PM me if you guys need help with the EGR system. I just passed CA smog with my modified system.
P0401 Defeated - with pics (4 Viewers)
- Thread starter Flank
- Start date
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Saved me a ton of headaches. Thanks so mich for this write up. Doing all of this over the weekend.
Tired of seeing that code pop up.
For easier fuel filter removal and install, slot out the rear (engine side) bracket with a dremel or something. This way you'll only need to loosen the inner bolt instead of removing it to get the filter out.
welp some 13 years since the OP and 3 years since last - am reviving this thread - p401 came on for me -
#1. removed the upper manifold - as daunting as this may look - it is only a few 12 bolts and nuts - three of which
you will be able to easily accces from below (they are all above the starter) - other than that is basically a
job -
from there replacing all the vacuium hoses is a breeze - as well as the VSV - quick tip - the VSV is held on by a tiny phillips -
be careful not to loose it.
obviously yer TB and EGR has to come off too - which makes it easy to clean up any gunk -
my egr port was clogged - but no where near the OP -
more kindly tips - dont forget the TB and EGR have gaskets - tis easy to forget or drop them out...
dunno if the hoses or the VSV "fixed" to the p401 code - but tis indeed gone....
no special tools at all are needed - 5 mm - 10 mm - 12mm - 14mm - long extenders and that be it -
it make take 2-3 vacuum hoses - of which you simply cut to length -
all in all maybe a job at most - requiring air cleaner - TB to first come off - then the upper manifold -
and hell once the upper manifold is off - u can also tackle the fuel filter more easily - but such too can be done from under the car with long extensisons -
anywho cheers all
when in dount - mud search it our...
bf
277k and running....
#1. removed the upper manifold - as daunting as this may look - it is only a few 12 bolts and nuts - three of which
you will be able to easily accces from below (they are all above the starter) - other than that is basically a
job -from there replacing all the vacuium hoses is a breeze - as well as the VSV - quick tip - the VSV is held on by a tiny phillips -
be careful not to loose it.
obviously yer TB and EGR has to come off too - which makes it easy to clean up any gunk -
my egr port was clogged - but no where near the OP -
more kindly tips - dont forget the TB and EGR have gaskets - tis easy to forget or drop them out...
dunno if the hoses or the VSV "fixed" to the p401 code - but tis indeed gone....
no special tools at all are needed - 5 mm - 10 mm - 12mm - 14mm - long extenders and that be it -
it make take 2-3 vacuum hoses - of which you simply cut to length -
all in all maybe a
job at most - requiring air cleaner - TB to first come off - then the upper manifold -and hell once the upper manifold is off - u can also tackle the fuel filter more easily - but such too can be done from under the car with long extensisons -
anywho cheers all
when in dount - mud search it our...
bf
277k and running....
So this weekend I did this fix pulled the manifold/throttle body cleaned both. Replaced all vacuum lines and VSV. Put back together and the truck won’t start. It turns over like it wants to but won’t fire to life.
I have some questions on some ports on the manifold itself. There is one by the EGR sensor connector and one on the underside of the manifold by the VSV (here in this pic I have the VSV hooked up to it) what are these for and where do the lines from the go to?
And here is some pics on my cleaning job
I did a ton of swaps this weekend.
Radiator
Blue hub fan clutch
Water pump
Fan
Upgraded alternator kit from Landrank
New fuel filter
VSV
All new water and vacuum lines
Was highly anticipating hearing this thing run with all the new gear but huge fail when it wouldn’t fire. Anyone have any ideas? All vacuum lines are correct bolts torqued everything seems in place. The only things in question are those manifold ports.
I have some questions on some ports on the manifold itself. There is one by the EGR sensor connector and one on the underside of the manifold by the VSV (here in this pic I have the VSV hooked up to it) what are these for and where do the lines from the go to?
And here is some pics on my cleaning job
I did a ton of swaps this weekend.
Radiator
Blue hub fan clutch
Water pump
Fan
Upgraded alternator kit from Landrank
New fuel filter
VSV
All new water and vacuum lines
Was highly anticipating hearing this thing run with all the new gear but huge fail when it wouldn’t fire. Anyone have any ideas? All vacuum lines are correct bolts torqued everything seems in place. The only things in question are those manifold ports.
RiverCityDave
SILVER Star
This lines shouldn’t keep it from starting, they’ll just make it run like crap if theyre hooked up wrong. Are you positive nothing else was knocked loose, or maybe a connector not seated? I’d go though the standard troubleshooting process to determine which of the big three (fuel, spark, compression) you aren't getting. Once you’ve ID’d that, you’ll have an idea which way to go with troubleshooting.
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Pulled the throttle body this morning and everything is in place. If I got a defective VSV would it cause no start? Would cleaning the VCV with throttle cleaner ruin it? If so would a failed VCV cause no start? I’m at a loss here I have no idea what the issue is I’ll try and upload a video
My guess would be you're not getting fuel after the fuel filter replacement. See if your fuel pump is pumping, you should hear it. If not check fuses. Make sure you are getting pressure to the rail.
Check the connection on the back of the alternator or battery wire to the alternator.
That's the primary thing you've changed that may stop start.
Also, check the plug above the distributor, it has been known to have a broken wire there, especially after messing with the intake and other things in that area.
I'm guessing you forgot to plug something back in or reconnect a ground wire (such as from the coil to the engine block lift lug)
I was also thinking this. Landtanks kit provided an upgraded fusable link but I felt if this was the culprit it wouldn’t even turn over. I have visually looked at those plugs but I should ohm it out now for continuity. Unfortunately the grounds are connected I wish it was that simple.
So since I had everything torn out I didn’t bleed the pressure to the fuel lines by running the engine and unplugging the pump before removing the filter. I lost a little extra fuel but no biggie. As for hearing the pump running I listened for it with the acc on and nothing but figured it may only run in the ignition on position
RiverCityDave
SILVER Star
It might sound crazy, but the truck will turn over with a fusible link bad. There is a procedure in the FSM for diagnosing the ECU startup with regards to the fusible link. I have a 94, and the process differs in the 95 and up. Do you have the FSM?
Malleus
Far west of Siegen
The fuel pump only runs when the engine is turning. It will not pump fuel with the key in the ACC position. I also recommend you get the FSM and start at the beginning of the troubleshooting section. You'll find the problem.
i do ill have to start reading i suppose. since im sitting here gripeing already ive got a gripe on the FSM... why are those damn pages so easy to tear out!?! a gust of wind will blow it right out of the book!
So here is a video of the issue
Let me know if you see something out of place
You could spray some starting fluid in the intake and see if it fires. It still sounds like you're not getting gas to me.
tried it didnt work. srayed a good 8sec burst through the TB with the throttle open then slipped the air intake back on.... no luck
