Way Outta Control
Join Date: Sep 1999
Location: The Palouse
Thanked 3 Times in 3 Posts
Re: OT - My Daughters Car Troubles :(
Jeff, don't discount there could be more than one problem contributing the overall "it ain't running" result. But try first to work on one at a time. I've seen MAP sensors foul up the EFI to the point the ECM is brain dead. It's a place to start. If the engine uses a two step process for setting the EFI, open and closed loop then in open loop the MAP and O2 sensor should be out of the loop. This condition is only when the engine's cold, like when you're trying to start it.
Does the engine cough or sputter? Is there spark? Are the plugs wet, fuel fouled?
More often a bad MAP can cause hard starting, stalling, and missing. In later model EFI even uses the MAP to help decide when to up and down shift the transmission as it is a fairly reliable indicator of manifold vacuum. This may be being used in Open Loop if the EFI's new enough.
As to the O2 sensor... heck you unhook it and the car should still start and run but like you said.. run rich. It's not a bad idea to take the O2 sensor out every now and then and wire brush the housing to free the vents. They can become clogged and then they're not able to sense the mixture and it drives the ECM nuts by sending it a false reading.
At this point I'm not thinking the 02 senosr is involved.
Drop back to basics... we need more input, again:
Do you have:
And you're right:
College + Kids = NO money. I've had kids in college the last 10 years and now you all know why my Jeep's the ugliest thing on 4 wheels... I think it still has four wheels... it's been a long time....[img]images/icons/frown.gif[/img]