fidelity101 Reader
Dec. 19, 2012 7:33 a.m.

I need help from the local GM TBI guru's I'm undergoing a simple motor swap in my suburban and I have these 2 sensors that are on the old block and I believe they are both oil pressure but my main question is are these required by the ECU to operate and function or is it just a dash gauge sending unit kind of deal (maybe a little half an half too)

here are the sensors in questions

and

I'm not running anything performance like cams and such its just a stock block (except headers) I plan on using my own water temp and oil pressure gauges because I don't trust my stock gauge cluster.

I know that the oil sensor by the starter is useless because it usually becomes unplugged and has no changes in engine performance. Lucky me the TBI is a relatively simple and easy EFI setup.

Ranger50 UberDork
Dec. 19, 2012 7:40 a.m.

The lower one looks like it is for an AM gauge. The top one is for the OP gauge in the cluster.

As far as I know, there isn't any need for the ECM/ECU to know OP.

fidelity101 Reader
Dec. 19, 2012 7:43 a.m.

In reply to Ranger50:

Learn me: AM/OP?

Ranger50 UberDork
Dec. 19, 2012 7:47 a.m.

AM= aftermarket

OP= oil pressure

Bobzilla UltraDork
Dec. 19, 2012 7:48 a.m.

The one by the dist is the one you need. It will not turn on the fuel pump if it's not plugged in. Ask me how I know.

fidelity101 Reader
Dec. 19, 2012 7:49 a.m.
Ranger50 wrote: AM= aftermarket OP= oil pressure

doh! I think I lack the required amount of coffee this morning.

Bobzilla wrote: The one by the dist is the one you need. It will not turn on the fuel pump if it's not plugged in. Ask me how I know.

thanks :)

I'm trying to get my tow rig ready for sno*drift

Gearheadotaku UltraDork
Dec. 19, 2012 11:20 a.m.
Bobzilla wrote: The one by the dist is the one you need. It will not turn on the fuel pump if it's not plugged in. Ask me how I know.

yes, this ^

Dec. 19, 2012 11:48 a.m.

Agree, top one is oil pressure and reports to your IP. Your TBI is not on speaking terms with it.

crazycanadian
crazycanadian New Reader
Dec. 19, 2012 12:02 p.m.

Your TBI computer shouldn't be on speaking terms with the OP sensor, but some older GM's had a fuel pump safety wired in with the OP sensor.. If it didn't see oil pressure the fuel pump would be turned off..

Keep that in the back of your mind incase you run into problems with your fuel pump not turning on.. It would be simple to by pass if you did run into it..

tuna55 UberDork
Dec. 19, 2012 12:09 p.m.
fidelity101 wrote: I'm trying to get my tow rig ready for sno*drift

Literally THE ONLY thing I miss about upstate NY, snowdrifting around in a Camaro. Gosh that was fun. Wife hated it though, so it was probably best for our marriage that I drive like an idiot during Lemons races instead of snow days.

Hope you get it ready in time!

Gearheadotaku UltraDork
Dec. 19, 2012 12:54 p.m.
crazycanadian wrote: Your TBI computer shouldn't be on speaking terms with the OP sensor, but some older GM's had a fuel pump safety wired in with the OP sensor.. If it didn't see oil pressure the fuel pump would be turned off.. Keep that in the back of your mind incase you run into problems with your fuel pump not turning on.. It would be simple to by pass if you did run into it..

This explains it better ^

fidelity101 Reader
Dec. 19, 2012 2:02 p.m.
tuna55 wrote:
fidelity101 wrote: I'm trying to get my tow rig ready for sno*drift

Literally THE ONLY thing I miss about upstate NY, snowdrifting around in a Camaro. Gosh that was fun. Wife hated it though, so it was probably best for our marriage that I drive like an idiot during Lemons races instead of snow days.

Hope you get it ready in time!

No, sno*drift is the season opener for rally-america. I'm gonna bring the party bus this year :) It would be easier to get to some of the stages with everyone inside.

I noticed that most sending units are just 1 wire and if that oil pressure sensor is just a switch to keep the fuel pump on, why don't I just complete the circuit ?

tuna55 UberDork
Dec. 19, 2012 2:06 p.m.
fidelity101 wrote:
tuna55 wrote:
fidelity101 wrote: I'm trying to get my tow rig ready for sno*drift

Literally THE ONLY thing I miss about upstate NY, snowdrifting around in a Camaro. Gosh that was fun. Wife hated it though, so it was probably best for our marriage that I drive like an idiot during Lemons races instead of snow days.

Hope you get it ready in time!

No, sno*drift is the season opener for rally-america. I'm gonna bring the party bus this year :) It would be easier to get to some of the stages with everyone inside.

I noticed that most sending units are just 1 wire and if that oil pressure sensor is just a switch to keep the fuel pump on, why don't I just complete the circuit ?

OOPS, I'll stop hijacking your thread now...

Dec. 19, 2012 2:06 p.m.
fidelity101 wrote:

thanks :)

I'm trying to get my tow rig ready for sno*drift

I will look for you, I am attending with a group of friends. Are you racing?

fidelity101 Reader
Dec. 19, 2012 2:21 p.m.

In reply to pilotbraden:

No I just get drunk. I got various friends racing. Its going to be 7 or 8 blurry years in row!

I may tow my rallyX car (rx7) up with it if all goes well and just spend buku bucks on gasoline over the weekend.

EDIT: ahh screw it, i finally posted the build http://grassrootsmotorsports.com/forum/build-projects-and-project-cars/1985-frankenburban-grassroots-hauler/58298/page1/

Dec. 19, 2012 3:18 p.m.

In reply to fidelity101:

That sounds like us. 5 guys are going to be at my cabin north of Fairview. One sober man drives on Friday and someone else on Saturday. Last year I drove much of the course on Thursday, it was very interesting and gives one more respect for what the drivers are facing.

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