99 Venture EGR

[mongo66]

Need help on a "p0401" EGR Insufficent Flow code", Have been going on trying anything to fix this, here's what I have done:
Replaced EGR valve, tested for +5VDC at sensor wiring, OK; cleaned exhaust manifold pipe up from Exhaust manifold w/ Seafoam, got good flow; Got good suction from intake manifold at EGR port; replaced EGR and reset CEL, drove 10 miles and light came back on. Had code read, same thing. DMV will soon start penalizing me for lack of cert. Dealership recommended replacing EGR and gasket at a tune of $365, so I've replaced the stuff myself.
Is there a way of cheating the sensor into reading "flow" so it will pass. the resistance is approx 5100 ohms. Would this even work, or is it related to engine load, RPM, speed ........?
Does the EGR relate to the Oxygen sensor to reduce NiOx emissions, Engine temp; could the Oxygen sensor be bacd if so? How does the EGR system work in general?

[rockwood84]

i always thought the thing recirculated exhaust to be burned again.the exhaust comes up the tube from the exhaust pipe and goes into the intake to be reburned. if the exhaust tube from the exhaust pipe has gunk in it then the flow will be off. if the piston and seat inside the egr are dirty then the egr can't work properly. if the part that takes the exhaust to the intake are blocked with gunk the the flow will be off and thus the codes. a neighbor of mine ran a brush down his egr pipes and fished a lot of gunk out. he made the little thing and it does the trick. hope i didn't sound like a smart*** but thats how they work.since you have flow both ways check the piston and seat. make sure the piston hits and seats .you can spray some carb cleaner in one side and see if the piston will hold it to that side or if it leaks it thru. if it leaks it thru then you have to clean the piston or the seat and see if it holds the cleaner once you get it clean it should hold the cleaner.if the o2 sensors go bad it will pop a code for that . i had to clean the #1 bank o2 sensor after i did the intake gaskets. you clean the o2 sensors by using carb or injector cleaner on the tip until it is clean let it dry the put it back in. if it still pops the o2 code drive it a day or two then take it out and spray it again until it doesn't pop a code.

[mongo66]

So, does the O2 sensor work in relation with the EGR in determining flow? If the purpose of the O2 is to sense reduction in Niox emissions of combustion, would that mean that my O2 sensor could be dirty or bad?; if it is a probable cause, what are the chances be that could be my whole problem?(100,50/50,25%). And could cleaning the O2 be the extremly easy fix??? instead of sinking any more $$$ into this?

[wafrederick]

Pull the throttle body and check the egr passage if it is plugged up caked up with carbon.I have seen this causing this code and it was fix after cleaning the egr port out very well.

[rockwood84]

i think the ecm tells the egr when to open and close. it is closed at idle and opens and closes during driving. the o2 sensors sense the exhaust gases and this is sent to the ecm .if the readings are not in the required levels then it pops a o2 sensor code. bank 1 is the one before the cat and bank 2 is after the cat.sometimes the o2 sensors will get a crust on them and can't read or sense the gases. they can be cleaned with electrical cleaner and a fine brush. it might take two or more cleanings to get it where it can sense again.if a motor has a blown head gasket and coolant is burned ,most of the time it kills the bank 1 o2 sensor. but most of the time the sensor can be cleaned with electrical cleaner. somtimes not. the egr hose from the exhaust pipe usually get a carbon build up in them and block the gases from going to the intake . have seen the whole egr blocked up with carbon before. the hoses and egr valve can be cleared using a cleaner and a small brush . the hoses can be cleared using cleaner and a brush on a flex cable . hook the cable in a drill and run it down the hoses. 1/2 " brush ought to work good.neighbor rigged one up or bought it somewhere, it works like a drain snake .

[97Venture_Chick]

Try checking the vacuum line(s), make sure it is not cracked. I had an issue a while ago when I was trying to pass smog. My check engine light was stuck on. Well, I took it to the dealership and told them that it needs a smog, but a few things need to be replaced first. I ended up needing to replace the egr valve and both the 02 sensors to get it to pass. But, Im not sure if your O2 sensors are the problem.

[mongo66]

Well replaced the O2 today, CEL still came back on. When I pulled the old one out, the tip was white; Is this normal? For those who want to swap the O2 out, best way is to get to is from under vehicle, one arm beside exhaust manifold and another from above the pass. side tierod toward the sensor. 7/8" wrench needed to get it out(with plenty of patience and letting the area cool off first). What next

[mongo66]

Well, took the van to the dealer to have it re-eval after suggested parts have been replaced; nice guy at the service dept. hooked up the scanner to the comp. and checked the EGR valve operation. After doing this and making suggestions that the passages still seemed clogged.(not charging for his advice and time(NICE)), took van home and stripped it down past the throttle valve and low and behold, clogged port(see pics). After using carb cleaner, pick tools and strip of cloth for ridding of carbon pieces(about 2/3's of a teaspoon), van runs much smoother and so far NO CEL.

[sinless1]

Mongo,
Same exact problem, and same exact solution. Like a dummy I replaced the EGR valve ($166 at Autozone), when my actual problem was carbon build-up in the orifice tube leading to the EGR port. It was almost completely blocked, solid carbon. But I had to pull the throttle body off to get to it.

I rigged a long coiled spring up to my drill, and bent the end a little. As the hole began to clear, I bent it some more. I used wadded up shop towels to keep crud out of the EGR exhaust port and out of the air intake, and nearly a whole bottle of carb cleaner throughout the process.

Last thing was a cut a strip of cloth diaper (leftover from four kids!), doused it in carb cleaner, and fished it through the hole to clean it out. So much carbon, I had to do this twice, cutting another strip.

Drove it for 20-30 miles, finally cleared the CEL, and passed inspection today! Today was day 15 since I failed, and in TX they give you only 15 days. Nearly had to pay for a new one.