Archived I filled it with unleaded...now what?

[Halfhand]

Late fill-up, new gas station, wasn't paying attention. It started running rough, loss of power on the way home. Drove it about 30mi. Didn't even occur to me till I took a sample from the filter housing this morning.

It's a no start now and I'm gonna need this thing soon.



I was able to siphon about 26 gallons out of the tank. I'll change the filter, drop the lines and blow them out, but what do I do with the injection pump? Suggestions on assessing engine/pump damage? What else should I be concerned about?



I've pumped nearly 9000gal. of fuel into that truck, just a moments distraction... It can happen to you.

 

[HHhuntitall]

Well, if you're lucky, you'll be fine. If you're not, well, you're not. You've already done most of the right work, I'd suggest pumping a quart or two of diesel through the injection pump, with the overflow/return line draining out to a seperate container. I don't think there's a drain on the p-pump. When you have the line off blowing them out, that's a good time to do it. Or, if you're not equipped with a seperate pump, clear your lines, refuel, then when you prime your filter housing, just keep priming for a while, draining through the return line. Then prime, vent injection lines, and start. If it runs normal, maybe you slid by the worst.



Hasn't happened to me, yet. I've pumped over 3,000 gallons of diesel just through my own tanks this year... ... .

 

[Missouri Mule]

Get all the gasoline out of the tank ( 1 gal mite not hurt anything if you can not ge it all out). The p7100 is pretty hardy plus it is cooled by oil and diesel fuel not just fuel. Buy a diesel fuel addiltive that lubricates the pump.

When you blow out the lines you will need to bleed the air out of the lines in several places. 1,crack the supply line to the fuel filter ( you can use the primer button for this). 2. Crack open several injectors and crank engine. ( better done with two people). Fuel is out of lines when you can not see any bubbles.

 

[MChrist]

Hopefully it all works out for! 30 miles seems pretty far. What percentage was gas and what percentage diesel?

 

[Halfhand]

I've never run that tank completely empty for obvious reasons so I'm not sure how much was still in there "on reserve". The guage was showing less than an eigth of a tank. I'm guessing 3 maybe four gallons of diesel. I topped it w/ 26 gal of unleaded. so nearly 90% gas...

 

[Halfhand]

Thanks for the help guys!





She's Alive!!



After draining the tank, blowing out the lines, dropping the screen, changing the filter, and bleeding the injectors... she fired right up. Easier than I ever thought she would. Smoothed right out in just a couple of seconds and sounded as dependable as ever.

I just drove it for about 15mi and she sounds tight, runs as well as it did on Fri. Woo-Hoo! I topped it off and will update with the mileage about the end of the week.



Of course I have no idea what the long term effects will be. I'm curious as to your thoughts on the condition of the injection pump/head gasket/valves/pistons...



Thanks again, Gentlemen

 

[HHhuntitall]

My biggest concern, and IMHO, the biggest problem you might have, would be any piston damage you could have. Watch for excessive oil consumption. These engines are dang tough, but if it cracked a piston, you could have a serious problem later down the road. Other problems could be burned injector tips and valves, but if it's running good now, it will probably be good for a while. Watch for no starts and white smoking on start up.



Good luck.

 

[Sticks]

I'd think it very unlikely that he would have suffered piston/engine damage. Injection pump or injectors worn from lack of lube on the fuel side maybe.

 

[HHhuntitall]

I'd think it very unlikely that he would have suffered piston/engine damage. Injection pump or injectors worn from lack of lube on the fuel side maybe.

Well, for his sake, I hope niether of us are right. I was just thinking of the worst of things I've seen happen. I've seen one that melted the center cone and cracked the piston from burning gas while pulling a trailer. According to the previous owner, it was only around a 50% mixture, but it ran well enough to pull the trailer for a while. They finally pulled in to a local shop because it didn't have any power and was knocking at an idle, found the problem, flushed it, and went on their way. I only found it several years later after I dismantled the truck. It had ran close to 75k after that, but it used oil pretty bad. It finally dropped the KDP and busted the front cover, so I got it cheap and parted it out. The injection pump is still running on another truck... . the transmission in another, the cylinder head is rebuilt, o-ringed, and on a truck I sold last year, the frame went under a wrecked truck ... ... . the block and rear end are still good, sitting in my storage building... ... #6 piston was the only one that appeared to be damaged.

 

[Halfhand]

About 60 mi so far, runs fine, but she's been hard starting cold. And not that cold, 55F this morning and 75F at lunch. once its running it's fine. Hopefully running this tank of fresh fuel though will help but I have my doubts... injectors maybe? As far as a hole on a piston, I should have some significant blowby throught the crankcase vent, right? I imagine it'll be a while before I notice any oil dillution. I'm afraid I'll have to do something before the fall.

 

[MChrist]

Sounds to me like you may have done some damage to your injectors. If it runs fine but takes time to start, it sounds like you aren't building enough pressure at cranking speeds to "pop" your injectors. But once running, you have no problems. Do you notice more smoke than normal if you floor it? Mpg going down?
I'm not q 12 valve guy, but those are just my thoughts.

 

[HHhuntitall]

Sounds to me like you may have done some damage to your injectors. If it runs fine but takes time to start, it sounds like you aren't building enough pressure at cranking speeds to "pop" your injectors. But once running, you have no problems. Do you notice more smoke than normal if you floor it? Mpg going down?

I'm not q 12 valve guy, but those are just my thoughts.

'd be what I'd think, too.....

 

[Halfhand]

I put my foot in it this morning and got some smoke, normal not excessive. Haven't run it enough to check the mileage yet. Unfortunately it's been steadily dropping over the last year so it may be hard to tell if this had an effect (went from 18mpg to 15. 5 on average, a whole nother post I was waiting on... ). I did strip the bleeder screw on the fuel filter housing. Light leak. I ordered a new banjo bolt, screw and washers from Cummins this afternoon. I was kind of hoping thinking maybe the leak could be causing the system to lose prime after the pressure is relieved. Parts should be here Wed. or Thurs.

Thoughts?

 

[Sticks]

Uh, yeah... gotta make sure everything else is fixed before finding new problems.

Hopefully you will come out of this OK.

Keep us posted.

 

[HHhuntitall]

I put my foot in it this morning and got some smoke, normal not excessive. Haven't run it enough to check the mileage yet. Unfortunately it's been steadily dropping over the last year so it may be hard to tell if this had an effect (went from 18mpg to 15. 5 on average, a whole nother post I was waiting on... ). I did strip the bleeder screw on the fuel filter housing. Light leak. I ordered a new banjo bolt, screw and washers from Cummins this afternoon. I was kind of hoping thinking maybe the leak could be causing the system to lose prime after the pressure is relieved. Parts should be here Wed. or Thurs.

Thoughts?

Hmmm, it's possible a small leak could be making it hard start..... I'd still lean more toward injectors, especially since your mileage has fallen off so hard recently.

 

[Halfhand]

For the record, I replaced the bleed screw I stripped and stopped the fuel leak. No more hard starting. Yea!
I've run it about 800 mi. and it's running fine but I am averaging 14. 9 mpg... I doubt this is related to the unleaded incident as it has been dropping for some time. I remember hearing about some parts wearing in the p-7100 and needing adjustment. I still have a "hard spot" in the throttle when coming off idle. It's more noticeable when operating the linkage by hand than by the pedal so It may have been that way for a while, ideas? I'll get under it soon and make sure its not the linkage binding...
Thanks

 

[fkovalski]

BHahulski- I hope all works out for you...



... and thank you for posting. You are getting the assistance you need and your tales do a lot for the folks here. I live vicariously through others' experiences and while posts similar to your come up every so often I read them all. It reinforces to me to be careful at the pump ... and I mean that in a good way.



Again, hope it works out int he end.



Regards,

-frank.

 

[HHhuntitall]

For the record, I replaced the bleed screw I stripped and stopped the fuel leak. No more hard starting. Yea!

I've run it about 800 mi. and it's running fine but I am averaging 14. 9 mpg... I doubt this is related to the unleaded incident as it has been dropping for some time. I remember hearing about some parts wearing in the p-7100 and needing adjustment. I still have a "hard spot" in the throttle when coming off idle. It's more noticeable when operating the linkage by hand than by the pedal so It may have been that way for a while, ideas? I'll get under it soon and make sure its not the linkage binding...

Thanks

Great to hear your leak stopped the hard starts!!



On the hard spot, I'd check your throttle cable at the bracket, see if the dust shield is catching on the front of the cable sheath/cover. It should only do it off idle, as it falls down and the two edges contact each other just off idle, then the shield slides over the front of the cable sheath to allow the cable to progess inward..... It could also be worn ball sockets on the linkage from the bracket to the rear throttle lever... ...



If you're truck is starting easily, has good power, and doesn't white smoke after start, I'd bet your problems lie somewhere other than the pump. I'd think injector nozzles are worn or you have a leak in the boost system, such as a hole in an intercooler boot or intercooler, itself. I see the lower, passenger boot, where it goes into the intercooler, cut by the fender all the time. The small hole slowly gets bigger, letting boost fall and hurting your overall power and mileage on the highway. Sometimes, they explode, and you think you've blown your engine..... those make for some cheap trucks, at times!!!!Oo.



Do you have a boost guage, and have you "tweaked" your pump?

 

[Extreme1]

Glad it all worked out. The 12 valves are much more tollerant of gas in the fuel, the biggest problem being injector pump lubrication (just the pistons, the rest is lubed by engine oil).



215k is a lot on the injectors and the pump. The pump cpould probably stand to go on a test stand and be readjusted to balance fuel delivery to all the cylinders. While it's on there you could have it turned up a little (they will grind a fuel plate for it) for aminimal amount (shop the fuel pump modification guys that advertise in the TDR, you local guy won't be as good, it's well worth the freight to ship it to somebody good). Then replace the injector tips (I recommend DDP's) and you could easily end up with more power and better milage for under $1k.



One other thing to examine for milage problems: the cat. Is it still there? At that milage it is probably fairly plugged.

 

[MChrist]

Not to stray too far off topic, but regarding the cat converter. . I know there is a pressure test for gassers where you put a pressure gauge in an O2 port (or drill a small hole) before the converter, and rev the motor up to 2500 and then check to see if pressure/resistance is less than 2. 5 psi.
Is there a test for diesels?