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Makenzie71 08-25-2004 04:19 PM

Coolant question and Idle question
Okay...I'm not a fan of antifreeze. Hate it, actually. Reduces cooling efficiency...makes a more toxic chemical you have to store around your home...etc. I like to run distilled water for a number of reasons. So will distilled water cause any harm to the engine in combination with a water wetter or something to lube the pump?


My idle is odd. If I rev the engine it climbs propperly, but the engine speed doesn't return. Once I let off the gas the engine stops deccellerating at arouns 2200rpm and very slowly goes back to 900. What do I ned to check/adjust?

adida(r 944) 08-25-2004 04:50 PM

distilled water will only harm your engine if the tempertures fall below 32 degrees F.

as for your odd idle play around with your throttle body (im thinking the return spring is weak) and maybe try FR Wilks 944na shudder tech article, dont think you got the shudder but may help you out.

Makenzie71 08-25-2004 04:54 PM

yeah if it freezes, it'll cause damage. That prompts propper twice a year the rest of my cars. In late October, everything gets either a 50/50 or 25/75 mix. March gets distillled water.


bearone2 08-25-2004 05:12 PM

you may not like it but it raises the boiling temp, provides corrosion protection and i've heard it does get hot in texas.

i don't think you're doing yourself any favors with distilled water.SmileWavy

Makenzie71 08-25-2004 05:20 PM

antifreeze has a boiling temp of 138* (usually) ina 50/50 mix, and it holds temps very well.

Water boils at 125* under pressure and cool much faster and does not hold heat well. Water is a much poorer conductor of energy than antifreeze.

Makenzie71 08-25-2004 05:38 PM

lots of stuff here

Also, as far as the raised boiling do know that a stiffer rad cap will do the same, right?

flangermog 08-26-2004 01:13 AM

So why you askin Mak? :-)

Makenzie71 08-26-2004 07:12 AM

because the block requires special coolants...phosphate free I believe? Are water wetter and such substances harmful?something HAS to be in the system to prevent corrosion and keep the pump lubed..

max29a 08-26-2004 08:06 AM

When I unplugged my throttle switch on the underside of the throttle body it caused the idle to do that, no matter how high the rpms were if I let off and pulled out of gear it would just kind of slowly creep back down.

So I would say to check your throttle switch.

Makenzie71 08-26-2004 08:20 AM

SV650...excellent bike...

I'll check the throttle switch...thanks.

NKN84944 08-26-2004 08:31 AM

I had a very similar problem, and it turned out that the hood insulation was sagging right above the throttle cam and caused it to return oddly. Hopefully this is your problem because it is a super easy fix.

Makenzie71 08-26-2004 08:27 PM

not so simple....:(

The throttle body snaps shut very quickly...but the RPM stay up there momentarily. Any other ideas? I want a rev-happy car....:(

Makenzie71 08-26-2004 09:02 PM

I just took the intake hose off to make sure the butterfly wasn't hanging anywhere. The spring is tight. It's decelleration seems to have no bearing on the throttle body position. I've adjusted both the throttle stop and the idle screw and have gotten nothing. What now?

CJFusco 08-27-2004 05:35 AM

have you checked the throttle cable? Perhaps it is too tight?

TCMdocs944 08-27-2004 05:41 AM

Vacuum leak?

A plethora of idle problem can be caused by one of those.

Phosphate free is because of the aluminum head no?

The biggest worry I would have is corrosion with plain ol H2o

Buddy 08-28-2004 05:04 AM

Don't you run the risk of blowing the seams on the radiator tank if you run too high a cap pressure?

BTW, are those temps you're citing in Farenheit degrees?

Makenzie71 08-29-2004 02:48 PM


Throttle cable is great...the butterfly closes completely. I've tried to find a vac leak but have been unsuccessful.

agentblr 07-12-2010 01:32 PM

Sorry guys,I know this thread is ancient but I am having the exact same hanging idle problem on my 87 924S. I am stumped on this any help would be appreciated!

fmartenies 07-12-2010 01:48 PM

The bigger problem is that Texas's water is defying physics and not boiling at 100 c anymore.

Makenzie71 07-13-2010 06:58 AM

Mine was an intake manifold leak. It's a 25 year old car by's probably never been done, and it's something that should be done on occasion. Strip the intake and replace all the gaskets and vacuum lines. Won't hurt to replace all the exhaust gaskets, either.

89-944NA 07-13-2010 08:10 AM


Originally Posted by Makenzie71 (Post 1481718)
because the block requires special coolants...phosphate free I believe? Are water wetter and such substances harmful?something HAS to be in the system to prevent corrosion and keep the pump lubed..

Phosphate free antifreeze isn't really required in the US, because the water here does not have the hard mineral properties of the water in Europe and many other countries. I have used water wetter and distilled water in all my 944's for many many years with no adverse effects.

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