tchdodg

Well fellas, looks like my IP is on it's way out. Truck starts fine when cold, but if the engine is hot, it cranks for 3-5 seconds before starting. According to my mechanical fuel pressure gauge, I've got 20-21 psi at idle, running 70 it holds at about 15-17. After reading on here for hours, I'm leaning towards the computer in the IP. The current IP is about 4.5 years old. Question is, should I check anything else, and who to buy from Blue Chip or MWFI? It's a stock truck and probably won't ever have more than a straight pipe, BHAF, and maybe an Edge w/ attitude. I don't think I need a hotrod pump, I like the looks of the X Blue Chip, but can buy two MWFI stock pumps for the price. What you experts say?

wyododge

I got the blue chip. You should see if you have any codes though. Key trick works on your truck. on (not start) - off - on - off - on. codes (if any) display in the odometer read out. might get lucky. pretty expensive part to throw at a problem though.

tchdodg

I've done the key trick, no codes, no check engine light, once it starts the truck runs/idles fine. I've got a couple of suspect ground cable ends on the batteries, but no other clues except IP at this point.

Junk Man

I'm not an expert but bought MWFI for 1/2 the price of BlueChip. You can add more power cheaper than the price of hot rod VP. Also, hot rod is LLESS reliable. Install was a piece of cake.

Others have said high FP can cause hard starts. Don't take it as fact as I haven't had that issue & don't really want to regurgitate rumors. Do your own research. My experience is that long cranks are frequently leak in the fuel lines. Cursory glance will mis the leak. You may have to get intimate with your fuel system.

Key codes on my 00 have been incomplete. I have also had a code on the key (ie apps) and another (ie VP) with the scanner. Sometimes only companion code has shown up (1693). My conclusion is that key isn't enough information to make a decision, only a request for more diagnosing.

You really don't have anything documented to condemn the VP. Keep your $$ until you do.

tchdodg

I'm gonna put in a new fuel filter tonight, and change the ground cable ends on both batteries, check the other grounds, and look for fuel leaks. I'm not ready to believe it's the IP just yet, more importantly, I don't want to pay for one either.

KATOOM

With those kinda fuel pressure numbers you're running, you must have an aftermarket fuel pump. Like a FASS, Air Dog, Raptor, etc.

If your truck starts fine when its been sitting overnight but doesn't want to when its at operating temps then yes, your VP's computer can be telling you its about to fail, BUT.....because you have a fuel pump other than OEM, I'm guessing your problem is that your fuel pump is placing to much fuel pressure on your VP while the engine is cranking. The quickest way to determine if this is your problem is when the engine doesnt want to start right away, simply takes the 10 seconds it takes to remove the fuse to your fuel pump and try cranking again. If it starts right up then what I said is your problem. Just remember to put the fuse back.
If it works then let me know and I'll tell you how to fix it.

GTSDave

I have an Air Dog and have been fighting hard starting for a while. Did a battery change and it worked until I filled up my tank.

For the last two days it has been almost impossible to start after it warmed up. Well when it left me on a job site yesterday I pulled the fuse for the Air Dog and it started instantly. It left me two more times where it would not start after I turned it off. Both times pulling the fuel pump fused allowed it to start instantly.

Once it lights off I put the fuse back in and all is fine until I turn it off again. I am going to do a modified version of the FASS hard start fix tonight. Basically using a normally closed relay attached to a fuse that is only hot when the key is in the run position. That should cut off the fuel pump when I am cranking the engine over and then allow it to run as soon as I release the key to the run position.

I have been checking codes like crazy and there have been No VP codes coming up. It must be that my Air Dog is pushing too much pressure while cranking. You can watch my manual gauge when I crank it over and see the needle pulsing from 5psi to pegging the needle at 30 psi. Once it lights it settles in at 17 or so and stays there.

-Dave

KATOOM

Bingo.

tchdodg

I tried pulling the fuel pump relay, and it didn't seem to make a difference. The LP I'm running was put in by a local diesel shop, it's not a FASS or anything like that, but it's been running fine with these pressures for about 2 years now. I changed the filter and replaced/cleaned the ground cable ends at the battery. It started better than it has in awhile, and my voltmeter idles at 14 and runs slightly higher going down the road now. It wasn't doing that last week. We'll see, it's also 15 degrees cooler here now than it was last week. I'm still suspecting a VP computer, but hoping for the best. I'll let you know.

KATOOM

From what you just described it does sound as if your VP's computer is going bad. There is one kinda backwoods way to tell if thats your problem too. When the engine is hot and its taking awhile to start then find yourself a bucket or something of cool water and pour it over the VP. This will cool the computer which sits on the top of the VP and essentially allow it to start as if it was a cool day. Try that.

johnh

i would say the pressure is too high, vp44s are designed to operate at no more than 15 psi input. some units will start fine for a long time at higher pressures, but some will have a hard start issue..... i used to have a setup that gave me 22 psi at idle but i read about all the problems that high pressures caused so i took the booster pump off. currently i have no more than 12 and no less than 5 psi and no problems!

johnh

my thought is , the vp computer either works or it doesn't. there is no half way.... to verify that idea call a bosch rebuilder

tchdodg

I'll have to try to find my paper work on this LP. It was a stock replacement, nothing aftermarket. I wasn't trying to gain performance or anything. I just needed an LP and the mechanic said this was the new version that was on the market. I think it's an Airdog, but I'm not sure.

KATOOM

Not stepping on your toes here johnh but both your statements are just not true. NO ONE at this time actually knows what the VP's input high pressure limits are. There's even guys out there running fuel pressure numbers as high as 40 psi with no apparent problems. As I've preached before, we ALL know what the low fuel pressure limits are and you are clearly in the warning area by running 5 psi. For that matter I think 12 psi is simply to low too. Whether or not your VP gives out or not is purely your gamble but at this point in VP knowledge of the masses, I wouldnt be telling anyone to risk running such low pressures.

Also, yes, the VP's computer WILL work randomly. Well, not thats its really working randomly but merely the solder in the VP's computer deteriorates under high heat conditions over time causing intermittent connection issues which can cause problems when its hot like hard starting, white smoke, and poor performance. Eventually the computer will just short out and the engine will immediately stop running. When? Who knows. But hot summer days are the enemy of the VP's computer and thats usually when the computer raises its ugly head. Cooling the computer off with water for it work again is a tell tale sign that its giving fits and which means you should be looking for a replacement soon.

tchdodg

Well, I experienced the hard hot start issue again last night, even with the cooler temps. I'm going to start the process of which VP to buy. I'll talk to a couple of local, reputable diesel shops and get their opinion. I'm also going to call the guys at Blue Chip, but based on their diagnosis page, I'm thinking it's only a matter of time. Anyone have any suggestions on who to avoid/not avoid on purchase of a VP?