1990 key decoder modual

[Reattasteve]

Does anyone have a used decoder modual they are willing to sell?

My mechanic tells me he needs one. I thought a locksmith could check the resistance on the key.

 

Thanks in advance,

 

Steve

[rogold]

Any good locksmith should have the module to test a key, or you can check it yourself if you have a ohmmeter. Here is a video that shows how to read the resistance of your key:

[Reattasteve]

The car is missing the key decoder modual and the theft deterrent modual. Apparently it's been rewired to by-pass it. My thought is it shouldn't start at all if it's a theft deterrent problem..

 

Doesn't the fuel pressure have to be at least 55 before the fuel injectors work?

[Ronnie]

Ideally, with a good fuel pump and pressure regulator the pressure at the fuel rail should be about 40-42 psi but for troubleshooting purposes the engine should run just fine at anything over 35psi.

 

This might help you.

[Ronnie]

I don't think it would start at all if the theft deterrent module was the problem. But, who knows if the wiring has been modified.

 

Basic troubleshooting is needed to solve your problem. These questions need to be asked when the engine dies.

1. Did it loose fuel pressure?
   
2. Did it loose spark?
   
3. Did the injectors stop firing due to a bad ECM, sensor or wiring?
   

[DAVES89]

I think Ronnie means the oil pressure sensor. If it is not working and doesn't read any pressure the car will not start.

[Ronnie]

I actually used the wrong word when I said it wouldn't "Start". I should have said I don't think the engine would "Crank" because the theft deterrent module, through the starter interrupt relay, prevents the starter from energizing.

 

The first photo with yellow highlighter shows normal operation. The second photo with the red diagram shows how the theft deterrent can be bypassed. Dave, remember this?

[DAVES89]

Yes this is a great story of Ronnie walking a former 1989 Reatta owner on the AACA forum [you can do a search] through a "no crank" issue. The owner's handle was "Snowdrift" and his problem started with swapping out an alternator without disconnecting the battery. The positive lead of the alternator shorted out against the engine causing an electrical issue.

 

As I was reading the series of posts [with a couple of other guys offering distracting advice] I was amazed at Ronnie's knowledge and willingness to help coupled with Snowdrift's determination to get it fixed. After Ronnie walked him through this issue asking Snowdrift to do a series of tests and came to one conclusion which Snowdrift followed and got the car started.

 

Snowdrift sold the car shortly there after to some guy in Wisconsin who owns the car to this day. That owner is me and I have never had an issue with the ignition system of that car now 7 years and 80,000 miles plus. I did solder the wire as Snowdrift only crimped it using a solderless butt connector.

 

Best repair story ever...