lo-z

I just installed headers on my 87 305 carbed. I didn't put the o2 sensor back on and now the choke is not working and the light is on. When the wire is disconnected there is power and no light. When it's connected no power and light is on. After I put the headers on it ran a little weird too til I tuned the timing, but it does seem to be a little rich.

KYLE87

iTrader: (5)

Im not sure if thats why the choke light is on, but I would put the O2 back on and see.

I know that you do need that since your carb is computer controlled and that plays a big role on the idle mixture, not sure if that would cause the choke light or not, but would expain your car running rich.

lo-z

OK, I put a new o2 sensor on the headers. I still have the choke light on. The choke does not come off high idle on it's own anymore. Any advise is helpful.

lo-z

Well, I put a new thermostat on and still no change in my situation. Please help.

five7kid

iTrader: (14)

Verify you have 12 volts on the choke thermostat wire when the engine is running. Did anything happen to the choke wire while you were putting on the headers?

lo-z

I do have 14.0 to 14.1 volts to the wire unplugged while running. I have .5v to the wire plugged in. I also just put a new thermostat on. The only thing I did while doing the headers is left off the o2 sensor, which is when this all started. I have since drilled out the bung hole and installed a new o2 sensor, as I didn't trust the old one.
Thanks for helping.

lo-z

I just got home from work and I did the jumper thing to get my codes and NOTHING. The lights came on but didn't blink at all.

lo-z

Ok, I found the problem for the SES light. I went to pull the codes and it wouldn't do anything. The light came on and stayed on, no flashing. Testing this and testing that led me to the fusible link at the battery.
Now I just need to find out why my choke light is on and why the choke is not functioning. It's getting 14v at the wire and the thermostat is new.

lo-z

OK, I think it's fixed. After wiring in a new fuse wire, reset the timing again because evidently it changes dramaticly without the computer. I took it for a run around town a bit. About 10 minutes into my cruise I noticed the choke light was gone. I won't know for sure until it cools down and I can readjust the choke for cold high idle and see if it kick down on its own.

five7kid

iTrader: (14)

The timing is supposed to be set with the connection from the distributor to the computer disconnected.

lo-z

I did that, thanks. It's running good again. Just need to adjust the Dwell on it. I am still getting a soft code 45.

lo-z

OK, after I let it cool down I adjusted the choke, fired it up. It was running nice at cold idle, but I noticed the light was back on and it didn't open up after it warmed up. Somebody said the relay was on the fender by the battery. I replaced that today, it was the same kind as the high speed fan relay. Still nothing. I'm not sure if that was the right relay.

87IROC-DAN61

Hello lo-z!!

Check that you have power to the mixture control solenoid after the car warms up, as no power makes the solenoid run at a rich setting, which should in turn, turn on the choke light!!

You can check the resistance in the mixture control solenoid also, that will tell you if it's good or not, the resistance should be 20 to 32 ohms.

lo-z

Ok, we have power to the mixture control solenoid.

87IROC-DAN61

Hello lo-z!!

Measure the mixture control solenoid resistance, did you get 20 to 32 ohms???

lo-z

don't know how to do that.

Jekyll & Hyde

You need a multi-meter set to test ohms or an ohm meter and put it to one probe to one side of the connect and the other probe to the other side. The result will be your resistance across the connection.

lo-z

OK, I can do that.
So, yesterday I went to my dad's house (ex-mechanic) to get him to put his diagnostic computer on it and see what all the sensors are doing. He could pull up the sensors and see them but none of the values were changing. Example: RPMs did not move when we excelerated the throdle, brand new o2 sensor not reading, mixture control solenoid did nothing, dwell did nothing. Now I just replaced the fuseable link wire that was broken last Thursday and the car started running good again. Could this be a bad ECM? The car seems to be running fine other than the choke not opening. If it is a bad ECM, could the choke be related to that? I was told the choke doesn't go to the ECM.

87IROC-DAN61

Hello lo-z!!

The mixture control solenoid goes to the ECM via a Lt Blu wire to terminal 18 of the ECM connector!! The same wire that the green dwell terminal is connected to!!

As for the diagnostic computer not seeing the changing values, was the diagnostic computer set to the right mode!! Usually you can capture data as a snap shot picture (no changing values), or real time (changing values as they happen)!!

lo-z

Well, I bought myself a dwell meter a few days ago, the kind that has the needle in a box. When I hooked it up it wouldn't move or alow for change in ajustment. This was why I went to see my dad and use his. I thought I was doing something wrong.
As far as what mode his diag comp was in, I don't know. I was going off his many years of working as a mechanic. I think he would know this but I will ask him to make sure. Tomorrow I am going to one of my club members house and let him plug into it and see if it does the same thing.

87IROC-DAN61

Hello lo-z!!

So, what did you find out?

lo-z

Well, with Dad at hand, I swapped to a new ECM, checked it with the diag computer and it showed us the status of all the sensors. The dwell is at 45 degree, but that is because the o2 is not closing the loop for the M/C solenoid to do it's thang. I will be getting a 3 wire heated o2 that should fix this.

Still no change in the choke.

87IROC-DAN61

Hello lo-z!!

Did you get your new O2 sensor?

Update me!!

lo-z

Here is the link to NTTGA.net where I have also been talking. Might fill you in more.
Still working on the choke issue though.
http://www.nttga.net/forums/showthread.php?t=22953
Thanks for everyones help.

onebad82z

iTrader: (7)

Is the alternator working/charging properly?

lo-z

Yep, it's at 14V. I even put a new one on because the old one was ugly.

lo-z

Alright, I got it fixed. It was the Oil Preasure Switch located under the back of the distributor. It was unplugged and the two male prongs were bent. I am thinking it came off when I jacked up the motor to do the oil pan. It's hard to see it back there and I didn't know it had anything to do with the choke but I guess it does. My dad pulled the choke diagram from his Diagnostic PC.