'85 300TD with weak power

[tomas_maly]

I have a neglected 300TD that seems to have some power issues. I replaced fuel filters, fuel injector tips, did a valve adjustment (it was pretty awful), and also adjusted the spring below the body that adds resistance to the accelerator pedal (not sure if that makes a difference).

It seems that maybe it's just not getting full throttle. I have a 300SD to compare it to, and the pedals work very differently - I have to press my 300TD's pedal down half way before ANY acceleration happens. I'm not sure if there's something with the throttle that can make my accelerator pedal more 'sensitive'? That's probably my first thing to adjust - it just really seems to never reach max power (like the turbo never engages) except some very rare cases. Maybe something is wrong with engaging the turbo? I'm not sure how that works, how/when that's engaged, if it's a throttle lever issue, or something else. I've been told that when you put the pedal to the floor, the turbo should always engage (it rarely does).


I'm thinking of getting a compression testing kit, to see if maybe it's something internal to the engine. There's one online for $60, with a manual - does that seem like a good idea to have in general? Or maybe just renting one from a local auto parts shop if they lend it out. I'm just not sure if it's worth bothering with if I can't do much in terms of fixing internal issues without an expensive/time-consuming overhaul. Maybe at least it'll give me peace of mind that it's NOT (or IS) a compression issue.

I'm also wondering if maybe I didn't install the fuel injectors back correctly. Is there a trick to ensure they are tight enough? I only have standard ratchets, should I get a ratchet that also measures torque and have the injectors fit to a certain torque? I don't think it's on as tight as it was before (probably was at factory setting), but I didn't want to force it too much and end up breaking/cracking something. I've read that doing it too hard can damage the injector casing.

Finally, is there a trick with the fuel return lines (the rubber ones with the fabric exterior) to make then not leak fuel? I got brand new lines and for some reason, one piece keeps on leaking - it doesn't look cracked, maybe there's some trick to how to cut/fit it. I'm just wondering if there's maybe some sort of air leak that's causing air to get into the intake that might be decreasing overall pressure.

Thanks!