Puff Limiter

[AussieE9SuperLINER]

Gday!

My E9 500 has an air leak from a small port on the side of the puff limiter actuator on the AMBAC V8 fuel pump. While almost perfect wife was placing an order to buy a replacement part (PN BI31QC212) the parts guy suggested this leak may be caused by some other air system failure elsewhere. I've been unable to source any info on the schematic for this air system or alternate reasons for this component's behaviour. It was replaced approx 9 mnths ago for a similar problem. Any ideas?

[Andy Wright]

Hi mate

I can't help you but Timothy Maikshilo on here runs a Superliner with an E9 from memory. He might be able to help but the rest of the guys on here will know what's going on.

Cheers

Andy

[roadusercharges]

Gday!

My E9 500 has an air leak from a small port on the side of the puff limiter actuator on the AMBAC V8 fuel pump. While almost perfect wife was placing an order to buy a replacement part (PN BI31QC212) the parts guy suggested this leak may be caused by some other air system failure elsewhere. I've been unable to source any info on the schematic for this air system or alternate reasons for this component's behaviour. It was replaced approx 9 mnths ago for a similar problem. Any ideas?

its the sort of thing . that you dont play with unless you have all your marbles, if you know what I mean, where did you take it to last time you had a problem?. Have you got that new low sulphur diesel that us kiwis have to endure now?, if so , your injestor pump may be bypassing on the seals.

Nigel

[fullfuel01]

sure of my statement for an E-6, so must be the same thing for an E9. the puff limiter receive 100 psi of air when you remove parking brake (this is why it's written park brake must be applied before starting on your sunvisor) the puff limiter must be fixed onto your intake. there is a line that goes in the front of the fuel pump with a little cylinder. this cylinder control your rack. when it recevie 100 psi from your brake, there with the help of the puff limiter maybe 28-32 psi of pressure reusse to push in the cylinder to put your rack at the minimum. when your truck pulls, boost goes up so it reduce the pressure from the brake line to rou cylinder, like if you have 10 psi of bost, maybe 18-22 psi reach the cylinder allowing your rack to give more fuel... at 28-psi of boost, nada reach the cylinder... we had lot's of problem with these puff limiter and now all the ambac and remack loose some air cause they told us that if they don't they breack.... to me it soud stupid but it's the answer from mack. if you notice it leack only when you remove parking brake right? maybe i'm wrong because this system is on an E6..

[AussieE9SuperLINER]

Thanks for the info guys.

Your feedback raises a couple more queries.

Firstly, my starter works whether the park brake is applied or off. Maybe it's been tampered with and modified to allow this to be the case. Even so, I prefer it this way because I've had (for one reason or another) an engine stall while in a potentially dangerous situation (e.g. halfway through an intersection or crossing a train line) and need to restart without having to come to complete stop.

Secondly, the air is actually leaking out of two small holes opposite each other on the barrel of the small cylinder which goes into the front of the injector pump. This air is also still escaping with the parking brake applied.

Methinks I need to get my hands on schematic diagrams of the air systems. Anyone know a site where they may be viewed?

This cylinder was replaced last time under professional guidance with attention being paid to the shims between the cylinder and the pump etc. Care was taken not to alter the positioning and travel of the cylinder as its piston when actuated has to be precisely correct.

Thanks again,

Tony M

[theakerstwo]

Thanks for the info guys.

Your feedback raises a couple more queries.

Firstly, my starter works whether the park brake is applied or off. Maybe it's been tampered with and modified to allow this to be the case. Even so, I prefer it this way because I've had (for one reason or another) an engine stall while in a potentially dangerous situation (e.g. halfway through an intersection or crossing a train line) and need to restart without having to come to complete stop.

Secondly, the air is actually leaking out of two small holes opposite each other on the barrel of the small cylinder which goes into the front of the injector pump. This air is also still escaping with the parking brake applied.

Methinks I need to get my hands on schematic diagrams of the air systems. Anyone know a site where they may be viewed?

This cylinder was replaced last time under professional guidance with attention being paid to the shims between the cylinder and the pump etc. Care was taken not to alter the positioning and travel of the cylinder as its piston when actuated has to be precisely correct.

Thanks again,

Tony M

You did not understand about the starting part he was talking about air pressure is being supplied to the reverseing relay valve that is on the intake manifold. air is supplied to it only when the park brakes are released so it will not limit the rack travel to full rack when the park brakes are set. You may need to see if you have any water or oil in you air tanks. oil will destroy the seal in any vale or air cylinder and water will cause rust.If it was not pumbed right you would have low power problem because it may not get full rack hope this will help. glenn akers

Thanks for the info guys.

Your feedback raises a couple more queries.

Firstly, my starter works whether the park brake is applied or off. Maybe it's been tampered with and modified to allow this to be the case. Even so, I prefer it this way because I've had (for one reason or another) an engine stall while in a potentially dangerous situation (e.g. halfway through an intersection or crossing a train line) and need to restart without having to come to complete stop.

Secondly, the air is actually leaking out of two small holes opposite each other on the barrel of the small cylinder which goes into the front of the injector pump. This air is also still escaping with the parking brake applied.

Methinks I need to get my hands on schematic diagrams of the air systems. Anyone know a site where they may be viewed?

This cylinder was replaced last time under professional guidance with attention being paid to the shims between the cylinder and the pump etc. Care was taken not to alter the positioning and travel of the cylinder as its piston when actuated has to be precisely correct.

Thanks again,

Tony M

And I failed to tell you but with the parking brake set and pump is in full rack on a cold day the engine will start better. glenn akers

[AussieE9SuperLINER]

Thanks all for the info.

Problem is cured. Fitted new piston valve on front of pump. No more leaks and holds air overnight again.