7.3 idi no start or excessive long crank - Diesel Forum

jetski86 · 07-12-2008, 05:30 PM

would some of you experts help me with this one. I have a 7.3 idi in a 85 truck. i do not know the year of the engine. It does not want to start after sitting. I have resealed all of the return lines and installed a clear hose on the return from the fuel filter. It has fuel in it instantly and it does not drain back. I have replaced the fuel pump and even the solenoid on the injection pump. it turns over fine and I used another 12 volt source to the pump. It does not want ot start without wd40 or ?. After it starts it will restart for approx 1/2 hour then it becomes a long crank again. Any suggestions? Thank you

Snotzalot · 07-12-2008, 05:40 PM

How old is the starter and how fast does the starter turn the engine over?

jetski86 · 07-12-2008, 07:19 PM

I do not know the age of the starter but it spins normal and sounds good. i have had some with a slow crank causing this but this one spins good. I also used a jumper with 12 volts to the pump solenoid to make sure because the voltage dropped to 10 volts while cranking. The only thing I can think of next is the pump. But if I am wrong the customre won't pay.

cdnsarguy · 07-13-2008, 03:31 AM

Sounds like the Glow plugs are not working........if they are blown or the controller is not operating she may not start. Can you plug in the block heater "if it works for an hour" then try to start. Engine year could be punched out on the oil filler cover tag.

If you want the GP controller test PM me your email......... Subject: 7.3 GP test

RMP8080 · 07-13-2008, 11:24 AM

check oil level, my ford would start, found low oil, after adding started fine.

Bill

jetski86 · 07-13-2008, 11:32 AM

I just did an oil change and was also asked to check th hard starting. I live out here in the desert where the low is in the 80s. The glow plugs should not be a factor. I think I need a pump but I wanted to make sure I am not missing anything else. Thank you guys fo the replies so far. They keep me thinking.

dakotajeep · 07-13-2008, 04:09 PM

This may sound too simple but how are your battery cable connections and quality in general? But I am sure you have that all up to speed.....good luck....

Kaliburz · 07-13-2008, 04:33 PM

Cranking speed is IMPORTANT. Buddy's 7.3L IDI, we thought the IP was going out. Starting it after shutting off for 30min was a dog. One day, it was slow to crank and quit. New batteries helped, but still nothing. Changed the starter..... had old checked...toasted. Now it turned over fast and started fast. All because one battery was bad and the starter was bad.... It 'sounded' good cranking, but it was too slow.... we couldn't tell.

We thought it was a bad lift pump or a suction line issue. Nope, just a bad starter and battery...... Two new batts and a starter.... all was good again.

Snotzalot · 07-13-2008, 04:46 PM

A bad starter will crank slower when the engine is warm giving you a no start.

danngreen · 07-20-2008, 10:47 PM

How slow is too slow for the starter? Mine is starting very hard, sometimes takes me 10 minutes. So I pulled a glow plug out and listened as I cranked for a few seconds. Roughly 1-2 "spurts" of fuel vapor per second, that's 60-120RPM. Too slow?

icanfixall · 07-20-2008, 11:40 PM

A gear reduction starter will spin the motor about 500 rpm. Mine usually starts before I can let go of the key... Get a Mistibuchi gear reduction starter. Its the differance between night and day....

danngreen · 07-21-2008, 01:39 PM

Quote:

Originally Posted by icanfixall

A gear reduction starter will spin the motor about 500 rpm. Mine usually starts before I can let go of the key... Get a Mistibuchi gear reduction starter. Its the differance between night and day....

That sounds like a nice thing to have, but I don't want to replace parts if they're already working. I tested the engine with a stop watch today and it's turning over at about 60RPM.
That's too slow, right? The batteries measure over 12V when off

Crank, crank, crank, it won't start, but after 10 minutes or so (alternating between cranking for 20 seconds and waiting a few minutes...) I can usually get it to start. Or if I bleed at the schraeder valve on the fuel filter while somene's cranking it, I can get it to start right away. Fuel (and air too?) comes spurting out of the valve, about at the rate I've read is right (1/3 pint per 10 seconds). I don't have a pressure guage to tell you the PSI, but it's spurting so there's pressure.

So that makes me think it's air in the lines, not the starter. I've bled it at the injector nozzles, but have done a few other things since then, maybe I need to do that again.

But this piece of info will help me problem-solve:
Anyone know how fast a starter should turn?

danngreen · 07-24-2008, 09:47 PM

OK, I pulled the starter and took it to the shop. ouch. they said it was a miracle i ever got it to turn at all. So apparently 60RPM is way too slow. I will post back with the proper RPM once I get the new one (should pick it up tomorrow), assuming my batteries are OK, so I'll post their voltage as well.

Snotzalot · 07-25-2008, 09:56 AM

One again it's the lowly starter causing a no start condition. All sorts of assumptions are made about IP's being no good at 100,000 miles, air in the lines, relays, phase of the moon, etc.........and the starter should be the first thing checked after GP's and batteries are found good......remember that folks!

FWIW air in the lines usually exhibits itself as "Starts the immediately dies".

danngreen · 07-26-2008, 10:30 PM

Quote:

Originally Posted by Snotzalot

One again it's the lowly starter causing a no start condition..

Exactly.

Put the new starter in, and BAM! it fired right up (albeit a huge cloud of white smoke and needed a little throttling to keep her alive as the air worked its way out.) Turned the key again in the morning and started right up. I meant to count the RPMs of the starter, but since it goes right away to 700 or so RPM, I can't really get an accurate count of the starter alone. But it's way more than 60RPM, probably around 120-200 or so...