dlovesfuel

So I just changed out the fuel pump in my 87 truck but after I reinstalled the tank and went to fire it up, I now have no power to the fuel pump. I checked it at the connector right before the pump and I have nothing! I have checked the fuse block under the drivers side dash and I also checked the fuse block under the hood but I cant seem to find anything wrong. From reading some threads it seems like I may need to check the AFM but I dont even know where that is! I purchased a Chiltons manual but it doesnt tell me crap. Can someone please help . Thanks for any information

mt_goat

On my 93 3.0 the AFM was on top of the air filter.

Kiroshu

Check AFM if the flap door is stuck shut the fuel pump won't turn on.

Kiroshu

And ye what he said... its that "thing" above the air filter box. Unbolt it off the air box(with the intake hose still attached and see if the flap door seems sticky or hard to open. Have someone try and crank it up while you hole the door open a bit. It will prob run.

dlovesfuel

So I checked the AFM this morning and it feels like the little flap opens pretty easy when I push it. ??So the design on the flap is so that it stays closed until the motor draws air and sucks though it hard enough for the flap to open?? Is there anything else that would cut the power off to the pump? A relay or fuse somewhere?

dlovesfuel

So I decided that I would put a wedge in the intake at the AFM flap or whatever you would call it and the truck fired right up. As soon as I pulled the stick out, it died. Does this mean that I need to replace the flap or is there some kind or sensor that controls this. Am I better off getting rid of this type of intake and putting on some type of aftermarket unit now. Thanks for any input

thook

I'm not going to say you're better off. I personally like the stock set up. It's calibrated just right.

What this means, though, since you're truck won't start when the flapper is closed is that you need a new AFM. I suppose you could try cleaning the tracks inside there, but I don't know how reliable that will be for you in the long run. IOW, if you pull that little plastic cap off the top that's sealed with silicone you'll see a needle that moves along a track. Well, there's circuits connected to that. The one that operates the COR (fuel pump relay) is bad. OR........and this a possibility........the terminal in the AFM harness is backing out of the plug and/or not getting a good connection. Diagrams would help you in this situation, but I'd have to get unlazy, find them for you, and post the link.

Okay.........so I did.

http://www.autoshop101.com/

Look for vane airflow meter on that page. Nothing else applies.

sb5walker

No, that sensor is critical to the operation of the engine. For what might be wrong, see this thread:
https://www.yotatech.com/forums/f116...-gives-212157/