Resurrecting a $900 1986 with 7.3idi swap. Fuel?

SkylabTech86IDI

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On a whim I decided to try cranking it over on a quick spray of ether into the intake manifold.

It didn’t catch and did not start but there was the beginnings of an ignition in the the starter RPM. Because of this, I’m feeling impatient for the fuel filter to arrive - I’m ready to try again! Is there a recommended way to by pass the filter/filter head besides running a rubber hose with a bunch of clamps?

Maybe fill the new fuel filter with ATF, that might help the IP when it finally fires.
Will do. To start off I’ll likely mix it 75% diesel and 25% ATF and then increase from there. I think I read once that putting straight ATF into the IP wasn’t the best idea, though I can’t remember the reasoning for allegedly why 100% ATF into the IP is bad. Maybe it’s similar to to the confounds of running WMO/***/WBF.
 

SkylabTech86IDI

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Haven’t searched any threads for this question yet but does anyone have an injector pop tester that they would recommend buying? are the sub $100 amazon pop testers too good to be true?
 

SkylabTech86IDI

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One last thing: I’m assuming the answer is yes but is 12.2volts enough at the injector pump? The batteries read 12.56ish volts.

The passenger side primary battery read 12.56volts, so the difference between 12.56ish volts to 12.2volts at the IP seems like a considerable amount of voltage drop - is .3v voltage drop normal when bolts are checked at the battery posts versus any of the electrical components at or around the engine?
 

snicklas

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If an IDI looses its prime, they can be a bear to get primed and restarted….

Let me share a personal experience to give you some encouragement….

A few years ago my oldest son saw an. 88 IDI listed for $800 non-running. He contacted the fella to see what was doing, and make arrangements to pick it up. He said there was some wiring under the hood that had melted, and he “fixed” it but was never able to get it running afterward…. He also told him that someone was on the way, so my son thanked him and that was the end of it…… or so we thought

Several days later, my son got a message from the fella, telling him…. It‘s still available and since you have to come ”so far” (it was maybe a hour away….lol) you can have it for $300…… I just want it gone…..

He got ahold of his buddy with a trailer and they went and got it (wasn’t the 1st IDI that had come home on a trailer for us) and they went and got it…. We discussed what it could be while he was on the way…. Money and title were exchanged, and my son asked if he could try a couple things to get it running, instead of having to winch it on the trailer. The fella then told him there were no batteries in it…….. bummer, so out came the winch line.

They got it home, and he and his buddy checked it over, put a couple batteries in it and gave it a try. It would turn over, but not start. It was getting late, so they quit for the night.

I went over after work the next day. I started going over it, and the wiring that melted, here is a surprise, was the wires for the glow plugs….. the wiring was in sad shape for them, and there was other non-factory wring in that area. So I carefully removed the junk wiring, including the feed for the glow plugs, reconnected the batteries (they had unhooked them the day before, just in case) and let is sit there with power for a bit and just watched. No magic smoke from anywhere….. so next we tried to start it.

I set a timer for 30 seconds, and the two of us started working to get it running. My son’s job (he was mid 20’s by this point and this was his 3rd or 4th IDI) was to run the key, and I was older the hood running the throttle and wielding the can of start ya *******. I started the timer, sold him to crank, and I healed the throttle wide open and started carefully spritzing the ether. When the time counted to zero, we stopped, and I reset it for 2 minutes, because patience is much easier than changing a starter, and we waited. At the end of 2 minutes, reset for 30, and started the process over again. I think it took a total of 5 or 6 sets of 30/2 cycles, but it eventually primed and fired up. We gave it a good once over, checked all the vitals,made sure the brakes worked and the clutch didn’t slip, and it was placed in service as his daily driver.

The wiring was repaired and he glow plugs were put back in service and he had a good truck after that. The body was beat, and a few different colors (he eventually painted it Ford Blue with a roller and a brush, which was a HUGE improvement from what it was) but the drive train was good. (Kinda wish he would have kept it, looking back)

But, the best part of this story, later in the week that he brought it home, he contacted the fella he got it from, and asked if the “other” (I don’t remember which one it was on) tank worked. He said he didn’t know, he never tried to use it, and why are you even worried about it. My son told him because he had been driving it all week and wanted to check before he tried to use it and had any problems. The fella was shocked, he said he figured that truck would never run again……..

So don’t give up……. Just because something will never run again….. doesn’t mean anything…..
 

Nero

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Do you hear the IP solenoid clicking when you apply power to it? Just because you have power doesn't mean it's mechanically working.
 

SkylabTech86IDI

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I suck at that stuff, your starter should be spinning pretty fast. If you know how to make a video we can tell you if it's fast enough. If you can't there's some videos of guys before and after starter swaps so you can get an idea of what you're looking for.

The best I can find is if you look at a recent thread called "I think I done burned up my starter" on page 2 there's a video that @Ky85 did and his starter sounds weak, that might get you in a right direction.
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Here’s a video of my 7.3 idi cranking with 2 new 820cca batteries
 

Jesus Freak

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I'm with @snicklas, it'll go. If it's a manual transmission, and I don't know why, they will crank up easier being pulled popping the clutch. In my opinion, and its my opinion, I think the starter sounds slowish.
 

Nero

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I dunno... That's as fast as my crew cab cranks, judging by audio.
Did you ever get fuel to your injectors? Stop spraying ether down the intake, the high flash point can cause damage.
 

Jesus Freak

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I think it is a little on the slow side too.... not "too slow to start" but ours always seemed to crank a bit faster.....
It doesn't sound consistent, it's the... whomp whomp whomp whomp whomp WHOMP whomp whomp whomp whomp whomp WHOMP. It might even be a sign of bad compression on a cylinder or 2.
I dunno... That's as fast as my crew cab cranks, judging by audio.
Did you ever get fuel to your injectors? Stop spraying ether down the intake, the high flash point can cause damage.
If you have a truck that will crank up, it would be fine. The problem, I think, is when you're truck won't crank an inconsistent starter is an issue. That said, when he gets it to live, and learns the the nuance of cranking HIS truck (because they're all different) then the WHOMP won't matter.......if that makes sense. Id lay off the ether though, Id prefer spraying it on the air filter.
 

SkylabTech86IDI

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I removed the intake manifold and hosed it down to clean it. Then I put everything back together and installed the new fuel filter. Right now I’m having a hard time getting fuel to the fuel filter head and I took some videos.

I hooked a vacuum gauge up to the fuel inlet side of the lift pump, and cranked the engine and the needle bounced from 0 to about 5psi. The international spec that I’ve read is from 4-8psi, or a pint? in 30ish seconds. The vacuum gauge seems to indicate that the fuel pump is good.

Here’s an additional video, and you can see that the movement of the diesel doesn’t get sucked upwards causing it to not reach the filter head. Instead the diesel dances up and down like the vacuum gauge needle does.

Is any of this normal behavior?

if it is, then why can’t I get fuel up to the fuel filter head if the lift pump has 5psi of vacuum which is within International spec?

I wish these trucks had something like a fuel primer…My hypothesis is the 5psi isn’t enough to overcome gravity and if the diesel fuel were already at the fuel inlet fitting then the pump would work fine.
I guess this is why so many people use electric fuel pumps
 
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captain720

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Try using a clear hose from a bucket to feed pump.

Also you probably just need a new pump they are 40 bucks, I made a you tube in how to replace them, and in my experience a good manual fuel pump with good batteries and a good starter primed the entire system from brand new replaced by me in 3 cranking cycles.
 

Nero

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When my truck is running it pulsates about 6psi max at idle. During cranking the engine is rotating slower, so lift pump should be a little less.
What's your pressure without vacuum? You're supposed to measure it without vacuum.
I usually measure the pressure at the Schrader valve too.
 

SkylabTech86IDI

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