91 IDI injection pump questions

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Dec 29, 2024 | 10:43 AM

Willey2

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Trailering

Joined: Dec 2024

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91 IDI injection pump questions

‘91 7.3 IDI has had a history of fuel delivery problems. Fail to restart after fueling, then start after overnight. ( transfer switch issue?), slow start, multiple attempts after sitting for a week (recent issue) then driving down a steep grade just quit. Followed by replace filter and bleed, glow plugs and injectors were working fine just prior. Pulled drivers side return to injector pump, flowed fuel but not excessively. Attempts at bleeding injectors not successful. Sounds like a IP failure but no prior indications, smoking, low power etc. Over 200k miles. No prior replacement. Better tests? Might also see my post on removing rear tank tank and apparatus. Checking air infiltration as well. Many thanks on experience.

Dec 29, 2024 | 12:29 PM

tjc transport

i ain't rite

Joined: Mar 2005

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From: Marlboro Mental Hospital.

if you know for sure the injector pump and injectors have over 200k miles on them, they are way overdue for replacement.

Dec 29, 2024 | 01:56 PM

Willey2

Thread Starter

Trailering

Joined: Dec 2024

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Likely yes

Glow plugs, controller and injectors replaced, more age than mileage on them. I’ll run down every issue from the tanks forward, then the IP. Everything else that bolts to this truck has been replaced, some more than once. Thanks.

Dec 30, 2024 | 09:09 AM

WCMtn1990

Tuned

Joined: Sep 2024

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From: Ougadougou

Although I haven't had it happen to me I have always read that one of the classic symptoms of a failing IP was no-start when the pump is hot--as in driving fine for a while then make a brief stop like refueling and the engine won't start until the pump has cooled down. Avoid Pensacola diesel when buying a new IP.