Engine/Transmission (1998.5 - 2002) hard starting

[FourBarR]

For the first time in over 600,000 kms see a change in the starting cycle .

No Codes. Fuel checked for water,none . Fuel filter changed 1000k ago.

Batteries load checked ok. starter new bosch 60,000k seems to turn over as fast as always.

No observed fuel leaks anywhere from tank to fuel filter,from filter to injection pump.

There are no driveability problems ,once started run perfect ,no skipping ,rough runing ,lack of power.

Fuel pressures 12 at idle,10 at 70 mph.

Planning to pull the over flow valve and check at 14 psi.

Any suggestions appreciated.

I still have original vp-44 and injectors .

 

[JLandry]

Wow... that's a LOT of miles (kms) on that VP44 and the injectors.

Assuming you don't find some other cause, I'd suspect the VP44 is simply wearing out. Also, with that many miles on them, the injector tips are definitely leaking fuel and will have pop off pressures well below specification. Worn out injectors sort of squirt fuel from the tips prior to popping off, which can't help starting any.

John L.

 

[gtwitch]

I agree with John L But check the primary fuel system form the tank thru lift pump and filter to the VP44. Look for air in the system!! Use the troubleshooting guide from Blue Chip's website (it is very helpful) I had a problem very similar and fought it for 6 months and all of the symptoms that you describe are what i fought!! The problem was that air was getting into the primary system from (of all places) a fuel pressure sensor on the filter canister top. I probably replaced the frame mounted pump (Holley Blue) unnecessarily, I still have it. My problem started when I was chasing failing or waneing fuel pressure issues and one at a time I first replaced the frame mounted pump and filters, then next the fuel pressure sending unit and this fixed the failing pressure problem and then shortly after this I started having the starting issue, turck ran fine after I could get started. I fought it most of the winter and a couple of times while in the mountains with snowmobile trailer, I had to use ether, hated to do this, but no options. On a good day above freezing in early April, I replaced the bypass relief on the VP44 to no avail and only by chance before I was going to put in the clear Tygon tupe from the filter to the VP44, I saw air bubbles comming from around the fuel pressure sending unit on the top of the fuel filter, removed it and carefully teflon taped the theads and replaced it tight and problem went away and has never returned. I kept going back to Chips troubleshooting guide (Thanks Chip)!!! Be careful with teflon tape in any fuel system!!!! Loctite makes a thread sealant which I prefer in fuel systems and hydraulic systems, but I did not have any at the tiime, but I learned years ago how to use the tape if necessary. Hope this helps.



gtwitch in wyoming

 

[gtwitch]

I beleive the problem in my case was air being sucked in around the loose theads on the sending unit as the truck cooled down over night and that large bubble of air was in the top of the filter, the truck would start OK all day after I first got it started in the morning and if I never let it cool completely down.



gtwitch in wyoming

 

[FourBarR]

problem solved, bosch starter new only 60,000k made in china. I had it re load tested with snap on 1000amp tester,showed over 800 amp draw. replaced starter under lifetime warrenty . starts like new, vp-44 and injectors still working fine.