7.3 Won't Restart

**Seafordguy** · 03-29-2010 02:38 PM

Alright - after replacing the ICP about 1000 miles ago, the truck ran well. It began hesitating a little over the weekend and grew TERRIBLE during Sunday and today....

I decided to replace the Fuel Filter as a precaution, and did about 10 minutes ago - fired it up, let it run about 5 minutes, backed out of the driveway, it cut off on me, and now it won't restart.

Any ideas?

Oil Level is not a problem, Fuel Level is not a problem - I did the CPS recall, but I am going to go out right now and look. I am worried that sounds like the culprit. EDIT - just looked, and I have the Gray one....

Thoughts (fixxxer??)

**phragle** · 03-29-2010 02:52 PM

airleak in the fuel system? will it fire off wd40?
Warning my diesel knowledge is very oldschool from the 6.9 I hd in my old boxvan...

**Seafordguy** · 03-29-2010 03:00 PM

Well - I just had a thought and went to check it.

Correct me if I am wrong but I am seeing NOTHING on the Tach when I crank, and I believe that signal comes from the CPS (CMP). I should have just never let them do the recall.

**txriverrat2001** · 03-29-2010 03:03 PM

Cam sensor.......

**Birdog** · 03-29-2010 03:43 PM

Originally Posted by txriverrat2001

Cam sensor.......

Yep.....Very common on 7.3s

**Magic Medicine** · 03-29-2010 03:46 PM

I was think cam sensor as well. Had one leave me high and dry on my 6.0.

**Magic Medicine** · 03-29-2010 03:47 PM

O and for the record, 7.3's had a cam sensor recall, PM me your VIN and I will run an oasis on your truck and see if you are covered under the recall

**Seafordguy** · 03-29-2010 04:02 PM

Originally Posted by Magic Medicine

O and for the record, 7.3's had a cam sensor recall, PM me your VIN and I will run an oasis on your truck and see if you are covered under the recall

Yeah - I had it replaced under recall, but I was hesitant at the time to do it.

I would love an Oasis report though, as I bought the truck with 75k on it....

I'll grab the VIN and PM you. I just replaced the CMP and it fired up. Going to take if for a spin....

**Seafordguy** · 03-29-2010 04:13 PM

Started up, drove about 200 feet, crapped out on me, wouldn't restart??

Can hear the fuel pump on the frame rail running.

When I took the cap off the fuel bowl and cranked it it filled the bowl in about 10-12 seconds. Is that sufficient fuel pressure? It will build pressure in the bowl such that when you let the drain petcock out it comes squirting out.

NO smoke at all.....

It just sat for a while and when i just cranked it, it started and ran for the briefest of seconds, and now won't restart at all?

**Magic Medicine** · 03-29-2010 10:23 PM

Bad fuel????

**speedreeder** · 03-29-2010 10:40 PM

Not bad fuel- It would really smoke bad........My guess is bad fuel pump on rail. Leave the key on and it will fill up the filter and eventually get to the injectors, Start up till the filter runs low and die.

**Seafordguy** · 03-30-2010 09:23 AM

Yeah - the filter is filling up, and it appears to be under some pressure because if I open the petcock it will pour out pretty good (obviously with an oil pan under it to catch it).

I am getting NO smoke whatsoever, not even any odor.

IPR maybe??

**Seafordguy** · 03-30-2010 10:04 AM

Update - this morning I just decided to crank it over and it fired up, and ran like it did yesterday morning - with the hesitation present.

Should add - It is full of oil, the fuel bowl heater has not blown the GP fuse, all fuses/relays have been swapped with other fuses/relays, I checked the PCM and it is tight, still no codes.

Edit again - I pulled the IPR and cleaned it (although I don't think it was very dirty), reinstalled. Now the hesitation is gone but it seems like it is only running on 7 cylinders - kind of knocking a little harder than normal at idle, and doesn't have as much power....

**fixxxer22** · 03-30-2010 09:20 PM

How many miles on the truck? Sounds like you have an inlet restriction in the screens of your fuel tank... Happens after time to ALL 7.3 trucks. You can obtain a gauge and special tool to measure inlet restriction. the screens can be cleaned and i would just do it as matinence. the problem is not fuel pressure it is volume. you can have good pressure all day long but not enough volume. losing volume will drop te farthest cylinders first. 8 and 7 the the remaining cylinders. they will also let the debris drop from the screens until you let them sit for awhile. so you leave her there for a couple hours and she restarts and then the debris comes creeping up the screens again and then she will stall. i have done soooo many of these repairs. it is really not hat bad to do.

I wish you could just drop the thing off to me.

**Seafordguy** · 03-31-2010 11:06 AM

100k miles.

Realized I had put the needle in the IPR in the wrong way - pulled it back off and put it in correctly - Now I am back to it not starting at all. Not even trying to catch, and NO smoke whatsoever...

shows good oil pressure, and tach shows it spinning (so I know it isn't the CPS).

I could be wrong fixxxxer but the way it is acting REALLY seems electronic....

**fixxxer22** · 03-31-2010 11:55 AM

check again for faulty icp. disconnect and see if it starts. verify engine oil level is good. since you do not have any codes i was thinking it were something mechanical. you can inspect the uvc harnesses and make sure neither has come loose under the valve covers. that is a big problem on these also but you usually get a p1316 for idm codes dected then you buzz the injecotrs and you will get a high to low side open code for the suspect bank. do you have access to a scanner with datastream. can you tell me what the icp reading is key on engine off and during cranking? we need at least 500 psi of icp to start and 100rpm cranking. also check and see what the vref pid is reading. have been seeing alot of faulty pcms lately. do you have a chip hooked into the rear of the pcm? also does the check engine lamp prove out when you cycle the key to run?

**fixxxer22** · 03-31-2010 11:56 AM

pull a fuel sample from the fuel water seperator drain. make sure it looks good as well. let it sit for an hour and see if there is any water in it.

**BUIZILLA** · 03-31-2010 01:33 PM

fixxxer22... I have a question

I have a customer with a 2007 6.0 that eats #2, #3 and #4 injector every 2-3 months, done it 4 times now in 8 months as of today, replaced with new in those holes every time, does it again... test the injectors each time they fail on our test stand and we get 30-40% low output on those injectors only..

what's up?

**fixxxer22** · 03-31-2010 02:00 PM

I see that mostly from low fuel pressure under suvere load. We now have a fuel system flow tester that simulates WOT full load conditions for the 6.0. without the proper ammount of fuel between the piston the injectors seem to hammer apart. have you checked fuel pressure under full load?

**Seafordguy** · 03-31-2010 02:15 PM

Originally Posted by fixxxer22

pull a fuel sample from the fuel water seperator drain. make sure it looks good as well. let it sit for an hour and see if there is any water in it.

No separation whatsoever....it is as green as Mountain Dew. NO change in behavior either. Now it isn't starting at all. Just cranking with no smoke, smell, nothing.

I put key in ON position with the fuel petcock undone and it was spewing out the bottom of the truck into a catch pan.

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