Making headway...have spark problem

[95silvergt5.0]

I have what I believe to be an ignition (spark) problem. When the car sits for a a couple of hours, I will not get any spark when I hook a spark plug up to the coil. However if I put it on 200 amp jump start, it seems to wake it up and I start getting a ballsy blue spark again. At that point it starts and runs great. After it sits it does the same thing again.

So far I have replaced the following parts (which haven't changed the symptoms):

Fuel pump and filter (At first I thought it was a fuel problem)
Cap and Rotor
Coil

My next thought was the Ignition Control Module? Anyone ever replaced one? It looks like u might have to pull the distributor out and remove the distributor shaft to replace it.

The computer does not throw any codes/

Also is the PCM (powerterain control module) the computer?

Thanks in advance.

 

[BlackVert]

what you are talking about is the pip.

the pip is the hall effect sensor in the dizzy. its purpose is to notify the computer of the position of the crankshaft. the "fix" you have doesn't seem to indicate a problem there, at least i don't see a connection.

i believe the ignition control module that you are referring to is the tfi, located under the maf on our cars. pre-1994, they were in the dizzy

the classis symptom of a bad pip is usually that the car will just die out of the blue after running for a while. then after letting it cool down, it is ok again. to replace it, you have to take out the dizzy and press off the gear, then replace the sensor and press the gear back on. it is usually easier to just get a new dizzy.

but i doubt that is your problem.

is the coil getting any current before applying the 200 amp start? does the engine turn over?

 

[95silvergt5.0]

Ya I figured that part of it out...any chance the ignition control module on the passenger side fender apron could be the problem? Or maybe the MAF?

 

[BlackVert]

i'd make sure the battery is in good condition before doing anything else.

 

[HISSIN50]

I have to agree with Mr Blackvert above.

You've found a variable (getting some juice going in the system) that makes it work - I'd work that angle.

Good luck.

 

[95silvergt5.0]

Ya the battery is less than a year old, i have trickle charged it as well

 

[HISSIN50]

Battery age does not matter - If it was me and the diagnostics to this point are valid, I'd get the battery load tested.

Good luck.

 

[95silvergt5.0]

Battery checks out....
NEW SYMPTOM:

When the car does start, it will die within a few minutes and just plain refuse to start, even when i throw juice at it...what the ***....this problem is seriously pissing me off

 

[HISSIN50]

When the car does start, it will die within a few minutes and just plain refuse to start, even when i throw juice at it...what the ***....this problem is seriously pissing me off

I'm not sure what throwing juice at it means.

If you use a jumper battery/battery booster on and it starts, it won't keep running with the booster still connected, or it dies as soon as you disconnect the booster?

 

[95silvergt5.0]

^ no it just wont start up again at all even with the battery hooked up 2 the 200 amp engine start.

 

[HISSIN50]

Ensure the battery-terminal connections and the battery-ground-cable connection are solid. When we use a jumper/booster, we tend to connect the alligator clips to the car's battery terminals (not the battery post directly). This bypasses a bad battery cable connection.
Also, because we hook the jumper's ground to the engine (a remotely located solid ground), that can offset a bad negative battery cable.


Good luck.

 

[smitty_64]

I know this sounds idiotic, but if the battery just has around 12 Volts after sitting for a while, the actual spark plug cables and battery could be hosed. Together with a lower battery charge and crappy cables, it may take the extra power to cause an arc that causes the completion of the circuit. Now all yall are probably thinking I'm smokin' crack, but I have been working with electricity for a long time and have seen similar problems with other components.

 

[HISSIN50]

Greg, a situation like that is what I was getting at too - I don't think you're smokin anything. I've seen some really weird issues with connections, IR, decent potential but no current (volts but no deep cycle CCA's), etc.

The situation I depicted with the funky battery cable connect (it turned out to be the negative battery terminal connection at the frame) happened to a friend. I was out in the boonies in the dark workin on it till I got it fixed.