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where is the ecm b fuse?

Low87

Low87

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Can't find it in the Haynes manual.

Stopped for a drink on the way into work this morning. Truck wouldn't start to leave. It cranks, but no fuel. I know there is fuel in the tank. Trying the easy stuff first since I'm not at work = no $.

From there I'll try other things I see discussed here.

Thanks.

Add it's an 89 Jimmy, 350 TBI.
 
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Under the dash in the fuse panel. Right next to the ECM A fuse.

What year?

You looked at the Injectors when cranking, and no fuel? If so, i'll bet $$$ its the ign module. Check all the wiring into it when you do, i think my repeated module failures were associated with bare wires back there. Once i fixed all the wires, mine has been going strong.
 
1989

I don't see a slot for either an A or a B in the under dash fuse panel.

I'll look a the ignition module.
 
They are both there on my 91.

Double check to see if the injectors are spraying.

If there aren't, and your fuel pump is working, you need an ign module.

The module is inside the distributor.
 
I found the fuse. My bad, had a little bit of stupid in my eye the first time I looked.

Thank God for camera phones. I'm out here alone trying to figure out how to start the truck and look at the injectors. Propped it up and took a video.
No fuel from the injectors.

No idea if the pump is good now. Any ideas on how to check solo?

I listened for a click when the key was just shy of start and didn't hear anything. But then again, I've never noticed it make any noise before.

Thanks for your help.
 
If you turn the key to ON, you should hear the pump prime, for sure.

I can hear it on my burb, the blazer tank is so much closer to you, you should be able to hear it for sure.

Double check if there is a fuel pump fuse. I forget.

But, if the pump isn't priming when you turn it on, it sounds like you are in need of a fuel pump. Hope your tank is close to empty!
 
I used to be able to hear it loud & clear on my 88+ trucks, but really haven't noticed it on my K5. Not saying it's not noticeable, just that I haven't.

The fuel gauge is pegged to the right also. I came across something I'm trying to find again that said pegged right is indicative of something not right. Not sure on that, but looking.

I'll look again for a pump fuse, don't think it exists though.

I think I've got just under half a tank, say 15 gallons. That's only 90 lbs. :waytogo:
Siphon time.

Oddly enough I've got a spare 31 gal fuel tank, plus a new pump and sending unit here at the house. Just hadn't planned on using it so soon. I'd like to know for sure that it's the pump before I get that far into it.
 
No great places to check the pump on these trucks. You can check at the wire connection that there is in fact 12 v running to it.

Have a friend lay under the tank to make sure its not making noise.

Other than that, break the fuel line loose at the filter, and turn the key on to see if fuel comes out.

If you check my burb build thread, i show a really easy way to drop the tank with a cheap trans jack.

Good luck.
 
Pull a plug, attach the plug wire, ground the side/thread of the plug, and turn the motor over.

BUT, if you have no fuel at the injectors.....its not going to run, spark or not.
 
Fuel gauge pegged right could be a bad ground at tank, should be a wire from sending unit to frame. I believe the pump and gauge share the same ground but not 100% sure.
 
Low87 said:
I used to be able to hear it loud & clear on my 88+ trucks, but really haven't noticed it on my K5. Not saying it's not noticeable, just that I haven't.

The fuel gauge is pegged to the right also. I came across something I'm trying to find again that said pegged right is indicative of something not right. Not sure on that, but looking.

I'll look again for a pump fuse, don't think it exists though.

I think I've got just under half a tank, say 15 gallons. That's only 90 lbs. :waytogo:
Siphon time.

Oddly enough I've got a spare 31 gal fuel tank, plus a new pump and sending unit here at the house. Just hadn't planned on using it so soon. I'd like to know for sure that it's the pump before I get that far into it.
Click to expand...

ok well im not going to take the time to read everyones comments etc.. so sorry if its already been covered. If the fuel gauge is pegged to the right, and you're not getting fuel to the injectors, CHECK THE SENDING UNIT PLUG, Under the truck. should be either on or above driverside framerail by rear tire. if that doesnt work. check the plug on the sending unit itself, IN the tank. and last but not least. Check the ground on the sending unit. to the frame.
if none of that works. use a test light, multimeter etc. to make sure you're getting power to the sending unit.
 
Finally had serious time yesterday to dig into this.

After 4 hours of getting the back bumper off, including use of a cutoff wheel, I could access the skid plate & fuel tank bolts.

Dropped the tank down a few inches and I could see the problem. Some dumbass PO had cut the fuel pump ground wire, then twisted it back together. No tape, no nuthin. It was pretty loose. Everything else looked fine.

Went ahead and pulled the tank out to replaced the pump/sender assembly. Everything in-tank looked good. The large vac line past the plastic thing on the vapor line was completely collapsed. Not sure what that affected but I'll get it replaced. Figured I'd replace the plastic thing too. Any idea what it is called? Quick check of catalogs didn't mention it.

tank.JPG
 
I'd guess a filter. I would think a check valve to be problematic on the tank vent.

Have not seen that before.
 
Thanks Dorian. Forgot I had asked that question here. I found it wading through the rockauto site. It's a vapor canister purge valve. Not cheap for what it is, but it's a perfect time to replace it.
 
Does it have a wiring plug on it or something? Trying to figure out why there would be a purge valve at the tank, all the setups I've seen the line to the EVAP cannister is "open" from the tank, and the purge valve is between the cannister and throttle body.
 
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