Spark but no fuel

[JOES89K5]

Hello Members I completely rebuilt and reinstalled my distributor. All new ignition. I have spark but no fuel. The pump is not coming on. It’s been a long day and I’m at my wits end. Does pump have a relay or fuse that might have blown ?? If so where are they. It’s a 1989 K5 with 5.7. Any assistance will be grateful.

 

[Wes Harden]

The pump should run for 2 seconds when you turn the key on. it appears the fuse link powers the pump side of the relay. fuse links is on batt cable terminal of starter, relay should be on fire wall straight up from starter. check that the fuse link side of relay has power. if it does you can jumper the pump side of relay and run the truck. if no power on relay side fix the open, probably fuse link. the 20 amp fuse is in the dash fuse box. the box on diagram labeled module is the tank unit. the pink black wire w/ fuse is gauge circuit.

 

[JOES89K5]

Hello Morning Thank you Wes Harden for diagram. I looked at other threads. One indicates if oil sending switch is bad it won’t send power to relay. I checked a fuse in engine compartment on top of AC box and it was good. It’s about 12” to left of relay. Now this all started when my truck backfired and stalled one day several weeks ago. I checked into distributor and it was bad rusted, cracked pickup coil wires so removed and rebuilt it. Everything is new HEI wires, cap , rotor all GM. I didn’t mess with the oil sending switch but since I was in there I should have. It’s s pain to get to with distributor in. I did change out fuel pump about 8 years ago.

 

[Wes Harden]

The oil pressure switch takes over after engine starts, the ecm bypasses the oil circuit for x seconds. So if your truck starts then shuts down maybe oil pressure switch.

 

[JOES89K5]

I get spark. No fuel don’t hear pump coming on like it should. I replaced pump about 8-10 years ago. I really did not use it because I was doing other repairs to it. So it hasn’t that many hours on it. I’m going to bang tank see what happens and check wires and relay. Try and jump it.

 

[Wes Harden]

Let us know the results

 

[89 jimmy]

As mentioned earlier, with everything very quiet, close all doors and windows and turn the key to the on position but do not engage the starter or start motor. You should hear the fuel pump run for a couple seconds. If it sounds weird or no sound at all it’s probably the fuel pump

 

[JOES89K5]

Update, It’s been busy at work but found some time to work on blazer. Ok not sure if tapping the fuel relay worked but I heard fuel pump activate and another activation a click under the hood. It didn’t start. I brought up TDC. I decided to check timing and found I was out 180 degrees. I guess that was part of the problem. I also decided to change out oil pressure switch and found it had been leaking. The connector and wires was saturated with oil. I know when I had my 7.3 ford PowerStroke Diesel the oil pressure switch went bad pushing oil into connector and wires causing a short. This was a known problem. Once changed the truck ran great. I will be changing the oil switch and connector before reinstall of distributor in right TDC position. I had to cut down some length on each wire to get to a fairly clean section to for splices. It’s very cramped space working behind engine. Let’s see what happens.

 

[Wes Harden]

180 out will keep it from starting

 

[JOES89K5]

Ok SUCCESS The Blazer started right up. Yes the 180 out probably kept it from starting. What was I thinking. This is what you get when you hurry the job because of other commitments. But rebuilding the distributor changing out oil pressure switch cleaning and installing new connectors and a host of other new parts which should have been changed out earlier has made it start without any hesitation. Thank you Wes and other members for your assistance. I’m moving on to the next project the windshield wiper switch in the column and steering box.

 

[89 jimmy]

Glad you worked it out