Community Forums

Chipnpr · 06-01-2023, 03:46 PM

6.8 gas in my 2008 Simba (2007 F53 chassis) stalled on the road while driving, won't start. Battery good, fuel pressure good, spark good but no start. Now what?

Arch Hoagland · 06-01-2023, 03:49 PM

Does it turn over trying to start or is it just totally dead?

Had you just gotten gas recently?

hastemaker · 06-01-2023, 03:52 PM

Could be the throttle body?

Mark_T · 06-01-2023, 04:29 PM

Check for obdii codes.
Check fuses.

Chipnpr · 06-02-2023, 06:20 AM

No codes showing. Plenty of gas and the generator runs just fine. I ran through the fuses at least once but will be checking them again. Still mystified!

Mark_T · 06-02-2023, 10:53 AM

Spray some starter fluid in the intake and try to start it. That will tell you if the problem is in the fuel delivery system.

ga traveler · 06-02-2023, 11:23 AM

Have you checked the camshaft sensor?

PS89 · 06-02-2023, 03:16 PM

Clarify the state of the thing. Is it a "No Crank" or "Cranks but does not fire/start"?

Different troubleshooting is required for each symptom. Any suggestions before knowing what it is or isn't doing is simply guessing.

Tachdriver · 06-02-2023, 05:19 PM

Stalled on road, fuel pump?

avfordguy · 06-03-2023, 11:24 AM

Quote:

Originally Posted by Chipnpr

No codes showing. Plenty of gas and the generator runs just fine. I ran through the fuses at least once but will be checking them again. Still mystified!

Impossible, get a better code reader and do a koeo test.

Chipnpr · 06-03-2023, 01:38 PM

The engine cranks just fine. The mechanic working on it said there were no codes. I think he did check the crankshaft sensor. Fuel is getting to the engine.

tiffy2000 · 06-04-2023, 05:04 AM

If the tach doesn't move while it is turning over, I'd go looking at the crank position sensor first.

Observe the check engine light while cranking. Does it stay on or go out?

If it goes out, the PCM is receiving a valid CKP (CranKshaft Position signal previously known as the CPS). If the light stays on, the CKP signal is missing or invalid.

CMP sensor (CaMshaft Position) will not cause a "no spark" condition.

Verify that fuse CJB F30 is delivering switched battery power to the COPs. Without power, the coils will never fire.

tiffy2000 · 06-04-2023, 05:10 AM

also found this
• Place the accelerator pedal ALL THE WAY TO THE FLOOR and start cranking.
• After about 10-15 seconds, start slowly releasing the the accelerator pedal.
• If the problem is what I think it is (a stuck Idle (IAC) Valve) it should start before 30 seconds of cranking.

Ford software will not turn on injectors unless it sees the throttle plate move during key on/crank

If you do a crank and get a no start can you immediately cycle the IG switch off/on and get it to crank then start up?

How about having someone crank for a few seconds while you tap relays and wiggle wiring harnesses. That will often expose and isolate an intermittent issue.
__________________

When it wasn't running I unplugged the mass air sensor and it ran. When I plugged it back in it stalled.
Problem is in mass air ( maf) either its contaminated or there is a wiring issue between the pcm and the sensor
Clean the map sensor with a spray cleaner for mass air flow sensors, let it dry, and plug it back in and cycle the key 3x from off to key on, do not start, after 3x key cycles see if it will start, does your code reader display maf voltage??
Could be mass air is defective, easy to replace.

I took the pcm relay and swapped it with the fan motor relay.
Now the truck starts fine but the fan blower does not run which confirmed the pcm relay was bad

Chipnpr · 06-09-2023, 09:44 AM

Thanks for all the replies with clues! Turned out to be the crank sensor. The problem was the wire from the sensor was routed quite close to the serpentine belt near the A/C compressor and could (and did) occasionally make contact with the edge of the belt. After 50k miles it wore through the loom and cut one of the wires. It took a mechanic with Ford 6.8 experience to find that problem but he had a sophisticated ODC reader helping him and he went right to it. Being young and supple didn't hurt when he had to crawl under the unit, either.