New EGR Valve didn't help ...

with the P0401 (insufficient flow) issue I've had on and off for a year now.

Just got done putting it on with a new gasket.

While I had it off, I compared it to the old - BIG difference, I for sure thought that it was the problem. The old one's pintle hole wouldn't hardly move, irregardless how much I cleaned it - and it looked pretty corroded.

I cleaned EVERYTHING while there - the TB (again), the EGR ports (AGAIN - 5th time in a year), the air filter's new, along with the PCV valve and now the EGR valve and gasket.

Went for a drive; not even 15 miles into the drive the check engine light came on again.

I'm completely baffled, and literally tired of dealing with this issue - as it doesn't seem to run any different when the light's on or off. I simply need to fix it so it will pass emissions in January!!

Yes, I disconnected the negative battery terminal the whole time I was doing everything = 30-45 minutes.

Is it possible the battery was not disconnected long enough for it to clear the code??

The ONLY code I get is the P0401 - EGR insufficient flow

Anybody have any other ideas??

a break in the wire going to the egr?

Ramblin, I remember earlier discussions on this, but dont remember the details. Do you have an electronic EGR valve or is it vacuum actuated?

Joel

Electronic.

Looks like an upside down can with only 2 bolts mounting it, and an electrical connection.

Sounds like the same feedback EGR system the 1998+ 3.2/3.5 uses. I just did a decarboning on my cousins 2002 trooper yesterday. First thing I would do is remove the EGR valve and start the truck. On the EGR mounting base you need to verify exhaust flow out the exhaust port and a strong vacuum on the vac port. If these are both a go, your plumbing is free and clear. The valve is new, so it shouldn't be a valve problem. Only other thing I can think of is there is some auxillary flow measuring system on this particular EGR setup. Vac actuated EGR valves use differential pressure or the MAP sensor to determine if EGR is flowing or not, the electronic EGR valves have a position sensor and temp sensor built in to verify flow.

Joel

ok, I have another thought here, I was just thinking that in all the times I've cleaned the EGR ports, I've never had the truck running.

Could it be the EGR port is not getting cleaned enough cause I'm cleaning it without the truck running??

If I were to clean it WITH the truck running, do I need to have anything plugging the exhaust port or can I leave it open, even while spraying intake cleaner into the smaller hole?

In other words, I'm not gonna light up like an X-mas tree, am I??

Just how much am I supposed to spray into that little hole with the truck running?

See if you can shoot it with some compressed air.

At idle, a small amount of exhaust pulses out of the EGR base. It's not high pressure at all. I actually just plug it with my finger. It takes a few minutes for it to get hot, or you can just put a glove on.:wink: The vacuum side should readily suck in a spray carb cleaner. If it doesnt pull in the cleaner, or you cant feel a vacuum, it's plugged & will need a coat hanger (or similar) snake-out. If all that is good, you've got some type of instrumentation issue, whatever indicates flow is not indicating.

Joel

See if you can shoot it with some compressed air.

With or without the truck running??

Thnx for the suggestions!

ok, just got done doing another cleaning WITH the truck running. Hey, when the EGR port is sucking all of this intake cleaner in, where is all this crud going??

Hope it's not into the cylinder walls and such, that could be harmful?? I'm guessing.

I only used half a can, put her back together and took it for a drive. The CEL was still on because I hadn't disconnected the battery at that point.

It is now sitting in the driveway, battery disconnected - don't need to go anywhere, so I'll reconnect it in a couple of hours.

Tomorrow will tell the story. If this don't work, I give up, I see no point in throwing any more time/money into that CEL code as the truck runs fine with or without it.

I'll simply have to take my chances and hopefully get the emissions test done on a good non-cel day.

Like I said, weird thing is, is the light only comes on once or twice every few weeks, but it's been on for 4 days in a row, something it hasn't done since last winter.

..when the EGR port is sucking all of this intake cleaner in, where is all this crud going??

Some of it gets sucked into the combustion chamber, the rest falls to the bottom of the common chamber. No worries. It's harmless. I've never seen the inside of a common chamber (dry intake) that wasn't all black and nasty. So you did have exhaust puffing out of the exhaust side and a good pull to the suction side? You need both. We still need to figure out if the 1997 3.2L EGR valve is a feedback unit or not. I'm thinking if it's got a 4-wire connector, it's gotta be a feedback unit (valve and flow sensor all-in-one). If your flows are good and a new feedback EGR valve still gives the low/no flow code, there has to be a bad connection or broken wire for the sensing portion of the valve.

Joel

Yes, it's a 4-wire connection prong thingy.

EGR port had good suction, and the bigger hole had good exhaust.

You mentioned having to snake the EGR port, but I have this tiny little fish aquarium type brush that I couldn't barely get in there. I stuck a screw driver in that same hole, and discovered that it obviously curves off in which a wire coat-hanger would for sure come in handy. Course, I don't have one.

Letting it sit overnight with the battery disconnected; if it does come back on and seeing as the crud is harmless, I'll get a hold of a longer wire type thingy and shoot a whole can of cleaner down it next weekend.

Am I using the right stuff to clean it; i.e. Air intake/throttle cleaner?

Thanx for your help.

If you've got flow thru both ports you dont need to snake it. The vac port/tube has a few bends so you really have to jamb a wire down it. This is a last resort thing & does not appear to be your problem. If the low flow comes back, either you've got a defective new EGR valve (not likely) or one of the circuits to the connector is dead.

Joel

Ok, well I did keep the old EGR valve just incase.

Well, it ran with a fairly rough idle for about 25 miles; and for a while, I thought it had a leak in the air intake area, could hear whistling noise - I did remove the intake to clean out the TB again over the weekend.

But, at about 35 miles or so, all of the rough running stopped, power smoothed back out, the whistle went away (whatever that was) and CEL is OFF - for now anyway.

Wonder if it was clearing out some more crud, I really didn't get the engine all that warmed up after cleaning the EGR again yesterday.

In the back of my mind, I can see it being a possibility for a connection to be bad, but wouldn't the CEL be on all the time, in that case??

In the back of my mind, I can see it being a possibility for a connection to be bad, but wouldn't the CEL be on all the time, in that case??

Not if it's an intermittent short/break.

Joel

Well, guess we'll cross that bridge if it continues. For now, it's off and I'm thinking about just getting my emissions done tomorrow, that way if the light comes on again, I won't have to worry for another 2yrs or so.

Cheap way out I know, but I see no reason to keep messing with it when the EGR valve is working and the pipes are clear; just have to satisfy the stupid CEL for emission control.

Hopefully they pass it while its off.

With any luck they will do away with the testing by the time you need it again. Not sure when they are supposed to have all that done but I see the roadside test vans here every few weeks.

What's that gasket made of? I took mine off tonight to check it/spray it out before getting a new gasket. I pounded it flat and reused it. Hope it's good.

I have reused my gasket many times, but I have a new one waiting in my box-o-parts.

Cool. Seems to run fine. Although there was some carbon in there the pintle moved freely and the passages were all clear.

I have reused my gasket many times, but I have a new one waiting in my box-o-parts.

I've never had to replace an EGR gasket either. They are a hard fiber type gasket.

Joel

I could've reused the gasket for sure, but figured the EGR valve was new, so I might as well put a new gasket on, was only $3 from Napa.

CEL is back on, never even made it to the emissions station.

I'm just gonna have to hope that Colorado does away with emissions testing by the end of the year; if they don't, I'll just unplug the battery the night before testing in February and hope it passes.

Really very aggravating. Maybe around X-mas or something I'll have time to play with the wiring around the EGR, but from what I can see, I see no obvious issues within the physical signs of connections.

I have the same general issue with the CEL... the EGR is my next target. I will clean it out... and by the way, thanks for discussing this! I have been following the conversation in every detail.

So I have a basic question... I read that what is required for the cleaning is a can of "intake" cleaner.... I did not find this at the Auto part store. I have seen carb cleaner available... and have read where people have used this. My question is... "what is the difference between the two? Is carb cleaner too harsh, flammable, etc?" I just want to make sure that I use the right stuff.

Thanks guys!

johngyver

John, I just use the cheapest can of carburetor cleaner I can get. I've used the $5 cans of name brand "throttle body cleaner" and $1.99 cans of generic carb cleaner. They both do the same thing! both are 'sensor safe'.

Joel

Thanks for the info.... carb cleaner it is! LOL

John

Ramblin, before you delve into troubleshooting the wiring to your EGR valve, you should refer to a system or wiring schematic specific to the 1997 3.2L EGR system. Again, we are not 100% sure the actual flow sensing is done within the valve itself (like it is on 1998+). Like I say, many EGR systems use a auxiliary DPFE / differential pressure flow switch and some use the MAP sensor to sense EGR flow. I know your 1997 has a MAP sensor, so that *could* be a possiblity. Dunno for sure.

Joel

I will reclean the MAP sensor this weekend; last time I couldn't truly get a clear shot at it cause the clamps on the intake wouldn't give.

It may or may not have the DPFE sensor, I'm not sure either. I'm not readily willing to delve into the wiring on the EGR system as I don't have anything to resort to, and as hard as I look, I can't find any books/manuals specific to the '97 model year.

I have the Haynes manual for the 91-97 Rodeo/Amigo years, but that primarily covers the 3.1L; 2.6L; and major areas of the 3.2L, but nothing very specific on the EGR for that year/engine. It only says that the EGR system is Linear and that it should be handled by a qualified technician.

How important is it anyways, to have this EGR system working correctly?? Nothing would thrill me more to see this stupid CEL stay off for good, but I'm not gonna keep throwing parts/money/time at it when the truck's running fine.

I'm beginning to think that no matter what I do, it's not gonna go away.

In my opinion, they've made too many errors on these 1990+ vehicles with the addition of extra emissions, computers for this, computers for that.

EDIT: Is the MAF sensor the same thing as the MAP sensor??

...How important is it anyways, to have this EGR system working correctly??

actually it is important. the exhaust gases it introduces into the cylinder actually contribute to the engine running cooler, so it is a good thing.


//bc

I will reclean the MAP sensor this weekend; last time I couldn't truly get a clear shot at it cause the clamps on the intake wouldn't give.....

EDIT: Is the MAF sensor the same thing as the MAP sensor??

No, MAF and MAP are totally different systems. The MAF in the air intake tract is not associated with the EGR system. MAP or manifold absolute pressure is a pressure transducer threaded into the intake manifold, downstream of the throttle body. Basically, engines that use MAP to 'sense' EGR flow pick up the reduction in vacuum associated with EGR kicking in or the EGR valve opening up.

Joel

Can this be cleaned without having to remove the intake manifold?

...
It may or may not have the DPFE sensor, I'm not sure either. I'm not readily willing to delve into the wiring on the EGR system as I don't have anything to resort to, and as hard as I look, I can't find any books/manuals specific to the '97 model year.

I....but I'm not gonna keep throwing parts/money/time at it when the truck's running fine.

...

get the factory manuals,the workshop manual and the electrical manual at the least. www.helminc.com (http://www.helminc.com) yes, they are expensive, but considering the work you do on your vehicle and the angst you (we) experience with every problem, the price will be worth it, really worth it (and fewer if any $$$'s thrown away on unnecessary parts.

at the very least Ramblin Fever, spring for the www.alldata.com (http://www.alldata.com) year subscription for about 25 bucks. that's what i did, and it convinced me to part with the big $$ for the hardcopy manuals. the electrical stuff is worth it weight alone...

//bc

Well, as long as it sticks to the EGR system, I can deal with it.

But if it starts having major electrical issues - it's gone. Been there, done that, you end up chasing and chasing and never finding. Don't forsee that actually becoming a problem though, at this point.

It's probably the stupid MAP sensor - only thing I haven't messed with yet; and the only possibilities after that in connection to the EGR insufficient flow -is the wiring to the MAP sensor or the EGR valve itself.

CEL is off again; we'll test the MAP this weekend.

Are there any other sensors connected to the flow of the EGR - i.e. throttle position sensor, idle air sensor, etc.

Did you ever chech the MAP sensor? I am having the same issues with my 2000. CEL lighr keeps coming back on after cleaning it with the same code.

Sorry, yes, I had gotten really frustrated one day and started a whole new thread; the problem on my truck was a broken map sensor and a corroded Idle air control valve (not sure if you have one on the newer models).

Thank's I'll have to check that out.

One question about the possible broken wire. If it was broken, wouldn't you get a P0403 error or something? I know I get that error when I disconnect the EGR to do the cleaning.

After reading this thread, I am going to check my flow on both ports. Now that I think about it, my car does whistle when I do a hard acceleration. So I guess I have an intake leak. Damn it!

All I had for 1 whole year was the P0401 code.

All I had for 1 whole year was the P0401 code.

Then I will replace it on mine to see if that fixes my problem since mine has been going on for a long long time.

Where the hell is the MAP sensoron a V6 98 Rodeo? Can someone take a pic of it for me please?

'97 is on the passenger side of the intake manifold.

thanks. I will have a look when I can find time. I am still unpacking boxes in my house I just bought. I have ordered the part which should be here by Friday or early next week.