Fuel pump trouble

[Pinger]

Well it hasn't-the tank is sideways on driver side-runing under the driver and passenger seats which imo opinion is dumb as hell-most of the time you have 100kg driver with over 100 liter tank on one side of the vehicle.

Ah - and HWB has explained why. Also explains why you can hear your pump (when it works) and I can't hear mine.

I can't find any info on grounds location on tahoes-apart from obvious ones.

If as per my Suburban, the pump +ve feed, ground, and gauge wire all bundled together and run all the way to the engine bay.

Found this online-I must say that my relay can get quite hot

Couldn't a poor connection with increased resistance be the cause of that? Or, a goosed motor I suppose. I'd look for a resistance value across the motor with a multimeter (in the absnce of a 'scope) for a ballpark figure and try and relate it to the pump motor's power output.
There's also the oil switch aspect - which I'm not overly familiar with - that should allow a running engine to continue running even with a bad relay. The relay isn't hard to bypass by bridging the relevant connections with a jumper wire (for test purposes).

 

[Nad_Yvalhosert]

Well it hasn't-the tank is sideways on driver side-runing under the driver and passenger seats which imo opinion is dumb as hell-most of the time you have 100kg driver with over 100 liter tank on one side of the vehicle. I can't find any info on grounds location on tahoes-apart from obvious ones.

Liters and kilograms, huh? 100 and 100? Is that a lot? I'm not a calculator so I cant convert in my head...
My '00 Yukon Denali can carry 25 gallons and my 240lbs without complaining.

The tank location is not dumb. Ever seen a pickup truck? Where would you dream we would carry the spare tire if the fuel tank was behind the axle? On the roof?

Step 1: verify fuel pressure.

 

[Nad_Yvalhosert]

Step 2: verify fuel pressure during your hot start no start.

My experience with my Vortec trucks is if the fuel system is already at 60 psi, theres no need to re-prime upon restart. Therefore I don't hear the pump run.

KISS theory: Keep It Simple Simon
Or this one: if you heat hoof beats, dont think zebra.

That means dont go for the uber complicated ridiculous potential reason why it's not running. Start with simple diagnostics.
Your first suggestion is probably right. Vortec fuel pumps are notorious for premature failure. Most from running hot due to constant low fuel level, or burnout from pushing through a plugged filter.

 

[Pinger]

Has this grounded you Dariusz? Or can you start on LPG? My mixer system will start on LPG providing the ambient isn't too cold. There's always a risk of an inlet backfire though and the risk increases the lower the ambient temperature. If you have an injection system then it won't be an option. Mixer systems can be tweaked to help cold starts.

 

[Dariusz Salomon]

Liters and kilograms, huh? 100 and 100? Is that a lot? I'm not a calculator so I cant convert in my head...
My '00 Yukon Denali can carry 25 gallons and my 240lbs without complaining.

The tank location is not dumb. Ever seen a pickup truck? Where would you dream we would carry the spare tire if the fuel tank was behind the axle? On the roof?

Step 1: verify fuel pressure.

Imma stick to dumb-if they design the tank to go on the passenger side of the chassis then there would be more weight balance,isn't it? Yes they would probably have to design the transfer box differently but this could've been done at the beginning of design process. NM that.
As to a pump-I'm thinking some corrosion somewhere-either a ground,or pigtail or alongside. I did measure voltages on relay on 2 occasions now-all seem fine-ground on 30 also seemed fine but will recheck.
Or the pump is going-like somebody said in similar thread-he has to kick the tank for it to start working. Fuel filter has been replaced not that long ago-I keep the tank full as when I didn't,the engine would cut out shortly after I started driving-so all this may indicate it's a pump.
Finally it primes nearly everytime as I drive on propane-but true that sometimes it doesn't.
And here is another variable which I have to consult with the guy who put the LPG(propane) instalation-how is the system affecting pump-cause it uses it all the time anyway.

 

[PlayingWithTBI]

Imma stick to dumb-if they design the tank to go on the passenger side of the chassis then there would be more weight balance,isn't it?

Well, the engine is slightly off center to the right side, ha ha.

 

[Dariusz Salomon]

Has this grounded you Dariusz? Or can you start on LPG? My mixer system will start on LPG providing the ambient isn't too cold. There's always a risk of an inlet backfire though and the risk increases the lower the ambient temperature. If you have an injection system then it won't be an option. Mixer systems can be tweaked to help cold starts.

I don't think I can start it without petrol-I would have to play with software and see if there's an option like this. When I call the guy about the pupm relation I'll ask about that too.

 

[Dariusz Salomon]

Well, the engine is slightly off center to the right side, ha ha.

Then it would hold 100l instead of 113 lmao

 

[Pinger]

And here is another variable which I have to consult with the guy who put the LPG(propane) instalation-how is the system affecting pump-cause it uses it all the time anyway.

I'm sure the pump running all the time and the fuel pressure regulator being in the same position all the time (close to wide open) caused mine to stick and caused me earlier starting difficulties. That's why I have a switch on the dash now to switch the pump off when it's not needed.
An injection system should have a programmable option to switch the pump off when running on LPG.

I don't think I can start it without petrol-I would have to play with software and see if there's an option like this. When I call the guy about the pupm relation I'll ask about that too.

If it's an injection system you won't be able to. Two giveaways - two banks of injectors feeding pipes into the manifold, the system changing from petrol to LPG automatically at a pre-set coolant temperature.
Or, a mixer system which can be programmed to always start on LPG (not advisable) and can be forced to do it by toggling the changeover switch. Ignition on, switch on LPG, switch it to petrol then back to LPG and if the yellow light shows continuously it will deliver LPG on cranking. Mine is set-up to feed (without being drawn) from the 'idle' screw to help this.

If you post a photo of your engine bay I'll tell you which system you have - mixer or injection.

 

[454cid]

Try starting the truck, if it won't start, hit the bottom of the fuel tank with a rubber hammer, and re-try. The fuel pump is inline with the fuel filler door, so aim the hammer there.

The ground wire is on the frame rail in the same area.

EDIT: Just relized you have a Tahoe.... I don't know the postioning of the various components on the SUVs, I was thinking of my pickup, but if you look underneath you can probably get close.