Just bought a new to me 2000 excursion v10 4wd with 154k
Brought it home, it was having long crank to start issues when I bought it, I assumed it would be a fuel pump or vacuum leak.
Here is what I have done:
checked over all the vacuum lines, didn’t see any issues.
-oil and filter
-plugs, and a set of coils
fuel filter
fuel pump and in tank filters
fuel pressure regulator
idle air control valve.
air filter
Ford crank position sensor. (Had to remove the a/c compressor)
Ford coolant temp sensor
Ford head temp sensor
thermostat
fuel pump relay
the non blue relay under the dash behind the radio.
I removed and replaced the degas bottle with a new one because it was rusty looking inside


Here is my issues I’m having, when cold and on the first start of a day, it will take 4-5 times cranking over to finally start, I’m going to pickup a fuel pressure gauge after work to see if the fuel system is priming on key on.

ive also had it do the protection shutdown two times, right after startup, immediately fixed with a shut down and restart.

heat blows hot and no puking of coolant, the cooling system isn’t pressurized, and temps are perfect after restart so I know I’m not overheating.

I think I’m chasing a electrical problem, but I have searched and searched and can’t find anything to help starting to diagnose this.

ive read a few things about the CHT problem from wiring to the back trailer plug, mine is disconnected with the plug open.
mom going to check over that whole harness running to the back and fuel pump after work as well: I’ve been under there replacing the brake line and it all looked perfect.... but I’m at a loss at this point.

any help is appreciated.

 

Hooked up the fuel pressure tester, I’m getting 30 psi running and 40 when you accelerate. Checked the fuel cutoff switch, wiring harness to the back looks good, removed and inspected the ground on the motor, it’s clean and good.

I’m at a loss here. it’s 34 outside this morning and it didn’t want to start up the first time this morning, had to crank it over 4-5 times and finally it fired.

I didn’t have the fuel pressure gauge hooked up to check morning start psi but that may need to be my next step. I’m also going to check for a full 12v to the pump.

im going to pull the head temp sensor plug and check for corrosion today, it hasn’t happened again but cleaning it can’t hurt.

 

I'd try some good old starting fluid. If it starts and runs rough for a moment and smooths out as it warms ... I'd say the fuel mixture is wrong for cold start conditions and not a fuel delivery problem.

 

I ordered a throttle position sensor, cam position sensor and a mass air flow sensor I’ll have tomorrow just to rule them out. I’m not sure why but I have a feeling the mass air flow sensor may be the problem. I’m doing the cam and throttle sensor because at this point I think I’ve done every sensor but them. Good preventive maintenance and I’ll know what is new.

Im also doing eBay long tube headers this weekend, I had the dreaded Ford mod motor exhaust leak tick. I’ve got one side off, and only 4 studs broke off in the head, so this should be a fun weekend.

 

Could also be a tune issue, could have a custom tune on it for a different intake, injectors, who knows, and the person reverted it physically before selling by taking out intake etc other parts but forgot or neglected to return the tune to stock. Had to have one of my mustangs re flashed to stock due to that.

My V10 catches within 3/4 of a second pre-rebuild, and now within 1/2 a second now that its been fully rebuilt.

 

The truck does have a AEM Brute Force intake on it, but I’m doubtful the guy I bought it from did anything to it before I bought it, he didn’t even own a Philips screw driver.

I have a OBDII scanner, the IAT sensor reading seemed wrong to me, but all the live values seem to jump around a lot into negative values when idling, I’m not sure if that’s the truck or my scanner

My understanding is that this motor is running a OBD1 system, and my scanner shows obd1 in the readouts. I was thinking that may have something to do with it, or the scanner itself is doing strange stuff

 

My truck is also a 2000 and it is running the PWM 1850 protocol, and i connect to it with both my SCT Tuner, and the Torque App on Android with a OBDII Cable, and there is no weirdness of values with 1 exception, the vacuum pressure will go into boost numbers when i punch WOT momentarily, but my Mustang GT demonstrates the exact same behavior which leads me to believe that the sensor is rubber banding physically causing that momentary positive pressure reading. Other then that everything is exactly what i expect to see.

 

I have a dongle ill try with my phone and See what it does.

I got the long tubes installed today, I had 9 studs broken off in the head, welded nuts to them and they all came out first try. eBay headers on, stainless heard ware kit also. No leaks and it fit pretty good.

The Maf, tps, and cam sensor were delivered late today, so I’ll put them on in the morning and see if that fixes my cold start issue.

I found some moisture and corrosion in the connector for the CHT, I cleaned it up and haven’t had a false overheat after, hopefully that is fixed.

I’ll post tomorrow about what the other parts did.

 

Well, I got everything on two days ago. It’s better but still not perfect, it kind of stutters when trying to start for the first time of the day.

I’m not sure what else to check/replace

could the timing components be worn causing the timing to be a bit off when starting? It runs fine after startup, with no sounds from the timing cover at all. I remember doing 4.6 motors and when the timing was worn in my old f150 it sounded like marbles up there.

does this truck have a oil pressure sensor that doesn’t allow startup before enough oil pressure is sensed? I was thinking maybe that could be something.

many other ideas??? I’m all ears...