Perkins AD3 152 missing at idle

[Bernard W.]

Have a Perkins AD3 152 in a 135 Massey that misses when idling. Seems to be worse after engine runs for a few minutes. Replaced injectors and injection pump which made no difference. Valve lash is correct and timing gears are not worn or sloppy. Adjusting timing on pump does not stop miss. Compression is good and when accelerating or under load it runs like a top.
What else could be wrong? Could a weak lift pump cause this?

Thanks for any advice or suggestions.

 

[Dieseltech]

What is the compression pressure? It still could be the injection pump too, if the incorrect blade rotor is in the vane pump. That part is phase sensitive, I do see that on pumps in for repair..

 

[ptfarmer]

My 135 with the AD3.152 misses at idle (makes the tractor shake a little bit at normal idle speed which concerns me a little), number one injector had a little oil on it when I swapped out the injectors. When I rev mine up if puffs out a little blue smoke, it has good oil pressure, other than that it runs fine above idle, and runs good under a load.

 

[Bernard W.]

Compression was between 385- 395 psi on my diesel compression gauge. Tractor starts excellent even when cold 15-20 degree F. Original injection pump acted the same way but it needed rebuilding due to leaks so I purchased a new injection pump from All State Ag Parts. Absolutely no change in idle quality or power. When first started for a minute or so the tractor idles smoothly then it starts to miss. Does not miss when accelerating or under any load. It has good power. After replacing injection pump I then decided to replace injectors. These are new injectors that are not rebuilt. It had absolutely no effect on idle quality. I then removed valve cover and timing gear cover to set valve lash and check timing gear play. All are within spec of the service manual. Tank has been removed, drained and cleaned. New fuel filters and flow to lift pump is good. Service manual states that lift pump should deliver 6-10psi at inlet to secondary filter. I have not checked this but don't know what else to do. I was thinking maybe the diaphragm is a little weak and at idle it would not hold enough pressure? Also what happens if the return line from the injectors were to get clogged or restricted? I haven't checked it yet to make sure it is flowing correctly. I am stumped.e]

 

[Phil Tibbetts]

Maybe it is just the nature of the 3 cylinder engine. M 205 seems to be running a little rough at idle too. I blame it onto the 3 cylinder not running as smooth as a 4 cylinder. My engine has been completely rebuilt and it still is the same as it has always been.

 

[ptfarmer]

The AD3.152 has a balancer inside the engine that keeps it from shaking, my brothers 150 has the same engine, and it idles super smooth.

 

[ptfarmer]

Balancer weight that bolts to the crankshaft.