Lift pump actuation whilst waiting to start

[matuva]

IIRC, on the 1996+ 6.5s, while you're doing glow cycle and waiting to start, the lift pump is powered by the PCM. Once you start the engine (successfully ), the PCM quits feeding the LP, and the power to LP is going through the OPS.

On 1995 and backwards 6.5, while you wait to start, the LP is not actuated, waiting power from the OPS once the engine runs and oil pressure is established.

Any of you already tried to wire a parralel power circuit to LP which will feed it once you wait to start, and then leave place to the OPS when engine runs, sale so as a 1996+ ?

Nothing critical, but I really prefer LP pushing fuel to the IP when crancking, rather than IP having to suck fuel at this moment...

 

[bshull]

I purchased the relay unit from Kennedy Diesel. It came with it's own oil pressure sender and wired in real easy. The unit will activate the lift pump for 30 sec after you turn on the key, then it switches to it's own oil pressure sender to power the pump. It also has a nice little button that you can press to activate the lift pump to aid filter changes.

Brian

 

[matuva]

Thanks for the tip Brian. I think you talk about this one? : kennedydiesel

Does the OPS in the kit replaces stock OPS, or should it be plugged in an oil port somewhere else? Just to make sure, as the OPS are sometimes failing, so that means in that case I should purchase my spare OPS from Kennedy, not ACDelco...

 

[bshull]

That is the unit.

You will still need your original OPS for your oil pressure gauge. Originally I put in a brass T fitting below my factory OPS and screwed the lift pump OPS into the other T port fitting. When I changed my engine I moved the lift pump OPS to it's own oil pressure port and returned the factory OPS to it's original configuration.

Brian

 

[bison]

You can also bypass the OPS with a toggle switch to provide power to the LP incase the LP packs it in on the road or to have LP power to pressure up the system while starting on the pre 96 models
I actually put a 2 way switch on both my 6.5's,the other side of the switch is spring loaded and powers the extra glow.

 

[Mudbath]

IIRC, on the 1996+ 6.5s, while you're doing glow cycle and waiting to start, the lift pump is powered by the PCM. Once you start the engine (successfully ), the PCM quits feeding the LP, and the power to LP is going through the OPS.

On 1995 and backwards 6.5, while you wait to start, the LP is not actuated, waiting power from the OPS once the engine runs and oil pressure is established.

Any of you already tried to wire a parralel power circuit to LP which will feed it once you wait to start, and then leave place to the OPS when engine runs, sale so as a 1996+ ?

Nothing critical, but I really prefer LP pushing fuel to the IP when crancking, rather than IP having to suck fuel at this moment...

Pre 96 6.5 also gets power to LP when key is in the "Start" position, then when it starts the power comes from OPS

 

[ak diesel driver]

courtesy of Buddy

 

[matuva]

Argh ak! the wiring seems to be promising, but can't read it: it's too small :nonod:

 

[jrsavoie]

Check the threads here. Somewhere there is a copy you can print full sized. I've installed the dual relays on 3 vehicles.

 

[ak diesel driver]

http://www.thetruckstop.us/forum/sh...List-for-1994-and-1995-6-5TDs&highlight=relay

it's in this document,at least for obd1

 

[matuva]

Thanks ak, I get it now

I extracted the wiring diagram and post it in that thread. As said ak, courtesy of Buddy

 

[jrsavoie]

On the 94's I came off of one of the studs on the left firewall for power and used the lift pump fuse wires for source from OPS & to supply the lift pump with power. I like to use a relay socket. That way if you pull a relay you just hAVe to plug it back in as apposed to worrying about where the wires go

 

[matuva]

I think I finally find my setup.

I will do the twin relay setup (thanks ak and Buddy), but instead of trigerring one relay via the glow plug relay, I will use a "ACTIVE" latching switch/timer like this one : http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140333447156 , setting the timer at 5 seconds, more or less, and I will get LP priming for a while, like on EFI engines