Archived 98.5 24v won't start....starts....won't start....starts....won't start

[FASTERTHANU]

My 98. 5 is having intermitant starting problems, but fer sure does not start as quickly as a healthy truck. This is what I know.....



1) batteries are kickass and turn it over like a tornado



2) fuel pressure at filter inlet and outlet are within a couple of PSI of eachother



3) cranking fuel pressure is at least the 5-7 psi recommended and when lift pump goes into 25 second cycle gets up to 15 psi



3) the return bypass valve is operational at 15 psi of pressure and is closed around 5 psi



4) lift pump pressure is about 15-18 when it does run and climbs to same during 25 second cycle



5) fuel pressure DOES bleed off after trying to start (is this normal?)



6) Once she starts she runs just like normal... no misses or stumbles pulls 18k trailer just fine



7) I did not have a check engine light at any time until I pulled the fuel pump relay while the ignition was on and now I have one and am waiting for reset.



The truck will start and then not start a minute later... . cold or hot does not make a difference and it has just come on in the last 48 hours. If you crank it for about 20 seconds it will sound like it is trying to start but won't or sometimes it starts right away. It can be running for 2 hours and then not start if you turn it off. I tried the 3 key cycle diagnostic a dozen different ways but cannot get it to work on this truck (works on my jeep though). All of this is occurring with or without the power puck plugged in.



i'm guessing at maybe an ignition switch problem... . crank sensor... . anything?



any help is greatly appreciated

 

[KWentling]

You will have to have it scanned. The key cycle trick doesn't work on 98. 5 or 99s. My 1st guess would be the crank sensor.



Kim

 

[mstephenson]

that is exactly my problem also!



+ no codes.

+ pressure up to vp44 is good.

- does not pull as well as should, but runs fine empty.

- acts like it loses its prime. once shut off; will not start again w/o much tinkering w/ injector lines.



mechanic says vp44 (but no codes); another guy says if it's mechanical failure there will not be code. only when electrical/electronic failure. it this true?



what should i do? start replacing sensors?



thanks



mich

 

[BIves]

could also be the electric shut down soelinoid, I have seen them act up from time to time, could be just a simple short.

 

[blmyachtsales]

Have a 96 and 06 but have had a similar problem twice on the old 96 12 valver first it was the pipe between the lift pump and pressure pump (it was old looked fine but actually had tiny cracks that would allow the system to lose prime ever so slightly). Secon time was a sticky shut off solenoit (have someone hold it up while you try to start it, if it starts you got the problem)

 

[FASTERTHANU]

I have NO loss of power... . tows strong.



Is there a shutdown solenoid on the vp44 trucks?



I even monkeyed with the steering column & ignition switch... . no joy



Reconnected batteries this morning and she fired right up about six times in a row. I could not reset check engine light by disconnecting battery after pulling fuel solenoid with the key on (I knew better than to do that) so I will take it to town to get codes cleared, drive it, scan codes and post results soon.



If it were VP44 wouldn't I have power issues or check engine light. I replaced my brother's VP in an '01 and he had both at the time of replacement but NOT this crazy intermittent starting issue.

 

[jebabb3]

i'm also having the same problem. '99 3500 4x4 160k mi bone stock except for a new rotory lift pump mounted in front of tank. getting excellent pressure and no CEL's. took it to dealer last month - they say lift pump dead, vp timing failure, crank sensor bad and a few other things -- OVER $5000. 00 !!!!! (BUT, we have a couple '06s left on the lot, bend over either way!!) Immedeatly got a pressure gauge and read no less than 8psi after filter(dirty) at 2500 rpm - on the ORIGINAL stock lift pump. after reading about all the poblems w/lift pumps i decided to replace w/ best one i could find- a rotory kit from glacier diesel power. works great no less than 15psi. but now it wont start. replaced the crank sensor - absolutly no effect. could my (napa) new out of box sensor be bad? BUT, if i bump start the truck ,or use the key for that matter and it starts , it runs fine and drives like a rocket. can't always park on a hill though. all my trouble started with 'the dead pedal', and this hasent been fixed. its been to 3 different shops including the dealer and noone can find the problem. im starting to lean toward a bad ecm? is any one else having same/similar issues?

 

[massdiesel]

You more than likely do not have a air leak cause it cant fix it self then happen again. Crank sensor is a good posibility i have seen in the last 2 months 2 tone wheels on the crank mess up. If that is good i would push towards a vp 44 if you need any help call the shop and I can help you out with diagnosing

 

[mstephenson]

my truck is already at the shop waiting for me to tell them what to do. where is the shutoff solenoid located? is it called something else in the manual?



i will be distraught about spending $2K just because a wire was loose.

 

[blmyachtsales]

I'm not sure if the 24 Valvers have shut off solenoids 98. 5 and up may not. My truck towed fine with the tiny craks in the hase once it was running but sometimes it wouldn't start at all, just my experiance, again not sure what the pump setup on the 98. 5 + trucks are like. Good like, let us know what you find.

 

[Graphic man]

Crack an Injector line lose and crank it over and see if you have fuel,..... if not then it could be a VP44



Scott

 

[FASTERTHANU]

OK... . cleared codes and drove around town doing chores. It is definitely not starting like it used to or like it should. Requires cranking for 5-10 seconds intermittently sometimes starting like a dream. Went back to shop and scanned for codes... . NOTHING. I will crack injector tonight to check for pressure after VP44. I'm still curious about the pressure bleed down while at rest.



Is it normal for pressure to bleed down below 5 psi after ignition is shut off?



Wouldn't a crank sensor cause stumbling/drivability as well as starting problems?



What does anyone know about mechanical problems with the VP that do not throw a code?



What is the situation with air leaks and how exactly do you test for them?



My daughters have a Jr rodeo this weekend and my other truck is down so I'm hoping I can fix/patch this... ... it's no good letting down little kids as they don't get the whole trucks not working thing

 

[MCummings]

Mine did that for about 2 months. Fixed itself.



Also check to make sure the ECM and Engine Harness are fully plugged into eash other. When mine was have poor driveability, and hard starting in '03, that was the culprit.



Merrick

 

[FASTERTHANU]

So the damn thing ran fine for several days and then did it again... This time I cracked both the injectors and the return bypass valve and found aerated or foamy fuel. Once the foamy stuff was purged it started right up again.



Is this the beginning of VP failure or do I have an air leak?



If this is VP failure why would it be foamy at the return line coming off the pump?



We're almost there... don;t let me down now!

 

[tp0d]

If you have foamy fuel, you are losing prime pre-lift pump, and the lift is refilling the system with air.



Have you inspected all the suction hose between the tank and pump? With the age of the truck, if the fuel lines havent been replaced theyre prolly dry rotted. I know mine were, on my 96. Caused hard starts, etc. . Could also be pulling air from the supply tube in the tank.



24v's do not have a shut down solenoid. Only 12v's.



If it isnt setting a code, I wouldnt suspect a sensor. Arent there two sensors (crank and cam) that do the same thing? Also, my dad's 99 would cycle codes with the on-off 3 times trick, so it should work.



good luck



-j

 

[FASTERTHANU]

That would be great if that is the case :-laf To be honest I dropped the tank a couple months ago because the fuel module had fallen apart. I did look at the hoses at that time and was pretty careful not to stretch or kink the lines but if that's the prognosis it sure beats a VP. It had done it twice before I dropped the tank but like I said the module was in two pieces when I pulled it out. The slide portion had just flat worn through and it laid there giving me eratic fuel level readings and may have let it suck air then as well. I'll take it out in the next couple of days and put "all new" in.



I read in another thread that there was a recall on the fuel line from the filter to the pump. Can air enter here or would it just leak? The tank lines are definitely suspect but a crappy job to do , I would like to just dot my I's before I pull it again... .

 

[RankRam]

I read in another thread that there was a recall on the fuel line from the filter to the pump. Can air enter here or would it just leak?... .

Yes air could enter there, since the lift pump is upstream from the tank it has to pull the fuel to the engine. I would say you are on the right track, it sure does sound like you have found the problem!



Good luck.



One other thing to add... ... ..... This would be a good time to add an aftermarket pusher pump like this one!



http://www.glacierdieselpower.com/product.asp?pf_id=3929852

 

[mstephenson]

after reading all the posts here i made the mechanic go over why it could not be anything on my list. he was very patient. then proceeded to install the new vp.



well, i just got mine back from the shop. the truck runs better than it has in years . there is no telling how long i have been gimping around on a crapped out vp. response it immediate; can rap out tach and engine sounds good; doesn't seem to be working hard. cruising altitude is no different than at 55.



that vp had +193,000 miles on it. i wonder if there is anyone else who has gotten that much outta one?

 

[Graphic man]

i have 160,000 on the org. VP44, i also have a new one in the tool box just incase :-laf



Scott

 

[JField]

Mine did the same. Replaced the crank position sensor and it took care of the problem