Weird Engine Sound

[sdg3205]

If any of you follow my restoration, you'll know that 3205 runs flawlessly until it bucks and stalls after about an hour of driving.

Anyway, I installed the spring in the pickup hose, it died again yadda yadda yadda.

Sooooooo, i put in a new fuel filter and pulled my injectors to check them and spray pattern. I just want to eliminate fuel before i start attacking ignition.

5 of them looked great, but the back left (behind the Idle speed motor/drivers head) easily spat out twice as much gas, while not doing a full spray until I pushed down the flap a good way. It just seemed to "pee" twice as much gas in more of a stream.

Anyway I cleaned everything up, put it all back together and got ready to work on the mixture with my dwell meter. When I started the car, i started hearing this noise that was like a pop or bang. It does it about 4 times in the video. I stopped the car asap because it doesn't sound healthy. It sounds like gas exploding in the exhaust or something.

The bang/pop is at 0:11, 0:16, 0:19, 0:22 and 0:23
http://www.youtube.com/watch?v=sDIMfI8JKBc

[WelmoedJ]

If you think it's gas exploding in the exhaust (after burner? or backfire?) then you probably run rich or have a timing problem.
- Do you also hear these sounds while gradually increasing RPM?
- Do you notice hesitation while gradually increasing RPM?

This "popping" problem also can be caused by the leaking injector (filling the chamber with fuel at the wrong time and so having a rich mixture in one cylinder when the actual quantity is supplied).
Perhaps you may have more leaking or badly spraying injectors.

Either have them professionally cleaned or replace them.
Our injectors only open on pressure (apprx. 3 Bar) and can't be cleaned internally using ultrasonic cleaning.

Differences in the fuel quantity in the distributor's chambers may also cause running problems as the ECU tries to equalize the quantity upplied and may cause low and high quantities in different, perhaps even successive combustion chambers. I had this.

Overly rich running eventually destroys your catalyzer.

First see to it that you have properly working injectors (good spray pattern, no leaks).
Then check for the pops again.

Good luck.

[opethmike]

Do the fuel injector test again, but switch which port on the distributor that leaking injector is using with another injector.

If the problem still happens on the questionable injector, the fault is in the injector. If the problem now happens on the other injector, the problem is in the fuel distributor.

[Ron]

Since the one injector spat out twice as much gas, while not doing a full spray....in a stream, I'd say it's the problem??

[sdg3205]

How stiff/hard should the plate be with no rest pressure? I can't remember.

[Bitsyncmaster]

How stiff/hard should the plate be with no rest pressure? I can't remember.

On my car, you just tap it and it will almost bounce on it's own mass.

[sdg3205]

On my car, you just tap it and it will almost bounce on it's own mass.

mine seems really stiff, which has me worried about PPR rings.

[Bitsyncmaster]

mine seems really stiff, which has me worried about PPR rings.

The PPR o-rings would not affect how stiff the air plate moves when you have lost all rest pressure. Most cars will loose all rest pressure overnight. When back the nut off the PPR then you will loose all rest pressure right before the nut comes off (do it slowly).

[Ron]

mine does like Bitsys. after several hours.

[sdg3205]

Ordered a new injector from Toby.

DMC is still the best and cheapest place to buy most parts.

Their coil - $38. Anywhere around BC is $100+

Their injector - $60, Anywhere around BC is $100+

Yup.