93 bravada running terrible with all kinds of codes


derhells
08-10-2005, 08:27 PM
So here we go, had this baby for the past four years, 186000 and now it is really acting up. When I am driving I have to use one foot on the brake and the other on the gas to keep it going, no power at all during take off and all kinds of codes stored. I tested fuel pressure it is fine, pulled of the top of the engine to check for the famous leaking cmfi it is as dirty as it should be. No gas in the oil. I need some help on this one come on Chris!!! Here are the codes I get when using the paper clip jumper method, 22 throttle position sensor circuit 32 linear exhaust gas recirculation system 33 map sensor circuit low vacuum 34 map sensor circuit high vacuum 45 heated oxygen sensor circuit running rich, No shit to the last one as the fuel economy is non existent. I know one of these codes is leading to the rest of the codes but need some help finding out which is the culpret. Thanks in advance

ericn1300
08-10-2005, 08:49 PM
a stuck EGR valve will give you real rough idle and stalling when you slow down to stop but the engine will run normally at speed and can cause the oxygen sensor codes. at that mileage you might have had a piece of carbon come loose blocking the EGR in an open position

derhells
08-10-2005, 10:41 PM
a stuck EGR valve will give you real rough idle and stalling when you slow down to stop but the engine will run normally at speed and can cause the oxygen sensor codes. at that mileage you might have had a piece of carbon come loose blocking the EGR in an open position
How so I clean it or do I have to get a new one?

ericn1300
08-10-2005, 11:27 PM
you might be able to clean it with a spray carb cleaner, don't know what a new one costs. if you were able to pull off the top of the engine, this should be an easy job for you, try cleaning it first. its mounted front and center on the intake manifold, angled up at about 30 degrees. when mine (on my 92) went bad i think the trouble code was 132 along with the oxygen sensor error codes.

If you do take it off NAPA has replacment gaskets that have a screen to catch the bigger carbon particles that cause this problem.

Chris Stewart
08-11-2005, 03:15 AM
I agree with Eric,
An EGR valve is easy to work on. It's under the rubber intake manifold air inlet piece, held in place with 2-10mm bolts and has an electrical connector. If you can change a tire, this is a piece of cake.
They're actually a pretty reliable piece except after running up the miles and carbon gets in it.
What happens is a little piece of carbon holds the plug valve in the EGR open and the computer finds out (pintle position sensor) and sets a trouble code. Removing the EGR, removing the offending piece of carbon, reinstalling the EGR and disconnecting the battery to reset the trouble codes fixes it quick. Installing a screened gasket Eric described is the permanent fix for carbon lodging. Another thing that occurs is the stem on the plug valve will accumilate a little coating which will stick it closed or open. Removing the EGR and simply working the plug valve in and out with something like a pencil unsticks the thing and after it works freely, reinstall the EGR. I haven't heard of anyone needing a new EGR...oh yeah, don't spray anything other than air in one unless you want to need a new one.
Sometimes, after the motor has been running poor, the sparkplugs get grungy and need to be replaced. The easy way to access plugs is through the inner fender rubber flaps behind the front tires...it's a straight shot. Are the plug wires old too? How 'bout a good old fashion tune-up?

derhells
08-11-2005, 06:27 AM
I just did a tune up about a month ago, I also pulled the egr valve and moved the little plunger back and forth and then put it back on. This did not solve the problem. I am going to take it off again and spray some air through it and see if that does anything different for me.

Chris Stewart
08-11-2005, 07:51 PM
The TPS code is odd to me but it looks like it affects everything except the EGR valve.
If the TPS is junk, the motor should still try to run with the map sensor values but it'll be rough-rough-rough.
Get 2 of your safety pins and the digital volt/ohm meter out.
Run one pin through your black TPS wire, that'll be your negative connection.
Run the other pin through your blue TPS wire, that's the TPS signal wire.
Now turn your ignition switch on and your DVOM to DC volts. You should see .45 to .95 volts at the idle TPS position and as you gradually open the throttle, the readings should gradually and smoothly increase to over 4.5 volts.

Now, if you're less than .2 volts with the TPS at idle, recheck your connections, and if everything's ok but the voltage still isn't there, take the pin out of the blue wire and run it through the gray wire which is reference voltage from the computer...do you now have 4 volts or greater? If so, you have voltage to the TPS but none at idle so the TPS is junk and needs replacing. If you don't have 4 volts or greater, connect the negative DVOM wire to a known good ground and check again. If there's still no voltage, the reference voltage is not getting to the TPS (uhh ohhh) . you'll have to find where the circuit is open...wiring inspection.

derhells
08-12-2005, 08:41 PM
Blew out the egr last night and seems to be running fine thanks for all the help

ericn1300
08-12-2005, 11:01 PM
I bought my 92 Bravada with the 4.3l engine partly because I've had great results with my other GMs with this engine. My 86 Astro van has over 250K on it now, but on more than one occasion the auto shops have recommended a carbon blasting or carbon vaccuming procedure.

I've always declined, and instead chose to use a good cleansing gas like Cheveron, and instructed my load leveler to do the same when she has to fill up.

Do these carbon blasting treatments help, or should i just continue using good gas?

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