87 V20 Suburban TBI 350 oil pressure sender for the gauge help

[93FatBottom]

I bought a new oil pressure sender at Autozone and went to install it, but the one that came off of it was 1/8" threads and the one the parts stores show is 1/4" threads. The 90 degree elbow has the 1/4" hole but there was a 1/4" to 1/8" reducer. The parts stores say the 1/8" sender is for the dash light but I have a gauge, so they keep saying it won't work. Has anyone encountered this issue before, and if so what was the outcome? About to start driving this thing daily and need my gauge lol.

Autozone ordered me the 1/8" sender since it's cheap, so I'm gonna buy it anyways and try it, but thought I'd ask here if anyone could tell me if I would be wasting my time or not?

Thanks in advance!

[Greenlee]

I bought one a few years ago for my truck, and I had a hard time finding the right one. Seems like I had to call around and then drive across town to pick it up. I wish I could be of more help.

[Front Range]

Here a copy of a Post I made on another website long ago when trying to switch from 87 V20 Burb dummy light cluster to gauge cluster.




Oil Pressure Sensor location and installation on a 5.7 TBI.

If you remember I had swapped from the dummy light cluster to the gauge cluster (post #246). That required changing the circuit board plug pinout and the sending units.

There are 2 oil sensors on the Burb; one for the stand-alone "TBI system" and one for the "Dash Cluster" (dash cluster = either a dummy light or a rally gauge). The TBI oil pressure sensor has a 2-wire plug located on the right side of the distributor at the back of the manifold. The Dash Cluster sensor has a single wire plug located on a brass fitting just above the oil filter. Now this can be confusing because the normal Dash Cluster gauge sensor location is by the distributor on the pre-TBI trucks. But once TBI came along they had to change that up. That means that you have a choice of two oil sending units each with a different size base BUT the same size body and shape. The smaller base thread sensor is made for the rear manifold port and the larger base thread sensor is made for the brass fitting above the oil filter.

A good example of this is our 79 Chevy C-10 which has the rally gauges. The oil sender for that truck is electric just like the 87 Burb. But because it is a carbed vehicle the sender sits by the distributor and has the smaller 1/8" -27 thread. Both the sender for the Burb and the sender for the C-10 look exactly alike with the only difference being thread size. If your shopping at a place like Rock Auto where they show all various applications and sizes in the same column - be sure to remember there's a difference determined by the sender location.

1/8" - 27 placed on carbureted trucks at the rear of the manifold
1/4" - 18 placed on TBI trucks just above the oil filter

There is also a difference in shape between the oil switch for dummy lights and the oil sender for gauges. The oil switch is small with a unique star pattern body made to fit a sender removal socket. The oil sender is large and fat. (see pictures below)




The sensor location above the oil filter is in a tight spot behind the driver's side exhaust manifold. It has a single tan wire running to it. There is a brass fitting which looks like a straight horizontal pipe with a hex head where the sensor screws into the top of it. With the smaller dummy light switch there's plenty of room but the larger oil pressure sensor won't fit without taking a 7/8 wrench and turning the brass fitting a hair clockwise so it sits near a 45 degree rear angle.

The single tan wire works for both the dummy light switch or oil gauge sensor, both are single male spade and made to plug into the tan wire. You'll notice the tan wire is wrapped into the same loom as the oxygen sensor. In fact the O2 sensor sits close to the oil sender so be careful not to break it off OR if your a young mechanic don't confuse the O2 sensor with the oil switch. O2 screws into the exhaust pipe and for a teenage kid looks very similar to the oil switch.

It's a very tight squeeze trying to get a sensor socket/ratchet up in there to remove the dummy sender unit. The inside edge of the fender well is like a semi-sharp knife and it doesn't take much to slice open your knuckle on the first torque loosening turn of the ratchet. So be careful and try to avoid cutting your knuckle like I did. Everything will be in your way from the frame to the exhaust to the manifold. Once you get the fitting to a 45 degree it's a lot easier to work with. Use a 9/16 wrench to tighten it up and then plug in the single tan wire. If you did your cluster pinout correctly you'll have oil pressure instead of a pegged gauge.

[93FatBottom]

Thanks so much! This nailed it! Sender has been replaced

Originally Posted by Front Range

Here a copy of a Post I made on another website long ago when trying to switch from 87 V20 Burb dummy light cluster to gauge cluster.




Oil Pressure Sensor location and installation on a 5.7 TBI.

If you remember I had swapped from the dummy light cluster to the gauge cluster (post #246). That required changing the circuit board plug pinout and the sending units.

There are 2 oil sensors on the Burb; one for the stand-alone "TBI system" and one for the "Dash Cluster" (dash cluster = either a dummy light or a rally gauge). The TBI oil pressure sensor has a 2-wire plug located on the right side of the distributor at the back of the manifold. The Dash Cluster sensor has a single wire plug located on a brass fitting just above the oil filter. Now this can be confusing because the normal Dash Cluster gauge sensor location is by the distributor on the pre-TBI trucks. But once TBI came along they had to change that up. That means that you have a choice of two oil sending units each with a different size base BUT the same size body and shape. The smaller base thread sensor is made for the rear manifold port and the larger base thread sensor is made for the brass fitting above the oil filter.

A good example of this is our 79 Chevy C-10 which has the rally gauges. The oil sender for that truck is electric just like the 87 Burb. But because it is a carbed vehicle the sender sits by the distributor and has the smaller 1/8" -27 thread. Both the sender for the Burb and the sender for the C-10 look exactly alike with the only difference being thread size. If your shopping at a place like Rock Auto where they show all various applications and sizes in the same column - be sure to remember there's a difference determined by the sender location.

1/8" - 27 placed on carbureted trucks at the rear of the manifold
1/4" - 18 placed on TBI trucks just above the oil filter

There is also a difference in shape between the oil switch for dummy lights and the oil sender for gauges. The oil switch is small with a unique star pattern body made to fit a sender removal socket. The oil sender is large and fat. (see pictures below)




The sensor location above the oil filter is in a tight spot behind the driver's side exhaust manifold. It has a single tan wire running to it. There is a brass fitting which looks like a straight horizontal pipe with a hex head where the sensor screws into the top of it. With the smaller dummy light switch there's plenty of room but the larger oil pressure sensor won't fit without taking a 7/8 wrench and turning the brass fitting a hair clockwise so it sits near a 45 degree rear angle.

The single tan wire works for both the dummy light switch or oil gauge sensor, both are single male spade and made to plug into the tan wire. You'll notice the tan wire is wrapped into the same loom as the oxygen sensor. In fact the O2 sensor sits close to the oil sender so be careful not to break it off OR if your a young mechanic don't confuse the O2 sensor with the oil switch. O2 screws into the exhaust pipe and for a teenage kid looks very similar to the oil switch.

It's a very tight squeeze trying to get a sensor socket/ratchet up in there to remove the dummy sender unit. The inside edge of the fender well is like a semi-sharp knife and it doesn't take much to slice open your knuckle on the first torque loosening turn of the ratchet. So be careful and try to avoid cutting your knuckle like I did. Everything will be in your way from the frame to the exhaust to the manifold. Once you get the fitting to a 45 degree it's a lot easier to work with. Use a 9/16 wrench to tighten it up and then plug in the single tan wire. If you did your cluster pinout correctly you'll have oil pressure instead of a pegged gauge.

[Front Range]

Your welcome, glad it helped.