Any tricks to OPS R+R?

[TJ Moose]

My '95 'Burb 6.5 TD had the stalling and driveability blues, which I've traced down to the lift pump not running because of a bad oil pressure sender switch. I have read all the posts, and everyone seems to talk like changing the OPS is about as straightforward as like the Nike Folks saying "Just Do It."

Maybe someone has hit me with stupid sticks - but I have yet to get my hand on the darn thing - and for the most part, I know my way around most engines. I understand its a bit of a challenge - but I can't even find the sender!

So - I've moved the glow plug controller out of the way, and can get my fingers kind of reasonably around between the engine and the firewall - and no matter where I run my hand back behind the galley, (drivers side, passenger side, down to the bell housing, whatever) I have yet to feel anything like what my hand is telling me an OPS should feel like. I feel a few what appear to be fuel lines (steel lines with screw clamps.) And of course - you can't see anything down there, nor even really fit a mirror in to take a gander. Am I making this too difficult or what? Should it be laying on its side? Which way is the connector plug facing? Any clues?

Now - the block is a '99 vintage, as GM changed me out the original on an extended warranty deal after a head problem ruined the innards. I know that shouldn't make a diffrerence, but after groping around there for 3 hours, it has me feeling kinda dumb, and I'll entertain any suggestions as to what I'm doing wrong.

Yes - I did just buy the 6.5 engine book that has a procedure written up in it, but I can barely wait until snail mail gets it to my door. The neighbors know I love my diesel 'Burb, but they are becoming concerned that I have taken to having unnatural relations with it, given how much time I've spent in front of the garage laying prone over the engine. Please help me before they call CPS (Chevy Protective Services) on me!!!

(Thanks for any tips or tricks. And a picture or two would be even sweller than that!!!)

[JohnC]

It's on the back side of the block just below the driver's side head. There's a 90 degree adapter it screws into and the connector end points toward the fuel filter. Remove the screws holding the fuel filter and move it forward. Get a long extension and a Lisle oil pressure sender socket and it'll be easy. Just do it.

[MTTwister]

Drivers side rear, buried kinda under the Fuel filter and associated plumbing - that's on a '96 tho'.

If you replace it ( and it sounds like your headed that way :) ) research and install the OPS Relay setup - it takes the current off the OPS points to extend their life.

[Robyn]

The early ones had it on a 90 degree fitting behind the glow plug controller.
Later ones have it under the intake manifold in the valley area on the drivers side about 6 inches forward of the bell housing flange. This was a real smart move. NOT

[TJ Moose]

MTTwister - for the right answer - you get the kewpie doll and the home edition of the "How to Fix Your 6.5 In 3 Easy Steps" game. I could not find the OPS behind the block near the firewall because it wasn't there. On this particular engine, it indeed is down in the valley - exactly where you said it would be.

As always - gratitude and thanks to TDP members for making another difficult task far easier.

[MTTwister]

I'll take the life-size inflatable kewpie doll. :p And if you haven't gone in there yet, maybe you should wait for that " making it easier" part.

Good Luck - oh and research that OPS relay option..

[JohnC]

Hmmm, musta changed in late '95. Mine was built in February and definitely was on the back.

[TJ Moose]

John C - I had a new GM engine out of a crate installed in November '99 (For once the extended warranty paid off - $200 deductible for new engine plus install) - so that is most likely the reason. Thanks all for the help.

[JohnC]

John C - I had a new GM engine out of a crate installed in November '99

So, you were witholding vital information!

[arveetek]

So, you were witholding vital information!

Actually, John, look about 4 paragraphs down in the first post of this thread....

Sorry, guy! ;)

Casey

[Robyn]

Once we figured out the easy way to get at the ones on the back of the block the engineers had to get even and bury it down under the manifold.

[TJ Moose]

For the OPS in the valley - actually - it is an easy R+R, once you get the right tool. Here it is -

Unbolt the fuel filter housing so you can scoot it out of the way. Get a Crow's foot for your socket wrench. Clearances are tight enough that I got a 1" Crow's foot using a 3/8" drive, rather than a 1-1/16" Crow's foot on a 1/2" drive. Then I took the grinder to the 1" and opened up the jaws just enough to fit the sender. (I think the 1/2" extension would have been big enough around that it would have interfered with the intake manifold.)

Once I got that all set - it was about 5 minutes to take the old sender out (plenty of room to swing the crow's foot extension) and about 15 to get the new one in and the plug back on. (Oh to have long, slender fingers.) Then tighten the fuel filter housing and done!

And yes - whoever was mentioning it to me - now that the 'Burb is back on the road - the next project will be the solenoid setup for the liftpump.......

[JohnC]

Actually, John, look about 4 paragraphs down in the first post of this thread....

Sorry, guy! ;)

Casey

Where is the smiley for :embarassed ?

[stingthieves]

Screwing in an oil pressure hose and bringing the OPS up to a nice junction block????