This has been going on two years now where everything is fine, then out of the blue, after I drive to a job, finish, and rdy to leave, the van cranks, but won't start. I tow it to my mechanic, and by the time he looks at it, it starts and he tells me there's nothing he can do becuase he needs to troubleshoot a failed start. I have wasted 5 tows with this, so I started throwing parts at it.

#1 had my mechanic replace a gas leak due to a crack in the tank (replaced tank) and at the same time we were both fairly certain the fuel pump should be replaced with a AC Delco fuel pump

The problem still persisted, so I looked on Youtube and found the fuse box under the hood burn mark under the fuel pump fuse, causing this crank/no start issue.

#2 Replaced fuse box under the hood

The fuse box seemed to solve the problem for a couple of months, until I had a crank/no start again. after checking fused for 10 min, and doing a hard reset, it started up.

Two months goes by and it happened again at a cusomters house, and it started after 30 min of waiting.

Last night (1 1/2 months later) it happened again at a customers house and after 45 min of no starts, I called a tow truck, dropped in my driveway, cooked dinner and went out after an hour and it started right up. I don't believe there is anything I can do to get it to start except letting it sit, which is making me think that it might be the fuel pump fuse burning the board, in the fuse box again.

I this point I have no idea what to do.

 

your mechanic is correct; fault must be active for diagnostics. If the fault is not active; any and all tests will pass.

are there any stored codes present after the crank no start occurs?

if you want to rule out fuel related faults...when the fault is active; spray brake cleaner into the throttle body (remove the induction tube to the tbody and spray a 5 second shot of brake cleaner while someone cranks the engine over)....if its starts and runs briefly...the fault is fuel related.

-the fuel pump should run for 2 seconds at key on in run...do not turn to start position. can you hear the fuel pump run during the 2 seconds?

 

I can't hear but that does not mean it's not running. My hearing is not great either. I will carry some starter fluid around. Also getting a fuel pressure guage to run my own tests, because this is so random it's impossible to replicate this problem at my mechanic. Also no codes but airbag, and that reason being I took the passenger seat out triggering it.

 

This is a vid of the fuse box that seems to be a common problem


I replaced but the problem came back

 

with a used ubec or new?

 

the fuse box? Yes, its new

 

ok. Fuel system is where i would start. Yep, it could be an electrical problem effecting fuel pump operation.

 

The no start happened again after a 1/2 mile drive to a customer late night last night. After a 20 minute job completed, tried to start it and cranked, and cranked. The customer gave me a ride home and I came back with my truck. Sprayed a little started fluid and it started up again and died. After 10 minutes it srated up again and drove home..

I pulled the box today and see another burn mark on B1.

The 2 under the hood fuse box boards. The one with the larger burn mark coming from B1 is the original, and you can see the other one has started make a burn mark. 8 months/under 4,500 miles on it.

 

good find. is that pin for the fuel pump relay?
that can occur from excessive draw from a bad pump or loose pin fit.
if it was me i would wire in an external relay instead of buying another fuse box. replace the pump and hopefully yr good.

 

Yes, B1 is the power feed to the fuel pump.