"Doesn't start" is a pretty generic statement that doesn't mean much. Also, "kept stalling" implies it was running, so "would not start" doesn't agree. Which is correct? Does the engine crank and fast enough to start? Do you hear just one loud clunk from the starter but it doesn't spin the engine? Do the dash lights act normally in all ignition switch positions? Did the engine stall previously or was it running fine until you turned it off? Was the battery recently disconnected? Is there anything you can do to keep it running?
There could be anything from a broken cam on the end of the ignition switch cylinder to worn solenoid contacts to a cracked flex plate. If the engine cranks fine but doesn't fire, you MUST check for both fuel pressure AND spark. Troubleshooting the first one you find missing can lead to a whole bunch of wasted time. There's three systems; the spark, the fuel, and the trigger circuit that tells the engine computer when to operate the first two.
Replacing the computer on a guess has also introduced more issues. There are no long term fuel trim values in memory, and until it learns minimum throttle, it won't idle on its own. It will stall every time you take your foot off the gas pedal.
If it starts and runs for two seconds, then stalls every time, it is in anti-theft mode. If your van doesn't have anti-theft built in from the factory, you MUST install a used engine computer without that programming. You can't tell from the part number. If a used computer has that programming, it will teach it to the body computer. When you finally put in an engine computer without anti-theft, the body computer will then upgrade the engine computer. They can go back and forth upgrading the programming in each other, and there is no way to undo it. Both computers must then be replaced at the same time before the ignition switch is turned on. The only way to be sure of getting two non-upgraded computers is to find both from the same donor vehicle, or buy two new ones from the dealer at the same time. A glitch or voltage spike can cause the engine computer to self-program itself to anti-theft status. It's rare, but I've been involved with three vehicles that did that. This is not an issue if your van has the factory anti-theft system built in. Any engine or body computer will work but then must not be installed in a different vehicle without anti-theft.
Friday, August 28th, 2009 AT 4:40 PM