Loss of power after injectors adjusted and overhead run

You shouldn't have lost power. I would assume they adjusted the overhead incorrectly.

 

Possible incorrect valve adjustment
possible ecm reflash with a lower power program or a low nox tune
Possible something is ####ed up separately, loose air piping clamp/ hows your egts compared to before?

 

Part of the overhead is setting injector height. There’s a few different height settings for different injectors. They may have them set wrong. Not sure if that affects power much. Main thing is they’re all set the same. Find out if they changed any perimeters in the ecm. Maybe the injector calibrations were originally all set at 75. That’s a common practice. Being a glider, I wouldn’t be surprised if they were originally set at 75. Supposed to increase pulling power. That’s up for debate. It definitely gives more throttle response at takeoff and lower RPMs. Sometimes causes a rough idle. Each injector has a 2 digit calibration or “trim” code stamped on them. They may have set them to the correct specs in the ecm. When the valve covers off, make a note of the injector part # and calibration code stamped on each injector solenoid for future reference.

 

Detroit uses the overlap method.

The height tool has a point that goes in a hole in injector you want the tool to just wipe off any oil film across the plunger top of injector.


My thoughts are since it started with the overhead adjustment, and it runs smooth look for loose boost clamps etc that they may have removed to get valve cover off. It’s possible the wrong height tool was used by mistake if the injectors are not what the engine serial number calls for. I’m not real sharp on 60 series upgrades. Wrong injector height could be bad if they are tighter as the will bottom the plunger out in the bottom of the injector and possibly crack the tip. Valves and injector settings can be off but consistent and it will run smooth usually.

I would lean more toward something was forgotten or lightly damaged due to age more so than over head set wrong etc. doesn’t take much of a leak to make a big impact on how one pulls and fuel mileage.

The trim codes balance the injectors. Each solenoid has a different resistance, the trim code is the calibration for that. Makes sure that when the ECM strobes each solenoid it picks the little spool that lets fuel in the injector body the same amount and time. Setting the codes to default will make some cylinders hit harder than others is why you get the rough idle, as well as increased power. I’ve never been a fan of using default codes and having cylinders not in balance for lack of a better term. However many get along real well with it and don’t seem to have any trouble.

 

I would call the shop and ask whom ran the overhead. Also would send them an email explaining all that is going on right away if you have a relationship with the shop manager. He could give you some information after he looked up your account that might explain it.

Also do you have any boost leak? Could be something popped lose while they worked on the engine by just messing around in the engine bay.

 

Im mostly with everyone else here, just take it back and explain its just not the same as it had been, youve worked with em for years, paid promptly, they shouldnt have an issue taking care of you.

BUT also, what else was done? Anything? New tall rubber tires from down to minimal tread? Thatll make it faster at the same rpm but feel more sluggish. Just trying to eliminate any other possibilities (as others were mentioning boots)

 

What’s the scoop buddy?