Skyhigh82

Engine idles for a couple of minutes, when I try to give it some gas it dies. Checked my TPS (Throttle Position Sensor) terminal “A” and I’m not getting 12volts. I’m thinking it my ECM. Am I right in assuming that 12v should come straight from the ECM to the TSP. Another thing, the only code I get from the diagnosis engine light is 12 no matter what. I’ve replaced the pickup and module in distributor still 12. Any thoughts? This is on an 82:confused:


[Modified by Skyhigh, 10:32 AM 8/8/2003]

stpman

Check your codes from a service manual, if memory serves me right a code 12 is a distributor reference and the code for a bad ECM is 55. also get yourself a good manual that has a good wiring diagram to follow the wiring one that gives voltage levels. I can check when I get home to see what I have that might be of help.

Steve :steering:

Astro7

[QUOTE]Engine idles for a couple of minutes, when I try to give it some gas it dies. [QUOTE]

I had this same thing happen to me. When you give it some gas it chokes & dies. Turned out to be the fuel pump going bad. Popped a new one in and it ran perfectly.

Skyhigh82

What year do you have? I can see the fuel injectors spraying into the carbs.

Skyhigh82

Ok, now I'm screwed, went out to do some more testing and now I don’t get anything. No engine light, no clicking and even when I disconnected my battery nothing, no noise at all. She died. I have 12v going to the ECM but not to the ignition switch.

Jvette73

I hope you didnt dis-connect the battery while the ignition key was in the on position. If you did then you have effectivly given your ECM a lobotomy and erased all of its memory to controll anything. If you dis-connected the bat and then turned the key on no problem. But if the key was turned to the run position when the bat was unhooked you wiped the ECM directives totally clean. Its like an infant that knows nothing.

When you test for codes the light first will flash a code 12 3 times before it displays any trouble codes. This This code 12 3 times in a row indicated a functiong ECM.


[Modified by Jvette73, 3:04 PM 8/8/2003]

Twin_Turbo

The TPS never gets 12V, it runs from 0 to 5, with the correct idle setting being about 0.525 V and WOT close to 5V.

Code 12 is always tripped, it's in the design of the system. 12 corresponds to system operational, no cranking/rpm signal. This ALWAYS happens when the ignition is turned on since the engine isn't running then. This is also the reason code 12 is used to test if the diagnostics work 9if noy 12 would not be present)

Check your system for vacuum leaks. Also, the CTS conenctor and sensor are a common cause for idle and throttle response problems. Check them and if not done already replace w/ 85+ weatherpack connector and sender. (it's the sender under the waterneck, hsa yellow and black wire)

What's the dile rpm? Black smoke? Fumes?... we need more info :)

Skyhigh82

Battery was not disconnected while the ignition was turned on. When the engine idles no black smoke. Before when I disconnected the battery to charge it I would hear clicking noise coming from the EMC, I think that’s normal. Now I don’t hear anything.

Twin_Turbo

the clicking noise is the fuel pump relay, you should always hear it clicking when you turn the key on. With no cranking the pump primes for 2-3 secs and shuts off, only to restart when you crank.

Do you have a scanner? if not, do you have a laptop and some soldering skills? Get WinALDL by Jonas Bylund, it's free and easy to use.

Skyhigh82

Checked the ignition wire (Pink w/blk stripe) at ECM and detected a ground/short. Pulled 10 amp ECM fuse in fuse block and short disappeared. So, that tells me it’s in the engine compartment, right! How where do I check?

Twin_Turbo

How did you detect a short? The pink/black wire is the ECM's 12V ign. switched feed. There's also an orange wire for the RAM power going to the juntion block, it will always pull a current, even with key off.

Skyhigh82

I have the battery disconnected and the ECM. The white plug has the ignition wire in it. I’m using an ohmmeter testing for continuity. Black wire to ground red to ignition wire and I’m getting an auditable tone. I think that the way it works.