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DieselAutoPower.com
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Discussion Starter · #1 ·
My truck has done this since I bought it. I replaced the lift pump since it died. So fuel isn't the issue. When to turn the truck on, you have to absolutely wait until the wait to start light comes on before the truck will start. I know the wait to start is there for a reason. But the wait to start only heats the intake air. It's warm enough now to not have to worry with it. If you wait, the truck will light no problems. If you jump in and start cranking, you'll just sit there cranking until the WTS light lights up.

I know something happens when it comes on. As I can hear relays/solenoids/exc. energizing/moving in the VP44 when the WTS light comes on.

The truck runs fine on the bottom end, but seems to loose power towards the top end of the peddle. mileage is horrible at ~15mpg. (Driving highways at ~65mph 1800rpm, 3.55 gears, 60psi in the tires)

The truck is drivable like it is. I just don't feel comfortable with the starting issue. And the mileage of course. Could the electronics in the VP44 be going out?

I also had a mess of a time dealing with a superchips (I know they're crap) tuner on my truck. But from what superchips said, the issue was with the tuner talking to the computer. Could all of this be related?

(New fuel filter and air filter as well)
 

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Don't mean to jack your thread, but I'm also having a hard start problem. Used to my pickup fired up on the first round... not so much anymore. It's been leaving me sitting every now and then also. Sometimes if I only bump the key and it doesn't run, the next time I try to start it, it just turns and turns but never sputters or fires at all. I was getting the P0366 code so I changed out the CKP and it helped a little, but I think my electronics are also going out. I don't think that my stock lift pump was working right when it was in because I had loss of power on the top end really bad. By the time I got my FASS in though I think it was too late. Do you get quite a bit of excess smoke also with your chip off? I am, which leads me to believe that my VP isn't strong enough to pop the injectors as efficiently as it used to. I think both of us might need new VP's... maybe we can get a buy one get one free deal. :$:
 

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Usually with the vp44's if you lose or get a weak lift pump it takes out the vp44.
 

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DieselAutoPower.com
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Discussion Starter · #4 ·
Only time I get smoke is at low end with the chip turned up to max. No smoke on start up.
 

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How much fuel pressure do both of you have at start, idle and driving?

IF you don't have a fuel pressure gauge your in the dark and need to get a gauge from someone to diagnose the problem. NEW OEM style lift pump can be junk when installed, so saying it is new does not verify you have fuel pressure.... you need to know pressure first, then our answers can help.
 

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BRAND new FASS on mine, 150 gph. It should have enough pressure. I don't have a FP gauge though, that'll be the next thing probably.
 

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DieselAutoPower.com
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Discussion Starter · #7 ·
I rigged up an oil pressure gauge to check mine. Disappointing to say the least. I've only got about 10-12psi. None when the truck is turned to on, then 12psi when lit, It's hard to tell but I'd assume it dropped to about 6-7psi giving it all she's got on the road. The pressure does come up if you bump the starter and let it sit for a few seconds. It'll run through the 20 second purge.

I'm going to install a new holley blue pump I've had laying around tomorrow to see if there's any improvement. It's a 130 or 140gph pump.
 

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Mopar1973Man.Com
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Ok first off...

Fuel pump dianostics...
Lift Pump Diagnostics

10 PSI IS MINIMUM PRESSURE

You also need to install a true fuel pressure gauge...:thud:
DiPricol Gauges

You might want to check for error codes...
OBD II Error Codes

As for clicking noises thats the relays for the grid heaters nothing else. The ECM reads the IAT sensor and if the IAT is below 60-65*F it kick the grid heaters.

As for the starting problem you might be loosing prime on the fuel system maybe...
 

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DieselAutoPower.com
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Discussion Starter · #9 ·
Please explain how if I am loosing prime on the system, and the fuel pump is not cycling on, why will the truck not start until after the WTS light has came on? The fuel pump is not cycling before or after the WTS light. Once the WTS light trips, and I start the truck, instant fuel pressure.

Let me correct the "noises". There is a 1-2 second noise at the WTS light. It's not a relay click (It was 70F today) It sounds possibly like the pump kicking for a second. But that doesn't happen until the WTS light.

Before I go tearing into things too much, first thing tomorrow. I'll prime the IP manually with the lift pump. I'll see if that makes any difference whatsoever on starting. But I doubt it will. This truck has always not started until the WTS light shows. Even the day after I installed the new cummins lift pump. I might also fit some clear tubing to "see" what's going on between the filter and IP.

I think it'd be for the best to throw that holley fuel pump on it while I'm at it as well. That should put me up to about 15-20psi.

Honestly, I'm more concerned with the pressure running down the road, than the fact I can't hop in and start the truck. After all, the WTS light is telling me to wait...
 

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Mopar1973Man.Com
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Please explain how if I am loosing prime on the system, and the fuel pump is not cycling on, why will the truck not start until after the WTS light has came on? The fuel pump is not cycling before or after the WTS light. Once the WTS light trips, and I start the truck, instant fuel pressure.

Lift pump might not be loosing prime but the VP44 could be loosing prime..

Let me correct the "noises". There is a 1-2 second noise at the WTS light. It's not a relay click (It was 70F today) It sounds possibly like the pump kicking for a second. But that doesn't happen until the WTS light.

Yes... The fuel pump bumps for just a brief second and it might build barely 3-5 PSI then fall again.

Before I go tearing into things too much, first thing tomorrow. I'll prime the IP manually with the lift pump. I'll see if that makes any difference whatsoever on starting. But I doubt it will. This truck has always not started until the WTS light shows. Even the day after I installed the new cummins lift pump. I might also fit some clear tubing to "see" what's going on between the filter and IP.

I think it'd be for the best to throw that holley fuel pump on it while I'm at it as well. That should put me up to about 15-20psi.

Honestly, I'm more concerned with the pressure running down the road, than the fact I can't hop in and start the truck. After all, the WTS light is telling me to wait...

So very true... The WOT pressure is the most important pressure if it below 10 PSI your needing a lift pump...:w:
 

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DieselAutoPower.com
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Discussion Starter · #11 ·
Primed it 3 times with the On-Off quickly - 25 second LP prime. Made no difference for starting. I sat there and cranked and cranked once I started to go for the first real light. Nothing, then WTS light, instant start.

Going to pull the lift pump now and upgrade it. But I feel as though somethings up with the VP44.
 

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My truck was pulling ok on the bottom end but then going "flat" in the mid range and top end. I have a hard time describing it, but there is a tinney sound that would come in that let me know that it was running lean on fuel. I took it to the dealer and they said the Lift Pump wasn't covered. New Raptor 100gph and now I'm running a constant 14.5 psi but it was still flat and tinney. I took it back to the dealer and after a small arguement they agreed that 1. the VP was bad and 2. it was covered under my 7y/100k warranty (I have 99,835 on the clock).
They had to do a flow test to check how much fuel it was moving as the issue was volume not presure. The thing is that during all of this, the VP never triped a code. If you are running at a constant speed and steady load and you hear the pitch change to the motor, it is most likely the VP starving out. Not That I'm the ZEN Master of diesels but this is the second time I've heard the Vp go bad in my rig and I picked off the same with a friends rig a week before his blew out. Turn down the radio and give a close listen... Good Luck... Chris
 

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Mopar1973Man.Com
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I lost my fist LP and IP pumps at 50K miles... Since 85K miles I've been running 2 cycle oil in the fuel and the VP44 has had zero issues. I've always kept the fuel presure above 10 PSI and never had a problem with the VP44...:thumbsup
 

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The lift pump running has nothing to do with the grid heaters cycling.
 

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Discussion Starter · #15 ·
A little more info. I swapped out the pump for the holley blue. Have 17psi at idle. 14psi at WOT. Power doesn't seem improved. I wired in a relay for the pump as well. When the WTS light comes on, the relay kicks for a split second. But fuel pressure never increases. The truck will start. When I cycle the power to get the 20 second prime, I can try to immediately start the truck. No dice. No matter how many times I prime it. (primed it 4 times in a row before trying to start) At this point I think it's something in the VP44 that's causing it. I'm not going to pursue it any further. I'll just live with the WTS issue. But if I start to notice any further performance loss, I'll start looking into replacing the VP44.

On a side note, I've also installed an EGT, Boost, Fuel pressure warning light, and the fuel pressure gauge as well.
 

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Discussion Starter · #16 ·
Oh forgot, I've also had an issue with surging with the truck as well. 4th gear, TC locked, crusing at 55-60mph will get a surge every now again. Sometimes with the XZT+ off, but more pronounced with it turned up to 65hp. Possibly related, but not certain.
 

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Mopar1973Man.Com
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Man all I can say is something is goofy...

I can hop in my truck on a cold morning like today at 42*F and nail the key and it will start up no questions asked. I don't need to wait the WTS lamp either... I can do this down to 25*-30*F range below this it becomes a bit difficult to start with grid heaters...
 
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