Dear all,

i have a wierd problem with my car. roughly once in 20-30 days i get the check engine light on my dash board and the engine switches off by itself in the middle of the road. If I try to turn the engine on then i get this click noise contineously from the left side of the dash board along with the check engine light.. (also had some burning smell one of the times) Then i wait for about 3 minutes and try to turn on the engine ..everythings perfect.

Background:

I am driving a 1992 mitsubishi Magna Executive TR Auto. it has done 197,000 kms. I bought the car when it had done 190,000 kms.Towards 194,600 + i started having this problem intermittently like once in 4 days or so. So gave it for a service. the mechanic said no problems detected by the car computer. he just changed oil and stuff after the service the car had no problems whatsoever. last month when i reading was about 196,500 i started having the same problem the reading now is 196987. had the same issue twice since then
i checked with one of the auto electrician. he said its the problem with the computer itself.. can someone tell me why i am having this problem and what needs to be done to rectify it .

thanx in advance

Shree

The Engine Control Unit (ECU) ie the computer is on the left hand side behind the glove box.

You need to have the codes from it checked to see if that will indicate a fault. Did your mechanic do this or was he just going by your description??

Rob

try disconecting both terminals of the battery over night or for more than 10 minutes this will restest the computer

Yes but if there is a fault in one of the efi sensors or wiring to the computer that is causing this then resetting the computer will not clear the fault.

Rob

hi all,

thanks for the reply . answering one of the questions, when i left for servicing the mechanic did say that he checked the computer for codes but found no problems .

As per your suggestion i disconnected the battery terminals and have put it back. how can one determine that the ECU has reset itself ? is there a perticular way of knowing it ..

but what surprised me was the problem i had with idling .. before disconnecting the battery teminals the car used to switch itself between 800-600 rpm at its will. This also also one of the issues that i wanted to understand. but it doesnt exist anymore. i kept the engine idle for abt 6 minutes yesterday just to see if problem is really gone, not once did it change from 800 for all that time ..

So what should i infer with this ..??

bad ecu

Do u mean to say that i will not have the ECU problem anymore.. ?? Because i had the problem only once in 20-30days..so i guess i have to wait .. Does resetting the computer eliminate all the problems ? i mean is this a permanent solution. Pl explain.

If its the EFI sensors or the wiring thats causing the problem , will the computer still generate the codes to indiacate that .. if not how is it detected ?

Shree

helpfull information follows

My biggest concern in all of this is the reported burning smell. But it would be very difficult to track down. ie removal of lots of interior trim such as the glove box, centre console and more and inspection of the looms for signs of overheating. Failure to do this could result in a vehicle fire or certainly more serious damage than at present.

The clicking sound from the left side I would believe is from the computer. My car gives a click from this area once about 2 or 3 seconds after I turn off the ignition so one click is OK. I cannot imagine what is causing the multiple clicks and the engine stopping on the road.

By disconnecting the battery and resetting the computer the codes stored in it are deleted so further diagnostics in that area cannot be done until the problem occurs again.

The list of codes for my TR Magna covers quite an expensive range of faults from the computer itself to many of the sensors that provide the data for the engine management and for control servos. However the codes do not provide all the answers as other faults not covered by them could be the problem. Generally wiring faults to the sensors etc show up as faults in the sensors but other wiring falts would not be indicated.

I'm sorry to make this sound so complicated but the efi system is complicated. It took me 6 months to track down an indle problem to the Idle Speed Control Servo (Stepper Motor) on my car so remote diagnosis is pretty difficult.

Sorry I can't be of more help.

Rob

I appriciate your valuable suggestions, Rob_D and Dirty Hands. i must admit i am learning a lot of things and i am liking it .But as i understand this ..i have to wait till the problem reoccurs.

But the one question still goes unanswered is how can resetting the ECU resolve the problem i had with idling. to my understanding the ECU controls various prameters of engine and stores information in the form of codes in case of any malfunction.

as i understand , any problem that accurs should have direct link to the cause. like in Rob_D 's case it was Idle Speed Control Servo causing idle problem or may be vacuum leaks as another example . i cant quite understand how my Idle problem is related to ECU ?

Shree

that ECU is the electrical heart of your car it contols the fuel/air ratio. the rpm. the emmissions . the timing .the distributor .spark
all the electrical sensors that the car have to be syncronised so it runs well
and that is what that ECU has to do


anything to add Rod -d ?

The chief faults that cause idle problems due to the ecu or its sensors and servos are:

Idle Speed Control Servo
Idle Position Switch
Engine Coolant sensor
Air Intake Temperature sensor
Barometric Pressure Sensor
Oxygen Sensor

Rob

The Check Engine Light indicates a problem with one of the following:

Engine Control Unit
Oxygen Sensor
Air Flow Sensor
Intake Air Temperature Sensor
Throttle position Sensor
Engine Coolant Temperatuer Sensor
Crank Angle Sensor
Top Dead centre Sensor
Knock Sensor
Ignition Timing Adjustment Signal
Injector

The above is for TR Magna and VR Verada but is probably true for most models round that time.

Rob

Thanks for the education.. i appreciate that .. i will wait for some days to see if the problem reoccur and plan the next action. In the mean time i hope to talk to you in my future posts

Shree

G'day Rob (et al).

Do you have any idea what the causes might be for the same thing in a TE Magna ('97)? I'm experiencing similar problems to tvsharsha - except that mine is that the light just stays on (almost at random, but always to cause the most inconvenience) when coming to start the engine. Yesterday the local dealer replaced the immobiliser antenna near the ignition switch because that's supposedly what the ECU told 'em was wrong. This morning the car refused to start, I returned to it an hour later and it ran all day, now I'm stranded at work (0330am) because the fault has returned again.

Cheers
Greg |;^)

i think the best thing would be to get the codes checked again for fault code in the ECU. i am sure for every fault a code is generated ..Am I right Rob_D ?

Just to clarify gnewt- does the check engine light stays contineously on even when the engine is running or only when the car stops.

Shree