starting trouble when hot

[RubberDuck01]

Hey fellas,I'm new in town here but I love this forum so far!!! I'm having issues with my 01 5 speed starting after it has ran for a while. The vp is only about 5 months old and the raptor 100 and the power puck went on when the vp did. It always starts perfect cold and it runs great all the time. I hasn't not started yet but it will turn over several times before it starts after it's warm. I had some water in the fuel issues a few days ago and I thought this may have caused it. I drained the separator and it straightened up for a couple of days and now it's back to the same old trick. I plan on checking the water separator again but the weather has been nasty here for a couple of days. It also has a brand new fuel filter on it. I'm praying this vp is not failing because I can't afford another one nor do I want to buy another one right now!!! Any ideas would be greatly appreciated!!!

[Mopar1973Man]

First off... Welcome to the family...Second off I need to know what you cranking fuel pressure is like. It might be the fuel pressure is just way too high during starting.

[RubberDuck01]

Hey, sorry I'm just replying to this as I forgot I even posted it. I don't have a fuel pressure guage installed yet as I am always on a budget with this thing, but now I see the desperate need of having one. What kind would you recommend? I need something trustworthy, but economical at the same time. Thanks!P.S. Truck hasn't acted up since I did this post! Maybe that's why I forgot about it:ashamed:

[Mopar1973Man]

Here is a good fuel pressure gauge and low price but high quality. http://www.alligatorperformance.com/gauge-mechanical-fuel-pressure-black-p-1678.html So after picking up some misc. fitting and air brake line you could be about $50 or so bucks. 

 

 

Edited February 11, 2022 by Mopar1973Man

[mehbohdi]

I had same problem yr ago, Had a loose injector line, just loose enough to let it bleed down and start hard, but not run rough. Gauge is a must, agree with Mike. Good luck

[Mopar1973Man]

I had same problem yr ago, Had a loose injector line, just loose enough to let it bleed down and start hard, but not run rough. Gauge is a must, agree with Mike. Good luck

That typical for guys that follow the book torque values for the injection lines. Most will tell you its by leak and feel type of thing you really can't exactly follow the book TQ numbers.

[RubberDuck01]

Thanks Mike, the guage is on it's way. Do you have a parts list for what you had in the pics??? Or do you have an article about it??? I'm not familiar enough with the fuel system to just look at these pics and know exactly what's there. I know I had see somewhere that you use 1/8 air brake line What are the rest of those fittings exactly? Thanks for the tips because I wasn't looking forward to paying $100+ for a guage:thumbup2:

[diesel4life]

You will need a needle valve along with a fitting to adapt from the fuel line to the 1/8" hose. Ive got the older style fuel canister and came right out of it with the needle valve then went to a 1/8" npt by 1/8" tube compression fitting. I think the newer fuel canisters like yours are different, so you will either have to install a tee in the fuel line between the canister and injection pump or I think theres even a banjo bolt "tee" to come out of the canister.

[RubberDuck01]

You will need a needle valve along with a fitting to adapt from the fuel line to the 1/8" hose. Ive got the older style fuel canister and came right out of it with the needle valve then went to a 1/8" npt by 1/8" tube compression fitting. I think the newer fuel canisters like yours are different, so you will either have to install a tee in the fuel line between the canister and injection pump or I think theres even a banjo bolt "tee" to come out of the canister.

Thanks for the info! This may be a stupid question, but what is NPT??? I know it's probably obvious but it's not ringing any bells???

[diesel4life]

NPT= national pipe thread. Ive got an older style canister with ports coming out the top and they are npt (pipe thread). Im sure one of the guys will chime in with the easiest way to run a guage off the newer style canister like youve got

[RubberDuck01]

One last question!!! Will I have to re-prime everything if I have to take the line loose between the filter and the vp??? I've never messed around with the fuel lines before so I'm trying to get all the info I can before I go to taking things apart!

[diesel4life]

Yes you will have to reprime the system. Generally I will bump the starter a few times to engage the lift pump, youll hear it running. Cycle the key back off when the lift pump stops running, turn key back on and bump starter again. Generally 2 or 3 times should get everything primed up, then its time to crack injector lines up by the valve cover. You always want to crack the highest lines you can to get the air out of the system. I usually only do 2 or 3 of them, some like to do them all. Just loosen them up enough to wear you can turn the nut by hand freely, careful not to take them too loose. Then go to cranking the engine. Dont crank the starter much longer than 20 to 30 seconds at a time before giving it a minute or so to cool. You may have to do this a few times, eventually it will start but run very rough. Now you should be ready to tighten the injector lines back up, and be good to go.

[RubberDuck01]

Yes you will have to reprime the system. Generally I will bump the starter a few times to engage the lift pump, youll hear it running. Cycle the key back off when the lift pump stops running, turn key back on and bump starter again. Generally 2 or 3 times should get everything primed up, then its time to crack injector lines up by the valve cover. You always want to crack the highest lines you can to get the air out of the system. I usually only do 2 or 3 of them, some like to do them all. Just loosen them up enough to wear you can turn the nut by hand freely, careful not to take them too loose. Then go to cranking the engine. Dont crank the starter much longer than 20 to 30 seconds at a time before giving it a minute or so to cool. You may have to do this a few times, eventually it will start but run very rough. Now you should be ready to tighten the injector lines back up, and be good to go.

Ok, so my guage came in and I went ahead and ordered the big line kit from Vulcan. I have the wires/plumbing set up so all I have left to do is hook everything up. The only question I have is what needs thread sealant and what doesn't? The indirections that came with the big line kit were kind of unclear about this. And will teflon tape suffice or will I have to get some other type of sealant???

[diesel4life]

I wouldnt use teflon tape. A little piece could get into the fuel system, if its after the filters its going straight to the vp. On pipe fittings I generally use just a touch of anti sieze for lubrication. Lubrication is critical for proper torque of bolts and its also important to ensure pipe threads seal properly. Pipe fittings rely on the threads to make the seal, if they go together dry (1) dry threads cause friction and you wont get the fittings as tight as you would if they were lubed, and (2) you could possibly gall the threads especially on harder metals like stainless. For tubing fittings of that nature nothing is really needed as they generally seal themselves.

[RubberDuck01]

All right, I got the big line kit and the fuel pressure guage installed. I'm showing 15 psi at idle, 13-14 at cruising speed, and 11 at WOT. I've read on here that you can adjust the fuel flow on the raptor??? Any tips??? I tried to turn the screw on the side of it with a screwdriver but it wouldn't budge. Do you have to loosen the nut up around it before adjusting the screw??

[cowtipper]

Aaaaaaaaa.... Yeah, its a jam nut. It keeps the inner screw from adjusting itself. Loosen the nut, turn the inside screw with screwdriver. Be careful, the pressure rises with very little adjustment. Do it in 1/4 turns. Shouldnt take more than that. After getting the idle pressure to 19. Hold the inner screw with screwdirver while tightning the jam nut. You dont want to move the inner screw while tightning the jam nut.

[RubberDuck01]

All right, I don't mean to kick a dead horse but my rig is at it again. I got the fuel pressure guage installed and I'm running 19 psi at idle, 17 cruising, 14 WOT. I changed all the quick connects on the raptor to pushlock. I was going to take raptor apart and inspect wiring because the pump wasn't always kicking on when it shoud ie: bumping the starter. When I got the wire harness apart it was full of water so i thought this may be the problem. I dried it out really well, put some electrical lube on it, covered it with MSHA tape just to help keep water out, then repositioned it so water wouldn't stand in it just in case. I cranked the truck, let it warm up to operating temp, then shut it off and she fired right back up so I thought the problem was fixed. Then I took her for a drive, about 20 minutes, brought it back home, shut it off and then it took probly about 10 turns for her to start back up. I have a draw straw that I haven't installed yet but I'm sure that won't help anyway. When I first turn the key on the fuel pressure comes right up to around 20 psi, but it falls right back off as soon as the pump kicks off. Is that normal??? When I start cranking, the fuel pressure comes right back to 20 then when it fires, it idles at 19. Could this be an injector issue??? Some kind of sensor??? Could it be something to do with the stock draw straw??? I don't have any visible leaks anywhere and I just don't know what it could be???It has codes with the key trick that are unrelated P1693(been there since I've had the truck), P0522( been there since I've had the truck) , and P0234( This is a new one, but I may have been a little throttle happy when driving the other day:ashamed:). I'm not sure where to go from here so any help will be greatly appreciated!!!

[Mopar1973Man]

P0234 is a over boost code and is caused from a rusted wastegate. This is NOT a MAP sensor error. The MAP sensor is detecting overly high boost numbers and ECM is defueling to protect the engine.

P0522 is basically the oil pressure sender has failed or there is a wiring issues.

Hard start while hot is a sign of a torn VP44 diaphragm and fuel pressure makes the VP44 hypersensitive. So if you disconnect the Raptor when it does this and it fire up them its confirmed and your going to need to do the lift pump relay mod.

[dripley]

just to answer a couple of the questions you also asked. When you first turn the key the ECM bumps power to the lift pump. That is why you see the pressure jump up. Bleeding back down quickly is normal. There is nothing in the fuel system to hold pressure on the low or high pressure side. The engine and pumps must be running to hold pressure. When cranking the ECM should cycle the pump so you have reduced pressure for starting. The VP does not want high pressure for starting. Especially if the diaphragm is torn. I typically see around 9 or 10 psi while cranking and 19 at idle. Try the simple test Mike describes and see what happens. As far as the lift pump relay, I know nothing about it, but Mike know his stuff and I trust him completely.

[RubberDuck01]

P0234 is a over boost code and is caused from a rusted wastegate. This is NOT a MAP sensor error. The MAP sensor is detecting overly high boost numbers and ECM is defueling to protect the engine.

P0522 is basically the oil pressure sender has failed or there is a wiring issues.

Hard start while hot is a sign of a torn VP44 diaphragm and fuel pressure makes the VP44 hypersensitive. So if you disconnect the Raptor when it does this and it fire up them its confirmed and your going to need to do the lift pump relay mod.

Ok, so I unhooked the lp this morning and the truck fired right up at operating temp. That being said, please forgive my ignorance when it comes to the mod you're talking about. Is there a write up with more detail about this mod??? And also, is a torn diaphram in the vp a big deal??? Is it something I need to have repaired or will the mod do the trick??? Thanks a lot for all the info and for helping a shadetree "mechanic" like myself!!!

I went out and looked under the hood and it appears that my truck already has this setup on it. There is a relay mounted to the firewall and it has the pos and neg wires, yellow wire, running to the lp, and brown wire running from the starter to the relay. Is this standard with the aftermarket lift pumps? Do I need to add another relay???