Thread: D2 - Really rough AND open loop!

Originally Posted by ozscott

Bugger....should leave things alone.

2 days ago - new double platinum champion plugs in the D2 and used Top Gun leads specfically for the D2. Drove like a new one. Then tonight driving along after 2 days of good clean running and ....rough...both on LPG and when on petrol! Waited for motor to cool and checked the coil packs...all tights. Checked the plug leads - all tight. Can see blue flashes at night under each lead onto the plug, but none on the leads themselves and non cross firing. Pulled pin on the MAF - no diference except idle got worse.

I noticed though that on the Scanguage II she is going open loop when warm even under part throttle or idle whereas it should be closed.

I also noticed that it sometimes couldnt make up its mind even with constant part throttle and would keep jumping from closed to open and back. Most of the time - 90% - it was in open loop. That makes me wonder if its a coolant temp sensor out to lunch.

The only other thing I did was install a low water alarm that passes less than 1 volt though the water...could that have buggered up the coolant temp sensor?

Any thoughts before stealership/equivalent with Test Book much appreciated.

Cheers

I guess the 1st thing to do is check the coolant temp sensor.

I think the RAVE CD had the numbers for that

This may help

I would disconnect the new coolant alarm to see if the problem goes away.

Thanks mate. I tried that on the way home last night, but it set off the alarm scream for low water. I will pull the power on that today and then pull off the low water alarm - cheers

PS. If the coolant temp sensor is the same sensor as the one that tells the computer what temp the water is at (ie there is only one coolant temp sensor) then it must be ok because my scanguage shows it correctly cold then warming up and then usual 90 degrees running etc.

Cheers

Hold on...it runs exactly the same on LPG. My LPG system is closed loop mixer with servo motor adjustment of idle and main tap - but only takes its feed on TPS and left bank O2 sensor. So it seems to me that it cannot be coolant temp sensor because that only changes injector pulses on petrol - so if it were that, then LPG would still run well. So that probably means another sensor or good old fashioned spark problems.