Interesting, I may have to give this a shot. See what difference it actually makes. Give it a shot on the dyno after I get my vacuum pump fixed, see if it changes power at all.
Sean

 

did this for the second time...volatge was at .348 and supposed to be at .469 ... has worked both times. anybody with one of these should try this

 

I should do this again; It was off last time I did it so it probably is again.

 

Sean,
Per our conversation, I should explain that the truck has run strong ever since the 110 hp injectors, intake, exhaust and edge comp. box install, but over the last couple of years it became more difficult to add fueling with the comp box. I assumed the comp box was going bad. Several months ago I started pulling a 12000 lb. RV trailer and couldn’t use the comp box at all without the truck bucking and jerking under any load. It has had an occasional “check engine” light that has became more frequent of late. I disconnected the comp box to get a clear diagnosis and found the “P0122” code (low APPS input). The local shop told me to try adding an auxiliary ground to the VP44 loom (black w/ brown tracer). That turned the P0122 light on every time I “cleared codes” and fired the engine.

When I read the APPS adjusting procedure that gurroo987 posted it made sense and I tried it. My APPS called for .559 vdc and was set at .368 vdc. I got it to .561 and called it good. It’s not the same truck! It pulls smooth with all the fueling up, even on max setting #5, from as low as 1000 rpm (haven’t tried lower rpm). The torque curve starts lower with out as much turbo lag. It really cut down on the smoke. Before I could fill a large intersection with soot if I put full throttle to it before the turbo could spool up, but now it leaves a light gray cloud with blue tire smoke (I may miss that smoke option). The truck has never been so well mannered and easy to drive. It seems to me that this will make life easier for the 24 valve motor and likely will cut fuel consumption. I will be checking the orange w/blue wire for vdc from time to time since its so easy to do and does appears to be a regular problem, even if its not out far enough to throw a code. I recommend this procedure for any one who has a digital volt meter with a “low” volt scale.

Sean, it still amazes me that I was away from home today visiting Santa Rosa and stopped into “TOTAL PERFORMANCE DIESEL” and the guy I was talking to was you. Thanks for the tour of the shop and more importantly, the projects! You guys have a great facility, even a dyno! Good luck this weekend at infineon raceway and the “Pinks” TV show taping. Nice web-site too.

Thanks Everyone
Bad Dad

1998.5 24 valve, intake, exhaust, edge comp box, 110 hp injectors and “holley” blue pump through the stock lift pump.

 

I know, it is a crazy small world sometimes, who would've thought that would happen without planning. It was nice meeting you, and definitely drop by when you are in town again. Also, I forgot to mention while you were in today, we will be hosting a dyno day on Saturday Oct. 30th. There is thread with a flyer in the events section about it. The thread says oct. 9th but we rescheduled because of some pulls and races that weekend, if you can make it, we'd love to see you there.
Sean

 

i read this the other morning and thought what the hell borrowed a voltmeter did it it called for .518 and it was at .664 and i got it to .516 havent driven it enough yet to tell for sure but just around town it seems smoother in acceleration and less smoke thanks for the write up on how to do this.

 

Here's a tip if you do this.
You know where you make the hole in the wire for the voltmeter probe? Dab a little silicone on it so it seals up the hole when you are done and if you wrap a bit of electrical tape on it, it should pull the silicone out the next time you need to do the adjustment.

 

Sup all,

I did the apps reset while I lived in Ft Lauderdale. Made a huge difference with my ride. However it seemed that it did not last long, maybe a year and I noticed it started acting funny again on the drive to Maryland. I have 290k on the clock and halfway up to Maryland got tired of the driving issues and woke up early while at the hotel and went out and adjusted it before the wife was ready for breakfest. Very easy to do and made the remianing trip smooth. When I got here, I broke down and purchased a TIMBO Apps. It was a very simple install and over the last eight months have made several trips to Roanoke VA and Knoxville TN with no issues like before. So I kinda feel like there is only so much adjusting that can be done before it has to be replaced. But it is amazing that such a smal peice can cause so many issues.
oudive

 

Mine is starting to surge quite a bit again; I will have to do this soon. The one from TIMBO might be an option for me down the road...

 

Yeah, they definitely have a limited life span just like any other part. But it is nice that adjusting them is an option at all. It sure beats buying a new one. One more question though. Is there any reason not to disconnect the plug from the PCM and test the pin itself, that way the wire doesn't have to be punctured? The other thing I would consider would be t-tapping the wire and then probing the tap. Then just leave it connected for future use. On other circuits that I use to check voltage and tune, I have added a dedicated test lead too it so I don't have to mess with it much each time.
Sean