Diesel lesson from Dr. John Voo

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Jackass of all trades
Oct 22, 2008
Stopped by Ateb to drop off the 81 for a compression check John offered me and saw him under the hood of a 5 speed full load VX Limited 81 that had a rough idle. Seems it had a newly rebuilt pump from Holmes just installed. I learned a ton from John as he brought out his specialized diesel tuning equipment- never knew you could use a timing light to check injection timing! After confirming timing at 5 degrees, he whipped off the top of the boost compensator and showed me how it worked and how to adjust it. Seemed it was set to full volume injection. He put it in a spot he thought it should be and put it back together. Small improvement. He then adjusted the total fuel screw incrementally by feel and 'ear' for about five minutes until the engine sounded truly silky. A quick rip around the neighbourhood and the owner was very satisfied. All the while he kept up a running commentary about how every component worked and had to interact correctly with the others to provide acceptable performance- the difference in smoothness and performance he made to this 81 was shocking. John was careful to point out that Raj at Holmes did a super job on the the pump, it just required fine tuning to accommodate the 'age' of this 21 year old engine.

Naturally, I asked if he would do the same for my engine! I have had smoke issues since I got it which is great fun for annoying Christian (lol) but nasty to live with. We wheeled my rig in and started the compression check- an HDT wants 498 psi for standard numbers- well I had 5 cylinders at 520 and 1 at 320... Fxxx! well you can imagine how bummed I was. I was ready to fall on my sword so I left for work with visions of $5,000 engine rebuilds (John's rough idea)... I was thinking about how the heck I was going to pay for this when 2 hours later John called and said I was ok with 520 psi across the board. One of my valve shims was out just enough to screw the reading. He told me he thought I had a valve out of spec but he had a nagging thought that it may be a ring, and he didn't want me to get any illusions until he could test it. Anyway, John is taking my truck home to give it a thorough test drive and further refine the fuel settings.

Kudos to John for being such a straight up guy and being willing to share his knowledge to anyone who is genuinely interested in these trucks. I mean, I was ready to pay to rip the cylinder head off but he cautioned me to hold off and talked himself out of a very expensive invoice. Nice work.

good to hear, and it's nice that there are still shops around that care about the customer and not the bottom dollar. Thanks for sharing that with us, usually when something bad happens everyone complains, but when a guy does something good nobody says anything, so thanks for the info.
Isn't it great to see a master at work. I love watching someone who truly understands how components work together and fine tune to perfection.

Truly a class act!
I have had smoke issues since I got it which is great fun for annoying Christian (lol)

I still cant get the soot and smell out of my shorts.... :flipoff2:

Nice read thou!
What were your shorts doing so close to his exhaust? :hmm:
You need serious help.
A big advantage for ATEB customers is John is incredibly experienced and he is the both guy you talk to AND the guy doing the work. At ATEB very little gets lost in translation between what the customer wants and what the mechanic thinks he needs.

In most other shops the guy you talk to is NOT the guy doing the work, someone often with less experienced. There is a big difference between these two types of organizations and same goes with home repairs – deal with the guy actually doing the work. Generally the customer is better off with this 'leaner' organizational model.
Yeah, he has sure helped me out a lot with my diesel gremlins.
Actually Graham was leaving the meeting, and drove off. Not knowing Christian was still attached to his tail pipe. What can I say, strange things happen after the meetings.
Yup John is great !
Yup!!! John and Phillip are the only two guys that work on my truck aside from myself. I'm really happy they've decided to stay in Burnaby a little while longer. It's nice to have a trustworthy shop like ATEB and not have it be a PITA to drop the truck off for work to be done.

Keep up the good work boys!! :D (and Helen, of course you too! ;) )
I just had John re-installed my injection pump and tune it for me after some rework he had done. I have been driving around with his spare IP since Graham and I took off for Moab last year. I had some issues with my pump still, even after it had been rebuilt at Fred Holmes twice. John has been trying to get to the bottom of things with my trucks performance, and it's a getting there. Through researching and conversing with friends in the field in Malaysia, he has started to learn more about our pumps, and putting it to practice on my IP. I will post some pics later on what he found.

For the first re-build after my ACSD failed, I was there for most of it, since it was my DD when Raj had it apart, and I didn't know John or ATEB yet. Raj found a wear mark on the main shaft of the IP, but said it wouldn't affect anything and polished the ridges that were left. I also had some parts with some slight browning (very light rust), that he polished by hand with some 2000 grit W/D sand paper. After it was all put back together, it never really felt the same, kind of rough, a little noisier, and I was down on power, with a rough shut off.

I was also having some idle issues, and something my Turbo Timer was sensing??? I found out about ATEB through Raj and reading the mud forum, that's how I found Fred Holmes. Raj and ATEB helped me with my idle issue, a seal from an additive bottle was getting caught in the pick up tube. Eventually, I started to get know John, Phillip and Helen a lot more, it also helped I lived not too far away, so dropping off my truck was easy. My truck has been a learning curve for John, since my issues have never come across them, until now. John has done a lot of research into my problems, and talking with associates in Malaysia. When another 81 showed up, that had the pump and injectors done at Northwest Fuel Injection, and was running horribly, so John systematically narrowed it down to the pump and had it removed and sent to Fred Holmes to be rebuilt. It came back better but still rough, so John installed his spare test pump that works properly. The truck ran smooth, even at a low 400 rpm. So eventually both IPs were sent (the good and the bad one) to Fred Holmes. Raj took them both apart to look for differences and replaced some parts on the bad one. So now my pump wasn't the only one that had issues, and was still running rough, even after getting the injectors done. John found out some things from his friends in Malaysia, and that some parts that were polished by hand at Fred Holmes are very sensitive to material loss. John removed my IP and put in his test IP into my truck, unfortunately I didn't notice much improvement, and now we weren't sure if being taken apart at Fred Holmes had an effect on the good test IP???

Well, I got use the test pump for the Death Valley trip, while my IP was sent back to Fred Holmes to get rebuilt again and a mini shaft replaced. While on the Death Valley trip in the heat, my truck started to run fine with the test pump, the sound from the exhaust, smoothness of the engine, and the TT wasn't sensing anything??? When we started coming home to the cold, it started to get rough again and the TT was sensing something. When I had the second rebuilt installed, it still had a bit of roughness to it, but up on the power? When the weather got warmer, my trucks idle would drop and start to hunt, kind of sounded like a top fuel dragster at the starting line. John tried a few things which helped, but even now and then the hunting would show up when it got warm, John got to hear it when we did Hut Lake, and the exhaust was dumping a bit more black.

So back to the drawing board. Another truck with pump issues showed up at the shop, it was hunting as well. In the end Raj recommended to replace the housing, since it had a bit of wear, and it seemed to have solved the hunting problem, and that's when Graham got a lesson in diesel tuning from John. Before, Graham and I set off for Moab, I had my pump removed and John's test pump put back in for the trip. I was going to have it sent to Fred Holmes and have the housing changed as well. John put it off, and wanted to research some more, before going that route. Part of the reason he found out some power mods for our trucks, and some for his EFI Prado. He told me he is learning more about the pumps, since I have been having issues, and mine is like the White Rihno of problems. It's forced him to be more inventive with testing our pumps, and doing more of the work than having to send it out, that way he knows what's been done and nothing missed. Instead of replacing the housing, John found that all that needed to be done, was to replace the bushing for the main shaft, instead of paying for a whole new housing. He also had the main shaft ground down and polish by machine, to remove the wear mark found from the first re-build, then having the bushing reamed to fit the new profile of the shaft. Before my pump was done there was about .006" of play on the the shaft, and now it's within half a thou. He also found an compressor wheel and it's leafs were fused together from friction, how it happened is a mystery. He found it when he was pressure testing the IPs. His test pump was pushing 17psi, and mine was 1psi at the most??? So he took mine apart and found the wheel and the leafs fused together, and replaced them, now it pushes 20psi. It brings me to where I am now, and the truck is a lot quieter, with the shut down really smooth. I just have to find out now, which factory sensor is the Turbo Timer linked to, and I think I will have found another source to my problems. What ever it is, its not intermittent anymore, and must of failed. I will be able to give my truck a good run later today, but so far I like the improvements.

Thank you, John and Phillip for all your time spent on my truck, I appreciate all you have done so far. I would be really lost without your help.
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It is quite the journey you've been on young Jedi.... The truck is noticeably smoother now, no more chugga chugga...
Haven't tested it out on the highway, when the is engine fully warmed and it was starts to chug. Or on a good incline yet, you know how it would stall out when I would go to climb something. Hopefully, I will find out later today at Stave.
Going muddin'?
F#@k no! My truck is some what half clean. I need Christian to detail it.
Good to hear that your issues are being sorted, Lance.

Zip it, Sailor!

Lance hasn't even begun to address his 'issues', Kim...

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