The Trash Man Posted September 18, 2012 Share Posted September 18, 2012 I recently had the injection pump rebuilt on a '87 MR with the EM6 237 engine. The truck actually ran well before I had the pump rebuilt except it had a very rough idle and the pump was leaking some oil which the DOT frowned upon last time I got pulled over. Other than that the truck always fired up at the touch of the key and had plenty of power. Anyways I had the pump rebuilt by a place that is suppose to specialize in rebuilding Bosch pumps although I have heard some people not having good results with them. The ol' boy who rebuilt it told me he found that the throttle shaft was badly worn along with the throttle shaft bushings and said that's what probably caused the rough idle. He also told me that someone had turned the fuel screw on the pump all the way down to where it wasn't putting out much fuel so he claims he turned it back up and calibrated it to the right specs. Well apparently he didn't do something right because now the truck won't hardly run at all since I put the pump back on. When I cranked it over it didn't even sound like it wanted to hit. I figured it just had air in the lines so I cracked the fittings at the injectors and cranked it until it showed fuel squirting out of them. Still didn't even try to start. Finally after giving it a few shots of starting fluid and pressing down on the accelorator pedal it started. However it runs terrible, it won't rev up past 1600 rpms and you can't let it idle down below 700 rpms or it will just splutter and die. Also the throttle is not very responsive, you press down on it and it hesitates a second or two before it wants to rev up. One other thing I noticed is that my chrome exhaust stack got very hot and turned blue, something it had never done before. I called the place that rebuilt the pump today and they are like "well we set it to specs and they only thing we messed with was the fuel screw." Before I had the pump rebuilt the truck never seemed to be starving for fuel to me and it put out a decent amount of smoke, now when I do get it running it barely puts out any smoke at all. I just wonder could it be that the fuel was already turned up and they turned it down? I would think they would know what they were doing but I do know another guy who had a pump rebuilt there and they put it together out of time so I guess anythings possible. I was wondering if maybe I could try adjusting the fuel screw myself a couple turns and see what happens. I know you pull the cap off the top of the pump but I'm not sure which screw it is. I see one that has a jam nut on it, is that the one? If it is which way would I need to turn it to turn the fuel up? Maybe I shouldn't mess with it at all but I'm willing to give anything a try now to get this truck running again. Thanks. Quote Link to comment Share on other sites More sharing options...
Brian Blaylock Posted September 18, 2012 Share Posted September 18, 2012 In my opinion the best thing you can do if possible is take the whole truck to the shop that worked on your pump and get them to fix it I would not break the seals they put on the pump because they could say you worked on it yourself and messed it up if the seals are in tact it is their work in question Quote Link to comment Share on other sites More sharing options...
MACKS Posted September 18, 2012 Share Posted September 18, 2012 If you re-installed the pump yourself are you sure that the engine is timed right? Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted September 19, 2012 Share Posted September 19, 2012 Sounds to me like some one cant time the pump. The guy that installed the pump is who you need to talk to.He may notnknow how so he may not be able to help you. Quote glenn akers Link to comment Share on other sites More sharing options...
skip Posted September 19, 2012 Share Posted September 19, 2012 I would re-check the timing before you take it back to the pump shop. Did you spill time it? It sounds like they only mucked around with the governor end of the pump so the front end will be basically untouched. There is only one way that pump can go on but there is plenty of room for adjusting timing with the slotted holes in the drive gear. I havent got the specs here with me, but someone will be able to help you on here. The pump might have a tag on it with degrees before TDC. If you make sure you have done that right, then you have the ammunition to go and ask questions of the pump shop.Skip Quote Link to comment Share on other sites More sharing options...
turckster Posted September 22, 2012 Share Posted September 22, 2012 Sounds like the pump timing is off. Any time an injection pump has been removed it should be timed to the engine. The problem is, it sounds like some damage has been done. You stated the exhaust stack has turned blue., If it got hot enough to do that imagine the temps inside the cylinder. I have seen piston crowns melted within minutes on an engine with incorrect timing. Hopefully no damage has happened but I wouldn't hold my breath. Quote Link to comment Share on other sites More sharing options...
39 Baby Mack Posted September 23, 2012 Share Posted September 23, 2012 Sounds like the pump timing is off. Any time an injection pump has been removed it should be timed to the engine. The problem is, it sounds like some damage has been done. You stated the exhaust stack has turned blue., If it got hot enough to do that imagine the temps inside the cylinder. I have seen piston crowns melted within minutes on an engine with incorrect timing. Hopefully no damage has happened but I wouldn't hold my breath.Do you mean something like this?Ron Quote Link to comment Share on other sites More sharing options...
rick harper Posted September 23, 2012 Share Posted September 23, 2012 Sounds like he didnt spline it correctly and advanced the timing way too much. Quote Link to comment Share on other sites More sharing options...
39 Baby Mack Posted September 23, 2012 Share Posted September 23, 2012 That would be pretty tough to do, there's a roll pin between two teeth in the drive and a low tooth in the celeron coupling on the pump that would not allow you to do this.!It can only go on one way!Ron Quote Link to comment Share on other sites More sharing options...
turckster Posted September 24, 2012 Share Posted September 24, 2012 Do you mean something like this?RonYes sir, that's what it looks like. Quote Link to comment Share on other sites More sharing options...
turckster Posted September 24, 2012 Share Posted September 24, 2012 That would be pretty tough to do, there's a roll pin between two teeth in the drive and a low tooth in the celeron coupling on the pump that would not allow you to do this.!It can only go on one way!RonSeveral times I have seen either the pin had fallen out or it had been sheered off. Seen some crazy stuff done to these trucks and engines. Should check the timing every time to cover your tush. Quote Link to comment Share on other sites More sharing options...
thomastractorsvc Posted September 30, 2012 Share Posted September 30, 2012 Trash Man what did you find out or did you trade it in for a Kenworth? Quote Robert"I reject your reality and substitute my own." Link to comment Share on other sites More sharing options...
The Trash Man Posted October 8, 2012 Author Share Posted October 8, 2012 Sorry for the late response but anyways the guys who rebuilt the pump swore up and down it had to be right. Well after having no luck with them I decided to just put a remack pump on the truck and guess what? It fired right up and ran like a charm, shows right there that those guys didn't put my old pump back together right. I hated to have to resort to buying another pump but I just wasn't getting anywhere with those guys. I should have knew better though because I knew a guy who had the same kind of truck I did and he had his pump rebuilt there and had no luck either and had to put a reman on his. It was a very expensive lesson learned but I know I will never have that shop do any other work for me. I've been telling alot of my friends with diesel equipment to stay away from that place also. Oh well I guess you live and you learn. lol Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.