Noticed pinging

[Tobi]

I just noticed some pinging when accelerating at 2.5 k to 3.0 k, using 93 octane gas.
I took care of it for now by adding 2 gal of racing gas which worked but can only be a temporary solution due to high price.
It is a newly (4000 miles) modified 1981 Fi and I am working on a better air intake solution right now.
I am also planing on retarding the ignition.
Any recommendations on what spark plugs I could use (Using Autoricambi's Bosch plugs now) and is there anything else I can do to take care of the problem?
Thanks in advance.

[focodave]

Set your timing to about 7 degrees BTDC, and run plugs that are 2 steps cooler than stock (owner's manual calls for Champion RN9Y plugs -- you would want to try RN7Y plugs).
If that doesn't help, on to the fuel system.......
But first, what do you mean by "newly modified"??

[vandor]

What is the engine's compression ratio?

[Tobi]

Thanks Dave!
I don't know, Csaba. I thought maybe some where in the low 10:1 area!?

[bradartigue]

2-3k is a point where most Webers will draw fuel from the secondary idle jet (one of the few times it is used). If ignition adjustments fail consider going up to the next size on that jet.

[Tobi]

2-3k is a point where most Webers will draw fuel from the secondary idle jet (one of the few times it is used). If ignition adjustments fail consider going up to the next size on that jet.

It's a 2.0l Bosch FI.

[vandor]

Thanks Dave!
I don't know, Csaba. I thought maybe some where in the low 10:1 area!?

So it is not stock? Stock is 8.1:1. Do you know what pistons were used (how high a dome).
Without programmable ignition your only choice is to retard the timing some. I'd try going back by as small increments as possible until it is gone.

[Tobi]

The pistons are Mahle-Mondial with a 5.2 mm dome and a mls 2mm head gasket.
Here is a link from last year with more info http://www.fiatspider.com/f08/viewtopic ... 17&t=24245

[fiatfactory]

.

[bradartigue]

It's a 2.0l Bosch FI.

With the engine modifications you've made you are likely outside of the range of L-Jetronic's capabilities. Run HO fuel and try to fiddle with the ignition or cam timing. You may not be able to force the fuel injection system to deliver in a way that best suits your engine; you'll have to compromise.