My '89 305 TPI / AT IROC has an intermittent NO CRANK condition. When I supply 12 volts to the starter solenoid, it cranks fine and has SPARK but NO PULSE at the INJECTOR SOCKETS.

Using the Factory Shop Manual (FSM) diagnostic tree, an early question raised "No crank ECM code 46, 53 present"? . My Actron Scanner reads "Unable to communicate". Assuming this is not a wiring problem, would lack of communication be in the ECM or in the PROM?

When I proceed with the diagnostic, on the assumption there IS NO ECM code 46,53, the tree concludes the VATS Module is bad

EDIT *******.SECURITY LIGHT STAYS ON DURING NO CRANK EPISODES..********* However, the "Security Light" operates in the normal fashion, during NO Crank episodes. Would this CONTRADICT a VATS caused NO CRANK?

Any ideas? Thanks.

 

Why don't you just get a paperclip and check for those codes real fast? Your scanner's lack of communication could be just a setup issue with the scanner. Some years require a 10k resistor over certain pins to start sending data, etc. It's always a small rain dance to get communication going for me.

The security light is going off when you try to start it? Or stays on? If it stays on, clean the keyway with a q-tip and electronics cleaner. Same with the key.

 

EDIT*****The Security Light STAYS ON ******when you try to crank it over.

I forgot to mention.........I bought the vehicle w/ a resistor buypass in the circuit. So it's not the key reader. Once I fix the problem, I plan on restoring the VATS system to original.

Do you know what terminals I jump, on the ALDL connector, to read code the simple way? Does the response include any OK type messages?

 

Terminals A and B (top right 2)



You will see 1 blink (pause) 2 blinks (pause) three separate times indicating the ECM is OK. Any codes are displayed after that (three times in a row, then next code). If you only see 1 - 2 repeated, there are no stored codes.

 

Thank TH for the paperclip tip. I just love a paperclip doing better than my $ 200+ scanner!

KOEO, It displayed code 12, over and over..............so, no trouble codes.


I have no VATS failure codes, the Security Light****EDIT STAYS ON****** YET, the FSM Diagnostic Tree leads to a bad VATS module. Can this be? Id' sure hate to drop $ 200 on a module AND hours of my time, and not solve the problem!

I guess I need to study the FSM more.

 

Vats timer is like 3-5 minutes. Been a while since I looked at vats but here’s a thread that describes where you can turn the key in the on position, wait 5 minutes, then jump starter. That should rule out vats. Refer to post 3
https://www.thirdgen.org/forums/v6/6...rn-key-no.html

 

Have you checked the resistance of the bypass and made sure the connections are good? I just used 2 resistors to get mine going.

 

You have given me a lot of good input and suggestions!

I did not mention, the the previous owner had a fused wire run from the battery positive, into the interior to a normally open, bush button "Crank" switch, that supplies 12V to the starter solenoid. I'll bet he did the wait 5 minutes with the ignition ON, and use the auxiliary bush-button to start, for a long time!

I will do some more reading(the thread "maks10" supplied and the FSM), some testing and reply back, in a day or so.

THANK YOUS very much!

 

UPDATE AND EDITS ******* I previously stated security light was OFF during no crank episodes. Tonight during a no crank SECURITY LIGHT STAYED ON****

Ether I was incorrect when I stated that the security light went off, during no crank episodes (my wife also told me it was off, when I started this thread) , OR the symptoms have changed. NOW the security light stays ON during no crank. It still has NO trouble codes. After a five minute wait, with the ignition left on , I jumped the starter and as before it was a no start with ignition spark, fuel pressure and NO injector pulse. I believe I will need to re-do the FSM diagnostic trees.

 

Once you are at the end of your rope, hit up Tuned Performance in my signature, he can supply you a stock tuned chip with the VATS deleted. Swap the chip, and never deal with it again.

I don't think VATS is really fending off criminals at this stage in the car's life.

 

UPDATE SOLVED I bit the bullet and installed a NEW Delco VATS Module. Problem is SOLVED! I will be installing a new ignition lock cylinder, to complete VATS full restoration.

Thanks all who contributed!!