My 4.9 seems to be picky about when it wants to start. I'll turn the key and have full power and lights, can hear the fuel pump run but have absolutely nothing from the ignition. I'll throw my battery charger on it and turn the key and it starts without an issue, doesn't even chug like a low battery. I'll drive some where and it may or may not start if I've shut it off. I had the battery checked out about a month ago and it passed all the tests. I'm at a loss as to what it could be, as the only thing I can think of is the Ignition module. Any ideas would be helpful!! I may change the module next week and see what happens.

it's a 91 Eldorado 4.9 with a 93 Deville 4t6oe automatic.

Thanks again!!

Dan

You might want to clean up the terminal on your battery. Remove, clean, grease w/petroleum jelly.

It's essentially a 1 year old battery with brand new terminals. Although I haven't done the petroleum jelly thing.

Dan

The ignition itself could be bad or your neutral safety switch could be acting up

By iginiton are you meaning the starter? I did try shifting from Park to Neutral several times with no change in conditon. It did do this last year and if I would jiggle (twist) the + cable on the battery it would usually fix the issue and pop right off.

Dan

[This message has been edited by DanFiero (edited 05-09-2008).]

From what you've posted, it looks batter connection related.

Make sure your connections between the wire and terminal are good (nothing half assed!), clean and grease between terminal and battery post (both pos & neg).

Are you saying it won't crank over----or that it cranks over ok but will not start (no fire and/or fuel injection)?

I doubt it is the ign module, unless your 4.9 swap bypassed the ecm as the primary controller for the fuel pump.
The fact that the battery charger 'cures' the problem, means you have an available voltage problem.
Look closely at the cables where the conductor itself enters the terminals-both at the battery and at the starter. High resistance connections are the same thing as placing a big resistor in line between battery and starter. Current goes up--voltage goes down. The problem could also be in the starter solenoid. Coil may not be holding the contacts tightly enough at the voltage you have available.
A high resistance connection can 'rob' voltage from things like the ecm and you take a chance of damaging things like the ecm, fuel pump, alternator.

It won't even try to turn over, but once I attach the charger it turns over like there was never a problem. I'm going to get underneath it and check all the wire connections to the starter and everywhere else I can reach. It is a fairly new swap so it may be teh connections vibrated loose or something. Unfortuanntely it'll be Monday before I can even look at it.

Thanks for all the replies!! + for all of ya!

Dan

Yeah!!! 2000th post

[This message has been edited by DanFiero (edited 05-09-2008).]

quote Originally posted by DanFiero: if I would jiggle (twist) the + cable on the battery it would usually fix the issue and pop right off. Dan

Tried replacing the cables?