1986 IROC with ZZ4 350

[Six_Shooter]

The ONLY time idle and WBO2 sensor is an issue is if the length of tube after the WBO2 (or any O2 for that matter) is less than about 16" In a full length exhaust system this is NOT an issue.

You don't convert the sensor you change it to a heated sensor that requires adding a few wires.

[ZEDRATED]

Sounds right or may not be getting hot enough because when I rev it to about 3000 and make it heat up and then let it idle it only goes a little lean around 16:1. Can you please post up a couple links for the sensor and connector just so I have an idea what I am looking for. For the 2 wires, should they be 12V hot in run and then the signal wire gets connected to the stock signal wire???
Thanks.

[ZEDRATED]

The ONLY time idle and WBO2 sensor is an issue is if the length of tube after the WBO2 (or any O2 for that matter) is less than about 16" In a full length exhaust system this is NOT an issue.

You don't convert the sensor you change it to a heated sensor that requires adding a few wires.

yeah I understand that I need to change the whole sensor to a heated one. Any links for one that'll work? How do I hook it up? 12V supplied any time the key is in run?
When I get a chance, I will take a pic of the WBO2 sensor location.

[ony]

look at am autoparts .com ,1993chevy 1500 pickup, it shows a pic of the sensor. the black wire hooks to the wire that your one 1 hooks to, the 2 white wire are 12+ 12 negative.sorry I don't know how to post links. ground 1 white wire and apply 12 volts when the key is turned on is what six shooter told me, it works good on my truck.i found a plug but you could use wire splicers if you wanted to.

[ZEDRATED]

Cool. Thanks.

[EagleMark]

When I add a heated O2 I do so with a relay. Easy to find a pink wire that is Key On to turn on relay, then power from batt to relay and power from relay to Heated O2 sensor. It's a little extra work but eliminates the chance over over loading a circut your tapping into for Key On power.

Along with the 93-95-98 IIRC heated O2 sensor get the pigtail for it. The plug is different and then you will have a clean install.

I hope that is your issue and it's not because of location of O2 sensor in header collector picking up bad airflow, more from one cylinder at idle. From what I recalll the O2 sensor has not moved back much further then stock? But headers if not ceramic coated do tend to cool quickly loosing all heat under hood.

If the O2 sensor has moved back? Then the INT Vs Airflow in bin needs to be increased.

[ZEDRATED]

I cant recall how stock was as I bought the car with the headers and my previous IROC I installed the headers myself but it was so long ago. Could also be the overlap of the cam on idle?
I'll try the heated O2 and see what happens.

[EagleMark]

Double or triple the INT Vs Airflow table. It won't hurt and see if it helps.

I hate to guess at cam specs from a name. Some names have many cam specs. So post up your cam specs or link to where they have been posted.

My experiance with a ZZ4 cam is no, idle vacuum is 19-20 at 800 RPM. If the ZZ4 hot cam then... still no with tuning. It's specs are to idle at 800 RPM and draw a vacuum of 15.5 which is acceptable! If your idling at 550 then yes...

[ZEDRATED]

I spoke to the local GM parts supplier and they said they only show a listing for an AC Delco AFS76 O2 sensor. Will this be ok or should I keep looking for an AFS74?????

[devind]

As for what I know this is need.

http://www.ebay.com/itm/3-wire-heate...e1f40d&vxp=mtr

[ZEDRATED]

I prefer to go with an AC Delco sensor. The harness I can make myself.
Just want to know if AFS76 part number would be ok or if I should go with an AFS74???

[Fast355]

Double or triple the INT Vs Airflow table. It won't hurt and see if it helps.

I hate to guess at cam specs from a name. Some names have many cam specs. So post up your cam specs or link to where they have been posted.

My experiance with a ZZ4 cam is no, idle vacuum is 19-20 at 800 RPM. If the ZZ4 hot cam then... still no with tuning. It's specs are to idle at 800 RPM and draw a vacuum of 15.5 which is acceptable! If your idling at 550 then yes...

I have tuned larger cams in 305s and they run well. I had an 846 or 847 can't remember which at the moment that I tuned in a TBI 350 Tahoe street manners were great.

[ZEDRATED]

I just picked up a Delco AFS-74 O2 sensor.
2 black wires and 1 blue. Can anyone confirm the the 2 black wires are for power and ground and the blue is the signal wire?
thanks.

[EagleMark]

Yes!

[ZEDRATED]

Thanks, I figured that but wanted to confirm.
What is the difference between type A and B in the 3 wire sensors. I notice one has little holes as opposed to the other one that has Swirl or D shape openings?