CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

1987 V20 Suburban 350TBI/SM465

I’ll jump in and say definitely stuck with the in tank pump setup. I’ve been down the other road and it’s not better. Here’s a pic of the tbi sender and filter sock on the bottom DF5577D6-0134-49C7-8EED-6C50406A0A54.jpeg
 
Thanks, y’all! So the tank, pump, and sending unit.

so I went back and added 5gal to the tank and tried to start it but no luck. I tried about 12 long cranks. Just going to tow it back home tomorrow. Parts should be in by end of week
 
Bummer, can you hear the pump prime? You'll want a new fuel pump relay as well to match all your new parts.

when you get it home, AAA I hope, If not try this first.

Put a 20amp fuse jumper wire, from batt+ to the red test wire 490 the fuel pump will run if it is good. If it does run, the relay may be bad or the wiring, or the computer isn't signaling the relay to turn on.
Relay is normally bolted to firewall above pass side valve cover.

tbi fuel circiut.gif
 
Free towing through my auto insurance so no worries there.

I'll try this anyway to test once I get it home.
 
A lot of times, the rubber hose between the pump and sending unit rots.

I wouldn't bother with a new tank until you get it apart. Yours may be fine.

Martin
 
Well I won't be upset about spending less money. I ordered the other items and I'll see how the tank looks when I drop it. Summit gets stuff here quick if I need it
 
Last edited:
Was there any back fire through tbi, recently? When it ran last, how was the power pulling away from a stop? Did it seem a little slower?
Did it stall and never restart or was it shut off and never restart
 
Haven’t noticed any backfires. It’s always been sluggish since I’ve had it. Last it ran, I just turned it off and it wouldn’t start again except when I was trying to get it started with spray. No telling how long those wires have been like that
 
Ok I was suspicious of the timing chain, but not as much now.
Fix the wires and the plugs.
Then check spray pattern, if fuel pump is working.
 
New pigtails on the way.

Should I be able to see those spraying if I pull the throttle cable? By manual says to do that with ignition in the off position but that doesn’t make sense if there’s no power.
 
You can see them spary at idle, w/o operating the throttle.
Should have a nice even cone into venturi. With out the air cleaner in place. Running is ok.
 
Well well well

C669A0BC-F0BF-4B7E-85CF-2835037DAD69.jpeg

View attachment IMG_4928.MOV

Only replaced the temp sensor and the injector pigtails. Need to clean up the splices with shrink wrap but it was good enough to start up. Going to go ahead and replace the pump, sending unit, filter, and do the TBI rebuild kit since I have them here. Won’t hurt anything
 
Been a bit since I posted but I finally got around to the fuel pump and sending unit. I dropped the front of the tank a bit to give me some room and cut out an access hatch. Used a marine grade hatch door with rubber seal to cover it. Haven’t bolted it down yet as I need to put rust converter down in the back first but it’s looking good. Going to put some Kilmat under the door too before I’m done.

So far I’ve replaced the fuel pump relay, injector pigtails, fuel filter, pump, and sending unit. The truck seems to idle smoother and has noticeably more pickup in 1st and 2nd. Sounds better too.

I went a few weeks where it started up every time but a few times recently it wouldn’t start. Only finished this up today but so far so good

95850FC8-4B27-4194-9E01-10F71F34EF4C.jpeg584BC63A-C8DC-4F56-AD6C-1BE06670FE5B.jpegE2E97F2A-404C-4727-B084-E9FABCA7D356.jpeg108D3494-3740-4444-BC03-A028EBF1BEB4.jpeg
View attachment IMG_5074.MOV
 
Developed a new leak. I’m not sure what this is…something to do with the clutch. Should that port on top have something connected to it?

or is it the line above the oil filter that’s leaking?

C6B072E3-FC3F-4760-8EE7-F61B625F8D9B.jpeg39B6B337-2B31-455F-96DA-D0E890A5835F.jpeg54C18592-EDEA-44F9-BF3C-A82C40D5FCC3.jpeg
 
Last edited:
The goldish colored part is the clutch slave cylinder. The port on top does not have anything connected to it. That is the air bleeding screw, used for removing air from the hydraulic clutch system.
I think you have an engine oil leak from the oil cooler line, or possibly else where. Always look above and work your way done when looking for oil leak origin.
 
Thanks for the info. After I posted, I crawled back under there to look more. Its a very tight fit in there.

The oil cooler lines runs off the top of the adapter that the filter runs to, right? Looks like a real bitch of a spot to get my big hands in to. Look more at those lines, they seem really poorly made. The plastic push fittings seem like a great spot to have a recurring leak. I'll have to look around to see if there is a better solution. Maybe those filter relocation kits with some better hardware, hoses, and fittings.
 
Last edited:
Yes the push in connectors do leak after awhile. You can unscrew the existing connectors and replace with AN fittings and braided hose.

IMG_20210530_132449.jpg
 
Actually looking at the the picture agian that is an oil pressure sensor. If one wire is for instruments, 2 or more wires is for fuel pump. Hard to see
 
Top Bottom