It is a VSV but not the VSV for EGR. I have never heard of one failing so whatever you do, don't mess with it.
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P0402 - Learn from my mistake
- Thread starter Steve7
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I'd like to add to this thread...
About 4 years ago and like others before, I changed the pricey EGR and Vac Modulator which made my code disappear for about two weeks just long enough to get past smog check. Of course when it came back, I ignored it until the last smog check 2 years ago. I believe I just had Autozone reset my code, head straight over to the check station and had it pass that way. Fast forward two more years and its time for smog check again, still the P0402 code is there. I forgot all about Registration and Smog two months ago, my tags are expired and I'm reminded via a late notice letter... time to hustle. I was hoping to get LT's MAF upgrade in through this next round of smog check (after I fix my code of course) but got pulled over by the Man and was forced to get this resolved quickly (can't wait, what a shame). This past Saturday I decided to take the throttle body off and poke around to try and find the infamous clogged tube.
I found it and yep, it was clogged... to help others know exactly what this is, I took some pics just to help with understanding this issue. btw, don't be fooled by the little hole in the carbon build up... I took the pic AFTER I tried reaming it with a drill bit... no paper clip was gonna pentrate this crap - its was hard and took a lot of effort to drill through it. Actually went 1-3/4" deep and still didn't break through... had to hand ream using the drill bit from the bottom (engine side) upwards another 1/8" to break through. No more codes.
Hope this helps!
WET
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If they are linked images, use the [ img ] and [ /img ] tags before and after the URL for the image. (No spaces, of course.)
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i did that originally... didn't work so I just uploaded the images from my hd.
Thanks anywho
Thanks anywho
Because if you don't it is really difficult to see the condition of the rubber hoses under there. I found several dried and cracked under there when I replaced the VSV a couple of weeks ago.
alia176
SILVER Star
Another thing to add to this is that if you so choose, you can simply by pass this nipple and run the hose from point A to point B w/o going through this nipple. You see, this nipple is simply a passage through the intake, it doesn't actually open up inside the intake.
See the picture below and you'll see the other side of the intake where the nipple comes out. It's directly to the left of the red circled VSV.
See the picture below and you'll see the other side of the intake where the nipple comes out. It's directly to the left of the red circled VSV.
Don't own an 80, looked at a few, but after reading this thread it makes me wonder, why the hell Toyota even put that vavle under the intake like that. And why they ran the line through it that way also. Why not just put all that crap on the fender like a 60 was.
I'm sure it was aesthetics, but what a pain. Seems like the whole deal could be replumbed and mounted where you could get at it easier.
I'm sure it was aesthetics, but what a pain. Seems like the whole deal could be replumbed and mounted where you could get at it easier.
I didn't take off the intake manifold, just the throttle body. I used a cordless drill from the top side to get thru the packed carbon but as i mentioned, I didn't have a small drill bit long enough to break all the way thru so I did it by hand from underneath. easily doable enough with just the TB off the IM.
Since I had the TB off, I cleaned it and replaced all the sparkplugs. Here's some pics of the TB before and after cleaning at 120K miles... not bad. After I passed smog check, I put a half pint of seafoam into my gas tank and the other half into my crankcase. Hopefully that'll help with all the carbon buildup throughout the rest of the system.
WET
Before Cleaning...
Since I had the TB off, I cleaned it and replaced all the sparkplugs. Here's some pics of the TB before and after cleaning at 120K miles... not bad. After I passed smog check, I put a half pint of seafoam into my gas tank and the other half into my crankcase. Hopefully that'll help with all the carbon buildup throughout the rest of the system.
WET
Before Cleaning...
After Cleaning...
alia176
SILVER Star
Excellent job dude!
No big deal. The VSV for EGR can be R&R'd without removing the intake and TB. The process has been documented many times. You can also clean that tube with a long drill bit. Again, no big deal.
You probably shouldn't read any of the HG threads or front axle service threads if this has you spooked on owning an 80-Series. The EGR system is actually quite simple.
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Some more pics for graphical representation.....
Not spooked on an 80, was more than willing to take the plunge, but decided to go a different direction. Picked up a T100 last month, Daily driver, 20MPG, plus it is quiet and can haul some stuff.
Still would love a locked 80, but I have a 60 to sell off and a 40 to play in, and the 40 has alot of sentimental value to me. What I should do is get an 80 for a family wheeler, but just can't give up my 40. I've read and read this section, good info on MUD for an 80 owner. I really impressed by the way some have figured out all of the systems on an 80. I'm better with my older cruisers, but it also comes from wrenching on them and getting familiar.
But with gas prices, I may be finding something even more effcient, too bad 80's were so hard on gas.
Still would love a locked 80, but I have a 60 to sell off and a 40 to play in, and the 40 has alot of sentimental value to me. What I should do is get an 80 for a family wheeler, but just can't give up my 40. I've read and read this section, good info on MUD for an 80 owner. I really impressed by the way some have figured out all of the systems on an 80. I'm better with my older cruisers, but it also comes from wrenching on them and getting familiar.
But with gas prices, I may be finding something even more effcient, too bad 80's were so hard on gas.
Reviving an old thread: On post 22 you can see the metal tube that clogs up giving the 0402 code, which I have had now since we bought the truck a year ago last December. I am going to try and see if it is indeed he tube that is clogged today. What I was wondering was how often does this thing clog up? For you guys that have already reamed out the little tube in the intake chamber, how many have clogged back up and how many miles / years has it been since your initial fix?
OK, so my tube was clogged and I reamed it out. Now, the truck is consistently throwing a P0401 code! Ridiculous, I tell you!
94SRUNNER
GOLD Star
Well...I suggest continuing to clean up the EGR system, you may have created a new weak point in the system that is tripping the code.
Was this the only point in the EGR you messed with?
Was this the only point in the EGR you messed with?
Don't know if this is any help or why this would happen but...when I run 87 octane I get a P0420 code consistently...when I run 91 octane I get no code and the check engine light goes off. It also runs smoother. Ive never cleaned anything in the EGR system. Open to explanations.
Have a '97 with a P0401 issue. Did the EGR clean out and still threw the code once a week for a year. I changed the plugs, wires and air filter and haven't had a CEL in 3 months.
alia176
SILVER Star
those of with the P401 code, check out the thread on the "external VSV mod". It'll help you in understanding the EGR system a little better and perhaps help with pinpointing the cause of this code.
Basically, the code is tripped because the ECU is not seeing the EGR temp sensor get hot for some reason. The temp sensor is on the driver side of the intake manifold, near the very top, toward the firewall. Some of us are making the ECU happy by simply sticking a proper valued resistor in the connector, fooling the ECU. So, that's about it - find out why that temp sensor is not getting hot is the ultimate goal! Why isn't hot EGR gas traveling around the back side of the head to that sensor?
Basically, the code is tripped because the ECU is not seeing the EGR temp sensor get hot for some reason. The temp sensor is on the driver side of the intake manifold, near the very top, toward the firewall. Some of us are making the ECU happy by simply sticking a proper valued resistor in the connector, fooling the ECU. So, that's about it - find out why that temp sensor is not getting hot is the ultimate goal! Why isn't hot EGR gas traveling around the back side of the head to that sensor?
