1 hdt rough running

[Imakora]

Hi All,

I've just rebuilt the engine on my 80 Series 4.2 TD 12 valve. The engine has been re-bored, and now has new pistons, rings, main and big end bearings. All new seals, cam shaft bearing, recon injectors, rebuilt fuel pump, new valve stem oil seals, a new thermostat, and I replaced all the sender units while I was at it. Once primed, the engine started with good oil pressure, and idles smoothly. However, as the rpm is increased, the engine starts to shake. This is most pronounced at 2500 rpm. As far as I can see, there are no leaks on any of the injection pipes or return lines. The valve shims are all "middle of the road", and all the cylinders are compressing well with virtually identical compression. I’ve tried cracking all the injection lines one by one, and all exacerbate the problem except for number five. With this line loose, the lumpiness disappears. I swapped no 2 and no 5 injectors around but this made no difference. Strangely, both injectors had a heavy carbon build up after slightly less than 500 miles. The timing is spot on. My next step is to try and measure the fuel flow to each cylinder, and perhaps that'll point me in the right direction? Any thoughts on how to solve the problem would be greatly appreciated.

Regards,

Ian.

[lshobie]

Check the injection pump, sounds like something isn't right with it.

[roscoFJ73]

Hi Ian and welcome to mud

I would start with cheap easy things.
Has the timing belt jumped a tooth?
Harmonic balancer not on properly or damaged?
Does the engine shake in neutral at 2500 or only on the highway?
Any smoke ,colour?

Maybe an injector or 2 isnt opening properly at higher rpms


You will have put some money into that I did a similar engine and pump rebuild a few years back and it tested my wallet

[lshobie]

Good points mate.

[Tapage]

When you was loosing the injector lines .. how was the spray pathern .?

Other thing to check .. opening pressure values ..

New Nozzle 2062-2205 PSI
Used Nozzle 1920-2205 PSI ..