Engine/Transmission (1998.5 - 2002) hard starting when hot...

[Ralph Heron]

Happened a couple of times lately. Starts fine cold, but after towing and then stopping for lunch, motor doesnt fire immediately (have to cycle through starting proceedure a couple of times before things come to life). Doesnt seem to happen unloaded.



LP pressure fine (around 13 psi post filter). When it originally happened, I checked the codes and found a 1693, cleared it and no new codes thrown. Also, I find that my fuel pressure to the VP can be as high (15psi -- pegging my LP fuel pressure guage (am I getting too much pressure on startup-- check valve might be going ??)). This happens when the truck fails to start and the 20sec LP run kicks in...



Also, when cruising up to a stop sign, LP pressure also gets very close to 15psi (14+ change). Based on threads read, I expect the check valve on the VP44 to be limiting the input pressure to 14 psi (is this the case ??). FP guage is an autometer electric unit.



When underway, truck runs fine (no misses and power seems okay) but just worried about getting stranded somewhere (use the truck for pulling a boat and not looking forward to needing to tow the truck/boat).



Where should I start looking ??



Have read some threads about the electronics in the VP having issues but not sure on how to debug the injection pump)



Engine wise, the truck is stock (except for AFE and guages).



TIA,

Ralph-

 

[Lockard]

I had the same problem, turned out to be a bad VP44. I drove it around for a few months with this problem because it wasn't throwing any codes. Well, near the end there were a couple of serious "misses" where the engine would buck badly under hard throttle. After this started I decided to replace the VP-44 and that fixed it. I looked into the other suggestions which have been posted here before during the the months where it was hard starting and tried a few (like the fuses, or new lift pump) and nothing worked. Good Luck.

 

[RJPotts]

I'd say its the VP going bad. 15 psi really isn't bad, and not enough to cause a hard start problem. Its usually with the FASS and stuff where pressure gets up around 20-25 psi when a problem happens. If it was FP related I'd say you'd have hard starts almost all the time.

-R. J.

 

[RacinDuallie]

Check this simple little thing we always forget: When the condition happens again- jump out and crack the fuel filler cap... ... hear a whooosh- time to change it... ...

 

[camnicolson]

Had a similar problem, hard start when hot, no codes. Chased most things then changed the VP44 and all is now well. Did notice a slow drop in power over the last few months, mostly noticed by the fact I could not get the egt over 1200 even with the PM 3 on level 9.



Cam

 

[sardoghauler]

my guess

Bad news bud,



That's a vp44 on the outs. I had all the same symptoms including increased pressure readings at vp44. The pump is going and is creating a slight restricion which is backing up pressure (or so I was told and was hypothesized here). It would start fine cold, lost power, wouldn't start hot, would cut out at stop lights or put in gear (auto) when warm. It didn't throw a code until it died for good in the dealers driveway.



good luck

 

[J.Keith]

I'll jump in here too and say that IMHO it's your VP44.

I also had these same symtoms, good fuel pressure, good power, no codes, great cold starts, but once it got hot that was it.

I tried alot of different things to fix it and in the end it was the injection pump.

My $. 02

Joe

 

[EGaskamp]

I also have a simillar problem. When the truck is cold it starts fine but now that it has gotten warm it doesn't start good at all. In the morning it fires right up. So i replaced the lift pump on it and that did not fix my problem. people were telling me that the injector pump was bad, so i replaced it and it still did not fix the problem. It has gotten so bad not it does not start at all when it is hot unless I bleed the fuel system. There is an unbeliveable amount of air getting in somewhere. I have checked for leaks, no leaks, and I keep my fuel filter chamged regularly. Can anybody help???????????



Thanks

Scott

 

[Oil Burner]

scott,



where are you bleeding the system? at the fuel line nuts or at the fuel filter???



if at the fuel line nuts... might be a nicked fuel tube.



if you are bleeding it at the fuel filter, it is a leak in the line somewhere. could be the tank connection or anywhere along the line for that matter.



I would just replace the line from the tank to the filter housing with -6. Won't cost much at all.



if you need a parts list for the fuel line fittings, send me a pm.



If you had a bad leak, it would probably show up more on a cold start than a hot start.



Jason

 

[Oil Burner]

Scott,



Just read your sig. sorry, its been a long month at work.



Did this start after your injectors went in?



if so, pull the valve cover and check the injector hold down nut torque. too much or too little and you could be getting the same symptoms.



if this problem was there before the injectors, then I had one too many beers tonight.



Jason

 

[EGaskamp]

what is the torque specs for the injector holders?

 

[Diesel Nut]

My buddies truck is doing this also. Hard start when hot, only code is 1693, still starts fine when cold. It also started something new. When starting with the hard start condition, he will blip the throttle and it'll start up, but sometimes it'll start up and be really respnsive, like too responsive, but won't let it rev over 1500 rpms. I don't know what he does, but it goes away somehow. Thoughts?

Oh, and the truck has a FASS pump.

 

[EGaskamp]

also the truck has no codes on it

 

[Oil Burner]

89 inch pounds.

 

[Herman8r]

Just experianced the same problems. Hard start when hot. Just replaced the Vp44,new cam shaft sensor, took out the Banks System & replaced with an Edge Box (no wire tap yet), new lift pump from Cummins, changed fuel filter (13-14 psi)---all this and still no change. Still hard syart when hot. HELP



As a side note: a special thanks to all the people who take the time to help fellow TDR Members with illustrated repair directions & resources. I just changed my vp44 & it went very smooth. Thanks guys!



Thanks, Herman

 

[AC]

I'm hunting the same problem. To date I've replaced the fuel filter twice, LP, CKP, CMP, and the overflow valve. I've tried unhooking my EZ (no change). I've also taken it to a shop where they tested my vp44 and it checked out good. I went to a friends house and swapped out our ecm's and that might be it. Watching the fuel pressure at start up with the two different ecm's I notice mine runs the gauge up to 15 psi when I first turn the key on and then it bleeds back off to near 0. The wait to start light then goes out and I try and start. ( usually this results in a long start of 2 or 3 seconds ) With his ecm the fuel pressure runs up to about 5 psi and then bleeds back off to neer 0 and then the wait to start light goes out. Truck starts better but not like it used to.

This is the really frustrating part. Do I throw another $500 at it in hopes to fix this or just wait until it leaves me stranded. If I do try the ecm I can get one of the new catcher's and at least I would be getting something better instead of just swapping out parts.

Anyone else try the ecm route? AC