Lets play another round of "Why won't my truck start?!"

[stmitch]

Truck: 2000 3.0 Flex Fuel with manual trans. Engine has a whipple supercharger/custom tune that have been working for a decade now.

Situation: I got in the truck after work the other day and it started up as normal. The wideband O2 display was showing a lean condition, so I let it idle for ~45 seconds and then it died. I cranked again and it started briefly but died within a few seconds. I could smell fuel when I popped the hood. I had FC p0122 (Throttle Position Sensor), and p0443 (EVAP Purge Valve). It cranks strongly but doesn't start.

What I've done so far:
Replaced cheap parts store TPS with Motorcraft part and cleared FC.
Replaced purge valve and cleared FC. Fuel smell seems to be reduced or maybe gone completely.
Confirmed engine has just over 50psi of fuel pressure at the rail when keyed on/engine off, and around 60psi while cranking.
Confirmed there's adequate fuel in the tank.
Can hear fuel pump (Walbro 450 e85 compatible pump) prime when key is on.
I have 3 PCM tunes (standard, 10% lean, and 10% rich) and the problem is the same for all three tunes.
Engine started once with starting fluid, but didn't stay running. Now it doesn't start even with starting fluid.


Any ideas for other things to check, or something that I may be overlooking? It's still in the parking lot at work, so I'm limited on what I can do. Is it time for a compression test?

 

[Curious Hound]

Confirmed there's adequate fuel in the tank.

Dang. I really wanted to say; “I know what’s wrong. Ain’t got no gas in it.”

 

[85_Ranger4x4]

For some reason I remember those having an issue with camshaft position sensors?

 

[stmitch]

Dang. I really wanted to say; “I know what’s wrong. Ain’t got no gas in it.”

Yeah. I wondered if the fuel gauge had died and I'd unknowingly run it out of fuel or something, but I added 5 gallons, so it's got at least that much in it.

 

[Uncle Gump]

I would pull a couple of the easy spark plugs and see if they're wet. They don't like to fire soaked in fuel. They have a hard time getting that mixture to lite.

You said you give it some starting fluid and fired up. But now that it doesn't... did you check for spark?

 

[stmitch]

I would pull a couple of the easy spark plugs and see if they're wet. They don't like to fire soaked in fuel. They have a hard time getting that mixture to lite.

You said you give it some starting fluid and fired up. But now that it doesn't... did you check for spark?

I have not verified spark yet, other than with the starting fluid. I was working alone, with limited tools and didn't have an easy way to do that.

 

[Uncle Gump]

Yeah... not always the easiest thing to do.

Usually with a spark tester... you can actually hear it spark ans not see it. It makes a pretty loud snap when 50 kv jumps the gap.

You could also try clear flood mode. I say that just because you can smell fuel. But if the plugs are soaked... it may not work.

 

[JoshT]

You've verified adequate fuel pressure is getting to the rail, as long as the injectors are firing like they should, the fuel side should be good.

I'd look to ignition. Starting fluid lights easy, that's why it's used for starting. Might be getting enough spark to fire the starting fluid, but not run on fuel.

 

[stmitch]

Yeah... not always the easiest thing to do.

Usually with a spark tester... you can actually hear it spark ans not see it. It makes a pretty loud snap when 50 kv jumps the gap.

View attachment 105475

You could also try clear flood mode. I say that just because you can smell fuel. But if the plugs are soaked... it may not work.

I forgot that I own a spark tester! I'll give that a shot and see what I can determine. Thanks!

 

[stmitch]

Spark looked weak on the initial test, and non-existent on subsequent tests.
Had it towed home yesterday so I can dig in further. Will pull some plugs and figure out a way to test the coil pack for starters.

 

[Air Filter McWingnut]

Huh, interesting conundrum... I'll be interested to hear how it goes.

 

[Fast Eddie]

Spark looked weak on the initial test, and non-existent on subsequent tests.
Had it towed home yesterday so I can dig in further. Will pull some plugs and figure out a way to test the coil pack for starters.

Guessing your engine might be highly modded. If ignition is stock, check the coil packs. Had similar prob - weak spark then no spark - with mine and wound up being the pack(s). IIRC, there's one for each bank on a 3.0.

 

[SenorNoob]

Coil pack can be checked like a regular coil. It's just three of them in a row

 

[stmitch]

Guessing your engine might be highly modded. If ignition is stock, check the coil packs. Had similar prob - weak spark then no spark - with mine and wound up being the pack(s). IIRC, there's one for each bank on a 3.0.

Yeah, it's more modified than most 3.0's. Most of the modded 3.0's that try to upgrade their ignition end up switching back to the Ford/Motorcraft stuff because it's really robust and just works.

There's only 1 coil pack on the Vulcan, but it's a "waste spark" design, so it fires 1 plug on each bank at the same time. But only one of them is at the right point in the cycle to ignite.

 

[boss3.0lranger]

Hello,
May ask who configuration of tunes? Company or tuner? What are you using also to flash these tunes you have? Injector size and manufacturer.
Thank you
I only have seen on cold start from hot, recently refueling? Station gas quality and if e85 maybe contaminated. Get many engine here flex that stall cold from poor fuel.