VSV is like 80 bucks or less. I did TB gasket, intake gaskets, fuel filter, new vacuum lines when I did mine. I am pretty sure my cause was the VSV for EGR.
P0401 Defeated - with pics (2 Viewers)
- Thread starter Flank
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1k-4k resistor at radioshack is a few bucks.....
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yeah...still tempted to go that way, but I might improve performance a touch if doing it the right way. Every bit helps when towing the boat.
I've personally tried about every configuration you can have. Haven't seen one single iota of change in performance or gas mileage.
I would not dump money into the EGR system in hopes of a performance or MPG gain. You simply will not get it. (And I tow a boat.
)
Flank
American by Birth, Texan by the grace of God.
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- #25
I dunno, exactly on total cost, would have to dig up receipts. My local dealer gives a TLCA discount that amounts to roughly 20%. If I were to guestimate everything, I would say maybe $300, $350ish for everything. Again, could be off. Beats paying shop time.
Flank
American by Birth, Texan by the grace of God.
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- #26
Forgot to report back on performance and mileage. I drive with a pretty heavy foot, so a scientific double blind mileage study where I keep the truck at 55 and 70 until empty is not my style. What I do know is that I typically got to half tank with about 155 miles on the trip odometer before, on average. I am now getting there with about 160, 165. If I were to guess a mileage gain, I would say 1/2 MPG. Flame away...
on performance - I equate this to cleaning the throttle body, but the truck seems more responsive on the pedal. When starting, it definitely had more of a roar and seems to catch quicker. Purely subjectively, I would call it a gain.
on performance - I equate this to cleaning the throttle body, but the truck seems more responsive on the pedal. When starting, it definitely had more of a roar and seems to catch quicker. Purely subjectively, I would call it a gain.
possible cheaper way to clear this code
Before you try this, move your cruiser outside as it creates a massive amount of smoke. I tried this on my 97 LC with a p0401 code that wouldn't stay cleared after replacing the egr valve and the modulator. (Code came back a few days after i replaced them). I will post later if the code stays clear. basically, I put about 6 ounces of sea foam in a clean glass jar, and after warming up the engine, turned it off, removed the oxygen sensor which is opposite the egr valve (make sure to remove the wiring clip which faces the windshield first, to avoid twisting the wire. use a 14 mm wrench to remove the oxygen sensor). After that I ran a 12 inch black rubber hose, maybe 1/4th inch diameter, from the glass jar with the sea foam to the hole that the sensor came out of. I had a friend start the truck which sucked the sea foam into the intake, (which should lead directly to the carbon buildup.) This causes the engine to stall, but if it doesn't, turn it off as soon as the sea foam is sucked up.
let it sit for about 10 minutes, then, outside with a breeze away from you, start the truck. It will smoke like hell for about 10 minutes, but as the carbon burns off, it gets clear. The truck hasn't thrown the code today, which it would have for sure the day before I tried this. It cost me 6 bucks for the can of sea foam. the only danger i could see would be if the sludge would mess up your valves, or plugs. so although it worked so far, maybe someone who knows more could say if this is a good idea. also, when removing the egr, you can remove the stud bolts using a 7mm star driver which makes it a lot easier to pull the egr.
Before you try this, move your cruiser outside as it creates a massive amount of smoke. I tried this on my 97 LC with a p0401 code that wouldn't stay cleared after replacing the egr valve and the modulator. (Code came back a few days after i replaced them). I will post later if the code stays clear. basically, I put about 6 ounces of sea foam in a clean glass jar, and after warming up the engine, turned it off, removed the oxygen sensor which is opposite the egr valve (make sure to remove the wiring clip which faces the windshield first, to avoid twisting the wire. use a 14 mm wrench to remove the oxygen sensor). After that I ran a 12 inch black rubber hose, maybe 1/4th inch diameter, from the glass jar with the sea foam to the hole that the sensor came out of. I had a friend start the truck which sucked the sea foam into the intake, (which should lead directly to the carbon buildup.) This causes the engine to stall, but if it doesn't, turn it off as soon as the sea foam is sucked up.
let it sit for about 10 minutes, then, outside with a breeze away from you, start the truck. It will smoke like hell for about 10 minutes, but as the carbon burns off, it gets clear. The truck hasn't thrown the code today, which it would have for sure the day before I tried this. It cost me 6 bucks for the can of sea foam. the only danger i could see would be if the sludge would mess up your valves, or plugs. so although it worked so far, maybe someone who knows more could say if this is a good idea. also, when removing the egr, you can remove the stud bolts using a 7mm star driver which makes it a lot easier to pull the egr.
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #28
I have seafoamed my truck as well, a search will yield much discussion on this for cleaning injectors and and plugs and such, but will most likely not clear an EGR code. EGR gets thrown for several reasons, either components in the system that have gone bad (modulator, VSV, Valve itself, vacuum lines, etc,) or from having a clogged port to the throttle body, Seafoam will not cure ANY of this. The sensor across from the EGR valve is a temp sensor, not an O2 sensor.
I am not against Seafoam, as I said, I have used it, but don't see it as a P0401 cure. OTOH, Seafoam has been linked to occationally screwing up O2 sensors in the exhaust, I have have read in Mud. I did throw THOSE codes after doing it and replaced my O2 sensors to the tune of $250.
I am not against Seafoam, as I said, I have used it, but don't see it as a P0401 cure. OTOH, Seafoam has been linked to occationally screwing up O2 sensors in the exhaust, I have have read in Mud. I did throw THOSE codes after doing it and replaced my O2 sensors to the tune of $250.
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I got the dreaded P0401 and after resetting ac ouple of times it would not stay off for long. I bought an EGR, VSV and modulator and installed them. No problems since and it has been 3 years. Not sure why people don't just fix the problem the first time instead of trying all these "methods" to fix it. I messed with it once and that was it.
I will post if I get the code again. I think the build up of carbon is caused by an inability of the engine to burn off carbon if the vehicle is used for primarily short drives. I have to use my LC to commute 9 miles to work. not enough to properly warm up the engine. If that is the temp sensor, I apologize for being ignorant, but the port worked brilliantly for a siphon. I am always optimistic, and I don't see what the harm is unless some one has had problems. There are instructions on the sea foam can on doing this very process. if people were losing their engines doing this, I hardly think they would promote it.
also, I did replace the modulator, vsv, and the egr, but threw the code after driving 9 miles, shutting the LC off for an hour, and starting it (to run an errand.) every time I have cleared the code, it has re-appeared within a day. I am just saying that so far, the code is clear, and I think the sea foam turned the carbon block into sludge, hence the giant smoke ceremony, which has so far stayed off.
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #32
When you replaced the egr, modulator and the VSV, did you make sure the port through the intake plenum was not clogged? Also, did you check all of the vacuum hoses? There are like 5 components of the EGR system that can cause a malfunction (including the temp sensor, cracked hoses, and blocked port). I have also heard of at least one case where someone here installed a new VSV that was bad...
I would strongly recommend you pull the throttle body and check the port for blockage, you could probably scrape out the worst of it without removing the intake plenum.
Seafoam is a temporary bandaide at best, but then again, the EGR is only for emissions. So if that does not bother you and the CEL does not either, and it works temporarily, do it before you get smog checked.
I would strongly recommend you pull the throttle body and check the port for blockage, you could probably scrape out the worst of it without removing the intake plenum.
Seafoam is a temporary bandaide at best, but then again, the EGR is only for emissions. So if that does not bother you and the CEL does not either, and it works temporarily, do it before you get smog checked.
I think if it comes back, I will solve the problem with a 2 inch piece of electrical tape, strategically placed. These codes will drive you nuts if you let them. cheers !
That port is the same one plugged on my truck. I posted on it back then and several times since. I did basically all the same stuff you did. Also replaced the PHH and had the injectors serviced at the same time. All this was easy with things that far apart. I did all that at 147k miles. Truck now has 221k mi on it and still runs like a top and no EGR codes since.
Glad you had good luck.
Update: I looked for my original post on all this back in Jan 2004, I don't find it ! I guess the system drops it after too long. Hard to believe that was four and a half years ago !
Glad you had good luck.
Update: I looked for my original post on all this back in Jan 2004, I don't find it ! I guess the system drops it after too long. Hard to believe that was four and a half years ago !
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Great info. Time for me to do this as well.
Okay, I did the quick fix on this last night. I didn't have any parts and I had even less time, but was having the code and severe pinging. I pulled the throttle body in about 10 minutes time and quickly noted that the egr port was plugged at the same place as yours. A little dental pick work and I had extracted the plug and cleaned as much of the "pipe" out as possible. Obviously, you should pull the egr valve and blast cleaner through the port to thoroughly get this job done. I see where you removed your upper intake, but I'm not sure that's really necessary.
Anyway, today the truck runs much better, no pinging, and no code.....yet. I still plan to do a bunch of prevantative, but this at least buys me some time.
Anyway, today the truck runs much better, no pinging, and no code.....yet. I still plan to do a bunch of prevantative, but this at least buys me some time.
Doing this one too - '96 LC
I'm working my way through this one right now. Just one note that might help some people: You can test the VSV valve by simply applying 12 volts to the terminals. You should hear an audible click. It's been a few days since I did it, but with the voltage applied you either can or can't blow through it. Remove the voltage and make sure the opposite happens.
Also, I tested my EGR valve by taking it to the auto parts store. They have a vaccum hand pump that you can use. Just use it in the store - then you don't have to plunk down the deposit. You should see the diaphragm move. Mine didn't, so I bought a new one for $165 - ouch.
I'm working my way through this one right now. Just one note that might help some people: You can test the VSV valve by simply applying 12 volts to the terminals. You should hear an audible click. It's been a few days since I did it, but with the voltage applied you either can or can't blow through it. Remove the voltage and make sure the opposite happens.
Also, I tested my EGR valve by taking it to the auto parts store. They have a vaccum hand pump that you can use. Just use it in the store - then you don't have to plunk down the deposit. You should see the diaphragm move. Mine didn't, so I bought a new one for $165 - ouch.
I never had a P401 until I took everything apart to get the injectors cleaned. When I had things apart, I cleaned it all up, then replace some hoses that crumbled over time, put it all back together....now I throw a p401 every time I clear it! Any suggestions, did I possibly screw something up,....should I get rid of EGR period?
Nice write up!!
Flank
American by Birth, Texan by the grace of God.
- Thread starter
- #40
I never had a P401 until I took everything apart to get the injectors cleaned. When I had things apart, I cleaned it all up, then replace some hoses that crumbled over time, put it all back together....now I throw a p401 every time I clear it! Any suggestions, did I possibly screw something up,....should I get rid of EGR period?
As bad as it sucks, if it worked prior, you probably messed up the order of some vacuum lines or something... Depending on where you live, you will not pass emissions if you remove the EGR.
