wcarson

Hi guys,

I'm hoping to get some easy and elementary advice from the CIS experts out there. I have done a lot of reading, and have some clue as to how the system works, but I'm hoping for some quick guidance.

Here's my summary:
1982 3.3L 930, K27-7200 Turbo, Kokeln IC, SC330 cams, Mildly ported heads, single plug stock ignition, Euro heat exchangers, Borla Muffler. STOCK 0.8 Bar Boost.

Brand new (Rebuild) CIS Fuel Distributor and new Leask WUR (The car has run great and the motor has 6K miles on it, but I recently had an issue with a failed fuel distributor, hence the rebuild of the FD. I also just got a new Leask WUR and also had my euro injectors tested and cleaned too). So now I'm trying to tune the new CIS set up.

I have installed an AEM Wideband 02 system for tuning purposes.

The Leask WUR came with the following info (I have not tested these numbers):
Cold Control Pressure 1.5 bar at 22 degrees C
Warm Control Pressure: 3.65 Bar
Enrichment Pressure: 2.4 Bar

My issue is this: I set CO to 3% with a Gunson Gas Tester. AFR at idle cold was 11-12:1, then when warm was 14.5:1. It drove terribly. With even minimal load, like 1/2 throttle, no boost, flat surface, it would be lean at 15:1 AFR and hesitate and buck a bit.

I then started to richen the mixture up with a 3mm Allen wrench and doing mild street driving, then getting more and more on throttle and boost while slowly making adjustments to the mixture.

I am now at warm idle AFR of around 10.5 :1 (Very Rich I would think) and the car seems to run and idle very well. But getting into heavier throttle while building boost at lower RPM's, I get lean areas where AFR is up to 13-14:1. This is in lower rpms on heavy throttle as boost is building. As the boost builds to higher levels, the AFR richens up to around 11-12:1, but at higher RPMs on full boost, it starts to drift up to 12.5:1 up to 12.8:1 or so. Currently warm cruise AFR is between 12-13:1.

So I need to lean the car out a bit when on low loads and cruise but richen it up when boost is building and at full boost.

What specifically do you all recommend adjusting with the mixture and the Leask WUR? I am thinking I will need to set the mixture screw back to leaner to achieve an AFR around 13-14:1 at warm idle, then perhaps drop the warm control pressure to richen the AFR when under load. And I may also have to lower the Full Throttle Enrichment pressure if it's still lean when on full boost. Does this sound accurate?

Many thanks in advance!!!!

Gasngo

Its been a while since I have been under the hood of a CIS car. Do you have a set of gauges to test. Its been my experience that the cars run better with the warm pressure at the lower end the range. Heres a link I found some info. https://jimsbasementworkshop.com/CIS...pressures.html At a glance pretty accurate info as far as I can tell with out have a factory workshop manual. So if your range on the WUR is 3.0 to 3.5 I would have it set closer to 3. I suppose you could play with various pressures and see what works best but I think that would be a waste of time. Set it around 3.2 which will richen it up and obviously you will be going back to the mixture screw and lean it out. Now backing up a bit the fuel system only does what its told to do. Is the enrichment system working? lower fuel pressure is enrichment. Again its been a while but I think 3% at idle is a little fat but that can be worked on. If you adjust fuel pressure you will adjust the mixture screw. Does the mixture screw hole need to be capped off once its set? or is it a air leak?

wcarson

Hi Gasno,
Thanks for the feedback. This makes sense. I do have the CIS pressure testing equipment. I plan to check the pressures to verify what they actually are and make adjustments from there. I plan to set the warm control pressure to the lower end of the spectrum and adjust the mixture setting after that. I'll follow up with some more data soon. The enrichment is definitely working- I can see the fuel dump as boost rises. Thank you again- it's very helpful!

Bernie930

Hello, first of all there is no such thing as Euro injectors! All 930 injectors are the same, there is however bigger fuel lines. Who rebuild your FD? Is it a cast steel unit or aluminum? My bet its either a bad FD or huge air leak.
B

Bernie930

Also what timing are you set at?

Gasngo

Good info to verify regarding Bernies input. I did not think about the Dist and timing. Does it have a retard feature or advance cant remember centrifugal working? Anyway take you time go over stuff and do testing. Fuel pressure test for sure.

wcarson

Thanks for the input. The FD is a rebuilt unit from RarelyL8 Motorsports. It's a black cast unit, like the one that I had on it previously. My previous unit had been rebuilt and modified for increased flow by CIS Flowtech. The current unit is stock, but the WUR is a Leask adjustable unit. I have not checked the timing since the motor was set up and tuned years ago- it ran beautifully for the last 20 years until the old FD failed. So I have not touched the timing at all. All I've done is pull out the old FD, the old WUR, and injectors.........and replaced them all with the rebuilt units. I will be checking all the pressures and also making sure there are no air leaks.

I think most people call the 930.110.225.02 the "Euro Injectors" (around 150-200$ per injector new), and the "non-Euro" ones are 931.110.225.00 (around 65$ per injector new). I have no idea if the flow characteristics are the same or different, etc. The cost is certainly a big difference.

Thanks for the input and advice gentlemen- I will keep you posted. I'm learning a lot about CIS in the process and I truly appreciate folks weighing in who are far more knowledgeable than me.

Gasngo

I checked out the Rarly 8 sire and looked at the adjustable regulator and I see the low pressure warm up nut and stud it appears but whats the round disc with a screw or something. Got some pics?

wcarson

Hi gents,

Quick update- the system pressure is 6.2 bar, within spec, cold control pressure is 1.5 bar and warm control pressure was 3.65 bar, just as it was supposed to be set at.....RarelyL8 included a spec sheet from Leask that had the preset values listed. Spot on. I decreased the warm CP to 3.4. I then leaned the mixture at idle so the AFR is 13.5 when warm. I also refit all the intake and intercooler fittings and hoses and re-tightend all the clamps very carefully. It idles beautifully. I will start test driving next week- just had to leave town for the next several days. Hopefully I'll get it sorted.

Gasngo- I'll take some photos for you next week. The unit is very neat. Fully adjustable WRT Cold CP, Warm CP, Boost CP, and Boost threshold. Pretty neat unit. Certainly the warm CP set screw adjustment worked just as advertised. Thanks again!

Gasngo

As I said a little rusty but what did you do to lower the warm pressure. My memory and I think Im correct on this the small modified button with the nut and stud only effects the cold pressure. The large diameter ring with the 2 fittings when either tapped in or tugged out will effect the warm and both actually. So if you had 1.5 cold and 3.6 warm with adjustment to 3.4 then your new cold will will be lower like 1.3 or something. Check it and see if Im correct on that. If so you will give the nut a turn to raise the cold so its not so rich on start up. I know its not easy to get to but you can run it without the electrical connected to the WUR so you have a minute or so to play with the cold setting.