Did a search on the boards and could not find a thread that answered my question.
Cannot start my 92 Z-28 w/305 and multiport FI. Car sat two years w/o a battery. I only get the code 12 when using onboard diagnostics. Engine cranks but won't fire. Originally thought fuel pump was bad so It's new.
Haven't fooled with cars since high school and college about 30 yrs ago. You guys gotta be way smarter then we used to be to troubleshoot.

 

If the ECM is bad, is getting an aftermarket ECM as good as a GM ECM?
(I'm just a points and condensor guy trying to figure this stuff out!)

 

Do the initial rundown before assuming the ECM.

Is it getting fuel?

Is it getting spark?

If its getting both, how much fuel pressure and whats the color of the spark.

No fuel: Check fuel filter and replace, drain gas and replace, may be dead fuel, put water remover / gas line antifreeze in it.

No spark: check and replace the plugs, wires, distributor cap rotor, and coil if needed.

If both: Check the coil and see if proper spark is emitting, Check the fuel pressure.

 

just do the basic tests........spark and fuel...the code 12 means there is no problem at this time..........also when you say will not start are you meaning won't crank and run or won't spin over............if it won't spin over make sure the vats system is operating properly.....but chances are your injectors may be clogged up with gas deposits becuz of sitting so long

 

engine cranks fine, I have fuel in the header. Haven't checked pressure but I have a new pump and filter. Don't hear the pump running when I turn on the key though. There was no gas in the tank and no battery for 2 years. Will trouble codes show up by cranking the engine over or does it have to be running? Any codes that were in the ECM would be gone w/o a battery?

 

did you check for spark? if you're getting fuel, then check the spark.

 

check your ignition control module as well. i replaced my head gaskets and the engine would not start. had spark, had fuel pressure, but the injectors weren't pulsing. they worked fine when hooked to the battery. found out that the icm was not sending the timing signal to the ecm. (no fuel going to cylinders)

 

Thanks for all the help. it's running now after changing all the wires and plugs, Still trying to get the idle smoothed out but that post is on another thread.

 

Hello all,

I am kind of having the same issue with my 92 formula. I has a
305 v-8 throttle body.
It cranks and it won't start. It has been sitting for the better
part of almost a year. I have put new plugs, wires, cap and rotor,
fuel pressure relay, fuel filter, oil pressure switch, 02 sensor,
new ignition coil, new battery, and when this problem started to
occur, I replaced the ignition control module and the car still
cranks and won't fire.
I will take the suggestion of draining the fuel and putting new
fuel in it as well as the anitfreeze for the fuel system. But just to
save some time, what else should I check for?????????
This car is driving me nuts. I've had it for a year and have only
driven it about five times. It doesn't want to run.

Thanks!!!!!

Craig

 

Here are some basics to get started with:

At key-on, engine-off, the SES light should come on, blink off, then come on solid. If not then something is wrong with the ECM. Or, if no SES light at all then the bulb is missing.

Jumper ALDL pins A & B together (the paperclip test), key-on, engine-off, and the SES light should flash code 12.

At key-on, engine-off listen for the fuel pump (FP). It should run for 2 seconds then stop. If not then either the FP relay is bad, the wiring is bad, the ECM is bad, or the FP is bad.

If the fuel pump did run, then crank for an instant and again listen for the fuel pump. Again it should be running and stop two seconds after cranking. If not then the ECM isn't getting reference pulses from the distributor. Ignition module, pickup coil is bad (or camshaft is broke in two and the distributor isn't turning ).

Take the aircleaner off and lean in to crank the engine with the key while observing the injectors. Note whether the injectors spray any fuel. If not then check fuel pressure , check for spark and check the fuse along the pass fender under the hood. The injectors will fire at each distributor reference pulse.

RBob.

 

Have to check the SES light suggestion but I have done the
paperclip test and it does the "handshake code 12". Nothing else
flashes.
I have to check the fuel pump suggestion to but last time I tried
to start it, I heard the pump running when I turned the key on
but don't remember if the pump shut itself off after a couple of
seconds. Just for my information, what is the problem if the pump
doesn't shut itself off after a couple of seconds?
Sorry for sounding so uninformed about diagnostics but
how do I check the fuel pressure ( and I have an old tire gauge
if I can use that)? Also, how do I check for spark and is there
a specific color the spark should be?
I just remembered that some time before all this I went under
the hood to "try" to look for some possible problems and noticed
that the distributor cap wasn't screwed down all the way I
immediately tightened it down and the car still didn't start. I
believe that the car did run a little before I check this. My
question is could this have damaged the cap and or rotor? Is
there a way to check to see if the cap and rotor are bad?

I don't have my own computer yet and I am limited to checking
the responses to twice a week and I am going to try to check
Saturday for responses so I can hopefully get this car running
and not have to sell it.
I appreciate all the suggestions and help that I have gotten
thusfar.

Keep those ideas coming guys !

Thanks again!

Craig