My son dropped his car in my driveway about a month ago. He had just had the fuel tank replaced but was also having problem keeping the car running and it would stall at traffic lights. He asks them to check it out. They said they would have to change the tank first before the engine could be checked.
When he went back to see were they were landed he was told that for 3000.00 dollars they could fix the car. Naturally he wasn't prepared to pay that kind of money.
I'm not a mechanic but ill try to help him out.
First the car wouldn't start at all. I checked the Main Relay.
When the ignition switch is turned to on The switch makes 3 to 4 clicks the engine light comes on but I could not here the fuel pump come on. So I checked to see if any current was present at the fuel pump there was a pour connection which I fixed, tried again and could here the fuel pump come on for 2 seconds.
Tried to star the car it would start but die after a few seconds.
Second checked to see if there was fuel pressure at he fuel filter by removing the service bolt and it check out OK. I changed the Fuel filter anyway.
Third I checked all the spark plugs for spark all plugs had sparks. After reading all the great information on this site I noticed that this car is equipped with an ECU. I checked to see if the ECU had a Code, which turned out to be Code 16 (Injector problem). I went to a junkyard and got a complete throttle body injector's included from a Model just like his that just rolled into the yard on its own power.
Forth I changed the injectors and there was a problem in the main injector.
I reset the ECU and started the car. To my surprise the car started but unfortunately it runs at fast idle (2000Rpm and up) and I can't get it to Idle and looks like white smoke comes out of the exhaust.
I detached the acceleration cable so it wouden't interfere with the idle speed started the engine but got the same result readjusted the cable to specification. Re-started the engine again with the same result but this time the ECU Code showed trouble code 16 again.
I reset the ECU by disconnecting the negative from the battery for 30 second. This time I disconnected the EACV to see if the ECU would give me a different code and it did (Code 14 Electronic air control EACV)
I reset the ECU again and started the engine same problem engines revs at about 2000rpms no idle and white smoke still comes out of the exhaust.
I replaced the ECU from another car and it gave the same result.
Any one has any Ideas what I should be checking next. Could the ECU have a problem is there anyway to have it checked out of the car. What else could cause a fast Idle condition.
Regards
Rjohns

High idle can be caused by the EACV itself. While you had it out, you should have cleaned it from inside. That's exactly what's causing my high idle after I drive and come to a stop at a red light. I have to hit the gas pedal a bit, then it settles down.

By the way, your car should idle at a steady 1500 RPMs while cold, and slowly go down to 750 RPMs when it gets at operating temperature.

White smoke should mean your car is burning coolant. Try to see if there's coolant missing (inside the radiator and the overfill tank).

Try to get the car to operating temperature, and see if the revs drop down. Also, try to punch the gas pedal a bit while it's running and see if the revs drop down (after the initial raise). Also, make sure it has enough oil and coolant before you try to run it.

By the way, that error code 16 is most likely caused by a main relay. Try to take it out, resolder it and put it back in. I had the same problem on the same car, and resoldering the main relay fixed my no-start-in-hot-weather problem.

Can a main rely be bad even though the main rely shows no sign of malfunction with its 3 or 4 clicks when the ignition is turned on and a bench test also shows that the switch should be good.
The car now starts revs around 1500 RPMs for about 30 seconds and then dies and the ECU sends the code 16.

Regards
Rjohns

Hm... code 16 has something to do with your injection system, and a main relay is a part of it. I mean, what does it cost you to get it out and resolder it? It can only help. Besides, 3-4 clicks sounds like too much for a main relay. There should only be 2. One before it starts giving power to the fuel pump, other when the fuel pump is done building up pressure. There should maybe be another click, but I never hear it due to engine turning over and producing more noise than a main relay.

Also, main problem with the main relay is that it goes bad when the temperature gets up. So you wouldn't notice it while testing it outside the car.

I just asked the question out of curiosity. I thank you for your reply
But I do have more questions.
Once I've re-soldered the main rely and the car still starts and runs for 30 to 40 seconds and then stalls. Could the stalling be caused by the fact that white smoke comes out of the exhaust which seems to indicates that maybe the head gasket is blown or worse!
Can a compression test be made even though the engine doesn’t reach normal operating temperature or is there a different method used to determine it the engine is still in fair condition?

Regards
Rjohns

Compression test can be done without engine reaching the operating temperature.

Search online for a "leak-down test". It gives you a better idea of the condition your piston rings are in.

Can you keep the car from stalling by keeping your foot on a gas pedal, and keeping the revs at about 2k RPMs for more than 30-40 seconds?

I re-soldered my main relay twice... thought I fixed the problem, but it always came back at a most inconvenient time. I bought a new one for $43 bucks, problem gone.

Before I get into doing a leak down test and changing the head gasket our there other things that can be checked first.
Main relay re-soldered
The condition remained the same. Car starts every time revs 1500rpms or more. If I press the pedal in long strokes the engine will hesitate but if I Press on the gas pedal rapidly it will keep the car running stutter a bit at low Idle and then revs at about 1500RPMS I can do this several time before it actually dies. So Far I haven’t got that Code 16 again but when I do I clear the ECU and the car starts right up unfortunately still has the same problem. Any Ideas?

Finally I got the engine going and must of the white smoke has disappeared.
Probably due to condensation.
But know that the engine is running I've noticed the Catalytic converter gets RED HOT! Is this normal? What could cause it to do that?
Could it be caused by improper timing help.

Regards
Rjohns

I have no idea whether it should get red hot or not, but if it's not supposed to get that hot, then your exhaust gases are too hot, causing the cat to get too hot too. And your "exhaust gas temperature" (EGT - search it on the web) can be too high if your timing is off. For example, if your spark jumps when your exhaust gases start to exit the combustion chamber, then they will still be burning when they enter the header...

This is just my logic... I have had no experience with this, but my logic tells me that improper timing could cause your cat to get red hot, if it's not normal for a cat to get red hot.

What are the steps to check the timing?

Generally, to see if the timing belt has jumped a tooth, you should turn the crankshaft until you see a white mark on the crank shaft sprocket align with a pointer on the timing belt cover (it's a sort of a "pin" sticking out of a timing belt cover, just above a hole where the timing belt tensioner would be). Now you should remove the upper part of the timing belt cover to access the cam shaft sprocket. There is a work "UP" written on it, and 2 horizontal marks (lines) are made on it. The lines should line up with the valve cover surface. If they don't (and the word "UP" is pointing up), then your timing belt has jumped a tooth or two.

Or if you have access to a timing gun, use it. I do not know how to use it since I never did, but I guess you could have a shop do it for you.

Had to clean the idle controller and at the same time decided to clean all the lings on the throttle body.
When I put it back together and started the car that’s when I noticed that
The converter was getting RED Hot.
Do you know how I can adjust the throttle body?
Believe that too much gas is being set to the cylinders and not enough time to burn up before it reaches the converter and finishes burning there.

There is no such thing as "adjusting the throttle body". If you mean that your fuel injectors are pumping too much gas, that cannot be controlled in any way other than increasing your fuel pressure WAY too much, or messing with your ECU settings, which you cannot do if you do not buy another (tunable) ECU or don't burn yourself a chip and do some soldering on your current ECU... besides, since you have a DPFI, I don't think you can control it in any way.

Did you check your timing?

To fix the idle problem I had to dismantle some of the throttle parts to get to
Some grim that was stopping the mechanism from working properly.
When I put it all back together and started the engine that’s when I noticed that the catalytic converter was getting red hot.
Noticed that the engine was getting too much fuel or to rich air and fuel mixture.
Then I noticed that on the side of the throttle body there seem to be a device that controls the airflow (three wires attach to this device) on the accelerator shaft. My Haynes manual doesn’t explain this apparatus, so does anyone knows who to adjust this device.
When the throttle is almost closed the measurement from the bottom and middle terminal read 719/720 ohms when in the middle it reads 1.820 ohms give or takes and when the throttle is fully opened now the middle and top terminals the reading is 918-920.
Right now the car starts, idles very low and will hesitates if the accelerator pedal is pressed to rapidly even a few backfires.

Well did you find out what the problem was?

My 90 civic lx is doing the same thing.

Starts and warms up and then shuts down..

Hello Alex, did fix the problem?
If you did not, I can help.