check engine light comes on and off!!

1991 s5 n/a

 

http://fc3spro.com/TECH/HOWTO/ERRORC...KI/kerror.html

 

hi does some one have the codes for reading on a 87 TII there is a link added on the the top but it does not work i am not getting any spark on my 87 tii and there is no electrical feed going in to my crack angle sensor bin told it should have a 6volt feed going into crack angle sensor once key is turned on ON

 

In that cited thread there is mention of the CPU and error codes. Kinda wrong in that aspect. Not a biggy though, still wrong.

 

thanx 4 the diags

 

ok i hooked up to the single wire, turned to run... waited and waited,

I have a 91? any clue

 

That is bogus information. Go to the FUEL AND EMISSIONS section of the free, online FSM. Go to the CONTROL UNIT PAGE. Get a meter out and backprobe all the wires on your ECU and compare the results to the FSM.

 

You say the light comes and goes. Maybe it's a loose connection. Wire goes open from a loose plug.........engine light lights up........plug makes good contact once more..........light goes out.

When you first turned the ignition to ON, did the engine light come on, and then go out. OR never come on?

 

with it jumped, no engine light, unplugged- engine light comes on...

first I seen on that.

 

Got me. Maybe someone with a series five can pipe in his opinion.

 

Screw the check engine light. Connect an LED between the two terminals of the green 3 pin connector right next to the single pin connector you grounded.

Stupid question but you did ground the connector on the driver's side of the car next to the battery and leading coil, correct?

 

I did the driver side, then the passenger side, and DO NOT!!! ground the wire in the middle of the 3 pin connector.... BAD Idea....


out of the 3 pin, and the 2 terminals on the 3 pin would be??

 

my lite will come on when ever i drive a couple miles then itll go off then come back on n wont go away!

Sumthin wrong!! im guessin cat convert!!

But im gunna diag it n find out

 

Sounds like either the TPS or a loose connection with the O2. Check the codes, once it throws a code it stays until the ECU is reset.

Can you rephrase this? Not sure what you're asking here. If you're following procedure and getting no code then I would think that the ECU isn't throwing one. To make sure you can probably disconnect a sensor (CAS, AFM, IAT) and check again.

 

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That is the TPS check connector. The center wire is power for the test connector. The other two wires go to the Relief solenoid and Switching solenoid and also go to the ECU. This is NOT the plug for checking codes.

Look at the wires on the relief and switching solenoids. They have two wires on each plug. One is black/white, the other wire color will match one of the two wires on the TPS check connector.

It's the single green connector near the LEAD coil that needs to be jumpered to ground. A good ground spot would be the batterys negative terminal.