooling fan and thermostat opens up normal also. Its just after about 20-30 mins it shuts off. The ECM has also been replaced 2 times already. Any info would help. Thanks

[Robby1870]

Im just throwing some things out there, blocked cat, bad EGR, or bad O2 sensor

 

Robby

[red93z34]

The car has been sitting for about 6 months, right before it was taken off the road the cat was replaced, could it be clogged already? I'll check in to the egr and o2 sensor. Thanks

[Robby1870]

I dont think the cat would be clogged that fast, I mean 6 months is a very short life for a cat.

 

Robby

[Slade901]

Let me throw another one. Faulty Injector.

 

A faulty fuel injection would short out when engine reaches a high temperature and flood the engine and shuts off the engine. It takes a while for the gas to evaporate and you have to wait a few minutes to start it again.

 

Try to disconnect the fan wire connector and directly connect it to the battery or try to make temporary switch so you can turn it ON when the engine is running and check to see if the engines dies again or not.

 

If the engine does not stop anymore around 30-60 minutes, you may need to flush your coolant thoroughly.

 

Try using a fuel injector cleaner first (needed every change oil) or the fuel injector needs replacement.