I've had intermittent engine dying for almost a year. I've replaced and or tested everyting and come to the conclusion it's VATS.

I bought a chip that's supposed to bypass it. I need to connnect it to the VATS fuel enable wire. I found a thread here that explained the 93 has a ECM not a pcm. I also found a thread that says the ecm is up under the passenger's side dash. Can anyone tell me exactly where to find the fuel enable wire on my 93? I'm thinking it's in the black box above the battery but I'm not 100% sure. If it's there, how do I tell which one it is?

 

There is not a VATS fuel enable wire as you think there is. There is a little more to it. The enable is really the serial bus communication between the CCM and ECM. A password is given between the two to turn on FEDS which enables your injectors thru the ECM.

VATS controls the start inhibit relay and FEDS. It will prevent a engine from cranking (relay), or running (FEDS) when the key is turned with a detection of the wrong key pellet resistance. VATS will not (not that I am aware of) kill an engine once it is running.

If the chip would eliminate the handshake between the CCM and ECM and you has a VATS event, you would not be able to crank the engine because the CCM still has to be satisfied with the key resistance to let the engine crank and close the start relay.

I hate not to give you the direct answers you are looking for but hate to see you mess your car up the doing an electrical no-no. It might be better to take a step back and tell the forum what the exact problem is and all you have done. Saying "I have done it all" will not give you any helpful information or good suggestions.

The 93 ECMs are known to cause many strange problems shutting engines down and other things. Of course many other items can kill the engine.

 

There are a lot of other people who disagree that VATS cannot kill a car once it's running. If the signal is dropped that keeps injectors firing, the car dies and that's what I believe is happening.

Thanks for the advice but I've done exactly what you mention through the forum and whittled it down to VATS. Of course, it could be something else and the ECM could also be at fault but I found a $20 fix for VATS and that's what needs to be eliiminated now before I can go on to look elsewhere.

 

Also, there DEFINITELY is a VATS fuel enable wire on pin 19 of the red connector to the ECM. I need to figure out which pin in #19.

 

If you have that quest then I would like to help as much as I can. I don’t have the exact 93 drawing for the ECM. I do have a 94 and up PCM drawings though. All the pin #s are a number and letter combination. I don’t know of a fuel enable wire or pin. As I said, the fuel enable signal comes in the serial bus. I don’t know what else to look for. Is there any other additional information.

 

Here is a picture identifying the 93 ECM connectors and pins, but like pccolt94 I think your information is flawed. My wiring diagram shows pin 19 in the red connector to be a green wire going to the third gear switch in the transmission valve body.

 

The different color connectors have different letters associated with them. So i.e. the red connector might have the "A" series of pins and then the numbers would be relevant to that connector. So I am assuming red is the A connector.

In reviewing some additional information I have which is non-FSM (but not a Haynes book), it shows that pin B19 (green wire) goes to the third gear relay in the transmission. The FSM is the book to go by. But my info is in conflict with Toptechx6 where he got A19. I'm sure his book is correct but is it possible the pin # was read incorrect where it should be a "B".

Don’t know if we are both right in regard to out information but thought it might just need a second look.

**And then maybe I'm wrong about my assumption.

I don’t see another pin 19 anywhere with the info I have.

 

Look again at the connector diagram I posted and you should notice that the red connector is designated as the "B" connector, not "A".

 

Totally missed the color and letter designations on your diagram. Needless to say my assumption was wrong. I just don’t have enough 93 FSM data.

All is good now.

But getting back to the main point, what is Funbooker up to now?

 

OK, what I'm looking for is supposed to be A19 on the red connector. It's also called circuit 229. Does this mean anything to anyone?

 

According to my 94 FSM, I don’t see a circuit wire 229. Which makes sense since it relates to a 93 and should be in the 93 FSM.

You are looking for A19 red connector. But according to the drawing in post 6, the red connector are the B terminals………….very confusing.

I'm out of help. Someone needs to bring a 93 FSM to the thread for more answers.

 

I have the 93 manual, but I can't help either as the information posted by the OP does not make sense. I suspect the information supplied to the OP applies to earlier vehicles without a CCM.
The wire to the red connector pin 19 is designated circuit 108, and as pcolt94 pointed out the red connector designation is "B", not "A".
A quick glance at my wiring diagram reveals no circuit 229 connected to the ECM.
As pcolt94 indicated in his first post theft deterrent information on vehicles with a CCM is communicated on the serial data circuit designated 800. That circuit connects to the ECM using pins 4 and 15 of the brown "D" connector.

Taking this one step further I just removed the ECM in my 93 to inspect the connectors in question, pin #19 of the RED "B" connector has a green wire as indicated in the FSM. Connector "A", gray in color has no wire connected to pin #19.

 

Thanks guys. You've convinced me that the instruction manual is completely off. The 32 pin, red connector is for later years that are equipped with a PCM. My 93 has an ECM and as you have pointed out, the pin configuration is 22 pins, not 32.

But somewhere in the maze of wires on my 93 lies a wire that's part of the VATS system and controls injectors. I'm hoping for an answer from the vendor I bought the thing from but anyone else who wants to chime in, I'm happy to get as much information as possible.

I've read a lot about VATS and lots of people seem to agree that it's bad technology and it's guaranteed to fail eventually. I love my 93 white convertible but it's starting to get like an extremely hot girlfriend I once had. She had a similar malfunctioning system. She always looked great but as time went on there were more and more complicated reasons why I couldn't just take her out for a ride.

 

There might be some discrepancies in the drawing (not from FSM) but it is pretty close or exact in most circumstances. It shows the injectors each side connected in parallel. This is batch injection where all 4 fire at once. You can see the ECM (PCM in picture) drives the injectors. The ECM makes the decision to fire based on all the input from the external sensors.

What the picture does not show is the VATS connection and handshake thru the serial bus. This is what enables the ECM to say "yes, I will fire the injectors". This can be read in the FSM in detail and full living color.

There is no one wire like a DC level that just turns on the injectors. I realize that talk about a "bus" is a bit more complicated than just a single voltage. But equate it the front bus in a computer, internet or anything that transmits digital data.