niceguypmp3 Posted August 22, 2008 Share Posted August 22, 2008 On our '83 Mack with the 237 we have just bought, we have noticed that it seems to be low on power. I'm not for sure on the model number at this moment, but I do know that the engine has 225 horsepower IIRC from the engine plate. I have read a few things on here about a puff limiter and that it can increase power if that is unhooked. Does this engine have one and if so, where would it be and how would a person disconnect it. From what my dad has said, "It barely, if any, smokes when your shifting up". It would just be nice to try to get a little more power from this motor. Any information would be greatly appreciated! Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted August 22, 2008 Share Posted August 22, 2008 Most common place for the puff limiter is tapped into the top of the intake manafold. there will be 2 air lines going to it. a quick test to see if it is working correctly is to set the yellow parking brake and snap the throttle to the floor. if should throw a thick black cloud...then release the brake and snap the throttle it should have less smoke if the puff is working.if you locate the puff pinch off one of the lines and it will throw smoke evertime you shift. the down side of unhooking the puff is that the excess fuel between shifts can work its way into the oil pan and delute the oil.Might try making shure the throttle linkage is alowing the pump to go to full fuel?Trent Quote Link to comment Share on other sites More sharing options...
fjh Posted August 22, 2008 Share Posted August 22, 2008 Most common place for the puff limiter is tapped into the top of the intake manafold. there will be 2 air lines going to it. a quick test to see if it is working correctly is to set the yellow parking brake and snap the throttle to the floor. if should throw a thick black cloud...then release the brake and snap the throttle it should have less smoke if the puff is working.if you locate the puff pinch off one of the lines and it will throw smoke evertime you shift. the down side of unhooking the puff is that the excess fuel between shifts can work its way into the oil pan and delute the oil.Might try making shure the throttle linkage is alowing the pump to go to full fuel?TrentAnd stop full off! Quote Link to comment Share on other sites More sharing options...
Guest 45LMSWM Posted August 22, 2008 Share Posted August 22, 2008 One other thing about disconnecting the puff limiter. I know the State Police here in New Jersey used to be pretty hip to that trick. It is illegal to disconnect it, and they would give you a stiff ticket if they nailed you doing so. Just something to think about.The strongest truck I ever drove blew almost no smoke at all, and I ran a DM800 with a 350 2-valve with a disconnected puff limiter...all it did was smoke, smoke, smoke. No power, whatsoever. It was like a giant electro-police magnet. They never even opened the hood to find the thing disconnected, they didn't have to. Big, big fine for just failing the smoke test.John Pearson Quote Link to comment Share on other sites More sharing options...
bulldoggin' Posted August 22, 2008 Share Posted August 22, 2008 Too get by the leagal junk put a pop rivet in the line that is the same as unhooking it.Done it,it works! Quote KEEP THE BLACK SMOKE ROLLIN Link to comment Share on other sites More sharing options...
niceguypmp3 Posted August 23, 2008 Author Share Posted August 23, 2008 Ok, I checked it out by using the parking brake and punching the throttle method and it seems to work. With parking brake on, it smokes a good dark cloud on full throttle. With brake released, less than half as much smoke. How doggy are these motors supposed to be. The truck that it is in is a "roll off box" truck. Truck's empty weight is a tad over 30k. Even empty, when starting to go up hills on the interstate here in south central iowa, it slows down, it seems to take forever to get to 55 mph. Today with 20k in the box, there were a few hills that had me down to 40 mph in 4th gear and still slowly slowing down and I have Yet to see it smoke from the stack. We're thinking maybe somebody before us turned it Down? we just put all new filters on it and that didn't help at all. I dont know how loud the turbo is supposed to be on these but i know that with the straight through stack it's loud enough already. We're thinking about having a local truck shop look at it and see if he thinks it can easily and safely be turned up some or if something is wrong with it. Any other ideas guys? I really appreciate the quick replies already. I'm loving this site more and more! Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted August 23, 2008 Share Posted August 23, 2008 I dont know how loud the turbo is supposed to be on these but i know that with the straight through stack it's loud enough already.By "loud" do you mean an excessive amount of turbo whine or "whistle"?A leak in one of the connections between the turbo and the intake manifold would cause a loud whistling noise when the turbo is working under load. A leak such as this would also cause a loss of boost pressure.Low boost pressure will not allow the puff limiter to allow the inj. pump rack to go to full fuel position, resulting in a lack of power with no smoke.Since I haven't heard it in person, I can't say for sure if thats what you're describing..Also, if your engine is set up to feed turbocharged air to the air compressor, there is a 1" braided line running from the intake manifold to the inlet port of the air compressor, and I have seen these leak before. A leak there would also cause a loss of boost pressure. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
Bullheaded Posted August 23, 2008 Share Posted August 23, 2008 Ok, I checked it out by using the parking brake and punching the throttle method and it seems to work. With parking brake on, it smokes a good dark cloud on full throttle. With brake released, less than half as much smoke. How doggy are these motors supposed to be. The truck that it is in is a "roll off box" truck. Truck's empty weight is a tad over 30k. Even empty, when starting to go up hills on the interstate here in south central iowa, it slows down, it seems to take forever to get to 55 mph. Today with 20k in the box, there were a few hills that had me down to 40 mph in 4th gear and still slowly slowing down and I have Yet to see it smoke from the stack. We're thinking maybe somebody before us turned it Down? we just put all new filters on it and that didn't help at all. I dont know how loud the turbo is supposed to be on these but i know that with the straight through stack it's loud enough already. We're thinking about having a local truck shop look at it and see if he thinks it can easily and safely be turned up some or if something is wrong with it. Any other ideas guys? I really appreciate the quick replies already. I'm loving this site more and more!Before you disconnect make sure the puff limiter hasn't just been re-shimmed. It's been a few years since I worked on one of these so I can't remember if turning it in or out makes the throttle response. One of the experts here can tell you. I had to take one of the ones I drove for the mandatory emmisions test we have here and the dealer shimmed it to make it pass. When I went to leave it had very slow response and would barely accelerate itself up to speed. I had to re-shim it when I got home.Also, instead of just plugging the air lines, I ran mine through an air switch. (same one as for a power divider or the one used for the deep reduction on the 12 speed.) That way you could make it smokeless if the dot is around, and get the power when you need it. Quote Link to comment Share on other sites More sharing options...
fjh Posted August 25, 2008 Share Posted August 25, 2008 Before you disconnect make sure the puff limiter hasn't just been re-shimmed. It's been a few years since I worked on one of these so I can't remember if turning it in or out makes the throttle response. One of the experts here can tell you. I had to take one of the ones I drove for the mandatory emmisions test we have here and the dealer shimmed it to make it pass. When I went to leave it had very slow response and would barely accelerate itself up to speed. I had to re-shim it when I got home.Also, instead of just plugging the air lines, I ran mine through an air switch. (same one as for a power divider or the one used for the deep reduction on the 12 speed.) That way you could make it smokeless if the dot is around, and get the power when you need it.Just proove out what and if you have a problem !Disconect the line to the bimboe on the fuel pump cap it off and run it with a load and see if you power is better on hills if so the reversing relay for the puff limit is likly fubared!The limiter may be working but incorrectly Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted August 25, 2008 Share Posted August 25, 2008 If the puff limiter is set like it is to be it will not kill power on top end but will slow the responce of the getting up to top end down some and kill the smoke and keep the black out of your oil longer and surely save some fuel. Cummins was the same way and alot a guys would set the no air screw in to were they could get smoke. Like some one already said if disconnecting the air line helps on power then the air relay will fix problem. Quote glenn akers Link to comment Share on other sites More sharing options...
niceguypmp3 Posted September 4, 2008 Author Share Posted September 4, 2008 Thanks everyone for the info. My internet has been messed up for a while and I finally got around to plugging off the puff limiter and trying it out. All I can say is WOW! This thing has alot more power now! We are alot happier than we were. We also figured out that the speedometer is about 10 mph fast for some reason. Close as we can figure, it gets around 6- 6.5 mpg which is half the trip around 55k and the other half empty at 31k and going 45-50 on the interstate. Top speed is 52 or 53 and the engine is topped out. These speeds are the adjusted correct speeds. Thanks guys. Quote Link to comment Share on other sites More sharing options...
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