1989 7.3idi n/a hard hot start/no start when warm??

Gwhise

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Hello everybody this is my first post on there and this is my first idi. I got it awhile ago did injector return lines and o-rings because I had air intrusion, would stall when cold and would crank long before finally starting. Also the fuel is turned up 2 flats in the ip.

The problem I’m having is that it starts and runs but feels kinda sluggish and probuces white smoke instead of black smoke under heavy acceleration, went out for a drive the other day and ran fine, but I got to my destination shut truck off, 10min pass get in truck to leave and it just cranks and cranks no smoke no nothing. Next morning I go out and the truck fires right up, any suggestions??

I’ was thinking of replacing the lift pump
and filling new fuel filter with sea foam? Maybe putting some atf in the fuel tank I’m not really sure any suggestions would be appreciated thanks.
 

Brian VT

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You may still have air intrusion from somewhere.

But you may be looking at new injectors and injection pump. Do you know when they were last replaced and where they were purchased from?

One thing to try when it won't start when warm is to pour water (not cold) over the injection pump. A quart or so. If it starts then you're probably due for a new injection pump.
I don't know why the water helps it start, but it works on mine.

I used to have white smoke when cold starting. It would smoke and fog the neighborhood until fully warmed up (like 10 minutes).
I bought quality injectors from one of the 4 recommended places here and now no more smoke. And it runs much better also.
I'm now getting ready/saving up for a new injection pump.

You could try filling your fuel filter with ATF. It might help something. Run the truck just long enough to where it starts to run differently then shut it off and let it sit over night.
Good luck.
 
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rreegg

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If you're looking to replace parts the fuel filter is a cheap/easy place to start
 

Cubey

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Hard starting when hot is often a sign of a failing injection pump. Try putting room temperature water on the hot/warm IP then try starting it, next time it does it.
 

Gwhise

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You may still have air intrusion from somewhere.

But you may be looking at new injectors and injection pump. Do you know when they were last replaced and where they were purchased from?

One thing to try when it won't start when warm is to pour water (not cold) over the injection pump. A quart or so. If it starts then you're probably due for a new injection pump.
I don't know why the water helps it start, but it works on mine.

I used to have white smoke when cold starting. It would smoke and fog the neighborhood until fully warmed up (like 10 minutes).
I bought quality injectors from one of the 4 recommended places here and now no more smoke. And it runs much better also.
I'm now getting ready/saving up for a new injection pump.

You could try filling your fuel filter with ATF. It might help something. Run the truck just long enough to where it starts to run differently then shut it off and let it sit over night.
Good luck.
Thank you,I’m not sure when injectors were replaced I’m assuming they are original because truck only has 171k I will try to recreate the problem and see if water helps after will try new filter full of atf like suggested.
 

Selahdoor

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My gut says that you need to turn down the fuel by at least a flat, then turn up the timing by the thickness of a dime, one or two times.

White smoke at startup is fuel that is not being burned.
 

Brian VT

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Yup. I had white smoke due to bad injector(s) and new ones fixed that.
Now I sometimes have hot start trouble so I'll be replacing the injection pump in the near future.

OP, injectors and IP expected lifespan is @ 100k miles.
If you find that you do need them (after trying/checking the cheap fixes), be careful where you buy them. Read the IDI Tech. Article(s) at the top of this forum.
 

Gwhise

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Alright guys will try everything suggested will keep you guys posted thank you all very much.
 

chillman88

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I thought it was more like 125k?

I've always heard 100k but I've also heard of some people not having any issues for double that. I guess to some extent it's luck. Probably a matter of excessive idle time vs all highway driving or something.
 

Cubey

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I've always heard 100k but I've also heard of some people not having any issues for double that. I guess to some extent it's luck. Probably a matter of excessive idle time vs all highway driving or something.

And maybe if they are using additives and how much since ULSD.
 

Gwhise

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Update:
I got home, drove the truck around town for about 10 miles, could not recreate hard start issue. Fuel filter was finger tight but full, I replaced it and filled with atf instead of fuel. Truck started up and ran “fine” still felt like it wasn’t getting enough fuel/ sluggish. Will fill filter up with atf again, run truck for 30 sec and shutoff for the night.
 

Gwhise

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Update:
I got home, drove the truck around town for about 10 miles, could not recreate hard start issue. Fuel filter was finger tight but full, I replaced it and filled with atf instead of fuel. Truck started up and ran “fine” still felt like it wasn’t getting enough fuel/ sluggish. Will fill filter up with atf again, run truck for 30 sec and shutoff for the night.
Looked underneath the truck and at return lines and couldn’t see any spots of wetness or signs of air intrusion. Worth adding that the p/o of this truck removed the rear fuel tank and was planning on converting to wvo but never did. Fuel level gauge doesn’t work and truck starts running out of fuel at around 13 gal used. 130miles or so give or take so maybe problems inside of tank at fuel pickup????
 

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