Backfire in throttle bodies on light throttle - 98 St2.

**Takka** · 21 Nov 06, 11:28 AM

Hi Listers. I have a prob with the old St2 (168,000km's) as I roll on the throttle it spits & backfires in the t/bodies. I will list what I have checked & if there is anyone with any idea I would like the feedback. Compressions, fuel pressure, all sensors & relays checked,TPS setting checked, also replaced & checked.Throttle bodies changed, ECU & eproms changed x 3, timing belts have been changed but also checked. Throttle bodies balanced. Run FIM diagnostic program & checked coils & fuel pump, no stored error codes.
As you can see I have checked most things that I can think off. Hope someone can help. Cheers Takka.

**ducati2242** · 21 Nov 06, 02:27 PM

were the throttle bodies changed with the injectors if so were they new injectors or were they reconditioned at all.

**gjbird** · 21 Nov 06, 08:08 PM

I had this on my ST2 - turned out the regulator had fried which was causing the battery power to down so not enough power was then getting to the ECU.

May be worth checking what charge is being returned to the battery and what it's holding?

Good luck,
Gareth

**Takka** · 21 Nov 06, 09:17 PM

Quote:

Originally Posted by ducati2242

were the throttle bodies changed with the injectors if so were they new injectors or were they reconditioned at all.

Hi. The throttle bodies were changed out as a complete unit, including injectors. I had a spare set. Thanks Mate.

**Takka** · 21 Nov 06, 09:21 PM

Quote:

Originally Posted by gjbird

I had this on my ST2 - turned out the regulator had fried which was causing the battery power to down so not enough power was then getting to the ECU.

May be worth checking what charge is being returned to the battery and what it's holding?

Good luck,
Gareth

Thanks Gareth. It's showing a charge, but I will double check & I think I have a spare I will change it out. The battery is holding a charge but I'll swap that out with the other St2. Thanks for your input. Cheers Takka.

**Swe_rob** · 30 May 07, 05:45 AM

Quote:

Originally Posted by Takka

Thanks Gareth. It's showing a charge, but I will double check & I think I have a spare I will change it out. The battery is holding a charge but I'll swap that out with the other St2. Thanks for your input. Cheers Takka.

I have exactly the same sympthoms on my -98 ST2. However it is charging fine as far as I know. Havent measured while riding though. The regulator has been replaced with a "japanease" :wink: one since the old one got fried.

My battery is also brand new.

So if you have any tips what could be the problem, i would be very interested!