Become a Fan!
Login
Username:

Password:

Remember Me

Lost Password?

Register now!
Main Menu
Who's Online
81 user(s) are online (50 user(s) are browsing Forums)

more...
Guru Dictionary
Print in friendly format Send this term to a friend  C3
Abbreviation for the 3rd generation of Corvettes built from 1968-1982....
Supporting Vendors
Platinum
Mid America Motorworks
Mid America Motorworks FREE CATALOG


Gold
FIC 770-888-1662


Registered Vendors
Guru Friends
Supporting Banners

TIRERACK.com - Revolutionizing Tire Buying


Shop for Winter Tires Now!




Support This Site
 Register To Post

CorvetteBob OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
Can the oil pressure switch behind the intake manifold be bypassed so the fuel pump stays on? Or do I have it all wrong?
Posted on: 2018/4/2 16:00
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
Actually the oil pressure switch is by-passed on a correctly working system. The ECM will activate the fuel pump relay for approx 2-3- seconds at first turn of key. If this fails, then the oil pressure switch will power the pump after approx 4-6 pounds of oil pressure is built when cranking the engine.

This is for a L98, can't remember your model.

Joel
Posted on: 2018/4/2 23:30
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
Thanks for the response Joel.
I have an ‘89. My build is a 383 with a FAST Multi-Port stand alone system.
I can’t say I really have understood the reasoning behind this switch. Why not power the pump in both crank and run key positions and be done with it? My intake makes plumbing the OPS kinda tough, and if all it does is power the pump, I thought it would helpful to just bypass/hotwire the thing so it’s not in my way and keep the pump running.
Any thoughts?
Posted on: 2018/4/3 2:40
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
The oil pressure switch in regards to the pump running is for a back-up system only. When the engine starts after the initial "pressure build" the pump stays on and pumping. Any unused fuel is returned via the fuel return line from fuel rail and fuel pressure regulator.


Joel
Posted on: 2018/4/3 3:12
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
So if I understand correctly, when the engine is started, for the first few seconds the pump runs until the OPS reads pressure around 5 psi. Then the OPS comes on, connecting the power to the pump while the engine continues to run. If I got it right, I appreciate the the help. If not, try not to zing me too hard.
Thanks again for taking time to help.
Posted on: 2018/4/3 15:57
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
Not exactly. Forget about the oil pressure sensor and the fuel pump, except as only a back-up system.

When the ECM commands the fuel pressure relay to run the pump, it does not matter if there is any oil pressure.

The oil pressure ONLY comes into play when the relay is bad/broken and no power is sent to the pump.

Hope I'm not confusing you with all this rambling.

Joel



Posted on: 2018/4/3 18:46
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
That last post is probably the best description of it that I've seen.
Thanks for helping to set me straight on this.
Posted on: 2018/4/3 21:22
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
You're welcome.Glad I could help.
Posted on: 2018/4/3 23:41
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
Now that Joel has me goin in the right direction, back to my original question in a modified form.
The OPSwitch is in the way of my intake manifold and now I’m wondering if I need it. The pressure sensor above the oil filter is responsible for the pressure reading on the dash( that one I’m kind of sure about). Does the upper switch by the intake manifold measure oil temperature, or ...?
Anyway, th thiing is in the way and if advisable at all, I’d just as soon be done with it.
Suggestions? Once again, if I’m wrong, straighten me out on this stuff.
Posted on: 2018/4/4 17:24
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
Well, I'll stick my nose in here again. That sensor above the oil filter is for the oil temp reading.

Joel
Posted on: 2018/4/4 18:02
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
That’s not surprising since I’ve gotten everything else wrong 🤪.
My reason for thinking the lower sensor was for pressure was that my Camaros (in the late 80’s) each had the pressure sensor go bad and they were above the filter.
So am I to figger the top one is for pressure and the aforementioned fuel pump backup?
Then again, with as wrong as I’ve been about everything lately, it wouldn’t surprise me if someone told me the pressure is actually monitored thru the drain plug. 🤯🤯🤯
Posted on: 2018/4/4 21:16
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
Thanks for being so patient with me thru this 🍺
Have one or more on me!
Posted on: 2018/4/4 21:19
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

joeld Re: OP switch behind intake manifold
Guru
Lawrenceville Ga
718 Posts
Member since:
2007/12/30 0:00



Offline
Any luck?

Joel
Posted on: 2018/4/20 23:51
_________________
1989 Coupe,L98 automatic
Transfer the post to other applications Transfer

CorvetteBob Re: OP switch behind intake manifold
Elite Guru
1409 Posts
Member since:
2008/10/19 18:34



Offline
Thanks for asking Joel.
I haven't touched it yet, and I think I'm gonna leave it be.
I'm gonna have enough going on as it is with this thing when I get it running, or try to.
If it turns into a problem, I'll try something then.
Posted on: 2018/4/21 2:07
_________________
Beauty, it’s in the eye of the beer holder
Transfer the post to other applications Transfer

You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.

[Advanced Search]


CorvetteForum.guru is independently owned and operated. This site is not associated with or financially supported by General Motors.

Copyright 2008-2015 CorvetteForum.guru

CorvetteForum.guru is a Guru Garage Site (Coming Soon!)

If you have any questions about our site, please contact us at Andy@corvetteforum.guru.

Powered by XOOPS 2.56 Copyright 2001-2014 www.xoops.org

Hosted by GoDaddy.com.