[9000CSE]

Hello everybody,
Got a slight prob with my 1996 cse at the moment - when I floor the accelerator the car pulls fine
up to about 3700 rpm, then it drops back to about 3500 rpm for a couple of seconds before it sorts itself out and carries on accelerating. The engine is not running rough and it always pulls smoothly. My first thought was the DI unit ( which is the original at 175k miles )but I'm not really that sure.
Any comments much appreciated. Thanks !

 

[StephenA]

It does sound like a DI problem which usually shows up round those sort of revs under load. If you can borrow a good one then thats an easy way to confirm it.

If it really is the original at 175K then its pretty good going.

Steve

 

[Lenn111]

I don't think it's the DI. If it works fine at 3700 rpm after slow acceleration, it would indicate its capable delivering the spark at that speed.

I think the significant issue is the "when I floor the accelerator" - that would indicate a sudden loss or change of vacuum. I would check all vacuum hoses to and from the manifold and the hose to the MAP sensor (on the firewall. Also check that the throttle body is tight and secure with no leaks.

The other and unlikely explanation would be; insufficient fuel pressure (by faulty fuel pressure regulator) not delivering enough fuel for the sudden increased demand, but slowly building up the pressure.

The vacuum leaks are very common on the 9000 due to aging and cracking rubber hoses.