7.3 hard start

[HIGHCOUNTRYMIKE]

I have a 2003 E350 4X4 7.3 300,000
new batteries

cranking to start is taking much longer than normal which was a pretty quick turn key and zoom off and running
now I turn the key and it's probably 5 (+ / -)seconds to start

The van has been sitting most of the winter (not much of a winter here in So Cal).

asking for opinions on the possible cause

HighCountry 2003 E350 4X4 7.3 SMB 300,000

[E-350]

Just to make sure: it’s cranking but not firing up?

Any rough idling or so?

A friend had a similar issue on his 1992 7.5 gas. Eventually turned out to be the fuel pump…
Not sure if the diesel might have the same issue though.

[BroncoHauler]

When is the last time the fuel filter was changed?

When is the last time the oil was changed?


Herb

[Lilnuts2]

If all is original parts, your are long over due for injectors and wiring harnesses.
Replace for fuel filter recently?
When does start is the exhaust smoke grey or black?
Once warm does start the same as when cold?

[robertg]

Sounds like a well used motor, last time Glow plugs and or controler replaced?

[REF]

All of the above plus maybe the diesel is a bit stale and going bad if it’s been sitting in the tank for a while. Add in some fresh diesel and a diesel fuel additive with cetane booster like Power Service Diesel Kleen with cetane boost, run it up to temp on the highway.

[shenrie]

When it does start does it seem like it’s running on 2-3 cylinders until it gets up in temperature?

[REF]

I gather what Shenrie is getting at is if it’s really rough at idle, and it sounds like half your bank is shut down, that would mean your under valve cover harness is shot and needs to be replaced, do both while things are apart.
The old design leads to broken wires from heat over time, they have a new design that fixes that issue. Once things are warmed up, the connection sometimes fixes itself and then it runs fine, until one day it doesn’t. This played out for us when down in Baja in 2019 that led us to driving 100 miles on 4 cylinders up the 5 to San Felipe, topping out at 25mph in 100 deg heat, good times…..

[1der]

Definitely get a deep reading (more than a scan gauge provides) off the OBD2 to see if trouble codes have been registered. That would be a good place to start.

If you run your block heater overnight, how does it start in the morning? What are the ambient temperatures when you are starting? If all good when the ambient is above 50 you are probably dealing w a sensor.

[HIGHCOUNTRYMIKE]

HARD START UPDATE:
reply to questions 1) it takes 6 seconds to fire up, no rough idling
2) fuel filter and oil filter changed 10.06.21 300,000 service
3) injector service 10.13.16 injector control pressure regulator, left &
right glow plug replaced, no smoke of any color
4) it was running on all cylinders and very smooth

I called my diesel mechanic and he said his 1st impression is is bad fuel or a air issue.
Recommended: POWER SERVICE/CLEAR DIESEL FUEL & TANK CLEANER add half of the bottle to the tank and go for a ride.
I drove 23.3 miles local streets and 210 freeway up to 65 mph. Returned home let it set for half an hour.
Bingo: instant start. Before the treatment it took 6 seconds to start. The real test will be in the morning after it has rested in a cool SoCal night.
Thank you all for your suggestions.
P.S.: 12.04.14 I had to replace Turbo Union and 2 supply pipes and reprogram the PCM.
11.19.16 Replaced intake and exhaust pressure sensors. 10.06.21 2 AGM Interstate batteries. I am very punctual about air, oil and fuel filters. The last fuel I purchased was in Bishop, CA and Independence, Ca 130+ days ago. Not sure what the shelf life of diesel is but it's obvious that it's less the 130 days. This won't happen again. Again thank you all.
HighCountryMike 2003 E350 4X4 7.3 SMB 300,000 (next mission has already been planned).Going to burn all that fuel as low as possible before I refill my tank.