NEW 93 burb owner... with problems:)

[superjay5]

Hey guys, I joined the burb family...........but I already have a problem :(

I just bought it, its a 1993, 2 wheel drive with the 5.7. I picked it up cheap $900. I took it for a test drive before I bought it and it ran pretty darn good. It has 185,000 on the clock but had a new motor put in about 20,000 ago. Anyways drove good on the test drive and drove good on the way home.

Now, I decided before I put it on the road I should do a little maintenance.

Replace plugs(AC delco) cap, rotor, wires.
Also it was missing the exhaust and tailpipe, so I picked up a muffler.
Also swapped out the temp sensor for the computer because I had read that could cause problems.

So I fire it up, runs great, but once it gets warm it starts to run rough. Runs fine in P or N, but if I put it into drive and keep my foot on the brake it will die. This only happens when it gets to operating temp. When it is in high idle, it idles all day long in D with my foot on the brake. Seems overall to drive better when it is cold.

Anyways, I don't want to throw parts at it. I do get a Check engine light when it gets up to temp, but will disappear. I have yet to hook a scanner to it, trying to beg and borrow one.

With all this, I figure something with what I did made this happen, I went and rechecked everything I did.

Couple guesses?

Timing?
02 sensor?
Exhaust is adding to much back preasure......meaning cat is clogged?


Thanks!

[chriskelley2003]

you know places like oreillys and autozone have scanners that you can borrow right?
i'd start with double checking the plug wires and making sure they're all on the right plugs. then pull the exhaust off and see if that helps, that would confirm or rule out your idea of it being the cats. past that check all the wires and sensors that were anywhere near anything you touched to make sure nothing got pinched or left unpluged or something like that

[nvetro]

Get the computer scaned for historic codes....perhaps O2 sensors? or throttle position sensor perhaps? Not sure, get those codes checked out, the historic code will be in the computer.

[superjay5]

Thanks,

Called every Auto Part store yesterday, and either they didnt have a obd 1 scanner, or they would not rent it out. They would scan if you took it to them. Problem is I am 30 miles away from any of them. So I called a buddy and he is coming over tomorrow with his scanner to check it out. I should know more then.

One of the places I did call said you could jump a pin in the scanner hook up and it would show codes using your check engine light, pretty cool, but I hate reading blinks.

[ct9a]

You don't need a scanner for this year.

1994 is pre-OBDII. You should be able to short the pins on the diagnostic connector under the dash to see what codes it pulls. If you look at the connector, you will see that there are several pins together, and then on the opposite corner, there are two lonely pins... short those with a paper clip or something similar.

Then turn the key on to the run position, but do not start the truck. you will see that your Check Engine light will start flashing. What it is doing is showing you 2 digit codes. The first time it will cycle through the number "12" 3 times to show you that it is working. (The light will flash once for the first digit (1), then pause then flash twice (2 for the second digit). So, for example, if after it shows you "12" 3 times, it goes "Flash flash flash (PAUSE) Flash flash flash flash) then it is telling you the code is "34" Get it? Good.

Now... I don't know that the OBD system in that vehicle will give you the codes for your ABS system... some of the older OBD systems will only give you engine codes.

WARNING!!! DO NOT ATTEMPT THIS PROCEDURE ON ANYTHING MANUFACTURED FROM 1995-PRESENT!!! YOU CANNOT READ THE CODES THIS WAY AND YOU WILL FUBAR YOUR COMPUTER!!!

[superjay5]

Thanks, I will give that a try tonite!


Does anyone have a list of all the codes????

[superjay5]

One more thing, I was going to replace the fuel filter tonite. Is there a secret as to not spill a ton of fuel????

[vncj96]

just google the code it throws, most codes are pretty universal, but there is a page that lists all GM codes

[superjay5]

Yup, I found them. Thanks

[Springthing]

One more thing, I was going to replace the fuel filter tonite. Is there a secret as to not spill a ton of fuel????

If you relieve the pressure in the fuel line (as I was told... just unscrew the gas cap) it will minimize any fuel leaking. A 1/2 cup of fuel leak is not a massive amount... and there shouldn't be much more than that unless you're truck is running while you change the filter..

I replaced my filter not all too long ago and it was easy as pie. (not PI...that's a tough one...) The fuel loss was very minimal

Good luck!