I own a 94 IDI that has quit starting sometimes when it get's hot. It doesn't do this if I restart it right away, only if I let it sit a while 20-30 mins. I plan on replacing glow plugs and fuel filter today, but this truck has always started even if 3 plugs aren't working. I replaced IP and mechanical pump recently,less than 20,000 miles ago I had all injectors checked had one rebuilt, all new return lines kit came with IP. But the clamps are those like the ones that came on truck originally. Before when I had a return line leak I replaced hoses and installed regular hose clamps. I have noticed lines being wet but I have seen this a lot on this truck since I bought it with 18,000 miles were on it. She now has 250,000. The injectors are the original ones, but they were tested 20,000 miles ago,and only one needed rebuilding. iI also would like to know where I can get glow pug harness to the plugs at relatively cheap, the plastic covers are getting very brittle, and a varmint chewed the insulation off one wire. I also read where the glow plug relay off an 86 350 could be used to replace my relay if it's bad without buying the whole glow plug system. I'm in need of help on this one.

 

Its your injection pump, do this test: Once you get that engine hot. shut it down and then take a bottle of COOL (~70-80~) water and pour it on the injection pump. Then try and restart it.

 

I will try that. But pump was rebuilt by supposingly reputable shop, less than 20,000 miles ago. I checked glow plugs all are working, but controller is where I belive problem is, it works great cold but after it gets hot it cycles sometimes and sometimes not. Truck won't start with ether either.

 

You shouldn't need glow plugs if the engine is still warm, get the injection pump checked out. Also if your injectors really have 250K on them, they really ought to be replaced. The injection pump and injectors supposedly last 100K before getting pretty worn out.

 

My 94 does this from time to time, usually after being shut down for 15-30 minutes. If I pour just a 1/2 cup of room temp water over the head of the pump (where the inj. lines hook up) it will fire right up. My pump was rebuilt by a trusted shop too, but I have a feeling they didn't replace the hydraulic head on the pump and it is getting heat soaked. I have had this problem since I had maybe 10K on the pump. Been like this for over 2 years, but I know it will let me down someday

 

I figured that was the case. Jayme Duty's 94 IDIT did the same thing.

 

No techie here but I had that problem with one of those uhaul pumps weeks ago. Freaked me out because my "old" pump never did that.

It was so bad that after up to temp you couldn't shut it off and let it soak. Then it would be over an hour with the hood up before it would even think of starting. I am a dummy and it took me a week of driving around and getting stuck before I found it wasn't me

With our truck you can have it up to temp and shut it off and leave it for a few hours in the summer and come back to it and hit the starter and it practically instantly starts with no glowplugs.

Somebody messed up the rebuild I would guess and if I payed I woudl take issue with that. Check your warranty.

I wonder how easy these pumps are to take apart to reseal and fix a specific issue like that with perhaps new parts? I just took a few weeks to breakdown a few old vw injection pumps and I was surprised at how simple it was. BUT there are certain parts I couldn't take apart and various settings to mark to leave stock.

 

Frank didn't replace that ip for ya damac?

 

I will try the water thing, but I drove the truck today and it started right back up after sitting 30 min's. That's why I'm at a loss because it doesn't always do it. The first time it did it was 3 weeks ago and it was 90* plus outside, it did it again 4 days ago and yesterday, but not today. Is there a temp sensor or a relay that might be causing this? It has never cycled glow plugs once it was warm before either, now it starts clicking off and on, sometimes it cycles like a cold engine and sometimes it just cycles once. The original pump lasted 16 years and 220,000 miles and like I said they tested injectors and all but one was popping correctly. I have been noticing a lot of black smoke on acceleration lately,last 6 mos or so.

 

sounds like injectors are dying too, then again your might not be getting enough air to the engine to burn off all the fuel that is getting sprayed into the engine.

 

Well I posted this issue about a week ago and was told that it was the Fuel cutoff relay on the top of the IP. I just went to Southwest Diesel who works on a lot of these engines and was told that this is a very common thing in the heat. I paid 106.00 bucks for the new relay and will let ya know this weekend when I do it if that solved the problem. My pump is fairly new as well as to why it does this no start but after sitting works just fine. I also carry a bottle of water with me just in case and it does the trick. I was wondering if anyone by chance had any diagrams of that relay just so that I have it in front be before just tackling it on my own.

1992 F350 4x4 Longbed Crew cab 236,000 miles second owner

 

So the water trick I told you works? That sounds like you have a perforated diaphram in the IP itself....

 

Ok I keep trying to post back but here goes. I drove her down and washed the engine to see if I could locate the leak. She has started without fail since. But I checked all the glow plugs with test light and all lit the light up. Now the Wait to start light comes on but no cycling noise from relay, amp gauge drops to nearly zero until she cranks, then after a few second it starts charging normally, I did see wet spots on top of filter near the electrical connection on top,and from hose pump to filter, and from left rear to rt rear injector return lines (rubber hoses on top of injectors). I'm thinking Controller or relay one is going bad. But would this cause the hard to start at hot temps? It has been cranking without fail since first post but the temp here has dropped 10-20 degrees outside. High idle works in morning when I first crank the truck.

 

Huh? I was under the impression that the IP is pretty much all metal parts with the exception of the cold advance solenoid and the fuel shut off solenoid. What diaphragm are you talking about?

TruckinTom,
It sounds like you need to replace the return lines (the rubber hoses from the injectors). You can buy a kit that has all the stuff in it, or if you're careful just replace the rubber lines and the o-rings under the plastic caps. You can get the o-rings (viton) pretty cheap from McMaster Carr and the fuel line locally. The wet spots on top of the filter sound like the fuel heater is leaking around the o-ring there. There are a couple threads on here that have some great how-to with pictures for that fix. As far as your actual starting issues, not really sure what else to say, but fixing the leaks can't hurt anything.

 

There is no diaphram in a DB2 IP, here's a breakdown of the internal parts.