DTC 1401/401 solved 01V6

[tireman]

1401/401 DTC code solved. 01V6 222K miles. Performed the usual checks nothing found. Replaced the DPFE sensor and EGR valve. Cleaned out the EGR channel thru throttle body of carbon. Used air compressor to check flow, good. Ran engine without EGR valve dettached, air flow, good. Used a bore scope to recheck EGR channel, more carbon buildup found, removed. Checked EGR pipe with bore scope, almost blocked by carbon, Removed lower half of weed wacker to get flex shaft out. Attached to drill and cleaned out carbon from pipe, worked great, used shop vac to remove carbon. Everything clean, still had code! Used air compressor to check rubber hoses from DPFE to EGR pipe. Large hose ok, small hose popped off connection when air applied. Blocked. Removed hoses, both had flaking interior rubber from age. But not the real problem. The problem was the small hose metal shaft on EGR tube had filled with carbon. No way to clean without removing EGR tube. Had to cut off EGR tube with dremmel tool then use an impact wrench and extention with 27 mm socket to remove EGR tube bolt. You maybe able to remove bolt with a crows foot if you have one. No way I could find to clean out small tube with EGR tube installed. Back end EGR tube nut frozen from age, impact wrench did the trick.
Update: used a dremmel to cut off the two DOFE pipes, both clogged with carbon, just a tiny hole remained about the size of a needle tip.

 

[T-Flip]

Is there a way to delete EGR without triggering codes?

Search on this forum remains inconclusive to the pros/cons, but it seems integral to this car for it to function properly. Emissions testing are no problem here as some shops will pass just about anything.

 

[tireman]

the car runs fine without the EGR, there should be a way electronically to set the output voltage at a steady rate, reference voltage is 5v. so you should be able to tap the reference voltage with a resister and feed it back to the PCM.

 

[milehighmikey]

Nice write up, tireman, but did you end up replacing the stainless steel egr tube? On mine, it has always backed off using just a huge Crescent adjustable wrench for me.

Question for you, Tireman: Do you do many WOT runs? I have always let it run hard above the 3500 rpm intake manifold tuning valve opening threshold on a regular basis. Unfortunately in 5th gear on my car, that valve doesn't open until around 90 mph, so I need to ensure that I am in a safe place when I do this, or do it in 3rd and 4th gear. Using a lower gear helps keep the speed more reasonable and safe. If I had an automatic, I would probably have done similar things in 3rd or 4th gear, just to clear out the cobwebs.

 

[tireman]

Nice write up, tireman, but did you end up replacing the stainless steel egr tube? On mine, it has always backed off using just a huge Crescent adjustable wrench for me.

Question for you, Tireman: Do you do many WOT runs? I have always let it run hard above the 3500 rpm intake manifold tuning valve opening threshold on a regular basis. Unfortunately in 5th gear on my car, that valve doesn't open until around 90 mph, so I need to ensure that I am in a safe place when I do this, or do it in 3rd and 4th gear. Using a lower gear helps keep the speed more reasonable and safe. If I had an automatic, I would probably have done similar things in 3rd or 4th gear, just to clear out the cobwebs.

Yes, i replaced the entire tube, my rear bolt was rusted shut, only way was to cut back the pipe at the nut and use an impact driver to remove, bolt and connector came out as one. then impact the nut off the connector for reuse. Question two, no I had a 25 year career investigating traffic accidents, I drive like an old lady........I've seen to much carnage out there.

 

[tireman]

Update - after replacing the EGR parts beginning with the DPFE, the fault codes came back. Some were not enough flow and others were two much flow. So what went wrong here? Everything was replaced right? Here is the answer. I replaced the DPFE first. The rest of the system and hoses were full of carbon and flaking rubber from the hoses. Some of the junk went into the new DPFE sensor before I started replacing other parts of the system. So I thought about it and decided it must be the DPFE and replaced it again. That was the problem. Running good now 227K miles and climbing.