Hi guys,

I apologize if someone has already asked this question, I searched and found similar things but not the exact problem I'm having.

Here's what's going on, it's a 93 with the 4.9 and when I try to start on the front tank, it cranks but won't turn over. I can hear the fuel pump come on before I start it. When I switch to the rear tank, it starts up fine.

I normally run off the front tank but noticed something after using the rear for a while. Before this problem, I would start on the front tank and the idle would drop a little and give a little sputter and then go right back to normal. I just assumed it was the engine, but now that I'm using the rear tank, I've noticed that it runs like new.

Any help is appreciated, thanks guys!

 

Does no one have any information that could help me?

 

Just because your hear the pump run, it doesnt mean its output pressure is normal or that it is getting the correct voltage feed.

 

Thanks for the reply! Is there a way I can troubleshoot to figure out whats wrong? Obviously I can check fuel pressure but how can I check the voltage feed?

 

very common problem with the dual tanks...your front tank pump is going bad...

 

Like tech says it probably the pump. You can check volts at the connector for the pump itself. These systems are known for dropping volts along the way so you end up with less then what the pump needs to run efficiently.

 

So I should just replace the front fuel pump? When I bought the truck, the owner gave me a fuel pump but I don't know if it's for the front or rear tank. Is there a number on it I could check?

 

Check your volts at the pump, check your pressure at the rail. Knowledge of those 2 items will give you enough information to decide to drop the tank and replace the pump. Or, if you want, empty the tank, get a ratchett strap or 2 and drop the thing and make it happen. But were I you I would check volts first, these truck are notorious for dropping volts along the way.

 

I apologize if this is a dumb question, but how do you check the fuel pump volts without dropping the gas tank?

 

Not a stupid question at all, no such thing as. Not easily... depends on if you can get you hand up in there and release the connector. If you can't then you could drop the tank with some ratchet straps just enough to get room to pull the connector. Or... you could just pull it all the way... do your volt checks... it the test comes up good, your golden, replace the pump. If not then we'll have to start troubleshooting forward to find the bad connection

Mine has a body lift so access is easy. The ones without are pretty tight.

The tank is fairly easy to drop as long as it has no fuel in it.