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mack ch613 no-start getting good fuel


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Hey guys I need a lot of help from someone knowlegable on mack e-7 engines. Basically I have a 1991 mack CH613 that wiped a cam lobe back in december of 2012, we replaced the cam in january and it went to work for one day and it shut off and never started up again. We towed it back to our shop where it sat from january up until last month when we got around to replacing the injection pump (which we found out had given out) well we timed it all up and had it running for a good while at our yard and it ran amazing so we sent it to work finally about last week... it worked under load for one 8 mile load and it shut off on the roadway and we had to tow it back to our shop. All it will do is crank over and blow heavy white/gray smoke (of diesel) but will not start. I have run out of ideas. Injection pumps and cams are not cheap and I expected this truck to work fine after these parts were replaced. Help guys! Thanks ahead of time for any insight.

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Staxx, if I carefully add ether to make it start then the electronic malfunction and engine shutdown light up as the engine roars to life but it blows out large amounts of gray/white smoke and smells like unburnt diesel. This is EXACTLY the symptoms the truck gave when the injection pump went out. We were told at the bosch shop that the 2nd plunger had to be hammered out due to excessive wear throughout the pump and it seized itself in place. After the rebuild we dialed it right up to the motor's timing amd it ran absolutely perfect... that is before it went to its first day of work.

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theakerstwo, you have a VERY good point on the cam gear that turns the injection pump. We had the gear pressed on at mack I really hope they didn't screw up, that was a $1600 cam and many hours of work to install it at our shop. I will be working on it this weekend and I will double check the pump gear itself for signs of movement through the access plate amd then I will re-time it. Y'all are right this does sound like a timing issuebut I sure hate timing these motors they are such a pain in the ***

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If it is running on either that means that everthing other than pump and injectors is ok . So problem could be injector pump or timing of pump to engine gear slipped on cam shaft or slipped on pump drive or bolts loosened at econovance coupling . If you are using a a-b lite timing tool to adjust / set timing be careful I have had some pump shops not get the back half of injection pump in time . Best to flow time with high psi or remove plunger and low psi time pump. Good luck let me know what u find.

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Theakerstwo, we actually tried that back in january when we popped the cam in there. The problem was even after sticking the cam in the freezer and the gear in the oven at full blast it still didn't want to slip right on, apparently it has to be heated AND pressed on. Well that's what the mack boys did anyway

Edited by 96bulldogpower
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Staxx, I will re-time for sure this weekend as much as I hate doing it lol as far as getting the governor timing done right I really hope they got it right and live up to their "bosch licensed" knowledge. I will double check the bolts on that pump gear where you set the degrees behind the access plate. I will keep yall posted on what I find out this weekend. Thanks guys!

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  • 2 weeks later...

Alright guys sorry for being a little late, it took me a while to get back to the truck but I finally got around to working on it. Staxx you were dead on with the drive gear on the cam that turns the injection pump.... its all points to the gear slipping right on the cam. I put the engine back in time with the injection pump and voila. It starts right up. I now realize the injection pump was never bad to begin with because all these problems started right after the cam job, and that we likely spent our money on a scam shop. Oh well. My problem now is that the cam we used was a PAI brand cam which I was told is the OEM replacement for mack. We had the old cam gears pressed on at our local mack onto the new cam. We thought it would work fine because the boys at mack said reusing the cam gears was ok so we just paid them for a new thrust bearing and keyway when they installed the gears. I'm wondering if there's a way to maybe drill in between the gear and the cam's face to thread and install a bolt and act as a key? Or maybe weld the gear right onto the cam? I'm not trying to be crude about the repair but in out of ideas!

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