4.3 cranks idles but dies.

[Dcblanton5]

2006 Tahoe q4 has a 4.3 mercury. The motor cranks every times but dies shortly after. I have put a new fuel filter, fuel pump, and replaced the hard lines. As soon as you give it throttle it dies. Seems like it’s getting spark but it just seems to not be getting the fuel it needs.

 

[alldodge]

Welcome, what's your serial number?

 

[Dcblanton5]

Welcome, what's your serial number?

Ow360556

 

[alldodge]

Ow360556

Thanks
TKS carb, TBV ignition, electric fuel pump

Correct if I miss something
When you crank the motor it will fire up but won't be long before it dies. If try to give it gas it dies.

If this is the case I would look at the oil pressure switch

When the motor starts cranking power goes straight to the fuel pump bypassing the oil pressure switch. Once motor starts the pump gets turned back ON "IF" the oil pressure switch closes to make the connection

When your motor is running feel and listen for the fuel pump, is it running?

 

[Dcblanton5]

I ordered a new oil pressure switch today. I will let you know from there thanks.

 

[Scott Danforth]

Did you test it before ordering parts?

 

[Dcblanton5]

Did you test it before ordering parts?

I did not. How do I test it?

 

[alldodge]

I did not. How do I test it?

Unplug switch and put jumper across the terminals. When key is turned ON pump will start to run. If this fixes the issue then its the switch.

Don't leave jumper there it's for testing only and not safe to leave i that way

 

[Dcblanton5]

I’m going to try that as soon as I get home. I completely unplugged the fuel pump yesterday and it did pretty much the same thing idled a few seconds then cut off.

 

[Dcblanton5]

Put the new oil pressure switch in today it will rev up fine but will only go about 5mph in the water?

 

[Dcblanton5]

Unplug switch and put jumper across the terminals. When key is turned ON pump will start to run. If this fixes the issue then its the switch.

Don't leave jumper there it's for testing only and not safe to leave i that way

Put the new oil pressure switch in today it will rev up fine but will only go about 5mph in the water?
Also I tried to put a jumper on I’m not sure if I did it right. I just put a wire in both terminals on the female end.

 

[alldodge]

Before we were looking at it not having enough gas and would die, not it doesn't die but has no power

When the throttle cables moves forward does the carb open up?

Has the timing been set correctly?

If above 2 are yes, then time to get compression test numbers