Decided to make this a separate post.
I spent the other weekend getting my fuel pressure on the WUR to within spec.
I ran much smoother overall.
I then installed my wideband to try and fine tune the system.
I tuned for an idle AFR of 14.7.
Which it idled very well at this.
But when RPM is increased it quickly leans out to around 17 AFR at 3k RPM while driving.
I adjusted the mixture screw down several times.
Right now the idle is at 12.1 AFR and at 3k RPM it's at 16.6 AFR.
It seems it just doesn't have much effect on the lean high rpm issue.
I will hook my pressure gauge back up this weekend and verify pressures again.
If i floor it the AFR will go richer at around 15.5
What would cause this type of lean condition?
Anything i should test?
Seems like the system is starving from lack of fuel at higher rpms.
I will pull the air filter box out and manual push the arm to see if its binding maybe.
Just to state for reference.
New Parts:
In tank Pump
External Pump
Accumulator
Injectors
All hoses
Air meter boot
Idle air valve
Thermo switch
Fuel filter- 1 month old
Ground to battery and block.
Rebuilt:
WUR
Fuel Distributor
Air meter box
Ignition Distributor
Flushed tanks
Every rubber fuel line
Recently adjusted valves.
Last edited by osburn383; 07-17-2018 at 11:24 AM.
just spitballing, maybe something with the sensor plate or fuel pump relay?
Yeah maybe.
I guess i will just have to make a list and verify everything works as intended again....
I tested a bit at lunch.
I unplugged the O2 sensor.
Had to lean the mixture screw some.
But it now idles in park at 1100 rpm at about 14.5 AFR.
In drive 900RPM not moving it leans out to 15.0AFR.
If i turn the lights on, blower and press the brake it will go to 16 AFR.
Voltage from park is 14.4. Voltage in drive 13.6 and goes lower with things turned on.
AFR while driving is better.
3k Rpm is around 14.6.
Full throttle drops to around 12.6
Without the O2 sensor plugged in voltage drop affects AFR more.
With it plugged in there was really no affect on AFR.
Forgot to add the O2 sensor is maybe 6 months old now.
Last edited by osburn383; 07-17-2018 at 01:51 PM.
Remember that the "idle fuel mix adjust screw", is mostly just that - primarily only affects idle speeds and low loads.
Originally there are 'cone' shaped filters in the fuel ports, under the injector-line banjo-bolts on the fuel distributor. Check to see if they're still installed and if so - clean them. Be aware there's probably debris floating around in there, so it's best to give the fuel distributor a little 'flush' before re-installing the cone filters. It's difficult to see the filters - must dry the ports, use flashlight. Gentle upward twist to remove the cone filters, with proper sized tool, ie: modified small flat-head screw driver or torx bit.
Be safe with the fuel!
Tbd
Yes. And remember you'll probably have to re-adjust the fuel mix screw after changing the wur presures.
The cone filters are a 'slight' press fit inside the ports. Some filter styles are plastic with little ridges for a tool to catch while twisting. I'm not sure about the metal ones, but hopefully they're not in there too tight. These filters are more finicky about dirt than the injectors, some folks permanently remove them (while having a clean fuel system).Yeah the filters are still there.
I tried to remove them when i rebuilt the fuel distributor but couldn't.
Didn't try a torx bit though.
Tbd
I didnt get a chance to try and remove those filters.
I did adjust the WUR.
Warm is at 47psi
Cold is at 33psi at 95F.
This seems to fix the lean condition in the upper RPMs.
It idles ok. It just fluctuates more than i would like. I have it set around 14.5 AFR.
It was smoother the last go around.
While driving it goes from 14.5 to 15.2 AFR.
If i floor it i have to get it to drop down a gear so it reaches a higher rpm before it will drop AFR to 12.6.
If i floor it any other time it stays pretty much unchanged.
It starts fine cold.
But has trouble hot.
If i unplug my brand new Thermo switch it starts instantly.
Seems like it getting to much fuel on hot start.
Any thoughts or advice on this?
The thermo switch is suppose to disallow the cold start injector from spraying fuel, while the engine is above a certain temp. I forget what that certain temp is, but it shoukld be stamped on the thermo switch.
If the idle is 'hunting', it may be a tad rich, or vacuum leak and over-rich mix to compendsate for the vacuum leak. Or - maybe over-rich mix to compensate for dirty filters. Check those filters.
Edit: If the AFR is not 'lean' during acceleration/full throttle, then those filters on the fuel dist are probably ok.
Last edited by epmedia; 07-23-2018 at 06:45 PM.
Tbd
I guess i was assuming if i unplugged the thermo switch it wouldn't fire any fuel on the cold start injector?
I can set the idle mixture to 15 AFR and see.
I really don't believe i have any vacuum leaks.
Everything as been replaced and checked 6 plus times over the last 5 months.
It sorta hunts.
On crank i runs at around 11 AFR.
Then after about a minutes of idling it will hunt higher and fall a touch then hunt higher and fall a touch until the AFR goes to 14.5.
After that it doesn't hunt.
It just feels slightly rough.
What about the wide open throttle?
Doesn't the micro switch control part of that.
If i floor it its stays a constant AFR.
It doesn't change until i get near 4k RPM.
Thanks for responded.
Edit to my previous post: If the AFR is not 'lean' during acceleration/full throttle, then those filters on the fuel dist are probably ok.
yes, if the thermo-time switch is disconnected, it should dissalow fuel spray from the cold start injector.
There's a switch for rpm (speed relay) and the full throttle switch. Above *3500 rpm, the switch is active, to enrich the fuel mix. Note: there's a temp switch in this circuit too, please see the electric manual (save a copy!)
One thing I forgot about 'hunting' idle: Another thing you can do is make sure the meter plate (60mm or 80mm diam) rests level and centered in it's bore (engine off). The stop plate (spring) under this meter plate will sometimes need a little adjustment (bending/persuasion). If it needs adjustment, you most likely will have to re-adjust the 3mm fuel mix screw.
Speed relay: closes (enabled) above 3500 rpm.
Electric manual:
1981-1983
http://www.findmymerchant.com/images..._1981-1983.pdf
Last edited by epmedia; 07-23-2018 at 07:48 PM.
Tbd
Thanks for the info!
I will look at the circuit and check the other components.
Thermo switch.
So if the engine is hot and i unplug it to get it to start that means its getting to much fuel then.
I will have to pull the cold injector and verify its firing when plugged in just to be sure.
If it is to much fuel would i need to tweak the WUR pressures?
OE specs on the thermo-time switch is 'open circuit' (disabled cold start injector) @ 95f. The cold start injector is not suppose to spray fuel if the engine temp is above 95f (or whatever spec your new one is). If it is spraying fuel above 95f?, I don't know what to say about that yet...
---
I was just comparing the wur pressure specs (from faq/diy thread).
Yours: Warm control pressure = 47 psi
Specs: Warm control pressure = 48-54 psi
Your 47psi means it may be allowing it to run a tad rich through the range. * the lower the control pressure, the easier the airflow meter plate will raise - thus, giving more fuel through the injectors.
Tbd
What is the voltage from the O2 sensor when the car is warmed up and at idle ? Disconnect it and hook up the leads for power and ground, it will center between 0 and 1 Volt and do some hopping around.
Randy
Last edited by 320iAman; 07-24-2018 at 11:00 AM.
Its about .7
In drive at 850 900 rpm.
If i unplug it in park it was .8 at 1100rpm
It also starts hunting if unplugged and in park.
I need to lower the idle speed some as it is higher now than when i set it over the weekend.
- - - Updated - - -
I will test the full cold start circuit this weekend when i have more time.
As for the Warm Pressure.
I had set it previously around 50psi.
I was having a lean at higher rpm condition so i set it lower to see if that would help.
I really need to get a second WUR and make it adjustable as i am tired of taking this thing apart.
I would think that 50 psi warm WUR pressure should have been ok for the AFR. maybe those little filters are a little dirty
---
I don't know how spark plugs will affect the AFR... Just out of curiosity, what type of spark plugs are you using and what are they gapped to?
---
What happens with the AFR when you press the brake pedal now? I can understand that pressing the brake pedal can lean the fuel mix momentarily, because 'initial' brake booster operation, but it should not be a constant 'lean' condition, otherwise there may be a brake booster vacuum leak. Also, the brake booster check valve needs to hold a vacuum on the booster so that the brake system will be 'predictable' without any brake system surprises and so there's no extreme fluctuations of the AFR when braking.
Tbd
I will have to pull them and check the gap. I know its a little bigger than stock.
The brake pedal was a voltage issue.
I would add more load to the system via, brake, headlights, blower.
This is with the O2 sensor unplugged only.
It would cause the voltage to drop and the AFR readings would go lean.
AFR will not run lean if the O2 sensor is plugged in.
I can press the brake pedal and no change in the way it runs with O2 plugged in.
New hose and check valve to booster.
I could clamp it and see if there is any noticeable difference.
Last edited by osburn383; 07-24-2018 at 05:39 PM.
Were you able to test the fuel 'system' pressure while loading and unloading electrical components? The fuel system pressure must remain constant, ie: no variations during voltage changes (except for possibly a little jitter on the guage needle during voltage changes).
I'm beginning to also think about those little filters again... I suppose you may not show lean or rich on the guage if the filters are Not equally dirty. ie: could be lean on one or more cylinders and rich on the others. Remember that if you remove/clean these filters, any debris in the ports should be flushed out. And Be Safe with the fuel!
Last edited by epmedia; 07-24-2018 at 10:48 PM.
Tbd
From FAQ'S
2 - Adjust by O2 Sensor Voltage
If you want to be more accurate for emissions reasons, you can adjust the mixture by reading the voltage from the oxygen sensor. Unplug the O2 sensor first so the lambda system doesn't interfere with your adjustments. Make sure the motor is up to temp and the exhaust is hot since the O2 sensor has to be above 600 degrees for an accurate measurement. Bringing the motor up to operating temp by idling won't get it hot enough, you'll have to drive. Adjust the mixture until the O2 sensor voltage is at .45v. Now reconnect the O2 sensor and verify that you have a smooth idle. If it is oscillating you may need to tune slightly by ear to get a smooth idle with the sensor plugged in.
An oxygen sensor will rise up to about 0.9 volts or so when the fuel mixture is rich and there is little unburned oxygen in the exhaust. When the mixture is lean, the sensor's output voltage will drop down to about 0.1 volts or so.
Adjust O2 sensor voltage down a little by ccw turning Air/Fuel adjustment screw a little,leaning the A/F ratio, its very sensitive at a certain point and will hop back and forth from Ve .2 to .3 to Ve .8 or so. Goal is near Ve .45.
The Idle should be steady when the O2 sensor is plugged in or unplugged when fully warmed up.
Randy
Last edited by 320iAman; 07-25-2018 at 01:58 AM.
Bump
Randy
Sure ,you can also try enriching a little too to + 0.8V to + 0.810V and see what is better for runability. Mine is happier in the rich mixture settings,+ 0.8V- Power Band Area.
o2volts.gif
Randy
Last edited by 320iAman; 07-27-2018 at 02:12 PM.
I think its to rich though at the moment.
At least for the first few minutes.
Just a moment i go i went out for lunch.
It was hard to start and stay running.
MY wideband showed 10AFR.
I held the gas at 2k RPM for about a minute and then i can watch that AFR go up to 13.8 AFR
After that i idles pretty good.
Seems like the Lamda O2 sesnor is reaching a certain temp then adjusting the mixture?
Start up is around 9-11 or so, rich and then should lean out toward higher stoichiometric Air/ Fuel ratio.
Randy
To update this issue.
I rechecked my WUR pressures.
Cold read 26 psi at 93 Degrees.
I adjusted it to 35 psi.
I will recheck that this weekend to verify where it's at.
Last time i set it to 33 and as above it read 26 psi a week later.
The fully warm psi is now 49 so that's within spec.
They car has any easier time starting on a hot day now after adjusting the cold pressure on the WUR.
Still have to hold the gas pedal down just slightly if i restart the car after just driving.
When starting this morning in 73 degree weather it shows around 11.6 AFR.
Which is better than the 10 it was showing before.
I tired to run the car with the oxygen sensor but it just causes the AFR to jump around to much and makes it run rough.
When warm its jumping from 14.2 to 15.7 that's idling or driving at a steady speed.
It runs very smooth without the oxygen sensor.
The AFR after fully warm will be 14.4 to 14.7 and even less fluctuation at a higher constant rpm.
It is only a few months old but i do have a second new one to try and switch it out maybe.
Heck i would run it without the oxygen sensor all the time expect that while in drive at a stop at about 700 rpm the AFR will go lean to about 15.5
I guess not enough air is passing through the air meter to lift up the plunger on the fuel distributor?
I do have to say putting the Wide-band on has really helped with trouble shooting the engine.
Its just nice to see the actual values as you makes adjustments.
I will recheck pressures again and maybe tweak the WUR.
Change the O2 sensor and see if there is any improvement.
Any thoughts?
Sorry for the wall text.
Last edited by osburn383; 08-15-2018 at 10:21 AM.
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