Hi

I have a problem with my 89 2.8 V6 automatic in that the engine idles roughly when warm such as when at stop lights and in drive.

Also when in park with the engine running (when warm) the revs surge and it nearly stalls out before recovering. On one occasion it was revving at 1700!

Fuel consumption seems high and the heater blows warm air not hot so this might be a cold start issue.

I have had the MAP Sensor and IAC checked so any advice would be appreciated.

TW

 

Have you replaced or disconnected the battery?
If so an idle relearn procedure will be necessary if it's an automatic. I forgot this step and it drove me nuts trying to figure out what was going wrong.
As for the heat thing, is your thermostat stuck open, not there at all, or wrong temperature range?
Quite a few here have helped me ALOT with my rs. Too many names to list, but thanks to them all.

 

Need More details.The range of what could be causing this is pretty wide.From a stat being stuck open and the temp sensor reading the wrong temp to a blown head gasket to a crack head to a EGR being carbon-ed open etc,etc.

If you have a steady stream of bubbles in the rad after the stat has opened,it is a head gasket or cracked head.

Have you checked for water in the oil yet??. Or the other way around with oil in the water.

Pull the plugs and see what they look like.

Fuel pressure check and FR test it.

Treat this like any other gas engine.It takes gas,air,and ignition to run it.

 

Thanks to you both

The car has just come back from paint and the battery had to be recharged although I don't know if it was completely flat. What do I need to do for the idle to relearn?

When I checked the oil a couple of days ago it was clean so no water in there.

 

Just found out what "idle relearn" by reading through earlier threads / topics. Some guys out there seem to think that a 2.8 litre V6 does not need to do through the relearn process.

One other thing - it takes longer to start now from cold.

 

The 2.8 does NOT require an idle relearn, PERIOD. This is according to the GM service manual.
Your car does NOT have a MAP sensor. It's a mass air flow sensor. It switched to MAP in 90.
When was the last time you did a tune up? What condition are the vacuum lines in? What else has been "checked" or replaced?

 

Dan

When I first got the car (May) I had a problem with it cutting out and loosing all electrics. I had the earth checked and the distribution board cleaned. The electrics were better but then had a problem with it stalling in drive so had the IAC has been cleaned and the emissions checked (June).

Now it has started to idle roughly in drive when stationary and when in park the revs surge. Seems to run ok when actually driven but seems to be using a lot of fuel. Thinking about changing the O2 sensor and fuel filter to eliminate the "easy" stuff.

TW

 

Take out the mass airflow sensor (the thing attached to the air filter can) and look inside the end pointed towards the battery when installed... There is an orange square in the middle, the frequency film. This MUST be completely flat, and clean. If it's dirty, you can find some airflow sensor cleaner and use it (but make sure everything's dry before you put it back together), but if the film is warped, you might be in a bit of a pickle as a new MAF is probably quite expensive over there.

Also, measure the resistance of the coolant temp sensor (the thing next to the thermostat housing with the ROUND plug) when the engine is COLD. And pull the spark plugs and note their color (on the cylinder end, not the wire end). To cover all of your bases, measure the resistance of each fuel injector. Should be 11.8 ohms or more, or less than about 10% difference between the highest and lowest... Any injector failing gets sent to the rubbish bin...

 

Dan

Thanks - I will give these a go.

TW