sand_man

I thought I'd post some info into a single thread for those of us dinosaurs still on CIS.

To recap: I have a newly installed Imagine Auto modified fuel head. The engine has been running VERY rich - rich at start up and rich on WOT full boost. I've had to dial back the fuel metering adjustment screw to the point that the engine would barely run...still too rich!

Just to give you an update: I tested all of my CIS fuel pressures with my new fuel injection gauge set. All were pretty close to spec except for my cold pressures which were at about 1.8 BAR at 85 degrees F (approximately 30 degrees C). It should have been around 2.6 BAR to 3.0 BAR. Just to give you my broken-shade-tree-jack-leg technical explanation on this, the higher the pressures the leaner things actually run....thus my cold pressures were rich.

I shared my findings with Brian Leask and his thoughts were that I should go ahead and modify my own WUR (he thinks it's actually functioning good enough) - then wait for the release of his newly developed RPM enrichment device (that RSRS is testing), which will help remove the mid-range to upper RPM rich condition that many of these systems have.

My fuel head and WUR discussion
Pictures of Brian's adjustable WUR
Info on connecting the gauges
How to modify your own WUR

So last night I removed the WUR, followed the adjustment mod instructions above, connected my CIS gauge set, and screwed my WUR "pin" up until the gauge was reading at 3.0 BAR. You tap the pin in to lower your pressures (lower is rich, up is lean)...my pin was too low. The car fired right up but needed me to richen the mixture control screw on the metering housing. Being that this is my daily driver, I had to button things up for the ride into work this morning, but the car ran very smooth. I haven't had a chance to test my AFRs, so I'm staying off the boost until this weekend. I'll post an update this weekend after some more tuning...

sand_man

One other thing that I want to mention: if you are unfamiliar with CIS, don't be fooled by this thing called a Warm Up Regulator! I think it should have been given a more appropriate name! The name leads you to belive that it's just a part in a chain of other parts to help with cold starting...it does a WHOLE LOT more than that! This is really the device controlling the pressures to your fuel head!

TrackDays247.com

My Brian Leask WUR should arrive today - along with his 'RPM switch kit' (official nomenclature).
The items Brain produces reflect his attention to detail and perfection learned from the "real day job" industry he is in - the schematics and pictures of the items are fantasically done.

Shop is trying to get fuel to the injectors - I should have an update and perhaps the car back in my hands on Tuesday - shop is closed Mondays, 10 hour days.

TrackDays247.com

I vote we change the WUR name to "Electric Fuel Pressure Regulator"
EFPR. I like it.....

sand_man

So with my cold fuel pressures set to 3.0 BAR at the WUR, my car is finally leaning out with the Imagine Auto fuel head! I'm still not pushing the boost too hard or pulling many WOT runs, 'cause I think I'm just a tad lean. I'm in the low 13.0:1 AFR range at about 5,000 RPMs with moderate boost. I'm not sure if it will go rich or stay lean if I push further. I'd like it to be in the 12s. I've added a tad more fuel with the fuel head adjustment screw. I'll take a lunch time run on the interstate and see what that does. I have noticed that my AFRs are much more stable and not jumping all over the place as they once were!

Right now I'm thinking that I'm going to have to tap my WUR adjustment pin in just a c_nt hair to bring my fuel pressures to about 2.5 or 2.6 BAR.

This tiny adjustment at my WUR has changed EVERYTHING! The throttle response has greatly improved, too!

A930Rocket

Keep up informed...

Olli

Good to hear the adjustments have had a positive impact on your car! And also congratulations on modifying the WUR by yourself. That's pretty good.

Just a quick question about the procedures you performed: The cold pressure was set at the WUR to be 3.0 bar (mine is in the 1.6-1.8 range) for leaning out the cold idle mixture. When you add a bit more fuel with the fuel head adjustment screw, doesn't that enrich everything, including the cold idle mixture, negating what you accomplished by the WUR adjustment?

I've been thinking that once I get the cold (1.6-1.8), warm (3.65) and FT (2.2) pressures correctly set at the WUR, I wouldn't want to touch the fuel head adjustment screw anymore, since in my mind that would change the situation. Am I wrong?

sand_man

When my WUR was originally at 1.8 BAR with the Imagine Auto fuel head, nothing I did in adjusting the mixture control screw would keep the car from diving down into 10.0:1 AFRs at WOT. The car smelled eye watering rich at start up and had sluggish throttle response once in the 5,000 RPM range. I had the adjustment screw backed off to the point that the car would barely run...yet when I got on it, it just continued to go way rich.

Now that I have my WUR cold pressure set at 3.0 BAR, I obviously had to adjust the mixture control screw as it had been previously leaned out to compensate for my overly rich condition. Now my AFRs appear to be steady stated at the 13.???:1 range and aren't nearly as spikey. I need to fine tune until I get 12.5:1.

I think what's happening is that the actual pressure to the fuel head is being changed...in my case things have finally leaned out. Now I can use the mixture control screw for the fine tuning. if I find that I still can't get to 12.5:1, I'll go back to the WUR and adjust it to 2.6 BAR...then back to the mixture control screw! NEVER ENDING!

Olli

Thanks...this is an interesting topic and naturally I hope you'll get down to 12.0-12.5 with the WOT AFRs. I will stay tuned

sand_man

Okay just got back from my "lunch time" run down Interstate 540. I got the oil temps up to operating and ran the freaking **** out of her! What a fantastic engine...so smooth, no hiccups, no misses, no hesitation! So after a tad more richening of the mixture adjustment screw (just to be safe), my AFRs on a third gear pull to about 5,800 RPMs are at 11.7:1 then up to about 12.2:1. Some of this might be eliminated with more tweaking or possibly Brian Leask's WUR solenoid. I smell like gas fumes and I think I might leave well enough alone. I don't know, maybe I'll lean the control screw a tad more. Right now my cruising AFRs ar 13.7:1 to 14.2:1. Maybe this is good enough?

Any thoughts?

Olli

Sounds like you are on the home stretch! That's really good news! The excercise you went thru modifying your WUR is a highly respectable accomplishment, at least in my opinion. However, for the capability of adjusting the warm and FT pressures as well as the cold pressure, and somewhat being able to control the FT threshold, I'd just go ahead and have Brian rebuild the WUR. Those adjustments are actually very easy, and they work like a charm. I am looking forward to getting his RPM switch as well. I ordered the solenoid from Pelikan but it's special order and they don't have any right now so it's on back order. I guess they have to get it from Germany. I believe that the solenoid is the one part you have to supply yourself in the Brian Leask RPM switch/solenoid solution.

sand_man

Some other observations:

-I once posted a thread asking about "POPPING" from the Zork tube when the car is idling. That has now gone away. The engine just has a steady, yet very deep rumble at idle.

-The smell coming from the tail pipe used to have an almost Keroseen oder to it. Especially when the B&B single tip was on. Possibly raw fuel? It was just aweful. People behind me in car-pool line at my son's school would jokingly fan their faces when they were behind me. Now the smell is much more gas like...what you would expect.

-Using an Innovate tail pipe clamp in my Zork tube, my idling AFRs would be as high as 20:1 and the car would still run...just quickly drop up as I started driving. I was told that was because of the outside turbulance that the O2 sensor must have been picking up and/or not having enough exhaust flow over the sensor for a good "at idle" reading. Using the same clamp in the same Zork in the same location, my idling AFRs are much much lower (close to normal) and pretty much stay there through the range! WTF!

-Before, my AFRs would just jump all over the place! Now, it's a much more flat and steady line. Still spikes up on decel, obviously, but none of this going from 20:1 down to 9:1, back up to 14:1 **** that I had before!

TrackDays247.com

Sand -

Can you tell us more about the Innovate setup - temporary, correct?
Where are the wires run?

I am installing the Leask WUR today, and the solenoid in the near future - I need a setup/method formeasuring the AFRs.....ideas per the above wanted!

sand_man

RS, yes my setup is temporary and I'm sure far from optimal. My Innovate LM-1 came in a "kit" that included the Innovate tailpipe clamp. The O2 wire I just carefully run over the rear fender of the car into the cockpit, through an open window. I do plan to have the bung welded to my Zork in which case I'll be running a permanent AFR gauge in place of the clock.

TrackDays247.com

Thanks!

That is exactly what I plan to do ;-)
In fact, I will probably buy a used LM-1/LM-3 setup from a Rennlist member. He set his up and is done with it.

IMO, periodic checks are all that are necessary once it is set.