hey guys. im back. My car is now officially screwed up.

[Jarrado]

Well here is my car model:

1987 grand am 2.5L straight 4. Engine Vin:U

Ok so .... an overview of my problem. Car will not start on its own. I have to give it a bit of gas and then, after it starts, it will not idle properly. Idle is supposed to be 1k-2.5k depending on temp. However, the car will start after it has heated up.

I suspsect its the spark plugs, but this is around the same time I took the throttle body completely apart to clean it.

I clean it every 6 months because of rust build up and dirt left over in the lines from sitting up for 5 years. his last time there was two specs of dirt present.

Now..... parts ive replaced or had my mechanic uncle check out.

Coil and coil module. I had a short at one point, I believe it is fixed, but it could have resurfaced.

Ignition module, Ive got the all good code.

Idle air control valve, replaced it last week. Old one was seized up.

No vacuum leaks

No fuel leaks

Pump seems to be fine

Idle air position sensor. I have an old one that I ued for testing. Checks out.

Oxygen sensor.

New cable wires.

Alternator seems to be putting out enough power.

Air filter is clean.

Pcb is working.

As far as I can tell from the manual, all the vacuum hoses are routed correctly.

........ i know right. This is what is annoying me. Doesn't look to be any problems.

Only thing i can think of is this.

Back in 2004 when I got the car and put in the new engine. It had a ton of rust in the tank and I didnt know it. I drove it like that for nearly 5000 miles. After which it started the dieing problem. So we figured it out and it worked ok. I had to keep cleaning out the system, cuz of all the ld build up, but ran ok. It would kinda "hang" when you gave it gas. Which im guessing was from a clogged fuel filter.

We then thought it was the cat. converter on the exhaust system, so we cut it out and put in some straight pipe. It helped power but made the hang more noticeable. I believe that is because it has some gaps which let some of the back pressure out.

Now for the part were I screwed up. I put an HHO system on my car. It did help and it ran better. I also got 33 instead of 27 mpg. But I wanted better mpg, so I wrapped the O2 sensor to lean it a bit, cuz HHO causes a lean mix. However, I crimped the O2 sensor and after a day it started to run terrible. So i replaced it. Helped but it still ran like crap. So I took off the system and took apart the throttle body.

I made another mistake here. I put the tophat in the diaphram in backwards. Im not sure what this did, but it helped cause a rediculously rich mix. I was getting about 10 MPG. This was because the MAP sensor had a vacuum leak. This caused fire to blow back out of the engine, cuz it wouldnt run unless you gave it half throttle, whic in turn sent pressure to my vacuum lines and popped some of them off there sensors. >> I know....

My uncle looked at it and put vacuum on the map sensor and the engine rev up to the right idle and then idled correctly after it had reached Opt. temp. After he fixed that. He said that it was "hanging" cuz the coils were going bad, cuz i had completely dry/ruined plug wires and they were grounding out. We also found out that cylinder number 4 was misfiring and that we had a really rich mix. So we replaced them and bought new plugs which were fouled to no end. After this it ran ok..... but it wouldnt idle up on its own. Only thing i can think of is the plugs. I changed the plugs, but they were pregaped for more engine, but they were .40 my engine calls for .60 the guy at the auto store said they were right as they were, but i trust the book not ppl. Im going to try and regap them down to .40 to see if it corrects the problem.

Also.... for some reason..... my radio doesnt work. >> It will keep the time sometimes. Or just freeze. And it started doing that when the engine started its business. <<

And is it ok to run it like it is.... idling at 500-900rpm?

So.......... should I sell this car for parts? I mean.... i only have it for the rain and bike insurance...... cuz i ride a 98 honda cbr.

Oh yeah. Uncle said the engine is in perfect condition. so yea..... -_-

[3100]

any codes?
what is coolant temperature needle showing in the morning when you turn the key to on position? is it completely cold or is it showing something else?

[Jarrado]

Originally Posted by 3100

any codes?
what is coolant temperature needle showing in the morning when you turn the key to on position? is it completely cold or is it showing something else?

I get an intermittent rich code. But i will check again. The engine light is not on. Also it shows cold when I try to start it. It shows normal when i try and it will start on its own.

[Jarrado]

So far only thing I can guess at is that the plugs arent right. Im gonna regap to 4 instead of 6 and see what happens.

[Jarrado]

Okay. I checked the gap and set it too the previous plug spec's of .040 it runs smoother but it wont idle correctly. My mpg is close to 27 which is what I got before it started messing up.

Is there a motor of something that controls the butterfly position?

[Jarrado]

Is there a sensor that could cause this rich mix and non-idle situation?.... i replaced the idle air vavle and the MAP sensor. but didnt help. the rest of the sensors are 22 years old haha.

[Jarrado]

Ok. Engine light actually came on this morning, so I got trouble codes :

35(idle air control system problem, cannot set rpm)

42(electronic spark timing circuit open or grounded during engine run OR direct ignition system fault-bypass circuit open or shorted to ground during engine run OR fuel cutoff relay circuit open or shorted to ground)

and 45(rich exhaust indication-o2 sensor volt. stays high after 1 min. of engine run.

So im open to suggestions...... ??

[scjibberjaws49]

Originally Posted by Jarrado

Ok. Engine light actually came on this morning, so I got trouble codes :

35(idle air control system problem, cannot set rpm)

42(electronic spark timing circuit open or grounded during engine run OR direct ignition system fault-bypass circuit open or shorted to ground during engine run OR fuel cutoff relay circuit open or shorted to ground)

and 45(rich exhaust indication-o2 sensor volt. stays high after 1 min. of engine run.

So im open to suggestions...... ??

sound to me that you have a computer problem, has anyone replaced it if so they probley did not change the prom from inside the old (ECM) or your prom its self has problems ( use a screwdriver handle) peck on the computer while it is running SEE IF it makes any differance or quits runnig if so you have a bad (COMPUTER !) Danny ! hope this helps

[3100]

how good are you with DVOM?

If you are good and if you serious to follow my instructions I will write them for you but if you are not going to use them or don't know much about electrical testing then I would hate to waste my time and wold recommend you to give this to pro. But if you have time and if you try to follow my instructions to the end you will narrow it down and solve it 100%. 3100


just short introduction:

it could be bad icm ignition control module, ckt 424 (tan/black wire at the icm connector) shorted to ground or open, and or ckt 423 (white wire at the icm connector) shorted to ground or bad pcm. I can tell you how to test this to narrow it down, but if you have extra icm (ignition control module) part that holds your ignition coils I would suggest you to try it and see if it fixes if not then we will go slowly from a-z and try to narrow it down. Test iac for resistance between terminal a -b and c-d both measures should show more than 20 ohms.

If I only had one guess for this problem to save my life I would say bad pcm ( check connectors at the pcm for bent pins) try another pcm from junk yard but try to find grand am with same options as your car. Or open several pcms on junk yard and take several PROMS to test them. I agree with Danny. But for you it is easier to find similar GA and take complete pcm I got mine for 22$ for 3.1

[Jarrado]

I dont think its my computer or the ignition control module/coils, probably anyway.

Im not getting a 4444 trouble code ( it could still be bad i guess, losse connection is possible-I hit a big bump sometime ago..... it happened to start a few weeks after that)

And I already tried changing the coils and control module. No effect at all.

Although there is a new development. The car is actually running smooth now. I dont know how or why. But one second it was running bad, then I go to start it again and its great. One problem, it starts fine and idles at 1000rpm cold, after heating up it idles up to 1500 rpm in neutral. I have way to much power at idle, I can idle to 25 mph. Something is bad wrong with that.

My dad suggested I may have something blocking fuel/air and that is causing a bad senor reading. Im not sure. I'll try messing with the computer a bit. Clean the pins, check wires etc.

@ 1300 I dont know what DVOM means, but Im sure I can figure it out. I work on computers and I taught my self. I'll be going to classes soon and my dad is an electrician. Ive done some electrical testing on my bike when the system fried and fixed it. If you want to write down those instructions I'll follow them as best I can.

Thanks for the help guys.

[doctorhrdware]

DVOM=digital volt ohm meter

[Jarrado]

Originally Posted by doctorhrdware

DVOM=digital volt ohm meter

We call them Multi-meters here. So it would be similar to the diode tests I ran on my bikes rectifier and alternator?

[Jarrado]

So any ideas on why my car starts fine now, but wont idle up until it gets hot? As far as I can tell my mileage is good. And in drive it behaves just fine, although I dont have to press on the gas to get to 25 lol

[Jarrado]

So Ive talked to some ppl... I got several opinions.....

A: I hit some huge bumps.... which i did..... and that loosened something.....

B: I have a bad valve....

C: Or.... I have a crack in a ring...

D: The rust that was in my tank screwed up my engine....

I think what Im going to do is wait till I can sell it... and SELL it. Then buy something with better mpg.... like a civic or corolla...

[thephantom1492]

You seems to have several electrical problems. I would check to see if your ground wires are correct, and that they are not coroded. I would also check for corosion in some wire harness.

As for you abcd... The bump could have caused a wire or harness to get loose somehow. as for bcd, have a compression test, should show up if you have such issues, but I doubt it cause what you have...

You said you dissassembled the throttle body, are you sure you connected the sensors correctly? and that you didn't messed up with any adjustement that I guess is there?

With the voltmeter, you might want to check from the ground of the battery to your car body, should be very close to 0V, same from battery to engine. Depending on the cars, some ground the motor to the body, other ground both body and motor directly to the battery. A faulty ground can cause tons of weird issues, including wrong sensor reading.