|01-29-2013 06:25 PM|
The holes looked black but not blocked. I didn't probe down onto the holes though.
Part 1 -How to Test the GM EGR Valve (P0401, P0403, P0404, P0405, P1404, P1406).[/QUOTE]
Thanks cdminter59. This is the kind of info I need.
I will run through these tests. Looks like this should diagnose the problem. I do have a code reader, so that should help.
|01-29-2013 10:19 AM|
Vortec 454 EGR problem?
When you replaced your EGR valve did you check to see if the hole in the intake was clear of carbon build up? This is the most common reason for failure of the EGR valve. You will have to use carburetor cleaner (spray can) and a piece of coat hanger wire to clean out the passage. Here is some information on testing the EGR valve. Part 1 -How to Test the GM EGR Valve (P0401, P0403, P0404, P0405, P1404, P1406).
|01-29-2013 07:18 AM|
|jaw22w||Thanks LATech, I will try the gasket thing under the EGR. Not sure what or where the MAP sensor is, but will have my buddy check it out I appreciate your taking the time to mess with my problem.|
|01-28-2013 07:37 PM|
It could be that it has developed a MAP sensor problem,either the sensor value is skewed, or the vacuum signal to it is not correct becusae of a blockage at the port for which it is hooked to. Check that out to see if it is clean, then scan live data and check the PID to see if it is within specs.
Reason I say this is because when the EGR is pulled open, the MAP sensor is used to measure a drop in intake vacuum, basically to signal the computer that the EGR is opening, causing a drop in vacuum.
Check it out.
|01-28-2013 07:13 PM|
Pic 1 is the electronic EGR Valve
Pic 2 is the Evap purge flow solenoid- sucks fumes from the canister up front that you mentioned.
70-80 % EGR flow seems high. There may be a service bulletin for the issue to help correct it. If not then
You could "trick" the EGR by cutting a soda can into a gasket shaped like the EGR gasket. Where the hole is for the pintle...Make it about 3/16 of an inch or 1/8 inch diameter. Be sure to cut a hole for the supply side too. This should provide flow, restrict flow and still allow flow, to satisfy the EGR demand and also to satisfy the monitors that trip the engine light. If it clears up the problem, make a more permanent plate out of 1/8 steel with the same size orifice.
|01-28-2013 05:40 PM|
|jaw22w||I didn't see the codes myself. They were interpreted to me by my buddy. He just said EGR problem. After I changed the EGR there were no codes, but the motor still chugged. I will check for vacuum leaks. Now that I think about it, he said the EGR was showing 70-80% at cruise. I don't know if this is normal or not.|
|01-28-2013 05:15 PM|
What were the codes originally.
I would look for a vacuum leak. On a truck that old the vacuum hoses begin to deteriorate.
|01-28-2013 01:57 PM|
Not sure on EGR type. Here is a picture. As for O2 sensor. It has never been changed, because I don't know where it is on this motor. What does it look like? Sorry for being stupid, but my race car motors don't have such things as EGR or O2 sensors. Race cars are all I ever worked on. There is an electrical thingamabob just ahead of the EGR valve on the left side of the vortec manifold, but it is not connected to the EGR in any way. It is connected to a canister mounted on the radiator frame via rubber hose. Would this possibly be the O2 sensor? It looks like 2nd pic.
|01-28-2013 01:41 PM|
Is this a totally electronic EGR valve, or a diaphragm type controlled by a solenoid?
With the EGR unplugged, it may be runnning open loop and eliminating the problem. Has the O2 been replaced ever?
|01-28-2013 09:03 AM|
Vortec 454 EGR problem?
Hey guys. I have a problem with my 1996 Chev C-3500, Vortec 454, dually with 133,000 miles. It hauls the race trailer. It chugs like it's missing at steady state cruising. It idles fine and accelerates fine with no missing, just chugs at steady state at any speed. The faster you go the worse it chugs. Code reader said EGR problem. I put in new plugs, wires, dizzy cap and rotor, and put in a new EGR valve. Also cleaned the MAS. Took it for a test drive and it did the same thing. Chugging at any steady speed. Called a buddy (pro mechanic). He hooked up his high dollar analyzer. It showed no codes. Then we took a ride. Analyzer showed no missing while the engine was chugging away. What the heck? He suggested unplugging the EGR valve. We did that and the chugging went away. Truck runs great. Of course I now have a check engine light. Any body ever run into anything like this? It has us both stumped. Any help would be appreciated.