Buick Century...won't fire up.

[Jack Flash]

96 Buick Century, 2.2 4 cyl.....will on occasion crank & run fine. when all is ok, everything checks out fine (pump pressure, injecters noid, etc.)

then...cranks over fine, all checks okay except injecters don't noid. we've swapped everything that I can think of from another cranking & running car. nothing seems to change this.

is there anything in a factory security system that could be causing this ?

this car has been to more than one shop & nobody seems to know what is wrong.

I'm wide open for any information or suggestions.

,
,

J...lost & sinking fast.

 

[BrooklynBay]

Do you see a check engine light when the computer isn't supplying power to the injectors?

 

[Jack Flash]

no check engine light, no trouble codes at all...injecters won't noid when this problem of no start occurs.

when it does crank up, better get all the driving done before shutting it off, 'cause it might not crank up again for a few days.

I believe it has something to do with a factory security system. GM has these two wires that run down inside the steering column to a relay. if one of the wires breaks, the car won't crank & run. we've checked for the broken wire.

J...still stumped

 

[BrooklynBay]

The check engine light will illuminate when the key is turned to start the electrical system. The computer is not getting power if it doesn't show a check engine light when you turn the key.

 

[Jack Flash]

check engine light comes on when key is turned on. everything works except the injectors when this anomaly rears it's ugly head.
,
,

J...not saying much, but the GM dealer couldn't find the problem...lol

 

[BrooklynBay]

Maybe there is a bad connection on the computer's circuit board such as a bad solder joint or foil trace?

 

[TedJ]

If this has the PATS system (or whatever that acronym is) where there is a little black "pellet" with contacts on each side embeded in the key, then that can cause some issues.

The pellet is just a good ol' resistor. The computer (may be a seperate modue or integrated) checks that resistance and will not give you injector pulse if it is wrong.

So basically, if there is goo on the key contacts, in the lock, or the wiring in the column is messed up, it's not going to start. Say like when you just ate BBQ and then grab for they keys in your pocket. Typically once the wrong value is given, the computer will prevent the car from starting for 10 min or so. This is to prevent a thief from just trying all of the resistor values (i want to say there are 7).

You can trace the wires / find them on the wiring diagram and connect a multimeter set to resistance there. Then put they key in and wiggle everything around. Compare the value with that measured from they key directly.

 

[Jack Flash]

thanks TedJ...I'll try that in the morning.

,
,

J...a shop can't make any money on jobs like this...lol.

 

[TedJ]

How'd it go?

 

[Jack Flash]

Back again...

The reason it's taken so long: it's a used car dealer's vehicle. He has been slow to pay, so the shop has been slow to work.

anyway. problem solved...one of the 3 wires coming up the column was/is grounded. cut the wire(s) and the thing cranks right up and stays running.

the olny weird thing now is the security light stays on, but, what the hey !

.
.

J...wonders what purpose security is to a $900 car...lol

 

[TedJ]

Heh... at least it runs now. It'd be a better car if it had the V6.. but with the 2.2 it is pretty much a theft deterrent in and of itself.