Fuel pressure at idle and WOT

[orrum]

Leroy my retarded Forest Gump butt has searched and looked and I cant find the OPS! In the pics its a round cylindrical thing plugged into wires. I have looked and looked and moved wiring around to the point I am afraid something is gonna quit working. Could u point me toward where the thing lives please???? Thanks.

 

[Burning oil]

Now that I think about it you may have a different style OPS. I seem to remember seeing the older style OPS on the 6.2. It had the metal body with a spade terminal on it. It will be located on driver side bell housing flange of engine, just rear of engine valley behind DS head. (It is a PITA and why I sell the OPS extension hoses.)
Maybe call auto parts store and see what vertion they pull up for it.

About the air filter muffler reducing down to 2", I wonder if that was done in hopes of the expanding air having a cooling effect on the air?

 

[orrum]

Leroy I just climbed up into the engine comp. and found the OPS, its right where u said and its a great big gray metal cylinder that has a harness with a gray, yellow and orange wire. That thing aint comin out of there until it quits working and then I will get a OPS hose off u n get it out of that terrible position. So I followed AK's advise and read up on threads and stickies and even read some on other sites, I am a little more knowledgeable and understanding now but still a little brain fused. Therefore lets approach this another way, can u or somebody please tell me how to do the OPS mod by cutting and splicing wires and while I am doing it I want to have my LP prime before cranking to give me easy starts and so I can bleed my fuel filter if necessary. Somewhere I read at least a dozen ways and they all had quirks, even saw one that the glow plug cycle turned the LP on to prime. Somebody please lay this out for me, and also somewhere there was a writeup on relays must have a diode to protect the electronis from damage.....brain fuse!!!! Help somebody this is a very cheap mode and I want to do this one ASAP.

 

[great white]

About the air filter muffler reducing down to 2", I wonder if that was done in hopes of the expanding air having a cooling effect on the air?

Nope, all done to reduce intake "honk"....

Bill;

the problem with pulling the reducer completely out is that it provides support for where the ducting clamps on to the housing.

If you pull out the restrictor (I've tried, believe me it's not easy!) it will be very flimsy and weak.

If you do pull it out, slip in a similar size of PVC/ABS pipe to give it strentgh and smooth the path through it.

If you want more air in, you could build what I built for my 89 350 silverado:

 

[handcannon]

Bill, since you've got the snorkle out, progressing with your intake air that way will probably be easier than what I was origionally thinking.

In post 38, the top pic is of the fitting between the fender and the intake muffler. Considering the concerns the BJ has about the flimsyness of the muffler if you take out the interior, is there a way you can eliminate the muffler and adapt a hard pipe between the fender adapter and the flex pipe coming off the filter cannister?

Since I've never seen a air intake like yours I'm grasping at straws right now. The intake in my 83 pickup started out similar from the filter cannister, but then the stock system went forward to the radiator core support. There was enough room between the battery and the radiator to get intake air directly from behind the grill. The origional intake muffler had a restricted area very similar to yours. I completely removed that muffler, increased the intake into the filter cannister to 4" and used the 4" vacuum tube to the core support.

Don

 

[great white]

Here's another option with the muffler removed and a section of piping installed:

 

[orrum]

WOW Great White both of those setups look good but the second is AWESOME!!!! Handconnon I thinK Great White has the way to go. Thats a basic easy fab too since my tools are limited and I looked yesterday and I have a scrape piece of 4 inch PVC. I am going to do that 2day for my exixting muffler, and add the second one when I find another breather system. Great White how far did u run the pipe inside the accordion shape muffler to air canister piece? How is it supported? Now next question Handcannon and Great White is should I be able to feel a difference with the air restrictions out of the system or see better gas mileage? What did yall notice? Thanks a bunch I will b on this one 2day. Hey Handcannon I am already picking tomatos from my garden and been getting sweet corn from the neighbor for two weeks and had to dig all the red potatos cause the vines had died and I wanted 2 plant the sweet potatos in their rows! Good luck with ur garden!

 

[orrum]

Hello Buddy are u out there????? I read a thread where u worked with a fellow on putting the OPS mod in by cutting and splicing wires. Can u walk me thru how to wire mine up and have automatic priming with the glow plug cycle and a push button bleeding of the air for filter changes? I know all help will be needed for easy starts since wvo is harder to start. My truck starts almost instantly now and I want to keep that happening. Thanks partner!

 

[great white]

I didn't notice any real difference on my tbi 350 with the "butt dyno".

Maybe a bit freer revving, more intake noise.

The pipe goes into the flex ducting the same amount as the muffler.

Taking the power off the ops switch is as easy as installing a relay in the pump feed line. Then run a power line through the relays to power the lift pump. This way, the ops switch only sees an amp or less that's used to pull the relay coil shut. The high draw to run the pump is handled by the relay.

Just make sure you use a properly sized and constant duty relay. I'd went 40a with my Raptor 100 lift pump install. Like so:

That diagram might be a little off as I think the OPS sees ground though the ECM instead of 12v. If the ECM pulls to ground, that manual switch in my quick diagram would not work where it is. It would have to pull to ground instead of 12v. it's as simple as pin 85 being 12v and pin 86 being ground. Then, the manual switch needs to be ground instead of 12v.

I essentially just removed the stock lift pump and installed the relay in it's place. Then powered the lift pump from battery though the relay contacts.

It's a pretty simple circuit but it takes the high current load off the OPS contacts, which is what the problem is in the first place.

I didn't bother with a manual switch in my application because at my Raptor's 90 GPH, the filter primes almost immediately......

 

[buddy]

The diagram in file I posted is the tell all for the OPS relay mod. Anywhere there is dashed wire is wire you have to add. The diodes and resistors are not absolutely required because the LP is not really sensitive to the reverse voltage spike caused by the relay coil. Cut the grey wire out of the OPS (with plenty of wire left to play with on each side) and butt crimp some wire to both ends to send to the relay. You can cut the orange wire out of the OPS and crimp an extra wire into one end of a butt crimp to send power to the relays (I never liked those splice things you clamp on), or get a ring terminal and pull power off the junction posts on passenger firewall behind that plastic cover. To get the priming during WTS, put a ring terminal on a wire to the Glow controller output (the output is the terminal without power normally) and send it to the second relay. For the relay terminals you can just use blade crimp terminals for each or get relay sockets. The sockets can come in single or dual sockets and typically have blade terminals with wire pigtails already inserted in them to where you would need to splice in your wires, like with butt connectors. When you look at a Bosch type automotive relay the terminals are numbered as they are in the diagram, or you can tell by the orientation of the terminal contacts.

Use at least 16 gauge wire on all of it. The three stacked lines in black mean ground, like an engine grounding point.

 

[orrum]

Hey Great White thats a easily understood schematic, now Buddy and Great White the fog in my brain is definitely thinning out but still a little hazy. What I am going to do is go out to the truck and while looking @ it I will draw what I think I am supposed to do with color wires included and post it 4 ya,ll to look at. One question first. I think I am supposed to use two relays, one for the OPS bypass mod and one for the Glow plug priming function. Where in this scenario would I put a switch to use to bleed air out of filter? Dont worry guys I am getting it, the key is to see it as two totally different mods and separate them in my mind that way they r starting to make sense. Also I dont have to worry about the diode thing right? I seriously dont need to fry my truck!

 

[Acesneights1]

My 93 runs 10 psi at idle and about 4-5 WOT with the stock LP.

 

[Acesneights1]

Here's a pic of mine. The terminal hanging in mid air with be the exciter circut from the OPS. I have the relay triggered by the power to the IP right now cause the OPS is shot and I was waiting for a socket from eBay to come to change it.
Yellow=12v batt
Blue->LP
Red<-from OPS(I have it on the IP power right now)
Black=relay ground

Also to add to GW's schematic, I would use a diode on the manual override otherwise if you left it on you could be creating some sort of power loop to whatever you took power from. Remember, the OPS maintains power for a few seconds after the truck shuts off so if that manuals switch was accidentally left on or hit on the OPS would back feed the circuit and who knows what...

 

[buddy]

The diagram points out in words (not drawn in) that with the dual relay method you could have a switch that is "isolated" as Aces points out the reason above. Simply put a 12V switched source to the center contact of relay 2. The dual relay method is so that no diodes are necessary, with complete isolation. If this were for a sensitive computer circuit then the relay coil supression diodes would make sense.

Just make sure to get the 5 prong relays, which means they have both the normally open (87) and normally closed (87a) contacts. Some do not have the center contact that is normally closed.

 

[great white]

Personal opinion time:

I'm not a fan of diodes in any circuit that draws in excess of 1 amp.

They usually just end up blowing right through the doping due to the difference in potential. They just can't handle higher amperage satisfactorily.

You're better off going with a double relay network if you're worried about current flow backing though the circuit.

Here's one I use for my back up camera:

Just ignore the camera and bubs stuff. Insert your lift pump and other bits where applicable.

The relay network is what you're after. You may have to suss it out a bit more, that's specific to my application with a twist here and there to make it work the way I want. But it should get you started thinking.

Pretty simple really. It's been used to power everything from high power cooling fans to small things like my reverse cam. Just size you relays appropriately.

 

[buddy]

Of course I already provided the double relay diagram that will work for you, and those that havent opened the file from the first page its a few pages into the document, or I also posted it in the OPS/LP troubleshooting thread, but its easier to read in the pdf here, because the site keeps shrinking all my jpegs way too much.

 

[orrum]

Ok if yall think this is ok I am going to do it this way. I am going to use one relay like in the diagram I put on here and splice in a 12 volt power source from my under dash fuse block into the gray wire coming from the OPS and put a push button switch there for priming and to bleed the filter. I have visions of the glow plug powering the LP at the same time that it is already powered up because my glow plug light flickers as I drive down the road every once in a while. Hopefully yall can read this.

 

[orrum]

oh no its too little to read, can some one tell me how to load it bigger?

 

[buddy]

Not sure on the pic size, sometimes it shrinks them a lot, even if they are already under the limit.

If you use a single relay and only want a priming switch, then you can do the OPS relay mod as GW originally posted and just put a powered priming switch to the center contact of the relay, that is the normally closed contact 87a.

It also would not hurt anything to have two sources of parallel power, and with the dual relay method the primary power is always isolated from the Glow power trigger regardless.

 

[great white]

oh no its too little to read, can some one tell me how to load it bigger?

Go to photobucket.com.

Open a photobucket account and upload your image there.

When you go to your album, you'll see an "img" hyperlink. click on that and your browser will copy the link (it will cay "copied" in the block when you click on it)

Then, come back here, right click your mouse button in the text block for "reply" and select "paste".

You're done and you img is the size it was when someone views it.

It does all the work for you.

Once you've uploaded it, you can open "edit" in photobucket and choose the size you want it to be (800x600 is a common forum size).

Cheers