I bought my Blazer last year, it did ok for a while, had some fun in the mud and snow. I havn't had any big problems with it untill now. It won't start, so I check it out and the fuel injectors aren't spraying. I replace the fuel filter, still nothing, I replace the fuel pump (didn't hear it come on in the first place), still no fuel. I don't hear the pump come on either, the gas guage works and it's running through the same wireharness, so I figure it's something up front. The engine turns over fine and when I pour gas down the intake it starts. Why isn't the fuel pump working?

 

Have you checked the fuel pump fuse and relay? Would have been the first thing on my list...

If those check out, then I would check for continuity between the power wire at the pump as well as at the relay. Test the ground wire for continuity to ground at the pump.

 

Swap the fuel pump relay with one of the other relays next to it. One should be a headlight relay. If that fixes your problem, replace the relay.

You need to verify your getting power to the fuel pump.

 

Thank you for your advice. The fuse is good, and I've heard alot about this fuel pump relay, and that It's under the hood. Is it one ofthe 2 small black boxes on the drivers sidefenderfirewall or is it in the larger black box near the brakes master cylnder? I'll repost if I figure it out first. Thanks again.

 

Are you sure that the injectors are not disconnected at the top of each injector. Do you hear the injectors clicking. If not you could have an electrical problem vice a fuel/fuel pump relay problem. Just for your information the oil pressure switch provides backup power to the fuel pump in case of relay problemand oil pressue builds up while cranking. It may be the fuel pump has gone bad. I am on my 2nd replacement and the last time it went bad I could run the engine with a little gas down the carburator. The fuel pump resides in the gas tank and the tank has to be removed to change the fuel pump. I had my local independant mechaninc change mine.

 

This picture should help:

 

Perfect thank you.

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Ok, it's been a day and I've tried multiple test with the electrical system. Bottom line is I bought a Chilton and it's helped me narrow down my search for the mystery fuel pump problem. I've got a brand new fuel pump, works fine when I direct connect to the battery. Works fine when hooked up in the fuel pump gastank bracket directly connected again. I've bought a new fuel pump relay, I replaced both relays to be sure. After all this the fuel pump still doesn't work when all hooked up right. So I start testing the wires connected with the relay. The orange wire (hot all times) lights up with the blk/wht (ground), but the gray wire (leads to fuel pump) doesn't light up with any wires, also the grn/wht wire (powers whole think from ECM) doesn't light up with any wire either. So I figure I'm not gettin any power from the ECM. What can I do about this? Do I have to track down the natorious grn/wht wire and look for a bad connection or is the ECM repairable and where can I find it. My chilton doesn't talk about it much. The problem has been narrowed down between the battery and the relay. More help please.. and thank you.


*EDIT by swartlkk* - Please use the edit feature to add additional information to your post if another member has yet to reply. Consecutive posting is considered another form of double posting which is prohibitted by the rules of the forum. Thanks!

 

Ok, it's been a day and I've tried multiple test with the electrical system. Bottom line is I bought a Chilton and it's helped me narrow down my search for the mystery fuel pump problem. I've got a brand new fuel pump, works fine when I direct connect to the battery. Works fine when hooked up in the fuel pump gastank bracket directly connected again. I've bought a new fuel pump relay, I replaced both relays to be sure. After all this the fuel pump still doesn't work when all hooked up right. So I start testing the wires connected with the relay. The orange wire (hot all times) lights up with the blk/wht (ground), but the gray wire (leads to fuel pump) doesn't light up with any wires, also the grn/wht wire (powers whole think from ECM) doesn't light up with any wire either. So I figure I'm not gettin any power from the ECM. What can I do about this? Do I have to track down the natorious grn/wht wire and look for a bad connection or is the ECM repairable and where can I find it. My chilton doesn't talk about it much. The problem has been narrowed down between the battery and the relay. More help please.. and thank you.

 

Autozone or most any autoparts should carry the ECM. The ECM is located under the dashIIRC it is mounted verticly but you have to take the cover under the dash out for access. When I did mine the replacement did not come with a PROM Chip and I had to transfer the old PROM to the new ECM. You could also try a junkyard ECM in order to save some money. Autozone also charged a high amount for the core charge it was over a $100.00 but I got that back when i brought in the old ecm.

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I forgot to mention that the ECM is located under the dash by the glove box.

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If you send me your email address I can email you the troubleshooting section for the Fuel Pump Relay out of the factory Service Manual. I tried toupload the file but have not been able to do it. you can email me at nolanpa@cableone.net I scanned the two pages as a PDF file.

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I think i got a file uploaded
[IMG]local://upfiles/10306/F9671378AA04417286620C3F409E9109.jpg[/IMG]

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here is the 2nd file

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hope this is better
[IMG]local://upfiles/10306/011EEB9BE3814CF18D55603BA88B8C9F.jpg[/IMG]


*EDIT by swartlkk* - Please use the edit feature to add additional information to your post if another member has yet to reply. If you are trying to upload pictures that are too large, the answer is not to use more posts, but rather to either resize the pictures or upload them to any one of the free online photo hosts available. If you need further information on how to do this, please PM me.

 

I forgot to mention that the ECM is located under the dash by the glove box.