My ECM pulse the voltage to the LP 3 or 4 times in about 1/2 sec. before remaining on. Is this normal or odd? I get a solid 12.5V when it stays on. I also have about .25V when the pump is not commanded to run 0 with key off. I am assuming this is do to the use of a silcon driver; does anyone know for sure?

Randy

 

When are you testing the voltage. Under what circumstances?

 

When I trun the key on. I forgot to mention that. Also after I bump the started to get the 30 cycle. Both times the pulse. Either with the pump disconnected or hooked into my relay.

Randy

 

Are you having trouble with the LP or just find a strange reading?

 

I belive I was having an intermitant issue with it not running. I assumed it was a bad spot in the brushes or armeture and while I was doing injectors I upgraded to -8 hoses and installed a Holly black. I noticed the fluctuations when I turned it on with the relay in place.I did just find out that a friends friend w/a '99 had an ECU take a crap on him for the same thing.

Before I did all the mod's I had begun having a warm hard start issue. I have not had the new set-up not run light the previeous LP, but the pulse bothers me. It is not good for a motor to go through that. The warm starting issue has become a lot worse then before. I know the VP is a likely cause but would rather not spend $1200 on a pump and then 500 on an ECM (catcher). Nor do I want to spend the money in the other order. I have double checked everything else and I haven't found anything. There are no codes other then those induced by my mods (one heater grid and Water in Fuel unplugged).

I don't know the exact milage on the pumpl. It has at least 56K. Hence my other post. What type of marking does your pump have? Do you know if dealer replacements have any rebuild markings on them?

Randy

 

that is totally normal, if it gave a full shot of fuel pressur you would have a hard start condition, ask the guys who wired their FASS to ign on source

 

I kinda thought the "baseline infomation" was not known here. Meaning we didn't know what "normal" was before he took readings. Glad high country knew what normal was!

Moral of the story; Know what "normal" is before we start replacing stuff! Look how much money we saved you! Now go buy GAUGES!

 

The Holley is "supposed to be" preset @ 14PSI. After the filter it should be 12-13 PSI. That is not enough to cause a hard start. Also it only does it when it is warm and had time to heat soak. The first 20 minutes after running it will start fine. between 20 min and 3 hours it will crank a while.

I was think a little more about it last night and I think the new injectors are the reason for the increase in the problem since my mods. The pop pressure is going to be a lot high on the new ones and if the VP is having issues with the old ones it would be worse with the new ones.

High Country,
Did you wire you carter to the LP wiring or did you use something else?

Randy

 

I used the stock hot lead to the lp as the excite wire for my relay on my pusher, the ecm senses load on the lp so not using a relay can in some cases throw a code, if you are getting hard starts when hot give her the ol' cool water on the vp trick that will tell you if it is your culprit. and you can get the hard starties with 12 psi my rig starts on 0-3psi and jumps to 30 once it starts. I know 30 is too much you say but been like that for a long while now and I would rather be high then low.

 

I have my sttock LP and have applied a pusher pump just ahead of the tank. I used a pump and kit from BD. The kit includes a carter P4601 pump and includes an oil pressure switch. This way you start the truck with the stock pump. Once the engine has started and the oil pressure increases, the oil pressure switch makes the connection to the pusher pump. This is an excellent system and eliminates any hard starts because of high pressure on a hot engine. It also makes an easy install without using any relays and messy wiring. BD has done the homework!!!
Here's the link to BD...check it out...
http://www.bd-power.com/ram/product....%20Kits&tt=ram

 

I no longer have a stock lift pump. I don't have a FP gauge yet but I have confirmed sufficent fuel flow. I don't think it is to high. It is ran from a relay using both stock pump wires. I used the pig tail from the LP to make a harness to my relay.

Randy

 

You are playing Russia roulette with your VP-44 without a fuel pressure guage. It could quit tomorrow and you would not know it.

 

I was going to put one in this weekend but could not get the parts together. It is not a great concern when the VP is already terminal. I'm either going to drive it till it won't start or get tired enough of it the spend the money.

Randy

 

Didn't read all of it but you should use relays for powering the L/P.Don't want to load the system.