What would cause a knocking on petrol? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

DansEdgli · 04-15-2004, 02:10

I got my EB back today with a RWC and a gas tune. Prior to which the car would struggle to idle.
On gas the car runs and idles perfect but when switched to petrol when the accelerator is applied there is a knocking sound coming from the engine bay. It struggles to move. It seems to do it less once the speed is up a bit.

Any ideas what is wrong with it?

Thanks a lot
Dan

RaceCraft · 04-15-2004, 02:34

chances are they timed it for LPG

TIKFD6 · 04-15-2004, 07:35

Either that or your fuel has gone bad.
But probably the tuning.

You have a PM.

TIKFD6 · 04-15-2004, 07:38

Either that or your fuel has gone bad.
But probably the tuning.

You have a PM.

PS Gas is for Taxis(tm).

DansEdgli · 04-15-2004, 12:47

Thanks guy, Ill go around there and ask them what the deal is. I got the rwc and tune up done at the gas place so maybe they did tune it for gas. Chances are the previous owners never used the petrol system to keep it working, it was below empty when I got it.

PM answered.

Dan

two heads · 04-17-2004, 11:36

Timing on EB's is not adjustable unless you re program ecu (different chip) so unless the tune you got was very exy the timing would not have been touched. Engines running on gas get very dirty in the inlet and around the injectors (Soft carbon type build up) when the motor is switched over to petrol the injectors can be partialy blocked or the spray pattern is messed up,no longer fine mist but fat globs which is not so good for firing.Try some injector cleaner in the fuel.

mongrelEB · 04-17-2004, 13:56

Umm you time it like a normal dizzy. I believe you're thinking of the EF?

DansEdgli · 04-22-2004, 06:00

OKay Ive decided that it is backfiring on petrol at low engine speeds when partly accelerating and not at all on gas.
The mechanic didnt get a chance to check it out.
Any ideas how to fix this problem.

Dan

mongrelEB · 04-22-2004, 07:23

Which fuel do you use more?

Is it a knock, or more of a rattle. If a rattle, it's probably detonation - back the timing off a little. Will lose performance on gas.
If a knock, probably not timing

check things like vacuum supply to regulator and MAP. TPS voltage, etc.

DansEdgli · 04-22-2004, 08:27

Ive been using LPG more but that is only becuase Ive had the car for 1 week and it runs like crap on petrol.
Im pretty sure its backfiring through the inlet manifold. Its not rattley

Would clogged injectors cause this? Im under the impression this backfiring only happens cause the engine is running lean or the spark is not good enough.
LPG requires more/stronger spark than petrol doesnt it (but LPG is fine) so therefore the engine has to be running lean on petrol.
It seems to be getting a little better since Ive put some injector cleaner and a full tank of premium in it Ive taken it for a 100km thrash through the mountains and switched it to petrol on the freeway tonight for half an hour in an attempt to flush the injectors a little.
If it keeps playing up and the mechanic cant get to the bottom of it ill put it on straight gas. I want to turbo the thing soon anyway.

Thanks for your help guys
Dan