The ignition is from the 94 LT1 Buick and I have had the engine running
before and it seemed ok but when I went to start it after it set for a
week it will not start.
The only thing that I have replaced is the ignation module.
Just a thought at this point... have you checked that the ignition module is
getting full battery voltage (maybe 11 volts while cranking)? The old
ignition systems used a ballast resistor in series with the ignition coil
hot side when running, and bypassed it when the ignition switch was turned
to "start." If something has left the ballast resistor in the circuit it
could be trouble like this.
That sounds pretty bad. Check the voltage across the battery when cranking
to be sure (although I'd think you'd notice 10 volts cranking) and then find
out where the voltage drop is coming from. More than maybe .3 volts drop
points to something wrong. Once the engine fires the voltage will rise
enough to ensure it continues. Anyway, if the battery is good the wiring is
certainly my prime suspect.
I've dealt with a few engines that wouldn't start because of bad batteries.
It can be a problem to diagnose, because just how much voltage sag is
allowable when cranking is not a science. A friend's seventy-something Chevy
truck with a large block V8 wouldn't even crank, and still wouldn't when
jumped. We changed the starter and still no-go! Replacing the battery fixed
Hi, je. Trying inexpensive guesses, why don't you take a look at the
plugs, as they may tell a story. To check proper operation of injectors:
If plugs are obviously too wet after attempting a start, then something is
amiss, either a no-fire situation, or a too-much-fuel situation. To
determine which, use a "noid light" to test whether injectors (one at a time
with 1 noid light) are firing to control opening of injectors. A constant
light while cranking could indicate a constantly-opened injector
condition--this would show wet plugs. A no-light (plugs would be dry)
indicates electrical problem before the injector & shows the injector(s) are
not opening at all--no fuel to combustion chamber which would result in dry
plugs. If it pulsates, AND fuel pressure is within specs, then you'd expect
a no-fire condition.
Again, this is an inexpensive guess-test for too little or too much fuel
caused by improper operation of injectors. If PAINLESS provided an aldl
circuit, nothing would be better than a scan of the system thru the outlet.
I checked the injectors and they seem to be ok I ran thru the checks
again and do not have any spark at the plugs now. The book tell me that
when I do not get voltage from the B terminal at the control module
when I crank that this is either in the module or the optispark unit.
This is the only test that is not like the book says and I put on a new
Ignition control module and get the same results. So far I have new
ignition control module, plugs, battery and had the injectors cleaned
and checked by a fuel injection company. I checked and cleaned all the
plug and coil wires and they look new and the wiring harness and
conections are new. I feel the optispark unit may be the problem and
want to know if there is a way to have them checked off the car. I may
be able to borrow one to try but do not have it now. I get 10.5 volts
when I crank at the coil and module also the voltage at the battery
drops to 10.5 when cranking. I have 12 volts with the ignition on and
Sorry, I dunno how to check them either--note I asked you about it on
1st reply (below). But they are noted for giving trouble. The 95 and up (I
think that was the year) had a somewhat improved design. Another
shortcoming here is I don't know if a later model can be substituted.
I really need to learn more, as I have an LT1 in my 86 S10 Blazer.
Never any problems in 4 years--sits for 2 months and fires right up as fast
as any car I've ever seen. No, I didn't build it; I bo't it this way. s
Finally got the engine to fire with some help from a mechanic friend
and a borrowed part.
The new ignation control module was bad replaced it with another and it
fired right up.
I sure learned a lot from tracking down this problem and not to assume
a part is good because it is new. Runs fine now so can get the rest of
the car together.
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