Intake Manifold Question

[Darwood]

In my case I replaced the EGR Modulator the VSV and cleaned out all the vacuum lines to and from these components. Mine were 100% blocked by carbon. The port that goes to the VSV through the intake manifold I cleaned out with a paper clip.

This doesn't sound to be your case though. I never did check the VSV, however I wasn't going to take everything apart again so I just replaced it to be on the safe side.

I would replace the EGR modulator and the VSV. If you still have a problem the only thing left is the EGR valve, but I also like shotguns

 

[DieselFJ]

My EGR port was completely clogged in the upper intake. A quick run with a .5 inch drill fixed it. Most complicated part will be the time to remove the intake, and keeping the carbon out of the lower intake.

I also had a mechanic previously clean the large EGR tube for the same reason.

I had to remove the upper intake to accomodate a HG job, and that is when / how I found the clog. If I were you I would clena all ports out. I bet this will fix you right up.

I actually removed my intake 6 months ago and did exactly what you are saying. I found every port in that intake and cleaned it. The funny thing was that there was not build up anywhere. I checked the EGR tube when I had the EGR valve off and it looked great as well. I really had high hopes for cleaning the intake, but I had no luck.

Thanks
Scott

 

[DieselFJ]

In my case I replaced the EGR Modulator the VSV and cleaned out all the vacuum lines to and from these components. Mine were 100% blocked by carbon. The port that goes to the VSV through the intake manifold I cleaned out with a paper clip.

This doesn't sound to be your case though. I never did check the VSV, however I wasn't going to take everything apart again so I just replaced it to be on the safe side.

I would replace the EGR modulator and the VSV. If you still have a problem the only thing left is the EGR valve, but I also like shotguns

I have replaced the vacuum lines, EGR valve, temp sensor, and cleaned all the ports in the intake. Still no luck. I am about to just get the VSV and the EGR Modulater so I can take both of the parts out of the equation, but I don't think I could take it if the light pops back on.

Does anyone know if it is possible to rent a Toyota Hand Held Tester? I would really like one to run the EGR temps.

Thanks
Scott

 

[IdahoDoug]

While this thread is front and center, I've also got a CEL on and a buddy checked it and the diagnosis was "insufficient EGR flow". I put on a new EGR modulator since it takes all of 60 seconds to unclip and replace, but now I need the light turned off to see if I fixed it. How do you do it on the 97s - I'm used to my good ol' 93's simple system.

Will unplugging the battery work? I tried the EFI fuse - no love.

DougM

 

[RavenTai]

Doug yes the battery unplug will work, something like 10 min or so IIRC, you can get a code scanner fairly cheap that will read and erase OBDII codes fr less than $50

Portal tek, I had a intermittent VSV, it tested OK per in the FSM tests when out of the trucks but turns out it fails when it warms up in the engine.

you can test the VSV and the rest of the system wile driving using a simple test vacuum gauge,

see this post

https://forum.ih8mud.com/showpost.php?p=1420736&postcount=1


the hand held tester mentioned in the FSM that can operate parts of the system is quite pricey and rare, you may or may not be able to source one locally,


I had not said anything yet as this surly means now I will get a p0401 tomorrow but I replaced the VSV two days ago and so far it is fixed. before it would only go part of a day before the light would return.

you can replace the VSV with only removing the drivers side brace, -B- Posted directions not to long ago on how to do it, you do not have to pull the intake or even the Throttle body, some hand contortion required,

 

[Beowulf]

Remove the brace on the intake. Remove one bolt from underneath with ~3' of extension. Remove hoses and VSV from top. Small hands help. You'll need to remove the hoses by feel.

Pulling the EFI fuse should clear the MIL. Others have reported that it doesn't. Most people don't have this issue but since it's you, I put more credibility into your report. I can't explain it... pull the Negative side of the battery for a few minutes and I promise you the MIL will be cleared. It will also idle very high and might run rough for a few start cylces (but you also already know that...)

-B-

 

[DieselFJ]

If it is as easy as you guys say I will pull and test it again and see if it still checks out ok, or if I can get it to fail. I am thinking my VSV only fails under certain conditions like heat as well.

I pull the 15A EFI fuse under the hood to clear the code. I only have to keep the fuse out for 10 to 15 seconds which works great.

Sometime I think I may have spoken too soon as well, I guess I should have never admitted to fixing the terrible PO401 .

Thanks
Scott

 

[Beowulf]

If it is as easy as you guys say ...

I didn't say it was easy. I said you can remove it without removing the intake. Small, flexible hands will help. I have neither.

-B-

 

[Proven]

Beowulf, I feel your pain about flexible hands. I read that too when I had this issue after purchasing my truck. I read that someone removed the VSV without taking off the plenum and I tried to defie physics to prove I could too!

What I found when I serviced my EGR, Modulator, Vacuum hoses, and Plenum was that most of my hoses were caked with crud (I won't call it carbon, but it was black'ish and built up like cholesterol in fat albert) and after replacing all the vacuum lines with new, that make little difference. So I took another look at the connections on the plenum and found some nipples that were caked shut also.

The most notable was one near the firewall that runs straight down, I believe from the EGR to the VSV underneath. It is a tube that passes through the plenum (read solid metal pipe) that connects to another vacuum line on the underside.

I had to remove my plenum and soak it with some cleaners to loosen all the crud up a little, then I used a drill bit (without a drill attached to it, and smaller than the bore of the tube) to fish out the aforementioned crud.

Thinking I was big man on the block, I reassembled....DOH!

I later found my VSV was frozen solid with rust and corrosion, thus wy I never saw vacuum readings.

I hope any of this is helpful...I learned my lessons well.

 

[DieselFJ]

I was waiting for the response from the easy comment I actually rember trying to remove it when I was troubleshooting, that is why I decided to remove the intake the first time. I was looking for all the the tell tail signs like sludge, or any other type of blockage in all the vacuum ports, but everything including my EGR modulator look great. Something that i find funny is that I reset the light on tuesday and it has not come back on. The thing that I have noticed is that the last couple of times the light came on the roads were wet. I am wondering if I have a bad wire somewhere that is getting moisture and causing a false reading. I have been waiting for the light to come on again before I pull the VSV to check, but nothing yet. I am not sure when the next rainstorm is, but if the light does not come on unless it rains I may approach it in a different direction.

Does anyone know if any of the wires that run the EGR system are run anywhere the tires could splash water?

Thanks
Scott

 

[RavenTai]

I do not understand why you are still agonizing over this, get a vacuum gauge and test the system wile you drive. it is cheap and super easy to do, you have already pulled the VSV once and it tested fine out of the vehicle, why repeat this when there is an easier way that will test it under real world conditions? that way the only time you will have to play hand contortionist is when you pull it to replace it.

my VSV worked fine until the engine warmed up, then about half the time it would fail open turning off the EGR. It worked every time cold, I could have removed it and tested it 20 times till I got carpel tunnel syndrome and it would have tested good wile out of the vehicle and cool.

the wiring for the VSV goes pretty much directly to the main engine harness inside the intake manifold then to the firewall to the ECU, not much exposed at all.

 

[DieselFJ]

I do not understand why you are still agonizing over this, get a vacuum gauge and test the system wile you drive. it is cheap and super easy to do, you have already pulled the VSV once and it tested fine out of the vehicle, why repeat this when there is an easier way that will test it under real world conditions? that way the only time you will have to play hand contortionist is when you pull it to replace it.

my VSV worked fine until the engine warmed up, then about half the time it would fail open turning off the EGR. It worked every time cold, I could have removed it and tested it 20 times till I got carpel tunnel syndrome and it would have tested good wile out of the vehicle and cool.

the wiring for the VSV goes pretty much directly to the main engine harness inside the intake manifold then to the firewall to the ECU, not much exposed at all.

I actually didn't think about testing while running. I am going to run down to Harbor Freight and see how much a vacuum guage is, if it is too much I may just put the money toward the VSV and be done with it.

Thanks
Scott