I have an '02 Avalanche and have developed a problem. I will appologize for the long post in advance. We hauled our trailer to go camping with no issues. The next day, we were on the way to church and the engine completely dies- no trailer- still at camp. So still had all of the gauges and other electronic items functional. Pushed the truck down the road to a turn-around area. Noticed the PCM fuse (20 amps) was blown- replaced with spare- still not able to start. Did not have meter or tools with me- so just started to swap. Finally go to the relay for the fuel pump and swapped with the Daylight running lights and was able to get the truck running well. I noticed that I had the drl still- so that really was not the problem.

I was able to pull the trailer back without a problem, but my wife complained about the truck stumbling randomly on takeoff. I took the truck and noticed the same. If I accelerate full throttle, it will work well; if I try again after a harder run, then I will get no real change in RPM (will vary no more than 1500) and no increase in speed. If I stop and try to start quickly, then it will stumble and not really want to respond. After a while of feathering the throttle, it will run fine again.

I took the truck to AZ today to have them get the code (have not got HPT or EFILive yet- hopefully soon) and it indicated EGR. Could it be this is all that is wrong? I do not think that it is electrical due to the relay described already. Any suggestions or past experience would be greatly appreciated.

Later, Jon

 

If the EGR is sticking open, it will cause the engine to stumble and possibly stall...it's like having a huge vacuum leak. I've seen it happen on a few different manufacurers vehicles, often after a highway run where the vehicle has been cruising consistently, then comes to stop (like at a toll both or off ramp), and the engine stumbles and stalls.

 

if the 20amp pcm fuse was blown it is more than likely a bad fuel pump drawing too many amps.

 

At the risk of sounding too stupid, I have another question. the engine is running worse now and is almost to a backfiring state (this of course is random still- but more frequent). It can occur at any time and happens more frequently as the engine warms up. Going at a steady speed is sometimes very exciting.

I was looking for EGR valves to replace, but is seems that I do not have one. I understand that it is on the right side of the engine, by the oil filler neck. I have no valve that remotely looks like the one listed, nor do I have any wires or tubes anywhere near that. I understand that not all 2002 had one(?).

Does any one have a refference drawing for a 2002 5.3 for the EGR?

If the truck does not have one, then what kind of error would make that code?

I will look into the fuel pump once the tank gets lighter

Thanks for any help.

 

Here's what the EGR looks like, it's actually an electronically controlled solenoid...it's the thing all of the way to the right, with the electrical connector on top, attached to the manifold (or shorty header in this pic), with 2 bolts. It has a black mesh covered tube that goes from it to the r/s of the intake:



If your truck is not equipped wit EGR, there might be some sort of PCM glitch...are you the original owner of the truck, and/or has the PCM been replaced or tuned? Maybe it was replaced with a PCM for an EGR equipped vehicle?

 

The fact that the 20a PCM fuse was blown is intriguing(sp?)....unless the EGR solenoid (if equipped) or it's harness is shorted.

bigbadwolf54's hypothesis makes sense and is quite possible...it would definitely be worth your time to check fuel pressure if you have access to a guage...

 

Thanks for the picture. I certainly do not have this!

I am the original owner. There are 160,000 on it- has been good until lately. I have had the SES for the cats already- replaced with the Magnaflow units (I know that it is not ory- but they still seem to flow very well- when the engine is running). SES light went off for a while and then came back on and stayed. I took it in to see what it was and that is when I got the EGR code. While I was looking for the EGR, I counted 3 ex manifold bolts gone. I only replaced one after cat o2 sensor (Factory crossthreaded it)- the rest are original.

As for the module, it never has been replaced. I was tempted to get a new one flashed- but really do not know if this would do anything. I really do not want to start changing parts for the sake of changing parts.

I think that is it for the problems (besides that abs module- which I will take care of on a free weekend), and what I have done so far.

Anything is helpful, thanks

 

sure sounds like a fuel pump to me...

 

Sounds like a fuel pump to me too...

Didn't GM delete the EGR in 2002??????

 

Than why did it throw an EGR Code????