Popping at Idle and Light Throttle

[Jp-oh]

Hi, my 1986 3.2 has light but audible exhaust pops at idle and when traveling at very light loads and very light constant throttle. Not sure if it does so cold but certainly when warm. It has a Magnaflow cat and Dansk sport muffler and a RB 93 octane chip. none of these items are new however the popping is, it did pop occasionally when just off the throttle etc but the cruising and idling popping is new.

Thought?

[fanaudical]

Two things to check first:

- Verify no vacuum leaks downstream of the air flow sensor.

- Verify your exhaust connections are tight.

[Jp-oh]

Was a missfire due to a bad plug wire.

[70SWT]

Extra pops and backfires? You’ve usually gotta pay double for that kind of action, Cotton. At least on modern cars.

On my last 3.2 that did this. I recall the issue was the O2 sensor, making it run rich.

[Jp-oh]

The culprit

[Missed Approach]

Hi Jp-oh- That's quite the corrosion- glad you found the issue! Kudos to 70SWT for the finest of Dodgeball references.


Cooking on a Porsche 911- The compound butter made the difference.
https://www.youtube.com/watch?v=FvXBR50rH9E

[cabmandone]

Looks like a little dialectric grease is in order for the new ones!

[Jp-oh]

I pulled the wires out and all the others are fine. Can I just replace that one? Rebuild it?

[cabmandone]

Your car, your call. I think I'd replace the set and be done with it if it was my car. Do you know how old the wires are?

[Bigtoe32067]

Find someone with a spare and put it on and see if that fixes it before I’d buy a whole new set.
Tony

[BER]

Get a set of Clewett wires from our host. You won’t be disappointed. 👍

[Jp-oh]

I ordered wires, dizzy, rotor and plugs from PP.

[Jp-oh]

I installed the new wires, distributor cap, rotor and plugs and though it is running better it is still popping at idle and at low rpm at light loads.

I have checked the vacuum by removing the oil cap and the idle drops, not a lot but some. But it's been like that for a long while now.

Any additional things to check?

Car is running well and pulling hard but the popping when just cruising makes it sound kinda hoopty and obviously something is amiss.

[pampadori]

Does the 3.2 have a throttle switch used to trigger idle motor?
Cht test good?

[Jp-oh]

Originally Posted by pampadori

Does the 3.2 have a throttle switch used to trigger idle motor?
Cht test good?

It has an idle position switch that is also involved in fuel cutoff.

[Jp-oh]

After some reading I don't think an issue with the idle position switch would manifest in the behaviour I'm experiencing though.

[Pedro '84 Coupe]

Remove the dist cap, rotor and dust shield and see if there is dirt or corrosion in the dist housing.

Distributor Tune Up - Repair

[AndreasK]

I have the same on my 2,7 l 77s. Tried various remedies, but no real luck. Apart from; Popping is un-burnt fuel, probably due to rich. Adjust too lean and it goes away. But then I get some serious popping when I get of the throttle, coasting, letting the engine slow me down. Maybe I just haven´t found the sweet spot in between.

[Ian Comerford]

Get your CO checked at a garage and see what it says, it takes little time

[Jp-oh]

Originally Posted by Ian Comerford

Get your CO checked at a garage and see what it says, it takes little time

I'm planning on stoping by my trusted Deutsch-car wrench today. Was going to ask him to check the mixture.