Hey ya'lls my 96 302 with OBDII had the check engine light come on shortly after i bought it. After reading it through the data port the truck reported insufficient EGR flow. Here is why that may have have happened; the tube running down from the egr valve rusted a hole, the guy i bought it from tried to repair it by epoxying the hole, like the ******* he is he just dripped it right onto the bare tube. it did seal but maybe a week later the hot exhaust had burned a hole though the epoxy resulting in a leak and the check engine light coming on with the insufficient flow code. I tried a more solid fix by covering the hole with panel bond (super strength epoxy with high heat resistance) and wrapping it in exhaust patch tape and finally with metal tape fastened with hose clamps. We cleared the code with the code reader and assumed the leak had been sealed because of the excessive measures taken. well no dice..... light comes back on with the same code.

My question is how can i correct this problem? should i replace the tube? and if so does anyone know why the one on my 96 is different from every egr tube i have found in the junkyard? Mine comes down from the valve and goes under the intake manifold then who knows where, every one i have seen goes right down to the headers from the egr........

i any event, my truck runs fine no problems besides a possible lack of fuel economy (i get about 15, but its a MDo5 with MAF and i hear they can do better....) I want to fix this problem so i can try the timing bump on a code free engine and also to make the light go off. Thanks in advance to anyone who can answer a few of my questions.....

 

'96 is the only year of OBDII on this body style, probably why the pipe is different. I don't think fixing the pipe will fix the problem, but I'm not as schooled on the OBDII stuff.

 

how could the pipe not be the problem? its the only problem piece under the hood and i can directly correlate its failure with the light coming on and getting a reading that describes perfectly a leaky pipe..... if i dont replace it what can i do?

 

You really aught to change the pipe, but a couple other possibilities are the EGR valve itself or the mount portways are clogged, the EGR diaphram is leaking, or the EGR solenoid that feeds Vac to the EGR valve isn't supplying sufficient Vac. I would check the Vac system pressure to make sure it's not a global Vac system pressure problem.

 

ahh been there done that, vac system is solid as is the egr it's self. I guess a shorter question is, does anyone know where this tube goes on a 96? so far i havent had the initiative to take off the intake manifold just to see where this thing goes without having a replacement on hand, they're pretty hard to come by apparently

 

tube goes from the exhaust to the EGR...if it isnt flowing the specified amount it WILL pop the code...I suspect the EGR isnt moving as it should...you need to test the valve actuation...make sure the solenoid has sufficient vaccum...if it is low the valve wont open as it should and cause low flow...

 

Like I said, I don't know OBDII. With OBDI there is no way for the computer to "see" the flow of gases passing through the EGR. It merely assumes the gases are flowing if the EVP says the EGR is open. I don't know if OBDII is the same.

 

I thought you said, If we told him, we'd have to............ you know,...... Long walk off the short pier bit.

 

Isn't the EVP sensor the one that determines insufficient flow by the position of the EGR valve? Same one that say's the valve may not be closing completely, by position of the valve? Which would imply the EGR Solenoid may not be supplying sufficient Vac or the Vac is bleeding out the EGR diaphragm.

 

My guess is that the bone head who sold it to you cleared the code right before you test drove it to extinguish the CEL. Actually, it's probably more than a guess, I'd be willing to bet on it. Fighting that same battle now on my 96 5.8 liter.