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04-07-2012, 07:17 PM | #1 |
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Join Date: Apr 2001
Location: DALLAS,TX
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89 R3500 7.4l oil psi/fuel cut-off switch location
Where does the oil pressure switch for the fuel pump go on a 7.4l bbc w/TBI? My assumption is a boss located on the driver side toward the front of block tucked behind the power steering pump set-up. I want to confirm this if possible.
Pics are always good if someone has them as well. Thanks in advance!
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
04-07-2012, 09:58 PM | #2 |
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
TBI system uses oil pressure switch as a back-up for a fuel pump relay. This switch is located in the back of the engine, to the left side of distributor. Usually there is a 90 deg brass riser into which oil pressure switch screws into. Depending on truck options it may have a three wire plug which should have gray, orange and brown color wires.
//RF
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"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
04-07-2012, 10:16 PM | #3 | |
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
Quote:
When I pulled the motor from my truck, I labeled most of the plugs/wires; some better than others. Where this 'plug' is on the 'engine' wiring harness is around the same location as the a/c compressor plug (front driver side of the motor). There's definitely not enough wire for it to reach the rear of the block. I also tagged it as 'crank front/side'. I couldn't remember where the switch originally went because the machine shop pulled it off & just tossed it in my used parts box w/the old p-rods, rockers, & stuff. The threads for the 'switch' seem to match the threads for that front port as well & it's @ the crank centerline of the oil pan rail. Was the location for these the same on sbc's & bbc's?
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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04-08-2012, 12:42 AM | #4 | |
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Join Date: May 2009
Location: Fort Worth, TX
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
Quote:
On a SBC its behind the distributor or above the oil filter pad. |
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04-08-2012, 01:53 AM | #5 | |
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
Quote:
#41 in the pic indicates its the 'water temp switch'. Anyone know specifically what this is as there's another water temp sending unit that was in the middle of the pass side head? I'm guessing one is for the ECU while the other is for the gauge?
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67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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04-08-2012, 09:19 AM | #6 |
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
#41 on my '92 K-3500 with a 454 is for the temperature gauge. The one in the passenger side head is for the auxiliary fan in front of the radiator.
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'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
04-08-2012, 02:09 PM | #7 |
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Re: 89 R3500 7.4l oil psi/fuel cut-off switch location
Ahhh. I started looking for it in the wiring schematics but haven't made it all the way through.
__________________
67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
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