keg1 Posted October 1, 2016 Share Posted October 1, 2016 The reversing valve( I guess that's what you call it) on the intake on mine has two lines coming out of it, one goes to pump, other to firewall to brake release. I also have a fitting something like a petcock which seems like a plug when I took it out. The valve on my parts truck had pipe plugs in every port so what I'm wondering is should I have another line going to the third port to make it work? At $250 for a new one I like to make sure mine is bad. It was unhooked when I got it but it smokes worse than I'd like. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/ Share on other sites More sharing options...
br549 Posted October 1, 2016 Share Posted October 1, 2016 On the top picture the line from the brake release is just blowing air into the manifold, which is wrong and it will not work. It should go into the supply port. If I remember right on trucks with a mack transmission they had a 3rd line coming from the transmission tor put air on the valve to cut the power down when in lo lo gear. Clean the other valve off and see if you can see if the ports are marked or move the line from the brake and move it into one of the end port and try it. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347472 Share on other sites More sharing options...
keg1 Posted October 1, 2016 Author Share Posted October 1, 2016 I'll try switching it. There was a plug in that port and the line was there so I thought that's where it went. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347481 Share on other sites More sharing options...
Popular Post j hancock Posted October 1, 2016 Popular Post Share Posted October 1, 2016 Here is a 691GC218CP5X that came off a 1985 285. The yellow dot is the port for the manifold SIGNAL. The red is OUT to the pump. The lime green is the port at the end for air IN. 4 Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347485 Share on other sites More sharing options...
keg1 Posted October 2, 2016 Author Share Posted October 2, 2016 7 hours ago, j hancock said: Here is a 691GC218CP5X that came off a 1985 285. The yellow dot is the port for the manifold SIGNAL. The red is OUT to the pump. The lime green is the port at the end for air IN. Thanks for the picture. I didn't get a chance to switch the lines today but I'll get it tomorrow and see what happens. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347525 Share on other sites More sharing options...
85snowdog Posted October 2, 2016 Share Posted October 2, 2016 Theres a lot of info on here about puff limiters. The thread that helped me the most is this…... http://www.bigmacktrucks.com/topic/44803-300-puff-limiter/#comment-332974 Swishy posted some shop manual pics in the very last post. They are very helpful. Thanks Swishy !! Another point that may be helpful , is in the pic that Jim posted you can see on the bottom there is a CP5X . You will find a they are all stamped with a number that ends with X. could be a 3X all the way to 9X (i think) The lower the # the less smoke you get. I have a 3X on my 350 and a 5X on my 237 . The relay valve is just part of it though. The rack limiting cylinder (where the line is going to from the relay) has to be set and working properly. The info Swishy posted shows how to test . 1 Quote Keith Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347568 Share on other sites More sharing options...
keg1 Posted October 2, 2016 Author Share Posted October 2, 2016 I think I have it working now. I pulled it off and found someone had soldered the hole shut in the fitting that goes into the manifold and the end of the line going to the pump. So once I fixed that and hooked the line up right seems ok. Thanks for the help. I've never had one hooked up on any of my trucks so wasn't sure how it was supposed to go. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347582 Share on other sites More sharing options...
39 Baby Mack Posted October 2, 2016 Share Posted October 2, 2016 A quick check to see if it's working. Nail the accelerator with the spring brakes applied, exhaust should look like a house afire. Release the brakes and try it again you should see a very noticeable difference!!! Ron Sent from my SM-G900V using Tapatalk 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347621 Share on other sites More sharing options...
keg1 Posted October 3, 2016 Author Share Posted October 3, 2016 40 minutes ago, 39 Baby Mack said: A quick check to see if it's working. Nail the accelerator with the spring brakes applied, exhaust should look like a house afire. Release the brakes and try it again you should see a very noticeable difference!!! Ron Sent from my SM-G900V using Tapatalk That's what I did. Definitely a difference. I don't mind the smoke but every time I started it I was blowing out a shovelful of soot. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347628 Share on other sites More sharing options...
thomastractorsvc Posted October 3, 2016 Share Posted October 3, 2016 I checked mine today. Last week when I would get into it more smoke would roll than normal and towards the end it would get a little gray. I had the mini-me push and pull the parking brake knob and I could not feel it move. I took mine of and shook it and nothing happened so I put air to the inlet side and it blew out the other so I stuck it in the vice and pulled it a part. I figured it wasn't working to begin with so what to heck. It has two buttons on the inside with a spring in between. A plastic lock ring and a diaphragm. I suppose what happens is manifold pressure creates a vacuum and pulls/pushes the valve to allow compressor air in to reduce smoke. I cleaned it up and removed the lock ring and looked under the diaphragm and seen it had some oil so I sprayed it out with some can solvent and air then reassembled it and put on the truck. With mini-me pushing and pulling the brake knob you could feel and here it click open and closed, which it wasn't before. If It starts up again I will check the valve on the pump and probably replace them both. What does the deal on the pump do when it gets air? I was going to take it off but ran out of daylight for what I had on my agenda for the day. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347649 Share on other sites More sharing options...
theakerstwo Posted October 3, 2016 Share Posted October 3, 2016 The deal on the pump is only a air cylinder and with air it limits the rack travel.If you take it off dont lose the shims that is under it. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347655 Share on other sites More sharing options...
thomastractorsvc Posted October 3, 2016 Share Posted October 3, 2016 Is there any way to tell if it is working while it is on the truck? I suppose it could have some oil or dirt in it and resticts movement. How much are they maybe I will just buy one and replace it andvsee v what happens. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347666 Share on other sites More sharing options...
39 Baby Mack Posted October 3, 2016 Share Posted October 3, 2016 Is there any way to tell if it is working while it is on the truck? I suppose it could have some oil or dirt in it and resticts movement. How much are they maybe I will buy one and replace it andvsee v what happens. Sent from my SM-G900V using Tapatalk A quick check to see if it's working. Nail the accelerator with the spring brakes applied, exhaust should look like a house afire. Release the brakes and try it again you should see a very noticeable difference!!! Ron Sent from my SM-G900V using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347667 Share on other sites More sharing options...
keg1 Posted October 3, 2016 Author Share Posted October 3, 2016 7 hours ago, thomastractorsvc said: I checked mine today. Last week when I would get into it more smoke would roll than normal and towards the end it would get a little gray. I had the mini-me push and pull the parking brake knob and I could not feel it move. I took mine of and shook it and nothing happened so I put air to the inlet side and it blew out the other so I stuck it in the vice and pulled it a part. I figured it wasn't working to begin with so what to heck. It has two buttons on the inside with a spring in between. A plastic lock ring and a diaphragm. I suppose what happens is manifold pressure creates a vacuum and pulls/pushes the valve to allow compressor air in to reduce smoke. I cleaned it up and removed the lock ring and looked under the diaphragm and seen it had some oil so I sprayed it out with some can solvent and air then reassembled it and put on the truck. With mini-me pushing and pulling the brake knob you could feel and here it click open and closed, which it wasn't before. If It starts up again I will check the valve on the pump and probably replace them both. What does the deal on the pump do when it gets air? I was going to take it off but ran out of daylight for what I had on my agenda for the day. Yours looks a little different than mine. The way mine is made you can't take it apart. Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347673 Share on other sites More sharing options...
theakerstwo Posted October 3, 2016 Share Posted October 3, 2016 That would be the later one made. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347674 Share on other sites More sharing options...
dek1581 Posted October 3, 2016 Share Posted October 3, 2016 hey 39 baby mack could you tell this new guy why the difference with spring brake on/off? Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347685 Share on other sites More sharing options...
39 Baby Mack Posted October 3, 2016 Share Posted October 3, 2016 hey 39 baby mack could you tell this new guy why the difference with spring brake on/off? The first emission system I saw was a steel line that went from the turbo down to the governor. It wouldn't allow the rack in the pump to open fully until there was sufficient boost to burn the fuel.(eliminating the initial heavy black smoke that the early Maxidynes were known for after an upshift in low RPMs)It eliminated the "puff"! This was fine except for trying to start one of these Maxidyne engines in cold weather. To get these started you needed to hold the accelerator to the floor to have the rack open fully. You couldn't get the rack to open fully with that set up. With the reversing relay the puff limiter didn't work until the spring brakes were released and the truck was ready to go down the road. This allowed for a full rack in the pump to get the engine started when it was cold but set the puff limiter in operation once the truck was put in operation Ron Sent from my SM-G900V using Tapatalk 2 Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347689 Share on other sites More sharing options...
theakerstwo Posted October 3, 2016 Share Posted October 3, 2016 I had forgot about line going to the governor.I have a freind that still has one. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347713 Share on other sites More sharing options...
keg1 Posted October 4, 2016 Author Share Posted October 4, 2016 Ran today and everything worked like it should. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347734 Share on other sites More sharing options...
39 Baby Mack Posted October 4, 2016 Share Posted October 4, 2016 I had forgot about line going to the governor.I have a freind that still has one. Glenn, Do you remember the first reversing relay, the one that was remotely mounted towards the front of the motor. If memory serves me it was mounted off the thermostat housing. It was made by Fairchild. How many complaints about an air leak did you hear about when somebody would shut one off in gear without setting the spring brakes? Couldn't take your time adjusting the brakes with the truck shut off and in gear or the bleed on the reversing relay would pop the brakes back on! Ron Sent from my SM-G900V using Tapatalk Quote Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347805 Share on other sites More sharing options...
theakerstwo Posted October 4, 2016 Share Posted October 4, 2016 Yes and it could be taken apart for repairs.However i have never been in one.They were also adjustable. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-347843 Share on other sites More sharing options...
thomastractorsvc Posted October 7, 2016 Share Posted October 7, 2016 Stopped by the Mack dealer and got some info, my truck has the AMBAC 300 pump. Part# cyl Assy 31Qc212 (mounted on front of pump) $79.62 PAI#EAC-3964 Part# Relay Assy 691GC218CX (mounted on manifold) $234.25 PAI# EVA-2775-001 There are a lot of shims available to shim up the air cylinder on the pump so part # 505GC19P15 will get you there. $3.96 PAI# ESH-3849-010 (.010 inch thick) Not sure on the PAI prices as I have not heard back from the parts guru. Quote Robert"I reject your reality and substitute my own." Link to comment https://www.bigmacktrucks.com/topic/47110-puff-limiter/#findComment-348084 Share on other sites More sharing options...
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