Questions and Answers

Toyota Corolla Barely Runs Anymore Q. Hi, I wonder if you can help me. I've got a 1990 Toyota Corolla 1.6 GTi (twin cam). Unfortunately it keeps stalling and will not restart for some time. When it happened about the third time I managed to bump start it (by rolling down the hill) and using the clutch and pumping the accelerator.

Even though I got it going (miraculously) it was still wanting to cut out doing 60 mph. The rev's kept on dropping up & down, after about 30 miles it seemed to sort itself out and I managed to do another 300 miles to get home. The next day it started and after two miles it just conked out (stalled). It's been recently serviced, I've had the RAC look at it and they've managed to get it started, they suspect something to do with the ignition system.

I got the garage to have a look over it and they couldn't find any problems although the engine management system light (I think that's what its called) comes on (only when it doesn't start, as I've managed to take it to the garage twice without any problems! About 5 miles in total). They said that engine management system is indicating that there is something wrong with the "mapping" to the injectors, but this indicates bad idling speed and poor performance which isn't the case, as when its running its working perfectly.

Please, could you shed some light on the problem, I will be very grateful if you can. I am intending to try and sell the vehicle but need to get an MOT first and I can't afford to go to a main dealer for them to fix, as it costs so much. We've recently had a baby, and I can't carry on with a two door car and an unreliable one at that!

Yours Hopefully,
Philip
London, England.

A. Well Phillip, I'll do the very best I can for you. I'm hoping the US and British versions are close enough where my advice will work for you.

The first thing I would suggest is to pull the codes from the computer and see what you got. The Malfunction Indicator Light (MIL) coming on is telling you it has stored a trouble code. This will go a long way in finding the problem. Diagnostic Trouble Codes - 1990 Toyota.

Some mechanical checks you can make is to check all the vacuum lines and make sure they are connected and in good shape. Cracked and broken lines should be replaced. Also check that the oil fill cap and dipstick are fully seated. This, believe it or not, can cause stalling with this engine. Next throw in a new PCV valve and check the PCV hoses. A bad PCV will cause stalling and a broken or collapsed PCV hose will be a major vacuum leak.

Next check the fuel pressure with a fuel pressure gauge and make sure it is, at Idle 30 - 33 PSI and at WOT 38 - 44 PSI.

Another thing to check is the Auxiliary Air Valve (AAV).

Testing the AAV:

1. Remove the air intake hose to the throttle body.
2. Start the engine and note engine rpm.
3. Put your finger over the air bypass hole to the Auxiliary Air Valve.
4. With coolant temperature below 176°F (80°C), the engine rpm should drop noticeably.
5. With coolant temperature above 176°F (80°C), the engine rpm should not drop more than 100 rpm, if at all.
6. If a problem is found, replace the Auxiliary Air Valve.

Now I am working on the assumption that the distributor cap, rotor ignition wires are in good shape and the air and fuel filter are good as well. If there are any doubts at all, replace them so you have a good troubleshooting foundation.

Additional Information provided courtesy of ALLDATA