PS Pump, Steering Box, Vacuum Rebuild...now this.

[npieske]

I have been working on the replacement of the original steering box on my 2000 3500 DRW. Along with the Borgeson Steering box from Geno's Garage, I replaced the steering shaft, both high pressure and return PS lines, rebuilt the vacuum pump and subsequently replaced the PS Pump with the Borgeson pump, also from Geno's.

I followed all the directions for bleeding the air from the PS Pump and related components from Borgeson and the factory manual. However, no fluid would pump from the PS pump into the Hydroboost system, thereby preventing fluid from even getting into the steering box. After reading several forums on the TDR, I found one that indicated the pressure relief valve in the PS pump needed pressure to open and allow fluid to pass. So, I followed the directions and increased RPM between 1500-2000 and presto! I had power assist to my steering. I then do all of the sequence for steering lock to lock and add fluid as needed. PS system is now working great....and then...

I have the wife come out and begin steering from lock to lock with and without the motor running so I can complete leak test and check for any potential clearance issues. Wife is in the middle of steering back and forth and the truck suddenly increased RPM without any pedal pressure to the throttle. My wife's first response was, "I didn't touch the gas!" After correcting her verbiage of her denial of any "throttle" application and she finished glaring at me, finishing with an eye roll, I had her shut the truck off.

I hop in and with the engine running, begin to steer from lock to lock slowly. I was able to get the RPM to increase randomly at different quantities without any rhyme, reason, or pattern.

What the heck happened? Is there a new problem, or is this "repair" I am trying to complete manifesting into something else?

Meanwhile, I am still driving the neighbor's 2018 Eco-Diesel....while mine sits on jacks stands in my garage.

Any ideas?

 

[Ozymandias]

How high is high that the rpms went up?

 

[GAmes]

If you had mechanical linkage like a 12 valve I'd suggest you check it for interference or a sticking cable.

 

[npieske]

How high is high that the rpms went up?

The first time it revved probably 500 rpm. The subsequent revs were a 75-200, if I were to guess. I am wondering now if I may have an issue with TPS, APPS, or injection pump? Like I need another problem...

 

[Ozymandias]

So it raised randomly... I guessed an empty battery so the PCM might raised it to give a sufficient charging.
But thats not random, so, forget about this theorie.

 

[Joe Mc]

Might be applicable, might not? When turning lock to lock did the "wheel turner" hold pressure on the wheel when reaching the stop? If so possibly placing load on engine that would increase rpm. Possible?

 

[npieske]

The revving didn’t occur near the steering stops. Like I said it was at random and odd times with no pattern.

 

[Joe Mc]

Sorry for forgetting you mentioned that already.

 

[JR]

I can't think of anything that would cause an INCREASE in rpm, except a load being placed on the engine. A diesel will increase rpm to maintain it's target idle, to a point. Engine rpm DECREASING followed by a very brief increase of 50 or so rpm would sound like grid heaters cycling but I'm sure you are well aware of that.

Never seen an APPS cause this issue but to test it out you can unplug it and run the test back. The engine doesn't need it to start and ide. You won't have any "throttle" It will throw a code which is easily fixable once plugged back in.

You don't have a TPS (it is the APPS).

Also never seen a VP do this but anything is possible. Any engine codes? That could be a starting point if there is.

Your neighbor is awfully generous letting you drive his brand new pickup. I get along well with my neighbors, we trade off food dishes and small Xmas presents. I plow their drive in the winter for free. But my pickup is off limits Gotta draw a line somewhere.

 

[Joe Mc]

JR, I have to agree with your assessment fully. I'm wondering if perhaps as turning lock to lock when the wheel stopped briefly and began to turn again at that point a small short load was recognized causing brief rpm changes. For npieske's sake, with APPS disconnected if any load is placed on engine as turning wheels he might/should experience a brief drop in rpms? I think a road test is in order myself to see if situation is replicated. BTW when mine is sitting still idling if I just turn wheel enough to put pressure on the pump the rpms will increase such a minor amount that you can hear it but so small amount that the tack barely moves. Hope this helps.

 

[JR]

For npieske's sake, with APPS disconnected if any load is placed on engine as turning wheels he might/should experience a brief drop in rpms?.

I could be wrong but I don't think it will have a bearing. If I understand The APPS function correctly it's only job is to send pedal % input to the VP. (Fly by wire)
The fpcm on the VP44 combined with the ecm control the fueling, hence my suggestion to disconnect the APPS and see if the condition still exists. I suspect it will, and will eliminate his suspicion of a faulty APPS.

 

[Joe Mc]

Thanks JR. Now reading your reply makes perfect sense. Still on first coffee so thanks for helping to shake the cobwebs a bit looser

 

[hcole]

I would look at a mechanical issue with the accelerator cable. Did you have to disconnect it when you worked on the PS pump? Maybe didn't fully seat cable housing in bracket? Put a meter on it capable of reading the percentage throttle opening and run the scenario again and see if throttle percentage increases.

 

[npieske]

Thank you for the input. I will try unplugging the apps and see if that changes anything. No codes at this point. something else occurred to me. The left hand battery was completely dead while I was doing this work. I charged the battery prior to doing a test start. That said, could it be a voltage issue? It sounds like I should take it on a test run and see what it does.

 

[seafish]

Low voltage can and will cause any number of ECM problems that can and will manifest in the various controls that the ECM helps operate, including idle speed. NOT saying that the low voltage is the sole source of your problem, but if in fact you are going to be keeping and driving the truck, you might as well kick down for the TWO new batteries now before you try to doing any deeper into this particular problem.

 

[Joe Mc]

you might as well kick down for the TWO new batteries now before you try to doing any deeper into this particular problem.

BINGO="ALWAYS" buy 2 new batteries, regardless of existing conditions...

 

[Ozymandias]

Thank you for the input. I will try unplugging the apps and see if that changes anything. No codes at this point. something else occurred to me. The left hand battery was completely dead while I was doing this work. I charged the battery prior to doing a test start. That said, could it be a voltage issue? It sounds like I should take it on a test run and see what it does.

Wait, you didn't do a test run or use the vehicle in any way because of this couple small hiccups your truck had?
I thought it is an ongoing issue.

And yes, empty battery i very bad, cause all kinds of electronic clitches that go away by them self using the truck.

 

[npieske]

well, yes and no. The only reason I haven't already test run it is because I didn't want to run the risk of castastrophic failure....and I just broke my arm in a motorcycle crash at work on Friday (which was also consequently my birthday)...so there is that. As soon as I can I will road test it.

Thank you guys for your help.

 

[DavidC]

You should at least load test your batteries.

 

[Joe Mc]

Ahhhhh, Happy Birthday? BTW: Motorcycle crash "at work"?