• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Finally left me stranded

SnowDrift said:
His does plug into the LP harness, but it has to pick up a contact from the OPS, also. I know there is a battery power wire, since there is a momentary switch to prime the filter, also.
Click to expand...
I like the toggle switch better than the momentary. I can flip it on and leave it on.

It picks up the contact from the OPS at the LP harness connection. The same way the lift pump would if still plugged in
 
I'm replacing a portion of my relay harness, but am just wondering what a portion of Leroy's harness looks like - mainly because I'm wondering if I can incorporate some of what he's doing in with my harness. I have power at my lift pump once the engine warms up - must be heat soaking into a connector, causing it to function. I think it's either the OPS pigtail or the portion I have made up to plug the factory harness into that resembles the OPS at the connector. I don't think all the connectors are shown in his video.

I asked him if he had considered making up a harness to make the LP run during the WTS period and he had said he didn't feel it was necessary. I do like to hear the LP run during this time, because I can verify it's running.
 
SnowDrift said:
I'm replacing a portion of my relay harness, but am just wondering what a portion of Leroy's harness looks like - mainly because I'm wondering if I can incorporate some of what he's doing in with my harness. I have power at my lift pump once the engine warms up - must be heat soaking into a connector, causing it to function. I think it's either the OPS pigtail or the portion I have made up to plug the factory harness into that resembles the OPS at the connector. I don't think all the connectors are shown in his video.

I asked him if he had considered making up a harness to make the LP run during the WTS period and he had said he didn't feel it was necessary. I do like to hear the LP run during this time, because I can verify it's running.
Click to expand...

iT HAS ALWAYS BEEN MY OPINION That the prime feature is very nice to have. I incorporated it with Buddy's schematic. I do not care for the momentary switch either. I prefer a toggle switch. I also prefer a mountable relay socket instead of a mountable relay.
 
SnowDrift said:
I'm replacing a portion of my relay harness, but am just wondering what a portion of Leroy's harness looks like - mainly because I'm wondering if I can incorporate some of what he's doing in with my harness. I have power at my lift pump once the engine warms up - must be heat soaking into a connector, causing it to function. I think it's either the OPS pigtail or the portion I have made up to plug the factory harness into that resembles the OPS at the connector. I don't think all the connectors are shown in his video.

I asked him if he had considered making up a harness to make the LP run during the WTS period and he had said he didn't feel it was necessary. I do like to hear the LP run during this time, because I can verify it's running.
Click to expand...

Or is it just taking that long for the OPS to build pressure and activate
 
IMO the prime feature (if its really needed) is masking a problem. All of my trucks start instantaneously unless there is a problem. If it starts to take longer to start then that clues me into "hey there may be a problem here". I can look for a problem instead of it getting so bad that it leaves me stranded somewhere because the prime feature was masking a problem.
Thats my 2 cents.
I am open to adding a prime feature though. It would cost more if another relay, wire and time is needed.
If you install a gauge (btw the most useful gauge on a 6.5) you can verify the LP is working instead of listening for it.

I provide a momentary switch because it not meant to be left on or accidentally left on. But if you must, a on/off can be easily added to my harness by customer no problem.
 
Check power and ground right at the pump connections when it should be,and is not coming in right after it starts. If it's got power and not turning on, remove the pump and clean it with some fuel sloshing it around. Hook up power with the dual lines disconnected and see it it is pulling a vacuum by putting the palm of your hand over the inlet side.

You need to determine if you have a pump going bad, or an electrical problem. You need to know what the electrical problem is (if there) before playing add the new wire/ switch game. That's just more to troubleshoot.
 
It's electrical. The pump works flawlessly. If I jiggle the harness enough, the pump works (or if it warms up from the engine heat soak).

I have a fuel pressure gauge and will install it soon. If I can't chase this issue down, though, I'm just throwing one more part into the mix that I don't want to mess with right now.

Agreed, I want the gauge to tell me the story and agreed that I want the whole system to run properly, but I also like the pump to prime. GM added it later on, right? There had to be a reason.
 
That's how my 95 hummer is- glow plugs on primes lift pump, or at least every key on. Iirc that's what the other pin is I use on my glow plug controller - feed out to LP relay. I could be wrong on the gp controller. It makes sense to me - ensure ip is full pressure before cranking.
 
My 98 Burb, with the key in RUN position (WTS) the LP comes on prior to turning the key to START. Can't remember with the 94 C&C, it's been a decade since it last ran.
 
it's pretty easy to make the LP run during wait to start. run a wire from the glow controller to the LP relay. I'd wait tell you get it sorted out. then do the LP relay harness with it added in
 
I have this, already, AK.

I'll give a brief summary.

Here's what happens upon a cold start (cold engine, not necessarily cold outside): turn key, WTS light comes on and LP run (through my relay harness I made), WTS light goes out and LP stops, I turn the key and the engine starts. LP doesn't run at this point on its own, so I've been removing the relay in the fuse block and jumping across the terminals. I drive for a few minutes to town (about 15 minutes away) like this. Once in town, I remove the jumper wire, replace the relay into the fuse box, go inside to get materials, then come back out 30 minutes later. I turn the key, WTS light comes on and LP run, WTS light goes out and LP stops, I turn the key and the engine starts and immediately after that, the LP starts to run as it is intended.
 
Burning oil said:
I am open to adding a prime feature though. It would cost more if another relay, wire and time is needed.
.
Click to expand...

Respectfully, Leroy, this is what I was getting at when I asked you about this feature last fall through the PMs I had sent. I realize it would increase the cost, but you had mentioned you didn't have an interest in making a harness with this "prime" feature, so I dropped it.

At this point, I was hoping someone could post photos of the connections you have on your harness. Most specifically, I'm interested in how your harness connects onto the stock OPS connector (not the OPS, itself). From your video and the small photo on your site, I see the connectors for the LP at both ends, I see the hot wire for the prime momentary switch and I see the ground wire. I also see what I thought was the connector that plugs into the OPS (this is the connector we discussed last fall that I was debating on replacing with an ACDelco part instead of the cheapo I originally bought). What I do not understand is how you tie all this into the OPS. You told me you do not use the connector that I mentioned at all in your harness, so it seems like you don't do anything at all with the OPS if you're not using that connector?
 
I can't help with Leroys system, Hummers is different.

But in reading your summary, it sounds like you have a failing relay or ops. The LP is getting its primary signal ok, but once the engine starts, the ops should send signal to the relay.

If you start the truck, pull the relay, then test for power coming into the relay from ops if you have power the relay is faulty. If you do not have power, replace the ops. My instinct is the ops is your culprit and what's happening is the contact switch in the ops is being made only once the heat from the warmed up engine is helping the arm move easily enough to connect.

I know everyone's favorite thing is changing the ops, right next to changing an ip.
 
His kit depends on the original system working properly. It only uses the signal from the OPS (which he gets at the LP to trigger a relay and then send it back to the LP. So in short if you have issues with the LP not working on a stock system the his relay harness won't fix it. Its more of a preventative measure than a fix it one.

Sent from my Studio 5.0 S II using Tapatalk
 
The way your doing it is not the best way because I think your still using 18a wire on your ops pig tail?
What wire are you tapping on the GP relay for Prime feature?

My harness gets it signal from the LP connection not the OPS. And yes it depends on your system to work. If I bypassed that it would eliminate a safety aspect. Once the stock system is working then my harness takes all the load off your system and provides a system capable of delivering all the current your LP need. It will make your stock system last for many years before an OPS is needed while also making the pump run better, pump better and live longer.
 
This is the pigtail I bought when I originally made up this harness - I don't know the wire gauge size.
http://www.amazon.com/gp/product/B001RPRLI6/?tag=jhuntlink-20

I recently purchased the ACDelco piece to replace this one.

For the prime function, I'm pulling power from the glow plug relay post. This is what is laid out in the schematic.

My harness is made from the schematic that I've referred to a number of times - Is this not the way to do it?

If your system gets signal from the LP connection, then how is the load removed from the OPS? If this is the case, then does the power have to travel from the OPS to the LP connector, then to the relay, then back to the other side of the LP connector?
 
As an Amazon Associate we earn from qualifying purchases.
If your tapping the heavy post going to relay then that is the wrong place IMO, that will overload your LP relay big time. I am betting this is where your problem is. Try removing it and see if LP will come on normally.
If I were to add a prime feature I'd tap into the control signal (one of the small wire on GP relay). I have not look into it yet so if anyone out there knows witch of them is hot only while in WTS let us know.

Load is removed because your only using OPS as a trigger to "trip" my relay to take on the load.
 
You must log in or register to reply here.
Back
Top