Timing or Injection Pump?

[adamsanders]

Hello everybody, so I just started to drive my 91 F250 IDI that I just purchased last week. I ran it out of fuel the first time, after that battle I will definitely keep an eye on that. Anyways, It seems to run pretty well but I have encountered a problem. I have read A LOT of threads on this so I feel like I have a pretty good idea of what I'm dealing with. The truck always cranks when cold, although it does take 3-5 seconds even with new GPs. However, after running for about 30-45 minutes I turned it off and it didn't want to start back. It was like it was trying very hard to hit, but just wouldn't. On the second crank it did decide to hit after 6-8 seconds and ran fine all the way home.

So I know a worn out IP would cause this but I believe I also have a potential timing issue and I was wondering if that would cause this. The guy I bought it off of said he had took the IP off and when he went to put it back on, he said he never could see the mark on the cam gear (I know you're not supposed to remove the IP housing anyways). He said he got frustrated and just bolted It back on and it ran. So I would venture to guess my timing is way off. And also the only time I can see any smoke is a blue/grey smoke on hard acceleration. I was thinking a properly timed diesel would put out a little black smoke under hard acceleration.

So in summary, I think I have a timing issue and is there any way to check this without removing the pump housing? I know how to check once off but that does take a while. Or is this definitely a worn out IP? The truck won't be used a ton, so is there any way to make this pump last for ~10,000 more miles if it is a worn out IP?
Thanks

 

[Macrobb]

The hot start issue tends to sound like IP, but I'd advance it a little(until you get black smoke under hard accel vs blue/gray) and see if that helps.

Also, cranking speed can seriously affect it - if you can get it to crank faster, it'll make /everything/ better.

Can you post a video if it cranking? Hot or cold?

 

[adamsanders]

I can, I'll be gone all day today for Fathers Day but I'll try to tomorrow. If the pump gear itself was out of time would the truck even run? I have a hard time believe that the PO just lucked up and got it close enough to run without seeing the mark on the cam gear if it's a narrow range.

 

[pelky350]

If it's running it's likely he happened to get the timing gear positioned correctly if it's one tooth back(retarded) it probably wouldn't start or barley start, one tooth advanced and it's gonna sounds like a powerstroke rattle with lots of black smoke. Try advancing the pump a little and see how it goes from there.

 

[adamsanders]

Alright I will and I'll post back. Thanks!

 

[chris142]

Pump not timing.

 

[icanfixall]

Kind of sounds like the heat soak pump issue. This is when a worn out pump gets running. then you shut it off and it gets warmer. This opens up the clearances in the pump and it wont make enough pressure to pop open any injectors. Remember the pump must make about 1800 lbs to pop open an injector. Do you know how many miles are on this injection pump? As for running a well worn pump you can "thicken" the fuel by adding any oil to the fuel. ATF or used oil will work fine. Read up on what others feel is the correct amount to add.

 

[Hydro-idi]

I had a similar issue with a 3010 John Deere that I recently acquired for work. It would start cold but engine was just plain lazy. It has 10k hours on the odometer but engine & fuel system had recently been overhauled, with reman badge nice n shiny on the pump.
After about an hour of running, it would take about 30 seconds to start engine back up. It also had absolutely no power. Could hardly pull a single row tomato cultivator behind it . So I decided to advance pump timing and....WOW, I went from hating this tractor to loving it. Probably gained about 30 hp and starts right up now. Now it has all the power it should have had to begin with. My guess is the PO had never had it properly timed after engine rebuild.
Worth a shot to adjust your IP, but it still sounds like you might need to end up replacing yours.

 

[adamsanders]

Here are the videos that may help describe my problem. I notice a couple of things right off. Seems I do have some dark grey smoke after all when it's warm and the cranking speed when warm seems a little slow to me. I don't know though. Also, on the hot start video on the second round of cranking there was noticeable smoke before it cranked. Does this not mean the pump is putting fuel in the cylinders?

Video 1 - This is a completely cold start. First start of the day.

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Video 2 - This is idle after the truck is fairly warm. Been running here 15-20 minutes or so.

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Video 3 - This is the hot start. It would have cranked had I held the key just a second longer but you get the idea.

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[bbjordan]

Get it timed and go from there. Or just try advancing the timing a bit (thickness of a dime).

 

[Black dawg]

It is cranking too slowly, pump could still be bad, but cranking speed is also to slow....faster cranking speed will help a bunch even it the pump is bad.

 

[adamsanders]

Alright I have an update on my situation. I went to advance the timing a little and after I loosened the IP mounting bolts, I could only rotate the pump just about 1/16 of an inch. It didn't seem to make much of a difference. I took it for a drive and it did seem to have more power and maybe smoked a touch more but nothing durastic. It still didn't wanna crank the first time after I turned it off and let it set for a few minutes. I tried to crank a second time and the starter wouldn't even hardly spin the motor. Could my starter be getting heat soaked and not cranking fast enough?

I then decided to check the cam/pump gear timing. After setting the crank at TDC, the IP did seem to be positioned correctly albeit somewhat off square (see attached picture). Would one tooth be this little off? I didn't check to see if cylinder 1 was on compression or exhaust but I figured if it was 180' out it wouldn't run hardly at all.

In summary, I don't know if it's cranking speed, timing, or a pump issue. I'm assuming I have good compression but I was able to spin the motor by hand with the gps in. Is this normal, I do not have a diesel comp gauge and would prefer to not test this unless this is a real possibility. I had an 18" breaker bar so did have some leverage.

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[bbjordan]

I'd say the pump gear is off by a tooth. (about 7 degrees). The top pump gear bolts in the picture should be parallel to the lemon cover bolts.

 

[adamsanders]

Could I simply unbolt the four IP housing bolts, lift the whole housing/gear/pump assembly up and turn the gear one tooth and set it back down? Or do I have to go through the whole procedure of marking the pump gear, etc.

 

[bbjordan]

You might be able to get away with doing that, but you'll probably have to undo the lines at the injectors to get it up far enough anyway. The only difference now is the three bolts holding the gear to the pump. Get a good 12 point 8 mm socket for that. Crack the bolts loose first before loosening anything else.

What takes me the most time doing this kind of work is scraping/cleaning the old crap & sealant off of the pump gear housing.

You won't be able to see the timing mark on the cam gear, but with a dental pick you can feel it. Line up the gears and put it back together. Then you will need to time it. With the IP in the straight up position, the timing should be close enough to start it.