mechmagcn

There should be a serial plate on the block behind the injection pump.

Hey guys, just stopping by for an update. Turns out that he had another identical truck start doing the same thing, just not quite as bad. They buy fuel in bulk, 6-8 thousand gallons at a time. Fuel ran low at the yard, so the driver of the worst truck started getting fuel at a nearby truck stop and the problem went away within a day. Same thing with the other truck when they filled it at the truck stop. Took about 4-5 days for the supplier to fill the tanks at the yard and within two days both trucks are popping again. I've told them to locate a lab to check the fuel. He called last night and said one of his contract trucks had started doing the same thing after getting a tank of fuel from his pumps. Any ideas on this? Bad fuel mixture? Low or high cetane? My wife works for another logging contractor and said he bought 15,000 gallons of fuel last week at a lower price because it was left over winter blend, any possibility that this is the fuel problem that my friend is having?

Yes, install is done with pump on the engine. Years ago I worked on a lot of older R-Models that were bad about loping, even when going down the road, this would stop most of that. If I remember correctly the kit consisted of a lightweight spring, a washer and a roll pin. It goes on the rack at the front end of the pump. I seem to remember that you have to drill a hole in the rack for the roll pin.

Not sure if they even offer it any longer, but there used to be a patch kit that was a light spring that held the rack against the slack in the pump. I did this on my R-Model years ago and it still runs great. Check with a Mack dealer that knows the older trucks or a reputable pump shop.

Really wish I could come out of retirement, the money was so much better when I was self-employed. But a broken down body and severe arthritis from being a field mechanic for 30 years keeps me stuck at a desk job now, watching others keep up maintenance in a small State Park. Damned kids now days don't have a clue on how to troubleshoot, plug the laptop in and start throwing parts at it.

Sorry guys, been too busy to check back in. As I said, I'm not the one doing the actual work, just trying to help a friend and former customer. The truck is a CH613. The truck will not do this just revving the engine, it only does it when taking off and usually clears up by the time you hit the high side. With this said, not sure how much an ir thermo would help. All fuel lines have been checked, the elbow in question has been pulled and resealed. E-ups have been pulled and a reman swapped hole to hole with no change. From the looks of it I'm going to have to come out of retirement and get my hands dirty to figure this one out. Thanks for the replies, I'll be sure to let everyone know what we find.

Thanks for the response. Valve adjustment checked, no engine brake.

Hey all, long time since I've been around here. A friend called with problems. 01 E7 460 after idling will pop through the exhaust when taking off from a stop. Sputters and occasionally backfires. This happens through 4th or 5th gear and then clears up. It won't do it again until it idles for some time, usually while getting loaded. Another friend, a rather good mechanic has pulled his hair out trying to figure this one out. My thoughts were low fuel pressure or sucking air, but he has pretty much ruled those out. Fuel lines have been changed, timing sensors checked, fuel pump changed, injectors tested bad and replaced, engine wiring harness had some wear so replaced, he even bought one E-up and swapped holes to see if that was it. I'm sure there's a few other things that he's tried that I'm forgetting. I'm a retired truck and heavy equipment mechanic that used to work on this truck, but seldom turn wrenches anymore. Just trying to get some insight into this problem. I never was one to throw parts at a problem and hope something would stick. I'm afraid the mechanic working on it has given up and that's what is happening now. I hope someone has seen this and can help a broke down old mechanic out. Thanks all.

Thanks Paul. Looks like you have done the research. I would be adding an exhaust brake for little reason seeing as to how my engine is a EM6-300R. This engine is governed at 1800 RPM, so the brake effect would be almost non-existant. I would guess my next question would be: How much does the engine brake cost for this engine? I probably wouldn't ever need it.... but would like to have it when we travel through the mountains. Thanks again, Jeff

I have a R-Model, with an EM6 300, that only pulls a 16K 5th wheel trailer. I was wondering if Mack ever used an exhaust brake? What would be the downside of using one on my truck? Some of the exhaust brake manufacturers are using a 4" brake assy. in the exhaust that just clamps in a flange like the turbo to exhaust pipe connection. This would be easier and cheaper for me to fit than to retrofit to a Dynatard or Jake. Jeff

Rob, did you ever find a valve cover for the Dynatard? I have a pair of them sitting on a shelf that I won't be using. E-mail me for price and shipping info. Jeff

On radial tires, I always set toe to dead ahead or less than 1/16 toe in. Bias tires require more toe to drive straight. Also, for marking the tires, I drive a nail into the end of a 4' piece of 4X4 at a 45* angle and cut the head off. Jack up tire, place nail against center of tire holding board down with knee, turn tire to mark. Do this on each side and then check toe with tape measure (just don't ask the Ol Lady to hold the "dumb end" of the tape) Jeff

Boy Barry, you must work fast. I got the E-mail to order the calendars! Looks like my Dog made the grade! WooHoo!! Thanks, I'll get my order in, Jeff

Hey Barry, what's the word on the calendars? Just wondering if you recieved my truck pics and when the calendars will be available. Jeff

Just one now, I had 3 parts trucks, but the city beautification Nazis decided that was too much. I still have as many parts as I could hide behind a 6' privacy fence though.

What a waste of classic iron.

I have run into this problem several times. Before going to any extremes, look for a vent on the rear of the shift housings,(if I remember right, it will be on the lower left side of the shift cylinder) sort of looks like a hole with a screen or rock type filter in it. If this is stopped up, the shifter can't let the air off of the off side of the piston. Jeff

It is definately governor related, my EM6-300 did the same thing until I installed the fuel rack "patch" kit to stop the bouncing at highway speeds. All it consists of is a very light spring and a roll pin in the fuel rack. Jeff

Turning the fuel up can get into your wallet, 3 flats netted me about 3/4 MPG less on a 2000 mile trip last week. But I will say that the dog pulls much better now. Jeff

Looking good, usually my light at the end of the tunnel is the oncoming train Jeff

:bmod1: Thanks Trent. I don't think I'll really have a problem with EGTs or boost, seeing as to how I'm only pulling a 16K 5er. I don't want to soot the trailer up, so I will only turn it up until I see some light smoke. Jeff

Hi all, I'm looking to turn a little more fuel to SuperDawg. Right now it is at factory specs with a EM6300R, the seal hadn't been broken. I want just a little more pulling power. This pump is one that I'm not familiar with. American Bosch, what to do for a little more fuel, no more RPMs. Thanks for any help. Jeff

From one woodworker to another, that is some fine work. We sure want to see the final pics of that project.