I have a '87 240 automatic transmission sedan with LH2.2 Jetronic fuel injection and a 1990, 5 speed manual wagon with LH2.4 fuel injection. The sedan needs a little premium gas mixed in with the regular in order to avoid pinging. The wagon never pings. I believe, that the heads are the same and that both engines have the same compression ratio.

Is that correct or is there some reason that one pings and the other doensn't. Could it be because of the difference in fuel injection? I wouldn't normally think this but, since I own both and see differneces it makes me wonder.

What would be involved with changing from Bosch LH2.2 to 2.4. I know that the ignition module will be eliminated. I am thinking that it would be a change in the engine control module and the complete engine wiring harness. I think the mass air meter, and idle speed controller would work.

Anyone know what else may be involved?

 

Can't help you with the swap, but my '85 has the LH2.2 and I'm running 87 octane (regular unleaded), no pinging.

 

yeah, our 87 240 has never needed premium. the timing is adjustable on those, by rotating the distributor.

 

Thanks guys, that does help. At least I know that the problem is confined to my car. The timing is spot on. But, that does get me thinking that perhaps the timing mark may be off? The vibration dampener has been changed to an aftermarket one. You would think that they could at least get this right. It could be from carbon build up. I don't have a borescope to look inside the combustion chamber. That would be a good way to check. Italian tune up?? We'll see.