M35A3 Idle adjustment

[RIDDLE1]

Anyone on here know how to adjust the idle on the 3116? Mine truck runs great but it idles pretty rough. I talked to a diesel mechanic and he told me to adjust the idle on the pump. That makes since but I have no idea were this screw might be located.

Does yours idle rough?

 

[goodguyzy]

I have one that idles rough because the rpm are to low, my temp fix is to pull out the throttle handle a bit. I was assuming it was an adjustment on the foot petal cable. Will stay posted

 

[RIDDLE1]

I have one that idles rough because the rpm are to low, my temp fix is to pull out the throttle handle a bit. I was assuming it was an adjustment on the foot petal cable. Will stay posted

There is an adjustment screw on the IP from what I understand. we shall see.

 

[goodguyzy]

so many little projects

 

[WillWagner]

MOST electronic engines have a low idle set point parameter that is only adjustabe through the ECM. Some have an externak switch that lets you change the idle RPM by 25 RPM increments/decrements each time the switch is toggled. It will be a three position, center neutral type switch located on the dash or under it. If there is a diagnostic switch, a switch that when the engine is stopped and the switch is toggled up or down, that can also be a low idle adjustment switch. If there is a cruise switch, the set/res is also an idle adjustment switch.

I know nada 'bout the A3.

 

[Rustygears]

Nothing on the A3 engine is electronic -thankfully!

 

[patracy]

There's a return orifice off the injectors and a pressure valve as well. That plays a role in low idle speed. Or there's possibly an injector imbalance. The cheapest thing to try first would be new fuel filters and a healthy dose of power service diesel kleen in the sliver bottle. See if that helps restore idle. If not, there's something mechanical. Remember, these engines have spent most of their life sitting with fuel in them that's about as old!

 

[WillWagner]

I thought it was!

 

[Rustygears]

Nope. All mechanical injection system that is classic Cat. I think that there are 3116 variants that have electronic fuel control, but they are not used for the A3 application.

 

[mktopside]

I don't think adjusting the idle is going to do anything besides burn more gas, and the hand throttle works fine for that. Everyone's A3 seems to idle the same....rough, so I wouldn't put too much effort into changing that.

However, my idle did slightly improve when I switched to DexIII in the trans. YMMV

 

[CobraCDR]

If you find the cure, let us know, seems to be a common problem.

 

[autigers35a3]

What does the ECM do on the A3 control?

 

[Rustygears]

Uh, what ECM? There is none. There is a mechanical high pressure fuel pump, that's all. The injector timing and metering on the CAT 3116 engine for the A3 is all mechanical and under the valve cover. There is no traditional Bosch or roosamaster metered pump like on the A2 or CUCV and definitely no ECM on the A3. The only thing in an A3 with a chip is the CTIS control head used to fill the tires (when it works) with air. That's it. This makes the engine EMP-proof. Same goes for the auto- tranny control. It's all mechanical too.

 

[CobraCDR]

EMP proof!! One of the advantages of being the only one running down the road when everyone else is dead in the water! Bring it on 2012! (We'll live without CTIS.)

 

[RIDDLE1]

Well I was going to start working on the idle adjustment today but it is raining. I will post when I get a chance to work on it.

 

[Rustygears]

Don't the zombies come out after the EMP renders everything unusable? That's why I bought my A3. The CTIS just pimps up the cab so I can get the chicks in my ride! It doesn't need to actually work.

 

[ApopkaFL]

My truck idles fine. Not sure what you guys are talking about as too the ruff idle.

 

[glcaines]

My truck idles fine. Not sure what you guys are talking about as too the ruff idle.

My A3 has a very low idle speed, but it idles smooth as silk. When I want a faster idle speed, I simply pull out the throttle a little. There is no reason a 3116 engine should idle rough, unless something is wrong. I would check filters, fuel and try cleaning the injectors with Diesel Kleen or something similar.

 

[1 Patriot-of-many]

EMP proof!! One of the advantages of being the only one running down the road when everyone else is dead in the water! Bring it on 2012! (We'll live without CTIS.)

YEEHAW. We're going to be in demand! So much demand we better have our ammo supply ready.

 

[1 Patriot-of-many]

My truck idles fine. Not sure what you guys are talking about as too the ruff idle.

Mine too. Don't know what they mean by rough idle. Like about to stall?