back fire woes

[aveale]

Have searched long and hard for answers to this one.

My 73-2.0 backfires when i decelerate - i am thinking it is a loose grounding cable.

It idles a little faster then I would like (1200 rpm after winding down the idle screw as far as it will go) but other than that it is good to go.

Any one have ideas??


Thanx

T

[Conrad W Peden]

Hows your exhaust.

Loose exhasut at the head can cause backfires. My carbed 914 will backfire with a loose carb, not sure if a loose runner on FI cars will.

[John Rogers]

Couple of things to check: first check all vacuum hoses since the high idle is a sure sign of a vac leak. Pull them off and look for cracked ends. Replace as necessary. Spray carb cleaner around the inlet plenum and the runners and gaskets while running as there can be leaks there. Finally pull the injectors and look for missing plastic tips which will let the injector be loose in the seal. That lets air suck in and it will also blow out some. Good luck

[Dave at Pelican Parts]

Air leaks and overly-advanced timing can both result in a high idle.

--DD

[lapuwali]

Loose or otherwise leaky muffler to HE fitting can also cause popping on deceleration.

An actual backfire is usually a big BANG, and is usually out the intake. It will get your attention quickly. Exhaust popping is much quieter.

Do NOT just crank on the exhaust nuts to fix this, either, or you risk breaking the stud, which may require you to remove the head to fix.

[aveale]

Thanx everyone for your help (I am very impressed!!).

The vacuum hoses certainly helped.

On to the next project!!

T