Engine/Transmission (1998.5 - 2002) Intermittent Power Loss - Suggestions?

[DieselDave]

Hi Guys- It been awhile but now I am back with yet another issue to resolve with your help & support. Sometimes when I push to go pedal everything is normal - boost builds up and I go. Yet at other times there is only just a little power to be had - never a complete dead pedal though. No smoke from the exhaust at that time and a minute later everything is good for as long as days. Never had a trouble code either. I just hate intermittent problems, they are the worst to troubleshoot.



I am assuming that this is a fuel supply related problem. My VP44 is original (227K miles- mostly unloaded highway miles) and the current transfer or lift pump has about 135K miles on it but sounds like it did when new. Fuel filter was changed 3K miles ago (FS19579B). I will likely change out the transfer pump this weekend with one from a friend to see what the effect is but any guidance or direction on your part is greatly appreciated. Should I be looking at anything else? -Dave

 

[JMetzger]

I would put on a fuel pressure gauge on. This is a must & easy to do. You can't tell by the sound of the pump. Mine sounded like normal but was putting out 2 PSI, I then installed a FASS. No more problems.

 

[DieselDave]

OK, understood. Where is the best place to install such a pressure gauge? A picture or example would be awesome!

 

[JMetzger]

I mounted my gauge on the top of the dash right next to the pillar boost & EGT gauges. I used a Auto Meter mechanical gauge with a dash mount bracket that I got at NAPA only because my daughter works for Balkamp/NAPA (good discount). I picked up the supply at the VP schrader valve. That way you will see what pressure the VP is seeing & fuel filter condition. You really can put it anywhere you want but I would pick up supply at VP. Hope that this helps.



Jack

 

[DieselDave]

Thanks Jack I will install a pressure gauge this weekend. One last question though - where can I buy the fitting to adapt the pressure gauge hose to the schrader valve? Sounds like a quick solution if you have the right parts to do so. I have a hose & a gauge so the adapter is the only missing link. Thanks again! -Dave

 

[JMetzger]

I removed the schrader valve & used a 1/4 flair nut with a 4in 1/4 copper tubing flaired & then put tubing in hose with hose clamp. I would take picture but truck is home in NV & I am at my sons home in CT. I hope you understand about the fitting & tubing. I also carry 1/4 flair cap to put on VP in case a line would break & you would have to remove the line as I removed the schrader valve. Again I hope this helps also when using hose make sure any hoses are diesel fuel compatable. NAPA sells diesel fuel compatable hose.



Jack

 

[DieselDave]

Well, I installed a fuel pressure gauge on the pressure tap at the VP44 yesterday. AC fittings work real nice on these schrader valves. I have good initial pressure at key-on 6 psig and then about 12 psig consistently when I bump the starter. Idling is also around 12 ± 1 psig. On a good accel I have seen the pressure at this port drop only to about 8 psig. Based on this pressure info I did not replace the lift pump. Furthermore, since I installed the gauge I cannot replicate the problem. Will drive it more over the coming week to see what happens. Could this be an early indication of a VP44 failure? I hope not but with 227K on the original I know that they don't last forever.

 

[JLandry]

Could this be an early indication of a VP44 failure?

Could be, but you'll just have to wait for more symptoms to appear long enough to do some troubleshooting.



It could just be your APPS (Accelerator Pedal Position Sensor).



Good luck to ya,



John L.

 

[SnoKing]

Have you checked for codes? SNOKING

 

[DieselDave]

I do not now or have I ever seen the check engine light illuminate on this vehicle. I guess that does not mean that there might be a code stored though - huh? I can check the codes late this week with a DRB scan tool from a friend.

I plan to take the vehicle on a 70 mile or so trip late this week to see how it goes. I have a long distance run planned towing a camper in two weeks and am a little aprehensive to go without knowing just what is going on. More once I read the codes.

Thanks for your continued support guys, I consider all of you an extremely valuable resource and joining TDR is one of my best moves in the past few years.

 

[JLandry]

II guess that does not mean that there might be a code stored though - huh?

True.

I can check the codes late this week with a DRB scan tool from a friend.

You may be able to check for trouble codes on your year truck by turning your ignition ON-OFF-ON-OFF-ON (leave on) and watch the odometer window.



If you can hang onto that DRBIII Scan Tool for awhile, it'll also allow you to see the APPS voltage and the "idle" / "not-idle" switch states to help verify if there's a problem with it when you exprience symptoms.



BTW I just launched a DRBIII User Group a few days ago. If you find you need help when using it or care to share your experiences, please feel free to stop by:



DRBIII : DRB III Users



Best regards,



John L.

 

[DieselDave]

I actually just did perform the key on-off routine before even looking at your message. I was looking at the DTC section of the service maunal for my truck and the routine was listed there. The only DTC there is P1693 then the word "done". According to my service manual, P1693 indicates that a DTC is detected in the companion module or ECM. Am I correct to assume that I need the DRB to go any further or look deeper within the ECM?



Unfortunately I can't get the DRB from my friend until Thursday or Friday.



I will look at your DBR user group. Thanks again!

 

[JLandry]

Am I correct to assume that I need the DRB to go any further or look deeper within the ECM?

Actually any good code scanner will do the job. They can be found for a reasonable price at your favorite auto parts store or even places like WalMart.



The DRBIII on the other hand will not only read DTC's, but displays a huge array of vehicle operating parameters in real time, and can conduct trouble shooting tests on the engine and power train. Being able to see what's happening in the engine real time can be helpful in diagnosing a problem.



Best regards,



John L.

 

[DieselDave]

Well, I was able to borrow an OTC Scanner from a guy at work today. I am just now in from the garage where I extracted 2 DTC's from the ECM: 1. ) P0234 - Turbo Boost Limit Exceeded; 2. ) P0236 Map Sensor Too High Too Long. Nothing else in there but those 2 DTC's. I then went to look at the data stream at both engine-off & idling conditions and recorded everything listed on paper as I have to return the scan tool tomorrow AM. The MAP at key-on/engine-off and idling was the same at 1. 9 "Hg. The temp sensors were all dead-on at 73 °F with each other and nothing else there really appeared to look unusual. I could not find a listing for the APPS only the TPS and that also looked to be AOK as I worked the throttle slowly up/down. My boost peaks at about 22 psi @ WOT under load but I don't go there often. Where do I go from here guys?

 

[DieselDave]

Posting the raw data from the scan tool:



Key On/Engine Off

Eng = 0 RPM; TPS = 0. 49 V; ECT = 73 °F; IAT = 3. 23 V; VSS = 0 mph; Battery = 12. 3 V; Calc. Eng. Load = 0%; IAT = 73 °F; MAP = 1. 18 V; MAP = 1. 9 "Hg; Oil Pressure = 0 psi; Oil Pressure Sensor = 0. 53 V; Water in Fuel Sensor = 5. 00 V.



Key On/Engine Idling

Eng = 823 RPM; TPS = 0. 49 V; ECT = 2. 37 V; IAT = 3. 02 V; VSS = 0 mph; Battery = 13. 8 V; Calc. Eng. Load = 0%; IAT = 108 °F; MAP = 1. 16 V; MAP = 1. 9 "Hg; Oil Pressure = 32 psi; Oil Pressure Sensor = 3. 02 V; Water in Fuel Sensor = 5. 00 V.



Anthing look unusual or suspect of this problem? Do I need to dig into my turbo wastegate to look for issues there now? It's Wine time now!

 

[JLandry]

Dave,



I think at this point I'd replace the MAP sensor, because if I'm reading the Dodge Diagnostic Manual correctly, the MAP sensor should only have between 0. 42 and 0. 58 volts output with the ignition on and engine not running. You measured 1. 18 volts with the DRBIII... too high.



This would seem to indicate the problem isn't with the waste gate, but the MAP sensor itself. If the MAP sensor intermittently had an excessive voltage signal, I could see the ECM being tricked into thinking the engine had a serious over-boost condition and defueling, giving the symptoms you've experienced.



Please keep us posted on how that works.



John L.

 

[DieselDave]

Jack, John & SNOKING,

I'm just back after the long weekend with a new 4931497 MAP sensor from Cummins in hand.



After installation - Key ON/Engine OFF voltage = 0. 41 VDC.



I cleared the DTC's and then took it out on a 30 minute ride where I tested every ability this truck has to offer.



The results - WHOA, what a difference a good MAP sensor makes!!! This truck has power like I have not seen in a year or more. Smooth acceleration, no more bucking at steady state speeds or sluggish accels. It pulls harder through the gears than I can remember. Upon my return home I read the DTC's again only to find none.



Thank you all so very much for your guidance, direction and support throughout this troubleshooting process. I learned a great deal here and will be ordering a DRB III for myself very doon so I can tinker more as time permits.

 

[JLandry]

Dave,



I'm really glad everything worked out well. What a great feeling!



If you have an interest in the DRBIII, please consider joining the DRBIII Users Group I set up over on Yahoo! Groups. There's not much content yet as it's brand new, but I'm hoping it'll develop into something worthwhile. Outside of the basics, I've found there's a real vacuum of in-depth information about the DRBIII outside Chrysler and Miller SPX (the manufacturer).



DRBIII User Group



Best regards,



John L.