I've been having problems with intermitant hard starts then intermitant NO starts. With the no starts, sometimes the fuel pump would cycle and sometimes it wouldn't.
On the last no start we towed it home jacked it all up, dropped the tank,found that the last person to put in fuel pump didn't install it properly-gasket fell down it tank, crooked in the hole. Anyway, cleaned it all up and tested the pump in a bucket of gas while conected to wiring harness and it cycled everytime. Tried it at least a dozen times and it always worked.
Put everything back together started it up, everything fine let it run for about 10 min., shut it off and tried to restart. Would not start but also heard a weird noise coming from the fuel metering assembly unit when we would turn the key on. fuel pump won't cycle now. Does the fuel metering assembly or anything else for that matter control power to the fuel pump? Sorry for the long post but we are at our wits end.

 

Have you checked the fuel pump relay? Where is this fuel metering assembly? Do you mean the sender on the pump? Or the gauge on the dash?

 

Have u checked for resistance ??? Check it at the fuel pump, if u don't have a good ground it will cause an intermittent issue.... My suggestion is to tap into the ground wire on the harness and found it to the frame

 

Also there was an updated plug for the fuel pump harness!!! Was this one replaced?????if it was check for half assed repairs.....

 

cubawashere: Relay is good, it clicks, we switch with another to be sure and it also works. The fuel metering assembly (the name the chilton book calls it) is a square black box with wires and a white plastic "do-hicky" (for lack of a better word) attached to it, sits behind the throttle body. It is making some odd sounds when the key is turned on.

07nhbpsi: We had the tank off and the pump out check the wiring harness, has new style pigtail, unwrapped it shored up the connections and retaped securely.

As I said we "bench tested" the pump by submerging in a bucket and pluged in to the harness, several times we turned the key on and off and the pump cycled everytime. Put everything back-it started, let it run, now it won't start back up.

This morning the pump is cycling but still won't start. So I wonder if the pump wasn't the problem in the first place but this metering assembly instead.

Also, just to add-we changed the fuel filter, it was restricted.

 

I'm going to guess, that's the top of the spider injector connector...dohicky...lol

Try doing fuel pressure tests, leave the gauge connected when cranking, then take note if pressure holds and what not. What yr and engine are you working with?

This link provides all the testing procedures:http://troubleshootmyvehicle.com/gm/...uel-injector-1
Let us know how you make out, Good luck!

 

Yes, that's what were going to have to do is some pressure testing. It's a 2000 4.3L 2 door blazer.

 

must be around 61-66 psi....truck with KOEO (key on engine off) & KOER (key engine running)....and hold to about no less the 51 psi or so for about 25mins when shut off....gradual decline also. Too fast, there's a leak

 

Maybe I wasn't clear....???? If there isn't a good ground it can cause an intermittent problem such as u are having.....run u a 10/12 gauge wire to the frame and solder it into the harness!!!! U mentioned u taped up the wiring???? Please tell me u soldered the wires, and used heat shrink tubingif there isn't a good ground the pump may not be cycling as it should....which could cause low fuel pressure!!!!

 

LOL-yes, he soldered and used heat shrink. Just taped the rest for extra protection.
he dropped the tank again and applied direct 12v to the pump and now it is intermittent again. So going bite the bullet and change the pump and see if that solves this. Just was trying to save a buck since money is veeeery tight right now.