Help! Changed timing and now have motor runaway!

[RSchwarzli]

Over the last few weeks I have done the following to the 1990. I will mist them all here so if by chance one of them had something to do with it and I am overlooking It, you can pick up on it.



Hx35 from 1997 12v cpl 2174 180 hp pump

BD exhaust manifold

KDP

Changed timing the correct way. Now reads 1. 79 mm lift at TDC

a few new injection pump banjo bolt seals

Vacuum pump seal

Boost gauge

turbo drive pressure gauge



Just started it up, let idle for 15 min, go through the rpm range and when I gt to 1900 it continues to gain without any more pedal movement till I removed all throttle at 2900 rpm. Then it dropped back to idle.



I don't get it. I changed nothing fuel wise minus timing.



Am I missing soemthing?



Thanks!

 

[RSchwarzli]

Oh. Just thought of this. My fuel screw is turned up enough to run the stock turbo to 30 psi, but I have never had runaway... .

 

[Paychk]

Check and make sure the turbo isn't bleeding oil into the intake?

 

[RSchwarzli]

Huh??? You lost me!

 

[JohnBoy5]

If the turbo seal is bad it will blow engine oil in to the intake and make the engine keep running. You have not had a runaway yet. Trust me. Those are words from having it so called hit the fan. lol



Pull the boots off the turbo and look for puddled oil if you have an intercooler check it also. If you find oil do not start the truck until you stop the oil from entering the intake and you MUST clean the intercool and pipes on the inside REALLY REALLY good to prevent it from actually running away.

 

[RedRamAndy]

I was thinking of setting the timing the 'right' way on my truck too. But I'm remembering the spec to be 1. 4mm. 1. 79 seems a little tall?

I'll have to check my Cummins supplement.



added: I checked my 1989 manual that spec (1. 4) is right. Maybe the spec is different for a '90 non-IC.

 

[RSchwarzli]

John - interesting. I was not aware it could run on engine oil.

Andy- Yes, it is a little on the high side. Interestingly, the turn the pump 1/8" meathod actually puts you at 1. 80 (at least on my pump). That lift was recommend to me by a Cummins tech from this site. I trust his knowledge and am not too worried. Timing I believe is the same for both, but not sure enough to bet money on it... .

Update: after having turned down the fuel screw 180 deg, I tried this revving thing and it is still there but not as severe. I did take it for a test drive and it all seems ok. Even when I rev it to the rpm it takes off in idle, it acts normally.

Starting to wonder if this issue was always there but just did not notice it as I had never sat in N and revved it like what I am doing.

 

[HHhuntitall]

Have you checked your return springs on the pump fuel lever? If they get removed or broken, it can take very LITTLE pressure on the pedal to move the lever a good distance. The coil spring on the pump gets weak with time and heat, so it's a good idea to check and make sure the little one is on the lever to the front of the gear case..... I had a '90 model that kinda ran away with me, once. Luckily, it was an auto, and only went to 87mph, so I went with it... ... actually, I didn't even realize it had run away for 30 minutes or so..... ..... still got 17mpg on that tank. Finally sold her to a friend's little brother around 550k. Still runnin on their farm the last time I talked to them. I think God loves a Cummin's, too.....

 

[RSchwarzli]

Good thought. Will check that. I think they are all there. But now I am second guessing... .



LOL on not noticing the runaway!

 

[JohnBoy5]

John - interesting. I was not aware it could run on engine oil.





yea any diesel can. oil on the intake is like gas on the intake or carb of a gas enging. if the supply is there is will turn as many rpms as needed to burn that supply or until something breaks and stops the maddness. i found out about the intercooler filling with oil the hard way on an 8. 3l cummins. there was a nice black oil spot on the celing and we tried to shut it down with a phone book over the turbo well it started suckign the phone book through the engine like a paper shreader. needless to say the engine was done in for after that... .



i will put it this way, i have no clue how many rpms that thing was twisting but it was ALOT and i wanted to run from it becuase it sounded evil...



were you making a funny about what i said or for real?

 

[JLEONARD]

I had a 1980 VW pickup runaway on me. The intake manifold got to the fill point with PVC oily yuck and it started to burn it up one day. Luckily I was on the expresssway on a hill with the go pedal mashed... . this time the vehicle actually acted like it had a motor. LOL 45 seconds it was all done and back to 52 horsepower!

 

[HHhuntitall]

John - interesting. I was not aware it could run on engine oil.





yea any diesel can. oil on the intake is like gas on the intake or carb of a gas enging. if the supply is there is will turn as many rpms as needed to burn that supply or until something breaks and stops the maddness. i found out about the intercooler filling with oil the hard way on an 8. 3l cummins. there was a nice black oil spot on the celing and we tried to shut it down with a phone book over the turbo well it started suckign the phone book through the engine like a paper shreader. needless to say the engine was done in for after that... .



i will put it this way, i have no clue how many rpms that thing was twisting but it was ALOT and i wanted to run from it becuase it sounded evil...



were you making a funny about what i said or for real?

I had an '85 Pete with a 3406A Cat engine... ... the turbo went and she went into overdrive... . permanently... . nothing like 916 cubic inches at 3500 rpms ..... finally got the intake boot off and shut it down with a 2x12 I pulled out from under a gooseneck trailer jack... . ... nothing like sheer panic to motivate you. And yes, they sound VERY evil running on motor oil... . I can only imagine what it would do if a rod came loose... .

 

[JohnBoy5]

I had an '85 Pete with a 3406A Cat engine... ... the turbo went and she went into overdrive... . permanently... . nothing like 916 cubic inches at 3500 rpms ..... finally got the intake boot off and shut it down with a 2x12 I pulled out from under a gooseneck trailer jack... . ... nothing like sheer panic to motivate you. And yes, they sound VERY evil running on motor oil... . I can only imagine what it would do if a rod came loose... .

the cummins 8. 3 that we had runaway was just rebuilt and i was struggling to find anything to stop the air. i can tell you a phone book was not the answer as it started pulling a few pages at a time in and before i could get it back it was gone... . I wish i had a video of this while at the time it was no where close to funny it sure would be funny to watch the 3 or 4 of us running around looking for ways to stop it.



I am not sure that we could have gotten an intercooler boot off or not. i guess the only thing that happened was we freaked out...

 

[PToombs]

My nephew is in the marines working on hummers and 7 ton trucks. He was telling me last night that they've had a few things run away. He said they put a clip board over the intake and it cracked the clip board, another time they used a phone book.



What I told him applies here as well, cut a piece of plywood and keep it nearby to use as a shutoff!