Mechanics

CHEVY 4.3L STARTS, THEN DIES AFTER A FEW SECONDS

1989 Chevrolet S-10

Engine Performance problem
1989 Chevy S-10 6 cyl Four Wheel Drive Manual Unk miles

The motor started and ran great towards the completion of this restoration project. The motor was not started again for a couple of months while other work was being done. When attempted, it would start and then die after 4-5 seconds as if you turned the key off. Upon closer inspection, both injectors quit spraying fuel even though there is sufficient fuel pressure. Now it tries to start but it backfires and carries on before dying altogether. Does not throw any codes. I'm stumped. Again, it was running GREAT before, nothing was done to the motor between then and now. Everything is new or reman'd including the fuel pump and filter. 12.8v at the battery. Initial timing is correct. Fuel pump runs for a few seconds when key is first turned on. In other words, everything checks out fine, but the injectors lose power and I can't figure out why!

Would falty distributor components cause the PCM to cut power to the injectors?
Avatar
Jeepmanjr
December 30, 2009.



Hello jeepmanjr

On Behalf of 2carpros, I wish you happy new year.

When an engine suddenly quits running, but then starts again and runs few seconds and quits running again ,the cause may be the loss of an important sensor signal such as the ignition trigger signal (engines with distributors)
Older GM HEI ignition modules also were prone to this disorder - especially if someone replaced the module in the distributor and forgot to apply the heat sink grease underneath to prevent the module from overheating.
your engine is a 4.3 L I believe and please correct me if I'm wrong so we can be on the right path.

Here is what we can do
start with ignition coil.

Disconnect the distributor lead and wiring from the coil.

Set the ohmmeter to the HIGH scale, then connect it to the coil as shown in Step 1 of the illustration. The reading should be infinite. If not, verify a proper test connection to be assured of a true test result and if still not infinite, replace the coil.

Set the ohmmeter to the LOW scale, then connect it as shown in Step 2 of the illustration. The reading should be very low or zero. If not, verify a proper test connection and replace the coil.

Set the ohmmeter on the HIGH scale, then connect it to the coil as shown in Step 3 of the illustration. The ohmmeter should NOT read infinite. If it does, verify the connection and replace the coil.

Reconnect the distributor lead and wiring to the coil.

print this for your diagnosis.


http://www.2carpros.com/forum/automotive_pictures/46384_0900c152801c8c06_1.jpg



pick up coil testing

Disconnect the negative battery cable.

Remove the distributor cap and disconnect the pick-up coil connector from the module

Connect an ohmmeter to either pick-up coil lead and the housing as shown in Step 1 of the illustration. The reading should NOT be infinite. If the reading is infinite, replace the coil.

Connect an ohmmeter to both pick-up coil leads as shown in step 2 of the illustration. Flex the wires by hand at the coil and the connector to locate an intermittent opens.

The ohmmeter should read a constant number in the 500-1500- range. If not, replace the pick-up coil.

print this for your diagnosis


http://www.2carpros.com/forum/automotive_pictures/46384_0900c152801c8c08e_1.jpg


Tiny
Mathiaso
Jan 1, 2010.