jwdrouyor

Hello i am a student that recently got a hold of a 1985 Chevy camaro v8 5.0 FI. I'm just now getting into working on cars i like it allot but my diagnosing skills are really bad. when i got it the battery was dead and the alternator was not working properly. i replaced both. now that it starts i now see that it doesn't like to stay running. On my way home it started to stop when i slowed down at a stop light. in order to keep it going i would try not to stop the car all the way and it would work. i got it home safely and did a tune up to try to fix it. the problem remained so i tried to replace the fuel filter. problem still remained. i noticed some of the tubes that to me look like a vacuum because they came from a sphere shaped object were damaged so i fixed them but i dont know if i fixed all the vacuum. now after all this when i start the car it will start nice and stay running strong but then the check engine light will come on and the rpm's will begin to drop. the engine sounds like its gonna turn off but it then the rpm's spike and the engine picks up and then begins to turn off again. it will continue doing this till it finally shuts off completely. what could the problem be?? im just getting into working on cars and i plan to do all the work myself but this problem has me stumped. thankyou for your time

mdacton

could be a few things....

do you have a service manual for the car? it will tell you how to flash the codes out of it...get the codes and report back...

jwdrouyor

i got the book and i tells me something but i dont know where to look for a code 12 that it says begins the diagnostic it says.

use a smaller jumper wire to conect terminal b of the ALDL to terminal a.

what do they mean and where would the terminal be and

i feel kind of dense right about now im sorry

marolife

I agree it could be a few things that are wrong. I also agree that the "engine light" would be a good starting point. The ALDL port on your car is located underneath the dash on the driver side. It's a square/rectangular connector ,made up of two rows, that when ports A & B (the far right two on the upper row) are connected will cause your engine light to flash and reveal what trouble code is causing the light to come on. Code '12' is simply used as an acknowledgment code, to let you know the computer is going to begin showing you the codes. The code/codes can be your starting point to begin your diagnosis. I hope I have helped you.

mdacton

it shows each code 3 times...

a 12 will flash the ses light one flash, puase....2 flashes.... thats a 12

keep a pen and paper to write them down

quickchicken

code 12 shows no signal going to the ECM (electronic control module).

make sure the brown wire on the pass side by the blower motor is plugged up. this is to be disconnected to set the timing and i have seen people un plug all sorts of things to try and fix these cars.

you sound like your on the right track with checking for VAC leaks. if you are good with the multi meter make sure your TPS is at the right voltage. .54 Mv is where its suppsed to be on a MAF car. a mis adj TPS will cause all sorts of issues. as for a shop manual, avoid the HAYES book you can get from AZ. its 1½ in thick and covers a range of years, the HELM manual for our cars is almost 2 in thick and it covers YOUR YEAR ONLY. the hays IMO is missing ALOT of info and there are too many small changes between years to cover them all in a book so thin(hayes).

the HELM book can be had on ebay which is where i got my books for my 89, 83 and my S-10.

chevynutman

as soon as you find out figure it out let me know my 85 tpi has been doing same thing for 2 weeks now does yours do it at curtain temps or all the time i'm thinkin coolant temp sensor but have no time to check it

mdacton

code 12= (diagnostic test active)

jwdrouyor

Thanks for helping me out on this problem everyone.

i found a differnt symptom. its really hard because the symptoms keep changing on me. well now the car rarely stops. it seems find now but ever once in a while the check engine light will flash on then go right off. It still idles rough. and now every once in a while it will go threw a really bad spell and the check engine light will flash on and off(no pattern to the flashing) and it will kind of hesitate. as im going it will kick back. i guess you could match it up with galloping like a horse.

now as far as figuring out the trouble codes. i went to buy some jumper wires or roach clips whatever they call them and i tried to connect both the terminals but i couldnt get them open enough to clamp on the a and b terminals. does anyone know the specific kind of jumper wire that my manual says i need.

ill look for that manual it sounds allot better then what i have

as for the temprature thing its not really a factor on my car

mdacton

I always just use a paper clip.....bend it and stick it in the and turn the key on. you can get the codes and search for them online

quickchicken

what RPM does the car idle at? when i said check the brown wire on the pass side is becase when that wire is un plugged it takes the timing down to base timing and the car can tend to sound rough.

this also would be a good time to check the timing as well. someone may have backed the timing waaay off and causing it to run rough. if your hood is orig there should be an emissions sticker that will have what the base timing should be.

after the base timing is checked and the TPS is checked then see what the IAC (idle air control) is doing. this is where you set the idle. but first ya gotta get the codes, this will help keep from blind diagnosing.

chevynutman

mine idles at 550

jwdrouyor

thanks for the paperclip idea it worked like a charm. the funny thing though is when i stated the diagnosis sequence it just kept flashing code 12. and that's it. i left it on thinking it would show some but it just kept flashing code 12. i drove it around the block till the check engine light flashed on then back off again. checked it again and still code 12. i started left it till it shutoff and it still only flashed 12. does that mean some how my computer is messed up.

quickchicken

sounds like a possible ECM issue. if you need an ECM i have one i'll let go for reasonable and yes its for an 85 TPI. my 89 did some weird un traceable stuff when my ECM went south.

chevynutman: 550 is waay too low. i know my 89 idles around 950-1000 but its a stick car. you sound like you need to set your IAC.

jwdrouyor

i noticed my car idles at 550 rpm as well would that indicate anything. when the check engine light begins to flash on the RPMs kick up to 1000 1500 and then drops back down to 550.