I really need some help on a problem I am having with my 82 collector.
The other day driving home from work I noticed my car was not running right.
It was running very rough. I kept getting a check engine light and it was
very lazy. It started to run so rough I barely got it back home. I burned a
whole tank of gas out of it on the way home from work when it was braking
down in this condition from a full tank less than 75 miles.
After putting the OBD tester on it for the check engine light. It was
calling out a O2 sensor failure and running lean, I changed the O2 sensor,
which was bad. When I got it out and shook it, was really noisy. I also
checked the EGR valve and it was bad too it would not hold a vacuum. I
changed the EGR valve and solenoid. I got rid of the check engine light,
but it is still really loading up with fuel. I put the OBD tester on it
and it is not showing me any faults. The throttle bodies are very clean and
they are spraying a nice pattern of fuel.

Well I figured I would check and make sure it was not something else. I
disconnected the O2 sensor and started the car, and I never got the check
engine light to come on . I thought that was strange with the O2 sensor
disconnected it should have given me a check engine light. and everything I
read led me to believe it was an ECM problem. I re-connected the O2 sensor
and ran the OBD tester again and I still showed no faults.

I changed the spark plugs again and I changed the coolant sensor the one for
the computer located in front of the smog pump along with that I changed
the ECM as well. I got it started but its still loading up with fuel. Does
any one have any idea . I am running out of service Manuel for checks.


Some back ground information as you know I put a new engine it about 3
months ago and it was running great. This is the first problem I have had
since that change. I have done maintaince on the car as well I put new
shocks ,new brake system, sway bar links, along with new hatch hinges and
struts that were made for me. I have a new radiator, new hoses all new
vacuum lines new cap, wires, plugs, and new rotor as well. I have a new
alternator, new smog pump, new A/C system converted over to R-134. I have
replaced the Hood Louver relay as well. I have new water pump when I
changed the engine. I also changed the fuel pump and relay about 3 months
ago too.

The problem I am having now with it loading up with fuel just started and
it happened very quickly. I am really stumped on this one. Can you point me
in another direction that I may be missing. I have been using the Helms
Manuel to do the trouble shooting........

 

had the same problem .it was the coolant sensor .the one that you have changed .did you put in the new type sensor ?if so did you splice in the wires correctly ?check for loose connection .have you checked the tps ?

 

Get rid of the Helms manual, and get the correct factory service manual for your car.

 

I did put the new sensor in ,that is the new type. The wires matched up .............yellow and black wire on the connector it came with.
I have not checked the throttle position sensor but then again I never touched it. I did not know that was a contrubuting factor according to the book.

 

thanks for the help/////////////

 

Sounds like you are throwing parts at it without really knowing whats going on. If you dont get a check engine light with the O2 sensor unhooked, there is most likely something wrong with the computer. But there are checks to find out for sure. A good scanner should show you what the sensors are saying and the computer is doing with it.

 

Seems like the only thing you havenot replaced is the Throtle Position Sensor and the Map sensor. I had a lot of problems with mine and it was a bad computer. Make sure to dissconect the computer from the battery to clear it after you make a change, then give a little time driving to adust. I changed all my sensors at one time so I would not have problems popping up down the road. The computer will go into a "limp home mode" when problems happen. Thats what you experienced when it just barely ran. Just because you put a new ECM in it does not mean that one is not bad also.
Good luck,
Dave

 

Well I guess you could say that, But here me out first. When I first put the tester on the car it did call out a lean system and the O2 sensor code flashed. I changed the O2 sensor (it was the originail one in the car) and that cleared the codes. When I ran a full systems check using the scanner it had no codes , basically its telling me eveything was working.

So with that said I went and changed the ECM because it did not make sense that with no codes showing up and no check engine light with the O2 sensor disconnected that something was a miss here. after changing the plugs and the ECM I got the car started but it still is
loading up. I changed the Coolant sensore next to the Smog pump which by the way is new too. I went crazy trying to find the sensor finially found one that came with a new connecter in the box. I spliced it in and tried again but still is loading up. Everything in the Hems manuel lead me to believe after changing the ECM, Coolant Sensor and O2 Sensor that I had probably fixed the syste, By the way all that I replaced so far was originail in the car so its been in there a while. Now with new parts you would think I may have at least inproved the condition of the car.

Whats next??

 

I am trying to help you. I have compared Haynes to Factory manuals. They are so generic, they sometimes give you the wrong meanings of codes. The factory manual will give step by step diagnosis for your specific year. If I hade an 82 shop manual, I would help you more.

 

Sir I appreciate all your help . But I am using the shop manuel for the 1982 corvette collecter edition. It has step by step instructions and codes plus how to read the wiring . I am using the Helms shop manuel not the Haynes which by the way I could not agree with you more the Haynes book is crap......... BUT the Helmes manuel is the shop repair manuel with evey instruction you can imagine.

 

Holy crap. I mis read . I swore I would not reply before morning coffee, and I did it again. I AM SO SORRY.

 

No problem I have been drinking a lot of coffee with this problem. Thanks Again!!!

 

It can be frustrating at times because, with fuel injection, the symptom and the cause may be opposite. For instance, with an old carburtetor, if you had a rich contition, you would naturally go looking for something that would cause a rich condition. But, with the FI, if it is rich, you might have to look for something that would cause it to actually be lean. Sound funny? Well picture this. If for instance lets say the O2 sensor, or something else, was showing a lean condition. The computer sees that and pours the fuel in and the engine then runs rich. What I am saying is that the proper thing to do is to go through the checks on each system and verify that things are right. That would involve the systematic checking of each component according to the recomended proceedures that are in the manual. Of course this is always predicated on the assumption that the engine itself is phisically OK and is capable of running correctly.

The crossfires are relatively simple. The two things that I see most often, excluding sensors, are bad vacuum leaks (usuall at the rear of the plenum cover),and bad rubber connectors at the fuel pump. The dual IACs and jack leg mechanics screwing with the balance adjustments cause idle and off idle problems.

Sometimes you just have to let the smoke clear.

 

Allright, I am going to take a stab at this. It's outside the box,okay?

The part that gives it away is the tank of gas in 75 miles.

I have an 84 Lincoln piece of s__t that did the same thing. No codes, etc. The pressure regulator was bad and dumping gas into the throttle body. Changed it, and ran great for a year. Then it ran the same way.Took it to a friend who is a Ford Certified mechanic. He found a bad injector. It looked fine to me, but when he changed the injectors, the car came to life .

I really believe a bad injector is the only failure that could dump in that much gas. Even in default mode, the computer would never call for that much fuel.

These early ECM's are not as smart as a Commodore 64. They do not pick up injector failure. It assumes the mechanics are functioning correctly.

 

not shure that its all your problem but,i would look for a vac leak there may be a hose broken .do your lights go up and down ok and are your power brakes ok .something is calling for a rich condtion .

 

Do you have stock exhaust? Catalytic converter in place??? If not you need a heated O2.

Bare with me but it sounds like everything thing is working and thats the problem. Your 02 is sensing too much oxygen and signalling to dump more fuel OR that new O2 is bad. 02 is cheap..I would consider trying another one. By the way I tried 6 EGR valves before I got one that wasn't bad.

If you are not getting codes its not sensor related. Fuel delivery seems good and strong (you said new pump) so its not the fuel system.

My guess is its vaccum related. You have a new engine...right??? The bolts on the throttle plate and TBI's tend to loosen allowing more air into the engine. Try tightening the bolts...throttle plate and TBI's. I wound not mess with the TPS...if it was set right to begin with then its still fine.

Make sure a hose hasn't been knocked off somewhere. Whats you idle cold? Whats your idle hot???

It could also be the diaphram in the rear TBI it holds the fuel pressure regulator. Easy to replace...and inexpensive.

Jim

 

Thank you to all . You are all very right . I have followed the book to the letter and I agree its time to think out of the box. I have recently changed the motor in this car about 3 months ago I have replaced all vacum hoses, lines and yes the lights work on no problem there. I changed the O2 sensor I changed the EGR valve as I said in my earlier post as the EGR was not holding a vacum. I replaced the EGR solonied and valve and they work as described in the book. I have put the scanner back on and I am not reading any faults..........which the other person is right the older cars dont give you as good a read out as the new ones today. I have been thinking about the fuel pressure regulators as well It is the only thing less the MAP sensor and TPS that is left. I change the Fuel Pump and relay about 6 months ago also.

 

Warrior...only one regulator...its in the rear TBI. Not likely there is anything wrong with the spring its most likely that cheap diaphram at the top.

Jim

 

Any good mechanics in Mechanicsville?

 

If you have a VOM and a vacuum pump, you can check the values of the TPS and the MAP. The book should give these values.