i'm here again !
my 88 really don't want tostart after 3 month storage !
i've cheked:filter, fuel pump , relay ,pressure , OK ! ; ignition good at spark plugs !, vats ok !!? 5 volts at ecm ! , tried another ecm !!: same ! i have bulb test at the injectors ok , but dim light , i'm not sure they work because ,i've no fuel at spark plugs !, injectors fuse ok , THE STRANGEST THING is if i turn the distributor for a lot of timing advance :it start at wot only ,for 1 or 2 seconds then dies ....question: how much voltage at d15 /d16 ecm pins when cranking ? could it be maf ? OR......? PLEASE HELP :mad

 

Pins D15 & D16 should show about 12Vdc most of the time, dropping to zero momentarily when the bank fires. However even cranking at 600rpm they will only fire at 5Hz with a very short duty cycle. This means it will be very hard to detect any deflection on a DMM or with a test light.

However my diagnostic chart says that the test light (connecte in series with an injector I believe) should flash while the engine is cranking.

Even with a bad MAF it should fire up and then run very rough and die out.

Have you done any R&R on the engine before trying to start it?

 

Here are a few thoughts:

TPS voltage. I posted a couple of days ago about my recent experience when my engine wouldn't start after I installed a new TPS connector. The connector I bought had the same wire colors, but apparently were routed differently, so when I installed it and soldered the new connections, etc., the engine would not fire.

So I disconnected the TPS and the engine fired and ran normally. I then switched two of the connector wires and the engine started and ran again with the TPS connected.

The Corvette manual (for my 86) says high TPS voltage or one that is sticking or binding will cause a no start condition.

High resistance in the coolant temp sensor or the circuit.

Fuel pressure

Water contaminated fuel

EGR sticking open

Check BOTH injector fuses

Check distributor for power output at ST-125; worn shaft, bare or shorted wires

Moisture in distributor cap

Pick-Up coil and resistance and connections

Loose ignition coil ground

If engine starts but then immediately stalls, open distributor by-pass line. If engine then starts and runs OK, replace the pick-up coil

If engine starts and stalls, disconnect the MAF; if it then runs okay and all the sensors are OK, replace the MAF.

Hope this helps.

Jake

 

For what its worth. my vehicle died like yours did, I checked everything. I finally gave in and had a shop check it. I found out that my battery acid had ate through my B+ wire. The wire going to the ECM at the battery terminal. I would put a hot wire to your HEI distributor and spray start fluid in the throttle body. If it starts and runs for a bit, its not any of your main engine parts. it probably has something to do with your ECM. Any codes? Mine didnt throw any codes when my B+ wire shorted. Hope this heips

 

just 12 code !! i'll try 12volt connect directely to ecm ...at the right places of course ...thanks

 

I would caution against doing that.

The Corvette Shop Manual I have for my 86 has four pages of test procedures for a crank but will not run condition, and I didn't see anything that recommended putting 12 volts to the ECM.

You can use a test light or DVM to check for 12V at the proper terminals, like A6, B1 and C16, but actually putting 12V there . . . Unless the manual for your car shows something different.

Jake

 

My manual says the brightness of the light doesn't matter. Test light should blink while cranking, which shows that the ECM is receiving reference signals and is controlling the injectors, but the brightness of the "blinks" isn't important.

Jake

 

Just a thought
When I first went to fire my LT1 all of the injectors where stuck shut. The stock GM injectors are bad about sticking after long lay up, over a year in my case. The way I got them to strart working was by taking two test leads connected to the injectors, one at a time, and connecting one lead to ground and the other to +12v (Using a switch) and tapping the side of the injector. I had the FP running constant durring this test so the FP would remain constant. If the plugs are dry this may be your problem. The LT1 is a snap to pull the fuel rail but your car is goint to be a bit harder so you may want to try it on the car.

Good luck


[Modified by FD2BLK, 1:34 PM 5/18/2004]


[Modified by FD2BLK, 1:35 PM 5/18/2004]


[Modified by FD2BLK, 1:36 PM 5/18/2004]