Another 7.3 idi won't start thread... I'm sorry...
- Thread starter Ryan Nunez
- Start date
TNBrett
Full Access Member
Ryan Nunez
Registered User
Thanks @Selahdoor and @Cubey. I’m curious about the alternator and it’s something I’m definitely going to check one I get it starting consistently. The batteries were replaced in October and I just had them checked the other day so I’m good on them for a while. I’m also thinking that once I replace the returns and the glow plugs if I’m still having trouble I’ll just go ahead and replace the starter. I was inspecting it and while it doesn’t look original it definitely looks a little weathered. It does sound like it is cranking at a pretty good speed though
Good batteries are a must, but so are good cables and starter. Check your cables and connections, and think about a new starter. Remember you are compressing to ignition so cranking speed really matters.
Good luck and happy holidays
Good luck and happy holidays
The_Josh_Bear
Full Access Member
I see 3 obvious issues:
1. Cold start trouble is caused by air intrusion, the boys have you on the right track for that.
2. A hot start problem which *may* have been caused by a lack of fuel but it's more likely to be a worn-out IP. 30 mins of engine off followed by a no-start is absolutely classic. The trick for this if it happens again is to pour cool(not cold!) water over the head of the IP(the bit where the injector lines are). Try a full 500ml water bottle. If it starts up after that you have a worn IP.
3a. Autolites. I personally would not even use the glows until they are changed. I would use ether carefully for the rest of my life rather than run autolites.
3b: Once you have motorcraft in there don't hesitate to use the glows for 10 seconds or even longer when around or below freezing. If it's really cold, like 0*, up to 20 seconds is ok.
Here's my tiny contribution to YouTube, what your starter speed should be:
It should be faster than you can count in your head. If it's not close to that you simply don't have the speed it get the job done consistently.
Happy wrenching!
1. Cold start trouble is caused by air intrusion, the boys have you on the right track for that.
2. A hot start problem which *may* have been caused by a lack of fuel but it's more likely to be a worn-out IP. 30 mins of engine off followed by a no-start is absolutely classic. The trick for this if it happens again is to pour cool(not cold!) water over the head of the IP(the bit where the injector lines are). Try a full 500ml water bottle. If it starts up after that you have a worn IP.
3a. Autolites. I personally would not even use the glows until they are changed. I would use ether carefully for the rest of my life rather than run autolites.
3b: Once you have motorcraft in there don't hesitate to use the glows for 10 seconds or even longer when around or below freezing. If it's really cold, like 0*, up to 20 seconds is ok.
Here's my tiny contribution to YouTube, what your starter speed should be:
xc_hide_links_from_guests_guests_error_hide_media
It should be faster than you can count in your head. If it's not close to that you simply don't have the speed it get the job done consistently.
Happy wrenching!
^^^^^ That’s a good sounding IDI starter.
Ryan Nunez
Registered User
Thank you everyone for all of your input. I replaced all of the return lines, o rings, and connectors today and after purging the system, i could tell the truck wanted to fire and a 1/2 second shot of ether got it fired up. I ran it for about 10 minutes and shut it down and half hour later it fired right back up again. Fingers crossed it fires up after sitting overnight as this was the main issue in the first place.
@The_Josh_Bear Your YouTube video is extremely helpful and unfortunately makes me want to spend the $100 on a new starter! I never thought to count revolutions while cranking but I like the way you stated that and its a great rule of thumb. Im going to have to see how it sounds compared to yours in the morning. The Motorcraft plugs should be here tomorrow along with the new oil filter and coolant so I can finish the rest of the preventative maintenance.
After all the fluids are changed I just have to rewire all the rear lighting so i can get it inspected. I guess the PO(POS more like) decided that instead of disconnecting wires when he changed the bed, it would be more efficient to just cut all of them and never reconnect them lol
@The_Josh_Bear Your YouTube video is extremely helpful and unfortunately makes me want to spend the $100 on a new starter! I never thought to count revolutions while cranking but I like the way you stated that and its a great rule of thumb. Im going to have to see how it sounds compared to yours in the morning. The Motorcraft plugs should be here tomorrow along with the new oil filter and coolant so I can finish the rest of the preventative maintenance.
After all the fluids are changed I just have to rewire all the rear lighting so i can get it inspected. I guess the PO(POS more like) decided that instead of disconnecting wires when he changed the bed, it would be more efficient to just cut all of them and never reconnect them lol
Ryan Nunez
Registered User
@The_Josh_Bear In reguards to the IP and pouring cool water over it, are you saying that if they are worn out they get overheated and will restart once cooled down? This is my first diesel that isn't controlled by a computer so I'm curious as to how the injection pump works
IDIBRONCO
IDIBRONCO
Yes that's right. To try to explain it in terms that I can understand, as the pumps wear, the internal tolerances get larger. As the internal parts of a pump get hotter, they will expand which also increases the tolerances. A pump need to be able to build X amount of fuel pressure in order for the engine to run. While the starter's turning the engine over, it's turning over at a lower RPM than while it's idling so the pump's not able to build as much fuel pressure. The cooling down with water will shrink the internal parts enough to shrink them enough to build more fuel pressure while the engine's being turned over with the starter. Eventually, the pump will get to the point that the parts are so worn out, even the cool water trick won't let it build up the fuel pressure to run.
Ryan Nunez
Registered User
@IDIBRONCO That makes sense. Thats definitely something that I'll keep my eye on.
Ryan Nunez
Registered User
So this morning after putting in the return line kit, bleeding the fuel system and running the truck it won’t start again. I’m still waiting on the new glow plugs but I had it plugged in all night so I think I still have an air issue. I traced the return line back to the tank but aside from there it changes from soft to hard line and back being dirty and seeming like a bad design I can not find anywhere that air might be coming in. My starter sounds good and my batteries are brand new. Any thoughts on where else to check? Everything seems tight at the mechanical pump and the filter. Or could this be a timing issue? The only parts out of the return line kit I did not use were the brass washers for the injectors because I did not remove them. Could this possibly be the problem?
Ant help is greatly appreciated, I’m starting to get frustrated at this point lol
Ant help is greatly appreciated, I’m starting to get frustrated at this point lol
bbjordan
Snow Monkey
That tells me it has something to do with the glow plug system. You mentioned that the GP relay was replaced recently. Just because it's new doesn't mean it's good. The GP relay has to pass a lot of current. I've had GP relays work intermittently too. The new ones just don't seem to be as good as the old ones. Some members here have gone to the White Rodgers/Stancor relay:
https://www.amazon.com/stancor-586-902/s?k=stancor+586-902
Kinda spendy, but you get what you pay for...
Perhaps the guys that got the W-R relay will chime in.
Before you throw money at the problem, pull an easy to get to glow plug and ground the body of the GP. Connect a booster cable to the negative post of one of the batteries, and the other end to the body of the GP, for example. Connect the GP to the GP wiring harness. Make sure the GP is not touching/near anything that can burn/melt. Turn the key on, and see if the GP gets red hot. It should take about 10 seconds.
If it doesn't, check the GP relay feed wires at the connector on the passenger side of the engine. There are 2 yellow wires that go into a connector. This is a weak point on these trucks. This can be a high resistance connection and can melt the connector in some instances!
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I got rid of the entire automatic GP system and went manual with individual relays:
https://www.oilburners.net/threads/manual-glow-plug-update.73571/
Ryan Nunez
Registered User
@bbjordan thank you for your reply, I have installed a bypass for the stock replay and I can hear it hold while I’m pressing my manual switch. I’m hoping that the glow plugs are the issue, the new ones were supposed to be here yesterday and now I’m waiting for them to come today. I’m literally sitting on my hands staring out the front door so I don’t go throw more money at the truck before seeing if the glow plugs are the problem haha. I tried to get the glow plugs this weekend at the parts store but I found out that every advanced auto around me only keeps one in stock. Now I wish I would’ve driven around to all of the. And bought one at a time so I wouldn’t be waiting
ISPKI
Welding/metallurgical engineer/Metalsmith
Something I had done a while back when I first got my idi was replace all the soft lines with versilon lines (C-210-A formula). Its clear, flexible, abrasion resistant. Doesnt handle much pressure or heat but plenty for the application. It remains clear for a long time which lets you see air bubbles forming if you have air intrusion. Its a bit pricey, around 3$/foot but you dont need much. I replaced all of my return lines and feed lines from my electric lift pump and fuel tank with it.
https://www.mcmaster.com/6519T12/
https://www.mcmaster.com/6519T12/
