MM951

After any sort of acceleration/throttle when the car is warm the idle surges about 50 rpm until it gets back into closed loop..... what would cause that delay? It didn't do that before.. If I add one click richer on the low arc-2 setting it seems to smoothen it out a bit quicker.

I also noticed sometimes when I'm sitting for a few minutes in traffic the temp goes from the 1st thin bar (where it spends 99% of its time) up to the middle bar. A quick rev immediately brings the temp back down to the first bar. The coolant level is consistent and I don't have any air in the system (knock on wood) - Normal or no? I haven't noticed this on any of my previous 944s.

333pg333

Not sure on the first question but I think most 951s will creep in temp in traffic and a blip on the throttle will raise the waterpump's workrate and the temp will drop down somewhat.
Are you saying that you have 3 bars on your temp gauge Mike? Or do you mean 2 bars but 3 segments? My car creeps up to about just under halfway in traffic. I think with the bigger frontmount i/c blocking the radiator I am seeing a bit higher average temps though.

ehall

The second is normal.

fbgh2o

Agreed with ehall.... and I now feel that I know the 951 collant system very well.

https://rennlist.com/forums/944-turb...e-coolant.html

Tom M'Guinn

Temp sounds normal. You might try setting your base idle, with diagnostic port jumped per the manual. If it is high, it takes a bit for the ISV to bring it within spec. Also, have you checked everything for vacuum leaks? That will also give you higher idle until the ISV brings it in check. And, most importantly, you would not believe how much better the new digital fuel controllers are, compared to the ARC2.

Rogue_Ant

Surging is usually a lean issue. Your car is lean, then the closed-loop richens it back up, stopping the surging.


-Rogue

MM951

Cool, I figured the coolant temp issue was a non-issue. I'm happy to finally be at these kinda problems

I know how much of an improvement digital fuel controllers are. I was counting on using my maxtronic but that hasn't quite worked out...I also had a greddy emanage I sold. I am now saving like mad/trying to sell wheels/parts etc to fund a vitesse MAF/piggyback. I wish I just started with that in the first place.

I agree on the surge being caused by a lean condition, it just seems like I could be chasing the arc-2 adjustment all day to keep it where it should be..