AFR check after new turbo
 

I just installed a new AFR gauge and an upgraded K 27 turbo. Some suggested I may need to adjust my WUR to accommodate. However after going for a drive it seems I'm at about 15 to 14 at idle and between 10 and 11 at higher rpm's. I believe this to be pretty good and hoping I can just leave my WUR as is. What do you think?

10 is drowning in fuel and leaving a lot of power on the table.

Ok thanks Tippy. Can you recommend a link where I can read about what my AFRs should be?

Sounds like you could just turn up the boost and dig it since you're getting more than enough fuel the way it is now.

I’ll let the CIS pros take care of you, but around 12 is a good median between power and safety.

Not sure how you adjust CIS to get you there!

Depends a bit where the fuel is arriving in the rpm range. If it is all dumping at boost onset, you are probably below 10s for a fair rpm range. Not good.
The simple fix is to harden the Warm pressure in the WUR - adjust the diaphragm screw in . But before you do that it is really helpful to know what the pressure is now (warm). Normal range 3.6 bar +/- 0.2. If you are on the low side, that is the first fix. Then see where you get to with AFR. Then you can eliminate/delay the boost dump with an rpm switch and solenoid valve on the WUR boost line (Leask switch). Those changes should get you a much more sensible AFR curve. Low-mid 12s should get you close. You WILL feel the difference - much sharper response. You are drowning in fuel - not good for the engine, or performance.
Alan

It's funny I already thought the car had sharp response. So how do I check pressures? Sounds like I have to buy some tools and do some more reading...

https://www.ebay.com/p/CTA-Tools-3420-Fuel-Injection-Tester-Bosch/1455414050

PM me your email address and I'll shoot over Leask's WUR tuning instructions.

I just ordered this one a few days ago.

https://www.ebay.com/itm/SG-Tool-Aid-33865-CIS-K-Jet-F-I-Tester-w-Case/400930491794?epid=672824579&hash=item5d5951cd92:g: RtgAAOSwstxVbMDB

pm sent
 

I have one , but have since gone EFI... I'm not too far. Philip

Trust me. You have plenty more 'sharp' to come. The engine will come alive. The sweet spot is around 12 AFR, but it gets progressively better as you eliminate the 10s and low 11s. You are being robbed of plenty of HP.
Basically you will need to tune the WUR to around the 3.6 bar spec, if not already at that spot. You can push it as high as 3.8 if needed (this leans your fuel out across the range).
The other problem is the diaphragm in the WUR sees the boost pressure at boost onset (3-3500 rpm), and drops this Warm pressure by around 0.5 bar (3.6 down to 3.1). You will need to test this too - make sure not more than this. So on boost you actually run 3.1 bar (richens mixture). The problem is at 3500 rpm you don't need all this fuel - maybe at 6000 rpm but not 3500. But it is a crude system. So you can make it a bit more elegant by delaying this fuel dump til further up the rpm curve. The Leask switch blocks this boost signal til a predetermined rpm point (rpm pills). Then it it drops to 3.1 bar. Ideally you will set it so at boost your rpm and AFR will increase with the AFR going to around 12, Then the boost dump occurs (around 4500 rpm) . The AFR may drop to around 11 briefly then climb in to the low 12s ideally.
So you only have a brief moment (maybe 250 rpm ) in the low 11s. The car comes alive. Hang on tight.
Plenty of guys here to help you thru the tweeks. Look foward to the reports.
Alan

You will need a CIS check gauge - prob some guys here that can lend one. But it is a good investment for your car (since you now have AFR). And a Mighty Vac for checking boost dump pressure on the CIS gauge. Other than that - basic tools to tweek the WUR - allen keys.
This is the best/cheapest performance upgrade you can do for your car, and help your engine at the same time. Maybe $500 all up - CIS gauge, Leask switch, Mighty Vac?
Alan

Thanks for all the info fellas. It really helps a lot! I realize now that I misunderstood AFR ratios.

Looks like I'll get Philips tool and start playing. ( where's Rawknees when you need him ) I think I can borrow a mighty vac from a neighbor. I'll report back soon!

^^^ He's fallen into the abyss known as the Political Forum. We need to put together an intervention.

Running excessively rich fuel (AFRs 9-11) means you have more fuel than needed, sloshing around in your cylinders. Apart from robbing performance, it dilutes the oil which is carefully sprayed on the cylinder walls.
You engine will like you and you will like your engine.
Alan

Ok interesting! Could this be partly why I'm going thru so much oil? Roughly 1 litre per 750 Km's?

Nope. Just that what oil is in there for lubrication is compromised with too much fuel mixed with it.
A leak down test would tell you the health of the combustion chambers (re oil consumption). Otherwise, likely valves/guides.
Alan

I think I'll grab a neighbour and go for a ran and get him to video the AFRs as I'm going thru the gears.
Does Leask still sell the switches? Anyone got one they want to sell? Does RarlyL8 have them?

So my AFRs are 14-15 at idle and 10-11 at top end, still to be confirmed soon via video camera, one evening.

But if I understand correctly. I need to enrich my low end and lean out my top end.

So I need to:
1 - set my cold pressure, or confirm its value compared to factory specs.
2 - set my warm pressure, or confirm its value compared to factory specs.
3 - Adjust the enrichment control pressure - lower the pressure to lean my mixture upon boost.

So correct me if i'm wrong, from what i've read, I believe I am able to correct my too lean low end with cold & warm pressures and correct my rich top end by leaning out the enrichment control pressure. However if i'm not able to get close enough I may need to enlist the help of a boost switch?

Also I believe my CIS is an early non lambda version from the 1975 chassis, i'm not sure how that factors into WUR adjustments I need to make.

Euro CIS would have the black iron fuel distributor and no Lambda.
You can tweak the WUR threshold settings on all but the earlier WURs. Go really slow with this as it is easier to reduce pressure than add it back when you get to the limit, you will be adding pressure on boost. The spec range I use is 11.5:1 AFR at boost onset to 12.2:1 AFR at 1.0bar boost redline. It takes some fiddling to dial it in as you are working with a see-saw where changes in one plane have some affect on others.
If using a mity-vac or air compressor you can control the pressure manually. Put a charger on the battery and run the pumps with the engine off and the WUR unplugged. Record system and cold control pressure. Plug the WUR in and observe the warm-up period until it is stable. Record warm control pressure. Introduce boost pressure slowly and record the threshold control pressure and the boost control pressure at 1.0bar. Raise the boost control pressure at the WUR slightly to the level you think it should be (based on where it is now in relation to AFRs). Drive the car and have a passenger read off AFR on boost. Repeat until the specs you want are dialed in.

http://forums.pelicanparts.com/uploa...1524754810.JPG

Thanks Brian, so when you say " The spec range I use is 11.5:1 AFR at boost onset to 12.2:1 AFR at 1.0bar boost redline."

Since i'm running .9 bar boost, I should use same figures correct?

That is the range I use, others may prefer a slightly different range. Yes I would use the same figures for 0.9bar boost.

Those numbers are about where you need to be. Engine running clean, and still safe AFR.
I set idle mix by ear - not AFR. You will find a range of AFR that engines seem happy to idle at.
Do the WUR adjust first. Idle mix last. Depress the adjust screw, insert 3mm allen key and anti clock = lean, clockwise = rich. 1/4 turn is a decent size adjustment.
So you need to check warm WUR pressures first, then boost dump pressure (Mighty Vac). Don't hook a shop compressor direct to WUR - you will blow the diaphragm. gentle. Max WUR drop is around 0.3 bar boost pressure - you don't need to blow more than 0.5 bar. Warm pressure should drop no more than 0.5 bar. You may need to tweek your WUR warm pressure up by about 0.3-0.5 bar to get AFRs up to Brians levels.
Regards
Alan

The Leask sw won't affect your AFRs at top end. It just delays when the fuel dump arrives. It 'evens' the fuel curve out a bit - so you can have decent AFR at top end without excessive fuel in mid range.
Alan

Thanks for the clarification on the Leask switch.

Also thanks for the info Alan & Brian, much appreciated. I received my CIS pressure testing kit today bought from fellow Canuck Phillip. I hope to get busy with it this weekend.

Yes if using an air compressor get a feel for how well you can control the pressure before hooking to the gage and WUR. You will find that the fuel pressure on boost has a very short range of about 0.3bar threshold to 0.6bar max. I slowly take it to 1.0bar and record the range.

Brian, Do you mean if i'm using an air compressor as opposed to a Mityvac? I have access to a Mity vac so that's what i'll be using.

^^^ Ditto. How would you use vacuum? I get the pressure to replicate boost.
I’m following along here too. I’m a week or two from needing to do this.


Sent from my iPhone while Driving

With the MityVac, I believe you can make it suck or blow, but Rawknees would know more about that than I. :D

I've used both, the MityVac is easy to use and safer than the compressor which relies on a regulator for pressure control. Dialing down the compressor gives more precision. Either way cuts down on the number of road tests needed.
The 0.3bar to 0.6bar range I spoke of is the boost response range where the WUR will lower fuel control pressure. Warm control pressure is maintained until about 0.3bar of boost and then drops as the boost pressure raises to about 0.6bar. Above 0.6bar the decrease in fuel pressure significantly slows then stops. That is the range you have to work with and make adjustments to.

Following this as well! Time to tune my WUR again as well!

You get the WUR warmed up - takes 3-4 mins prob. You don't need to run the engine. pull the plug behind airplate. Turn key on and pumps should run and you will have voltage at WUR. Which will warm it up. Have your CIS gauge hooked in the system before you do this. Warning - you need to make sure you have good power going to the pumps - they suck a fair bit of juice and will pull a half decent battery down over this time. I hook jumper leads to an adjacent vehicle and have THAT engine running. Measure your warm WUR pressure (WP) - when it has stabilised. Pull the line that feeds in to the WUR from below the throttle body butterfly. This is the boost signal line. Either end - whatever is easier to get to. If you pull it at the WUR you need to hook another line from the mighty Vac to the WUR. The Mighty Vac works two ways - it has a slider valve on the end - suck/blow. Pull the valve back to the body (blow side). Hook on to warm WUR, and squeeze trigger a couple of times - you will see the gauge pressure rise to 0.5-1.0 bar. Don't go over 1.0. (damage daiphragm)
You will see the WP drop. Measure WP and the drop and report back. Then have a beer and wait for replies. Did mine y/day.
Alan

Chris - have you checked your system for airleaks? Just a thought - without trawling back thru thread. Your symptoms are also typical of airleak in the intake system - lean idle AFR, rich boost. Any airleak will suck more air in at idle (vacuum) and loose metered air at boost - which the fuel system won't compensate for = rich. You need to be sure there are no leaks before tweeking the fuel system.
Alan

Guys, while you are in there - you may as well measure Cold Pressure too (CP). This is the pressure you first register as soon as the pumps kick in. Note that, and the room temp at same time. That way we can relate whether is in spec too. The other pressure to note is the Rest or residual pressure . That is what is measured after you shut the pumps down. This tests the function of the fuel accumulator. it should hold decent over 30 mins or more. May as well collect all the data while on the job.
One more pressure - while in there - System Pressure. Pumps running, shut the CIS gauge valve off. Gauge should rocket up to around 100 psi. Note this reading too.
Alan

Great thanks again Alan, i'll check for air leaks. I don't believe there is any. It seems to run fine, and 3 out of 4 times it starts with a flick of the key, the 4th time I have to hold the key in start position and modulate gas and it finally starts. So maybe this weekend, I'll do my best to check for any air leaks. I'm not sure i'll get enough uninterrupted time to check pressures.

I have a battery charger with 3 charge settings, i'll use this while doing the tests.

There are various ways to check for leaks - posted on this forum. I prefer to pressurise my system - from the rubber elbow after the airplate. Works great - no more than 5 psi.
Most people don't believe they have leaks - until they check. If you haven't done so, I would suggest this first. Otherwise your WUR tweeking may be premature.
Regards
Alan http://forums.pelicanparts.com/uploa...1524860597.jpg

Didn't check for vacuum leaks yet, the weekend was too nice had other work to get done. I went for a rip yesterday afternoon and noticed the car pulled the best as the AFRs were 12, and the pull went away as the AFR's went into 11, 10, 9 territory. Tonight i'm going to spend a bunch of time on it. Check for leaks, then check Cold Pressure, then Warm, then Full throtle enrichment pressures.

Alan, where yo say "depress the adjust screw", I don't recall anything in the WUR instructions about pushing a screw to adjust it, I thought I just put the Allen key in and turn it?

Also my adjustable WUR I bought thru Brain @ Rarly L8 and he sent it roughly configured to my engine mods as I described to him. I believe there was some hand written specs on my instructions which I dug up recently. So i'm hoping I wont need major changes to get closer to what I need pressure wise.

Specs are set according to the engine modifications so should be close. System pressure, boost pressure and idle mixture all play a part. The idle mixture screw is spring loaded, you must push it down (gently) to engage the receiver. Push down too far and the engine will stall. Adjustment should be CCW to rich first then CW to lean. Only a tiny adjustment should be needed if any at all. I would set the idle mixture first, if needed, then verify warm pressure before going on to boost pressure. Once all done recheck the idle mixture.

Sounds hopeful if you have a pre adjusted Leask. But yes you need to be in the 12s. You can notice the difference. The idle mix is independant of the WUR - the spring loaded screw by the airplate.
Looking foward to the data. If you can get to 12 on boost now, prob more a small tweek and a boost dump correction/leask switch. Then .......wahoooo.
Alan