Engine/Transmission (1998.5 - 2002) Hard Start

[RamSport01]

I only drive my truck once every few months, and I have been having a problem with tough starting. When I go to start it, the wait to start light goes on and cycles, but when I turn the key it cranks for 5-10 seconds, if I start to pump the accelerator it starts. The ECM was replaced about 5,000 miles ago due to other issues. I have a friend that is having a similar problem with his truck and his truck is stock. It almost seems like our trucks are losing prime. Not sure where to start on this one. My truck has never not started but it just seems like its excessive wear and tear on the starter and batteries. Thanks in advance for any suggestions.

 

[JLandry]

It sounds like possibly the VP44 is having trouble producing enough pressure to pop off the injectors while cranking.



How many miles on the injectors and VP44?



Did you have trouble starting it before replacing the ECM?



John L.

 

[Sticks]

That or the fuel is bleeding down during the extended time between running.

IIRC pumping the throttle while cranking will have no effect on the injection pump starting. During cranking, it is at full fuel and advanced timing until the ECM sees the RPMs hit xxx value.

Next time you have an extended time between running, try bumping the starter to engage the transfer pump prime cycle (it will run the LP for 20 seconds or so) then start and see if that makes a difference.

I kind of had the same problem (normally starts in 3 revolutions, was taking 5). Check your MAP sensor connection at the Edge harness, and your Edge power and ground connections.

Check for any codes in the PCM/ECM as well.

 

[JLandry]

IIRC pumping the throttle while cranking will have no effect on the injection pump starting. During cranking, it is at full fuel and advanced timing until the ECM sees the RPMs hit xxx value.

Sticks,



I don't believe this is entirely true. Let me explain...



I was under the same impression as you for the longest time until I read here in the forum, and experienced it myself, problems restarting an engine after getting air in the high pressure injection lines due to a VP44 change or swapping the fuel injectors. In many cases, the engine still wouldn't start even after loosening and bleeding the high pressure lines, and also filling the low pressure lines by bumping the starter to activate the lift pump, etc. It's not until you hold the accelerator pedal to the floor, the engine will fire right up with a bit more cranking.



It makes sense if you think about it...



If you hold the accelerator to the floor, you're telling the ECM you want maximum rpm and power. The ECM then commands the VP44 for maximum possible fuel output and advance for the given rpm... even when cranking... thus it pushes a greater volume of fuel through the high pressure lines and injectors.



I agree the act of PUMPING the accelerator pedal isn't necessary (as there's no accelerator pump on our fuel injected engines like the old carburetor days). However, holding the accelerator pedal to the floorboard while cranking definitely can help in certain situations. But it shouldn't be necessary and there is an underlying cause that needs to be found and repaired.



Best regards,



John L.

 

[RamSport01]

Guys, thanks for the responses. The VP44 only has about 60,000 miles on it and the injectors about 70,000 miles. I didn't have this problem before the ECM change, but I never let the truck sit before like I do now, so I can't give a true comparison. My friend's truck has 90,000 miles on it and is experiencing the same problems. His however will do it even after the intial start. If he drives it somewhere and shuts it off, it may start hard or may fire right off, you never know. Mine seems to start everytime after the intial hard start after a long term rest. There are no trouble codes present in my truck and the Edge functions properly, I will check my conncetions, and clean them anyway just to eliminate that possibility. I don't know if there's some sort of anti siphon valve to prevent losing prime or anything similar in the fuel system. I should probably drive the truck a few days in a row and see if it only does it after sitting for a month at a time or if it will do it everyday. Thanks again for the replies, and giving me someplace to look.

 

[PBliss]

Have you looked at the check valve on the VP 44? I had similar hard start when the truck would sit. I replaced my check valve and no problems, less than $30 and took a few minutes.

 

[southpaw]

mine just started the same situation

thanks for the help, my 02 just started acting up its auto with 25k yep. the lift pump pressure is 18 pounds eng turns fast it may hit the first time or not cranking over repedly it has always started no codes. it feels like a fuel supply problem. I also changed the fuel filter. now where is that check valve? i,ll grab my shop book and try to locate it. I also have parked it in a nose down position it has started twice like this with no misses to date but on level or nose up no start.

 

[southpaw]

update on my hard to start, I parked the truck nose down let it set for 4 to 6 hours hit the starter it fired off the first turn. looked in my shop book for the check valve couldnt locate it in the book is there another name for it?

 

[Sticks]

The only "check valve" you have is the fuel return regulator on the injection pump (banjo bolt on the return side).

You have a leak in one of your fuel lines that is allowing it to pull air in and drain back to the tank.

 

[PBliss]

In that bajo bolt on the return is a check that prevents all of the fuel returning to the tank. I found a pic in another post, if I can find it I post a link.

 

[PBliss]

Couldn't find a pic but it was called overflow valve in another post.

 

[RMacneil]

It looks like this thread has died. But I am chasing a similar problem on my buddy's `01. I would like to solve this and see this thread through to a successful end. This problem Ram is a 2001, w/205K miles, 2500, MT, 4x4, Utility Bed, Reg. Cab, w/ a chip in it (not sure what kind. )



Problem is, when he lets it sit overnight, it takes a while to fire in the morning (hard start. ) This only happens when the truck is parked on level ground or uphill. We've found that parking it pointed downhill, even slightly makes for an easy start. Even plugging in the block heater makes for an easy start in the AM. The following list of fixes I have affected, I gleaned from searching posts here on the TDR.



I have replaced:

-the fuel return check valve @ the VP44

-the flexible portion of the return line (86'd the plastic connector and just replaced the section from the back of the block to the frame-rail with high quality fuel line and hose clamps)

-installed the OEM lift pump relocation kit that puts the pump in the tank

-replaced the plastic lid on the fuel filter w/ new

-tightened 5 of the 6 injectors (we were unable to get a wrench on #6 - I suppose it's possible that may be the problem)

-VP44 has been replaced in the past- but not sure when



This truck is very well maintained and runs excellent once started. Any ideas? I'm thinking leaky injectors, but that's an expensive "guess" fix. What's the best way to perform a pressure leak-down test on the high pressure fuel side? That would isolate the injectors and tell me if they are bleeding off the fuel pressure. He doesn't do oil analysis, so no fuel oil dilution indications. Any ideas or tips would be great. We've been chasing this problem for about 2 years now. Thanks in advance.

 

[southpaw]

Mac here is an update on my pain, changed the overflo valve 2 times,no fix pressure tested all fuel supply and return lines, a lose nut on the fuel heater tightened no fix, cked fuel cap fuel filter cap again no fix im waiting for warmer weather to track more possibles it still starts in a nose down position but not on flat or up. this thing has only 22k on the odo. good thing i have a good 93 that runs.

 

[RMacneil]

Whatever your problem is, it sounds exactly like my friend's issue I'm trying to fix. I'm glued to this thread. Be sure to post when you find the fix. I'll do the same if I figure it out on my end.
Thanks for the update.

 

[RAJohnson]

You boys have a air leak some where in you fuel system. When you find it, it will be fixed. Check all rubber hose's or replace them due to age, from the front to the tank. I had a 95 once that had the same problem and I finally found a cracked or weather cheeked fuel line that was the problem. Mine was as your nose down and it would start every time, flat or nose up and she would crank for some time before firing.

 

[Sticks]

Wow, like 3 or 4 people with this issue.

The easiest way to check or a leak in the fuel system is to pressurize the fuel tank with compressed air to about 10psi. If you don't have the proper attachements, this means a blow gun hooked to the air compressor and a rag.

Park on a spot where the ground is clean and dry. Keep the tank pressurized for about 5-10 minuets, then look around on the ground for any puddles or drip spots.

Old weathered rubber fuel lines, quick connect fittings at the transfer pump, return line at the back of the head, and on top of the tank are usual suspects. Also the metal lines along the frame rail behind the tank are know to get rubbed through.

 

[Sticks]

For you 12v guys, the fuel heater wiring and bowl are most common.

Easy check for the heater wiring. Disconnect it. If it is wet, it's leaking.

 

[southpaw]

still having start problems. sent the truck off to a shop the guys there are cummins owners they are going thru and re testing everything. its been in the shop for 2 weeks nowstill no word so i will ck monday. gotta keep trying. any one else having good results?

 

[Turner766]

I had the same problem with my 03 5. 9. It was my number 3 injector had it replaced with further isues.

 

[Turner766]

No further issues.