1996 5.7 timing light jumps around

[dead boat]

I have a 5.7, 1996 thunderbolt V ignition, timed it with the purple w/white tracer to ground. after I removed the jumper from ground the timing light jumps around. Is this normal? The engine runs good in the drive way but knocks under load at 3000 rpms.

 

[rbh]

Re: 1996 5.7 timing light jumps around

last time I had that problem timing chain was streched.
rob

 

[bruceb58]

Re: 1996 5.7 timing light jumps around

If it doesn't jump around while you set base timing then it can't be the timing chain.

What are you setting the base timing to?

 

[Maclin]

Re: 1996 5.7 timing light jumps around

If the timing light is steady in base timing mode then "Not normal" would be my first blush assessment of what happens when you remove the jumper wire.

First, be sure you are following the procedure exactly, meaning is removing the jumper wire while running ok, that kind of thing.

The Tbolt V has some sensors and modules that work together to advance or retard the timing based on rpm and conditions. For example, it has a spark knock module that allows the spark to advance more up until knock is detected. If a module like that is faulty then the TBolt V computer could get confused. I'm not saying that is the problem, I'm just sayin' that in my opinion something needs attention and you should test each ignition component per the manual if possible.

 

[Don S]

Re: 1996 5.7 timing light jumps around

Have you tested the knock module and knock sensor? If not, have a look at manual 17, page 4B-21.

 

[dead boat]

Re: 1996 5.7 timing light jumps around

10 degrees btdc

 

[dead boat]

Re: 1996 5.7 timing light jumps around

the knock module is not there.

 

[Don S]

Re: 1996 5.7 timing light jumps around

See your new post about the knock module.