Engine/Transmission (1998.5 - 2002) Tapping VP44 pump wire

[JRihani]

All,



I was planning on getting an EZ but listened to the advice on here about going ahead and getting the Comp. Yes, I realize a lot of people here go for the MAD ECM (now the Smarty I guess). Here are my questions:



1. I am planning on NOT tapping the pump wire, but does the tapping of the pump wire alone harm the VP44 or is it only if you get into levels 2-5 that you begin to potentially fry the VP44?



2. Is the Comp sending ANY signals to the pump on level 1, or is it only on 2-5? If I go ahead and tap the pump wire but keep it on level 1, will the VP44 see anything from the COMP? (Same question asked two ways).



I have my gauges and such but I haven't dealt with the auto transmission yet. I don't want to toast it for a while and really wanted the Comp on level 1 for potential fuel savings. Once I deal with the transmission I will start to play!



Thanks for your input!



Regards,

John

 

[SnoKing]

All,



I was planning on getting an EZ but listened to the advice on here about going ahead and getting the Comp. Yes, I realize a lot of people here go for the MAD ECM (now the Smarty I guess). Here are my questions:



1. I am planning on NOT tapping the pump wire, but does the tapping of the pump wire alone harm the VP44 or is it only if you get into levels 2-5 that you begin to potentially fry the VP44?



2. Is the Comp sending ANY signals to the pump on level 1, or is it only on 2-5? If I go ahead and tap the pump wire but keep it on level 1, will the VP44 see anything from the COMP? (Same question asked two ways).



I have my gauges and such but I haven't dealt with the auto transmission yet. I don't want to toast it for a while and really wanted the Comp on level 1 for potential fuel savings. Once I deal with the transmission I will start to play!



Thanks for your input!



Regards,

John

Well with a 2002 depending on mileage, you still have an engine/VP44 warranty. So I would say leave it untapped. 2002's have had their fair share of pump failures.



Yes if you tap and stay on 1 on the main level, you are not adding fuel via the tap wire.



I have mine untapped and set at



1x1

2x2

3x3

4x4

5x5



That way as I easily change the main levels (with up and down buttons), I am effecting only the sublevel for when in the boost curve the fueling comes on. I leave it on 3 most of the time.



SNOKING

 

[WardJ]

What kind of mileage numbers do you see?



Jack

 

[JRihani]

Thanks for the input Snoking, I really appreciate it. I have close to 85,000 on the truck right now (bought at 67K). I'll let the warranty run out before tapping the wire.



Jack, who were you asking about mileage? With mixed driving I am getting just at 21mpg. On some long trips I have touched 24mpg going 68mph with the cruise on. All of this is hand-calculated.



Thanks again,

John

 

[Gary - K7GLD]

I have no actual proof as to what happens with various Comp settings when the pump wire is tapped - obviously, the higher you go with settings when tapped the greater the power.



But when UNtapped, it's my understanding there's a sort of maximum power availability at some point, where no additional fuel or timing is applied regardless of Comp settings, and no additional power increases.



Like you, I don't know exactly what that point is, or if it is the same with all revision levels of the Comp.



What I do know, is that after adding my larger injectors, exhaust smoke increases dramatically, even with the Comp switched off - so I started leaving the Comp on 1x1, and smoke was dramatically reduced.



Can't say about fuel MPG, but last check 2 months ago delivered 22. 2 MPG at highway speed in seriously varying mountain/level driving, empty (truck unloaded), and that was hand calculated.



I only use the higher Comp settings when towing our 5er...

 

[SnoKing]

Without the pump wire, it is like an EZ with 5 levels. Timing is always the same, 1-5 sublevels control the boost level that fueling starts at. Set at 1 the fueling is delayedm, a little less delayed, 3 is around stock, four fuel start sooner than stock and 5 takes less boost for fueling to occur. So 1 is the least amount of low speed smoke and 5 will create the most smoke. SNOKING

 

[Boondocker]

SNOKING has the right configuration for non-tapped Comp. When the wire is not tapped, there is only one power level. Level 1 tapped or not tapped is the same.



The sublevels are about WHEN the fuel comes in. Edge is not crystal clear about these settings, but there is a relation to boost and throttle position. Sublevel one fuels less than stock (how much, how soon). Sublevel 5 delivers maximum fuel right away. At full throttle, full boost, it's all the same.

 

[RDHamill]

I Have had my pump wire tapped for about 5 years now. Truck has 415,000kms ( 260,000 miles). My pump was replaced 60,000 miles ago.

We have had other trucks without tapped pump that have had the pump replaced earlier.

check out http://www.bluechipdiesel.com/injectionpumpfailures.html

While there are many opinions on this issue, seems to me that the main thing to watch for pump longevity is fuel supply and lubrication.



note that I have a TST.

good luck

 

[JRihani]

Thanks for the link to the Blue Chip site. That is some of the best information on the VP44 I've ever read. I've even been on that site before but had never noticed that link.



I'd really like to get everything else in the truck set up so that I can use a bit more of the Comp but, like many things in life, that will require patience

 

[KBaucom]

On the comp box settings 1(40hp), 2(60hp, 3(75hp) are all timing settings. settings 4(90hp) and 5(120hp) are fuel. you will be fine if yo don't tap the wire however watch out power is addictive

 

[SnoKing]

On the comp box settings 1(40hp), 2(60hp, 3(75hp) are all timing settings. settings 4(90hp) and 5(120hp) are fuel. you will be fine if yo don't tap the wire however watch out power is addictive

That is not what my manual says. It says the 1 is timing only and 2-5 are fueling. SNOKING