Hey guys.

So in replacing my Injectors with a new one (Upgraded style), it would appear my fuel lines above the transmission have sprung a leak. Fluid dripping at a concerning rate (Not alarming, just... concerning) and with a gasoline smell, but only when running, so in theory only when pressurized.

I've already ordered new lines to replace them. My question is thus:

How do I de-pressurize these lines properly?

Replacing the Fuel Filter and the Injectors, I lucked out in that the old Injectors never liked to hold pressure anyway, so there was no fluid in the lines.

I don't see a Fuel pump relay or fuse, so is there another way to de-pressurize the lines so that when I remove them, I'm not taking a shower in gasoline?

Thanks,
Border

 

A: If they’re leaking, they’re already de- pressurized

B: Exactly where are they leaking from?

 

A: Not de-pressurized enough for my liking, especially when it keeps enough pressure to still start up and run fine.

B: I can't see the EXACT area, but i was able to watch a flow of Gasoline (Sniff test proved it to be gas) flow from the fuel lines somewhere up near the engine to down around the transmission area, where it would then drip down onto the transmission shift linkage boot. I can also see that the lines are redder than the surface of Mars, so they're overdue for a change out anyway. Checking up near the engine shows no gas on the lines going into the spider assembly, so it's somewhere where it can't easily be seen. My guess is a couple pin-hole leaks.

 

I usually pull the fuel pump fuse while it's running. Then crank it a little after it dies.

 

That's what I usually do on my cars too, but My Blazer only has the fuse block inside the driver door, no underhood fuse block. And I cant find any fuse for the Fuel pump, unless it's part of another system?

 

if your truck is able to be retrofitted to MPFI injection you have an underhood fuseblock. its forward of the ABS box, labeled DELPHI, with a small twist screw that holds the cover on, read the diagram underneath to find the fuelpump relay.

 

Mine does not have that. In front of the ABS box is the Air box. Nothing else.

 

engine bay picture? what model year of truck do you have.

 

The only fuse box on the 96-97 S-series SUVs is the one on the driver side of the dash unlike the 98+ trucks which have a main fuse box under the hood along with the auxiliary fuse box on the side of the dash.

As far as disabling the fuel pump, you can either pull the ECM/BATT fuse or locate and pull the fuel pump relay which I believe is located in the glove box. I was able to find the electrical components diagram below; although it is somewhat poor in quality it should help with other things:


Be aware that your truck likely is equipped with an oil pressure activated switch that may activate the pump with sufficient oil pressure (typically >10psi) so if you are cranking the engine to relieve pressure, it may activate the pump through that part of the circuit. To defeat that as well, you should disconnect the electrical connector on the oil pressure sensor/switch which is located to the driver side of the distributor at the back of the engine.

Ofcourse, the easiest solution to this whole thing would be to rent/borrow a fuel pressure tester from your local autoparts store and connect it to the fuel pressure test port on the top of the engine. You will then be able to use the valve on the tester to relieve the pressure into a suitable container. Or you could just wrap a rag around a screwdriver and push the schrader valve in the test port...

 

Swartlkk Already mentioned. But mine's a 1997. Here's the Engine bay and the driver's side as a closeup.




I hadn't thought of the rag and scrrewdriver approach. But thanks for the tip on the oil pressure switch and such. I know of the Glovebox fuses, but I think I have like... 4 in there. So not sure which is which. Still, this is helpful, thanks!