farmall130

My wife's truck is a 1997 Olds Bravada, same as a Blazer. Lately it is very, very hard to start after sitting overnight. Morning to afternoon it starts OK. I can take off the air cleaner, pour in a little gas, replace it and it will start right up. Is there a check valve in the fuel pump that is bad, causing it to lose prime? These fuel pumps are high dollar, I don't want to change it if it is not really the problem. Would something like fuel injector cleaner clean the valve if it is sticky? Sorry if I'm asking dumb questions, I'm from the old school fuel pump on the engine generation (a lot less money!).

oldchevy

There is a check valve in the fuel pump. It is probably bad. You can add a check valve in the fuel line and that should fix the problem. I did that to my Silverado and the problem was solved. I bought the check valve on Ebay. I cut the fuel line near the tank and used fuel hose to make the connections. Just make sure all the parts you buy are rated for fuel and the fuel line you use is rated for fuel injection, do not use regular fuel line.

farmall130

Thanks for the info, it sure beats $300 for a fuel pump...

honolulujoe

my blazer (2000/2001 4.3 v6) just conked out yesterday after I got about half a mile, when I left the house the tank was showing half empty (which was about right for the mileage I had done since the last fill).


after it conked out the gauge was right at the bottom and the low fuel light was on.


the aa breakdown said the fuel pump had gone I was towed home by a different company and the driver said it was more likely to be a relay not the pump.


who is most likely right the tow truck driver or the breakdown chap please?


or could it be that someone had siphoned off my fuel and the gauge had stuck - I assume most cars have some form of siphoning protection now.

ThatChevyGuy

it is possible it could have been siphoned, you could always check that.
To check if it is the fuel pump or the fuel pump relay, you can test one of two ways:
1. hook the fuel pump up to another power source and see if it operates
2. replace the fuel pump relay to see if the fuel pump works with a relay you KNOW is functional.

honolulujoe

thx will stick a small can of petrol in and see if the gauge changes and buy a new relay then if no joy will move on to the pump

ThatChevyGuy

also there should be a fuse for the fuel pump and relay. on some chevy's it's the same one as the horn fuse. not 100% sure about yours

honolulujoe

thanks for your reply, didn't get a chance to fiddle at the weekend so had a look today and may be near to a solution, according to the manual there are 3 fuses that refer to the fuel pump in their descriptions; horn is a separate one on mine and all on its own according to the fuse box diagram. these are;


ign A - starting and charging, ign 1, 4 fuel pump


a big chunky one that has fpump on it, I assume this is the relay, its the one the breakdown chap took out and connected his meter to.


ECM B - engine control module, fuel pump, oil pressure


ecm b appears to be blown, the breakdown chap didn't touch this fuse, without the manual you wouldn't know it related to the fuel pump.


hopefully I will get time to visit the local gm dealer tomorrow or Wednesday, although Chevrolet have withdrawn from the uk they should still be able to hook me up with the right fuse I guess. I have some spares in my sub but they are wider than this one.


fingers crossed that's all it is and I don't have to replace the pump

ThatChevyGuy

exactly hope for the best, but expect the worst lol

honolulujoe

ok replaced the dud fuse, initial euphoria as the fuel guage read half full


didn't start so swapped the relay with the horn relay, horn still worked but still wouldn't fire, so looks like the breakdown chap was right and it is the pump. bugger have to lift it up and get at the tank.