930 CIS Issue - Low Idle and Hard Cold Start
03-15-2006, 10:42 AM
#31
Rennlist Lifetime Member
Actually there are 4 different WUR for that year. All of them have different pressures. We really need to know the WUR Bosch number and I can tell you what the pressures need to be. The systems are fairly sensitive and the pressures need to be correct.
The system pressure is too low. That is for sure.
The system pressure is too low. That is for sure.
03-15-2006, 01:04 PM
#33
Rennlist Member
I know the hard starting is probably least of your worries, but it may be because you're not getting enough fuel. You're not pulling air over the flapper plate until your AAR closes (ref vent filter on AAR inlet). It's normally plumbed through normal inlet path.
03-15-2006, 01:37 PM
#34
Racer
Join Date: Feb 2006
Posts: 295
Likes: 0
Received 0 Likes
on
0 Posts
The specs I gave you are correct for that part number according to my book. I agree with JoeMag, you can't vent the aar like that. It needs to be plumbed back into the intake before the throttle plate.
03-15-2006, 02:15 PM
#37
Rennlist Lifetime Member
Oh man....I missed that. Why would it take 8% to idle...Lets think about this. Sure when the car is cold and the control pressure is down the car gets plenty of fuel...as it warms up and you are trying to idle the AAR has closed right....Well sort of. You still have a slit. If it is an early numbered AAR it is hole the size about the tip of my pinky. Even closed these units are not sealed. They leave some opening to help regulate idle control. As I am reading this my feeling is you have an intake leak and un-metered air is getting into the system hence the need to crank the CO...So you do have an intake leak. If the AAR is out like that you have a leak all the time. It needs to be in a closed loop system.
03-15-2006, 02:33 PM
#39
Instructor
Thread Starter
Join Date: Jan 2006
Location: Alabama
Posts: 204
Likes: 0
Received 0 Likes
on
0 Posts
Wow, this is great, we are for sure in the right direction now. I will add that hose tonight and see where it leads us. Just remember, before when the CO was set at 3% hot, the car missed, surged and even more difficult to start at normal running temp.
03-15-2006, 02:46 PM
#40
Racer
Join Date: Dec 2005
Location: Tracy,Ca
Posts: 350
Likes: 0
Received 0 Likes
on
0 Posts
The early ones (at least on my 77 930) had the half moon inside and no slit like the later ones Stephen is reffereing to. Who knows what you have in there. I chucked mine altogether on my 77 930 and eliminated the last of any low and high idle issues. Basically one less problem that can happen. When I first start my 930 up, depending on the temps outside I might need to help hold the throttle for a minute or less until it can idle on its own. Or, I can pull up the throttle lever in the middle of my front seats (factory eliminated these throttle levers on the 78 and up 930's) and use that for holding idle if I need to walk away from the car. Makes a great manual cruise control too!
03-15-2006, 06:45 PM
#44
Racer
Join Date: Dec 2005
Location: Tracy,Ca
Posts: 350
Likes: 0
Received 0 Likes
on
0 Posts
...Man, I feel like i've moved up one notch (be it a small one) on the 930 knowledge scale.
03-15-2006, 10:24 PM
#45
Instructor
Thread Starter
Join Date: Jan 2006
Location: Alabama
Posts: 204
Likes: 0
Received 0 Likes
on
0 Posts
Ok, here is how the evening went. Got home and went straight to the shop. Put the breather on the car, then the Intercooler, and the the 3/4 hose that was missing to the IC. Hit the starter and it fired right up in 2 seconds and went to 1500 rpm,then about that time I got instant wood, lol. Cranking problem solved, after 2 min's the idle came down to 1000 rpm, the only problem I see left right now is it is so Rich, you can't stand behind it even in a open shop. I really want to thank everyone for sticking with me thru this problem, the way you guys was talking back and forth to each other in this thread discussing this problem was great. Thanks again.