Newbie here so please be gentle. I have a 99 24v, 4x4 auto 134k miles that started idling at 1000 rpm's and has a miss to it. Happened out of the blue while wife was driving. Idle stays at 1k and misses unless put in gear. when put in gear, it idles @ 900 rpm and smoothes out under load of trans while in gear. Truck runs out great as long as its accelerating but when you let off throttle you can hear it miss. Fuel psi is 19 at idle with a air dog 100 lift pump. Truck is stock besides lift pump. Only code its giving is p0234 and I found waste gate stuck. All exh temps from exh man are within 40 deg f of each other. Iat, ect , and map look good on scanner. Batteries are 6 months old and test good. I have checked and cleaned grounds. I have a timbo apps about 1 year old. Truck doesn't smoke any out exh pipe. I checked for ac voltage and got a high of .030vac. Any ideas? What will make a cummins idle high? ecm? I have auto enginuity on my laptop to scan with. Please help!

Edited April 6, 20169 yr by Itaintez
forgot to add some info

Just talked to a diesel shop here local. $1395 for rebuilt pump with new electronics and 2 yr warranty. Does that sound like a fair price? I asked and he said they do rebuild the vp44 pumps. I asked about upgraded injectors and he said $72 each. Would I see much power increase from bigger injectors with a stock pump?

3 minutes ago, Itaintez said:

I asked and he said they do rebuild the vp44 pumps.

 

Be careful. Like BlueChip rebuilds pumps be unable to calibrate or flash a new PSG unit because BlueChip does not have a 815 test stand. If this company does have a 815 test stand can you please post up the information so I can add them to the list on the article database.

 

 

Edited April 11, 20169 yr by Mopar1973Man

I agree with Mike on the pump. Many re sellers and few rebuilders. You could check with DAP or Vulcan performance. Both are vendors here. They both sell pumps with new PSG's, 2 year warranties and one year warranties.. This will give you something to compare with. 

Curios as to how you checked to be sure you are not getting air into the system?  it just sounds so much like that is what is going on. Hate for you to throw $1500 at it and not solve the issue.

You are right @dripley I have not ruled out air in system. I've opened filter drain while running and cracked inj lines to look for air. I plan to do a bucket test from lp inlet and work forward with clear hose. I'm just pricing parts to get ideas if my pump is bad.

The rebuilder I called is Dixie Diesel in Columbia,Tn. I called back to verify they have an 815 Bosch test stand and he verified they do and are one of few that do. Mike you can add Them to your list.
 

 

Tonight I took the fuel supply hose off the steel line under the cab and put it in a 6 gal can of diesel. I started truck up and got the same stumbling/miss as before. Next I removed the supply hose from the lp inlet fitting and installed a new hose and clamped it to inlet fitting, this eliminated the quick connect fitting like you see on gasoline fuel hoses. also I stuck the new hose in the diesel can, started truck up, same results, stumbling/missing. I tried lowering fuel pressure and this didn't help either.

Question: Would it benefit me to install a clear hose between the filter housing and the lift pump. I know that side should be pressure and not suction and I'm not leaking any fuel there or anywhere.

My next step will probably be removing injectors for a pop test and if they're good ,on to the vp44, sound logical?

If your not making fuel and have good fuel pressure I'd leave those lines alone. 

 

Get the injectors tested and if they come back good then you can diagnose the VP further.

21 hours ago, Itaintez said:

Just talked to a diesel shop here local. $1395 for rebuilt pump with new electronics and 2 yr warranty. Does that sound like a fair price? I asked and he said they do rebuild the vp44 pumps. I asked about upgraded injectors and he said $72 each. Would I see much power increase from bigger injectors with a stock pump?

 

Yes, injectors will help, just can't go too big or your tranny will take a dump. If you need new injectors anyways, upgrade to the rv275s or a 50HP injector. 

But you can verify your current injectors for a either a very low price or free. Like my local shop with pop test for free as long as there is no adjustment of the injectors.

Edited April 12, 20169 yr by Mopar1973Man

Yep, They told me $6.50 each to test injectors. 

Well, injectors checked good, so I got a new vp44. While I was at it, I installed a set of RV275 injectors, replaced crossover tube orings, replaced the pushrod cover gasket , intake gaskets, return line fuel seals on the back of the head and adjusted the valves. I haven't gotten to drive it yet, but man that ole cummins sounds good! For future reference, I had no codes leading to a bad vp44. Thanks guys for all the suggestions.

Congratulation.