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Chevy K5 oil pressure sending unit help.

Ok I just went out and found the second oil press sender, by the oil filter, it’s the bell shaped style. I grounded the wire to it and the gauge pegged. So this is definitely the sensor I’m looking for. However, I’ve never heard of that style sender being in that position. I thought that spot was for a sender that tripped a warning light. So maybe that style sender can’t read the proper pressure at that location?
by the way my gauge is a 0-60 gauge .My only issue now is getting my fuel pump working again. I messed it up by grounding the wire to it which I now know is tan and white. If anyone knows where the fuse is for this that would be great, I’m hoping I just blew the fuse. By the way thanks for all the help guys I really appreciate it.
 
Never mind, I looked at that diagram that Wes posted (thanks Wes) and I saw the fuse for “ECMB” which I remember seeing in the fuse block under the dash. I checked that fuse (10amp) and sure enough it was blown, threw in one from the turn signals and it works perfectly. I let the blazer run for a little while and the temp gauge never moved. I’ll replace that sensor and the bell shaped oil press sending unit and hopefully get my gauges working properly. Thanks everyone who helped I really appreciate it.
 
Thought to myself when I read the title of the post that you had an '88. I also have an '88 TBI and have recently had the same problem and wondered about the sensor being reversed from normal. Also I think that you still have the computer just not the TBI.
 
Couple of things. For the entire run of the square bodies, there were only two electric senders (sender is gauge, sensor is computer) for oil pressure. 60 and 80psi. 80psi was diesel only.

Second. It was mentioned at least once in another post, but that's almost certainly the wrong distributor for a carburetor. You can pop the cap and rotor off if you like, but I'm pretty sure you will find there is no advance mechanism. Gm did some funky stuff with the distributors in the 80s, but I am pretty sure they never used one of those ignition modules (where the plugs go) with a mechanical/vacuum advance setup.

Engines will start and run with 0* advance (it's how tbi motors were set for base timing) but you'll just be stuck with 0* all the time without a mechanical method of advancing it.
 
I think the computer is still there and probably running the timing advance on the distributor, hopefully the knock sensor is working.
 
Might work, although it would definitely be in limp mode, which is sub-optimal.

Better idea in that case is to toss the carb and put TBI back on it. Lol
 
Dyeagar, You may be right but my Standard/Blue Streak catalog from the 80's does list different sending units for both gas & diesel depending on the gauge being 0-60 or 0-80 psi...

The 80's engines sometimes used a HEI "EST" spark distributor with no mechanical advance,timing was taken care of by the 7 pin ignition module and possibly a small computer hidden up under the dash..
I deleted a few of those by installing a older HEI with a vacuum advance and the 4 prong module..

I'm confused about something--he says the engine has a carb,but he's still using the in-tank electric fuel pump from the TBI to deliver the fuel ?..wouldn't that be too high a pressure for a needle & seat valve in a carb to handle ?...if the block has the provision to mount a mechanical fuel pump I'd use that instead..
 
@dyeager535 @Wes Harden @diesel4me, do you think it would be best to get the proper distributer and a mechanical fuel pump? What else would I need to do to make it run right, I haven’t driven it all that much since I got it but it does seem sluggish and a little weak. For example it sometimes acts like it might die when it’s cold and put into reverse. What’s my best bet? I really don’t want to put fuel injection back in.
 
I also have to replace my fuel sending unit because my gauge doesn’t work so now might be a good time to clean all this up to standard carb parts
 
I'd put an older HEI with a vacuum advance in it and use a mechanical fuel pump...at least one of those you can replace without dropping the gas tank,and no wondering when the electric fuel pump may decide to take a dump..

You may have to remove the electric pump from the tank anyways to use a mechanical one (it might prohibit the mechanical pump from getting a steady supply of fuel,sucking gas thru it with no power to the electric pump)..so yeah,replacing the sending unit with one for a carbed engine would solve that issue..

If your not getting any timing advance with your current setup that will affect the performance a lot..as in lack of power,poor mpg,etc..

Just about any carbed engine will want to stall after a cold start if you put it under a load instantly--the choke has to be set right and the choke pull off working properly to keep a cold engine idling and most still need at least a few minutes of "warm up" before they'll run good..
It's not like fuel injection ,where you can cold start it and drop it in gear and go instantly...takes time for the intake manifold to heat up enough to vaporize the fuel better..
 
diesel4me said:
I'd put an older HEI with a vacuum advance in it and use a mechanical fuel pump...at least one of those you can replace without dropping the gas tank,and no wondering when the electric fuel pump may decide to take a dump..

You may have to remove the electric pump from the tank anyways to use a mechanical one (it might prohibit the mechanical pump from getting a steady supply of fuel,sucking gas thru it with no power to the electric pump)..so yeah,replacing the sending unit with one for a carbed engine would solve that issue..

If your not getting any timing advance with your current setup that will affect the performance a lot..as in lack of power,poor mpg,etc..

Just about any carbed engine will want to stall after a cold start if you put it under a load instantly--the choke has to be set right and the choke pull off working properly to keep a cold engine idling and most still need at least a few minutes of "warm up" before they'll run good..
It's not like fuel injection ,where you can cold start it and drop it in gear and go instantly...takes time for the intake manifold to heat up enough to vaporize the fuel better..
Click to expand...
Great, thank you. Do you mind if I pm you? I have a few more questions
 
You can but I wont get back to you right away,I have to go do some errands..be back online later today or tomorrow morning..
 
dyeager535 said:
Might work, although it would definitely be in limp mode, which is sub-optimal.

Better idea in that case is to toss the carb and put TBI back on it. Lol
Click to expand...

Without the TPS sending any info the ECM would definitely be in "limp" mode. The oil pressure gauge is the least of your problems.
 
Definitely go to older HEI distributor.
I had a mechanical pump on my sub it wouldn't provide enough fuel to run at cruise speed with overdrive trans. The pump failed with 6 months anyway. I blame alcohol in our fuel for that.
I used an Edelbrock electric pump, iirc max pressure is 9 psi.
Mounted at tank near the bottom half.
Check the gauge instrument fuse also, might solve gauge issues.
As for current performance, what size tires, gear ratio, transmission are you running atm.
Pic of fuel pump installed.

IMG_20190605_194606.jpg
 
You can buy a carbed distributor probably for ~100. You can't put one together for that.

I'd probably suggest a mechanical fuel pump if the block is setup for it. They generally work fine, although with today's plethora of cheapest bidder chinese garbage parts, you never really know.

If all the wiring is there for TBI though, and it's a TBI motor, I think you are missing an opportunity getting further away from that.
 
diesel4me said:
Dyeagar, You may be right but my Standard/Blue Streak catalog from the 80's does list different sending units for both gas & diesel depending on the gauge being 0-60 or 0-80 psi...
Click to expand...

I have a hard time looking parts up in the GM manual on my phone, so I can only go off what I saw in the past when I used to be a semi-pro at collecting 1980's GM instrument clusters. I have never seen an 80PSI gauge (stock) in any truck except one with the 6.2L diesel. Which to my recollection was exactly two, from back when square bodies were the predominant trucks in wrecking yards. Wished I had opportunity to have grabbed more, both gauges I grabbed are gone. Though I had one left but haven't seen it in years.
 
Just because my catalog lists both 0-60 or 0-80 PSI gauges for several years in the 70's and 80's doesn't mean they actually HAD them..

I also have Champion spark plug catalogs that lists 454's being factory in some G series vans in the '80's,but I've never seen one "factory",even in G-30 cube vans..seen some put in by the owners,but not the factory..

Does it mean they do exist,and I've just never seen one ?...or is the catalog just wrong ?...hard to say..I'd lean towards the catalog listing being wrong..
 
dyeager535 said:
You can buy a carbed distributor probably for ~100. You can't put one together for that.

I'd probably suggest a mechanical fuel pump if the block is setup for it. They generally work fine, although with today's plethora of cheapest bidder chinese garbage parts, you never really know.

If all the wiring is there for TBI though, and it's a TBI motor, I think you are missing an opportunity getting further away from that.
Click to expand...
The issue is some of the wiring is gone and I don’t know exactly how much, it seems to me like less work to go full carbureted at this point but then again I don’t know how involved either process is and exactly how far along I am. I still have the computer under the dash, is there no chance that it’s properly controlling the distributor still? Also couldn’t I just install a fuel pressure regulator to get the right pressure to the carb? Last thing, I have a spot on the block where the mech fuel pump goes but this it what it looks like, any thoughts? 9270F1E8-AE4C-4EEC-8BE9-B4FF8BF969F3.jpeg
 
It us possible to get the pressure down low enough for a carb, I did it 25+ years ago when an old employer couldn't find anyone who could fix an '87, not even the dealer. We changed the camshaft, intake manifold and distributor, slapped a Q-jet on it and then it would run better and not die.
Good safe connections to the fuel feed and then returning the excess fuel is a big factor in my opinion.
 
yes you can use a pressure reg to get to 5-8 psi for Qjet. I would use a regulator with a return to tank. Where you able to check the gauge/instrument fuse?

@diesel4me our fleet had many 454 G30 vans( I hated them). Ours where 87 thru 02, some had duel air pumps and more piping than a steam engine.
 
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