I have a 1987 240 (LH 2.2) manual that when pressed hard under acceleration experiences a violent pulsing, this is particularly obvious in first and second gear. Driven gently, it seems to drive fine. The idle behaviour is perfect, and will rev freely to redline when stationary.
I have replaced the in-tank pump, the fuel filter and the main fuel pump. I also swapped the fuel pressure regulator with one from another car that was working well. I have also replaced all the plugs and checked the leads, all appear to be good. No relief from the problem. The clutch is solid with no slipping at all.
I use this car in autocrosses and rallying, and would like to sort this problem out soon.
I have a spare ECU and ignition control module, and am considering swapping these to see if they will help. This problem has me beaten at present, and I would appreciate any advice.

Cheers,
Richard.
Distributor cap and rotor OK? Coil OK? Distributor OK? Does sound like fuel system has been thoroughly gone though so ignition would be my guess. Also check anything that could be related to engine rocking under load - loose wires, perished harness, bad grounds? Interesting issue.
Replace engine wiring harness to rule out wiring shorting
Thanks carnut222 and ramrod,

I have checked out the distributor/cap/rotor, replaced cap as it looked a bit tired, however problem still apparent. Rotor etc checks out OK.

Looked further and found some bio-degradable wiring (exposed sections of wires running parallel to each other on the intake side tucked up near the block....... Clearly that is not going to help. Will replace / repair this weekend and will keep you posted.

Thank you for your advice, very much appreciated.

Cheers,

Richard.
7 days later
Ah well, the fun continues....

I have removed and repaired the wiring loom, no improvement, I swapped out the ECU, no luck, swapped out the ignition control unit, no joy there either! Starting to feel a little defeated, luckily my home workshop now has a car hoist installed, so taking my mind off the annoying fault in the 240......

I will swap out a few other parts in the EFI system this weekend, and hope that the problem is resolved. Will also take a careful look at the distributor as well....
Coil? AMM? Other shorts in wiring that you can't see?

Does it do this hot and cold?
Hi Ramrod,

It happens both hot and cold. Coil is OK (have substituted two coils, without success).

AMM sounds like a possible, will see if I have a spare one in my pile of stuff. Will also swap out the idle air valve (a bit of a long shot I suspect..).

Thanks for your assistance.

Cheers.
Does it do it at less than full throttle?
One more thing to check although you'd think it would affect idle etc - is the plastic hose between the AMM and the inlet manifold OK (i.e. not worn through on some of the corrugations where they usually contact the strut tower). Also is the air filter box, air filter, and warm air intake system all OK (if you haven't already deleted the warm air intake system and plugged it off like I do! :) Things to check but unlikely to cause such a big issue...unless air filter is completely blocked or something!
My LH2.2 turbo 240 did a similar thing when a hose clamp came loose on the intake manifold. The AMM was losing its mind trying to figure out where the air was going. Only did it under load.
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