Printable Version of Topic
Click here to view this topic in its original format
914World.com _ 914World Garage _ Way too lean...
Posted by: Olympic 914 Feb 17 2019, 10:23 AM
Put the engine back in after removing it to repair the trunk hinges and finished hooking everything up yesterday. After a couple turns of the key to purge the fuel lines of air, I hit the key to start it.
After a few turns it started and when the AFR gauge finished its 20 sec countdown, I was looking at 16.0 on the AFR gauge.... way too lean.
That is the upper limit I have set to display on the Autometer Wideband AFR so I really don't know what it was, I just know its too lean. I won't idle, just shuts off, but will start right back up again.
Double checked all the vacuum hoses and everything is connected correctly. and if there was a vacuum leak the idle would be waay up. I know that from experience.
One of the things I did while I "was in there" was switch out the 037 ECU for a 044 ECU I had purchased. The 037 being used on both the 1.7 and 2.0 in 1973 and the 044 being used on the 1974 2.0
Also set the valves and changed the oil.
I left the MPS as I had it set using the 037 ECU and it was richened considerable to get it to run good. I really had expected it to be to rich for the 044 ECU also.
These are the MPS specs from P Anders site.
For comparison this is what mine was set at.
0 Hg 1.51
4 Hg 1.34
15 Hg 0.85
Richer than the chart but worked for my engine mods.
2056 w/ Raby 9590 cam and HAM RS+ heads D-jet 2.0 FI system 123 Ignition.
Looks like my next step will be to put the 037 ECU back on and see what that gives me.
I had unplugged the O2 sensor when I removed the engine and it would probably register a failure if the wire wasn't plugged back in right. I had changed the 123 dizzy setting from 1 to 2 which was the recommended setting for the 044 ECU but that would not / should not affect the mixture.
I thought that the ECUs usually did not fail and the engine did run but I wonder if I got a bad one??
What else would cause this.
Well down to the garage to switch out the ECUs , I'll report back later.
Posted by: worn Feb 17 2019, 10:59 AM
Put the engine back in after removing it to repair the trunk hinges and finished hooking everything up yesterday. After a couple turns of the key to purge the fuel lines of air, I hit the key to start it.
After a few turns it started and when the AFR gauge finished its 20 sec countdown, I was looking at 16.0 on the AFR gauge.... way too lean.
That is the upper limit I have set to display on the Autometer Wideband AFR so I really don't know what it was, I just know its too lean. I won't idle, just shuts off, but will start right back up again.
Double checked all the vacuum hoses and everything is connected correctly. and if there was a vacuum leak the idle would be waay up. I know that from experience.
One of the things I did while I "was in there" was switch out the 037 ECU for a 044 ECU I had purchased. The 037 being used on both the 1.7 and 2.0 in 1973 and the 044 being used on the 1974 2.0
Also set the valves and changed the oil.
When I built a 2056 I set the MPS as per Anders. I found I had to futz with it beyond that test drive futz test drive futz. My car ran better when leaner but too hot. Perhaps because I bumped the compression. I have it set pretty rich at the moment. One problem is there is no way to alter the slope of the curve. You can set idle and you can set the point where the second diaphragm cuts in and you can set the max. And that is it.
Good luck!
I left the MPS as I had it set using the 037 ECU and it was richened considerable to get it to run good. I really had expected it to be to rich for the 044 ECU also.
These are the MPS specs from P Anders site.
For comparison this is what mine was set at.
0 Hg 1.51
4 Hg 1.34
15 Hg 0.85
Richer than the chart but worked for my engine mods.
2056 w/ Raby 9590 cam and HAM RS+ heads D-jet 2.0 FI system 123 Ignition.
Looks like my next step will be to put the 037 ECU back on and see what that gives me.
I had unplugged the O2 sensor when I removed the engine and it would probably register a failure if the wire wasn't plugged back in right. I had changed the 123 dizzy setting from 1 to 2 which was the recommended setting for the 044 ECU but that would not / should not affect the mixture.
I thought that the ECUs usually did not fail and the engine did run but I wonder if I got a bad one??
What else would cause this.
Well down to the garage to switch out the ECUs , I'll report back later.
Posted by: r_towle Feb 17 2019, 01:25 PM
Valves may be too tight, that would cause lean.
Timing also, but at idle you would see less impact.
Then, back to the other ECU.
Those heads will flow better than a set of stock heads, so that will also cause lean.
Posted by: 914_teener Feb 17 2019, 01:27 PM
Are you SURE the sensor is calibrated correctly?
Is it cold where you are?
I'd just put the 037 back in.
Posted by: Olympic 914 Feb 17 2019, 01:45 PM
Valves may be too tight, that would cause lean.
Timing also, but at idle you would see less impact.
Then, back to the other ECU.
Those heads will flow better than a set of stock heads, so that will also cause lean.
Cro moly pushrods set at .002 instead of zero lash
Didn't change dizzy position from previous just changed dip switch to position 2
Are you SURE the sensor is calibrated correctly?
Is it cold where you are?
I'd just put the 037 back in.
Same MPS calibration as before, didn't change that.
I just put the 037 ECU back on and it started right up cold (50* in garage)
AFR at 10.7 - 11.0 idle As I recall it would idle when cold out but not as good when temps were warmer, until engine warmed up.
Going for a drive. We shall see.
Posted by: Olympic 914 Feb 17 2019, 03:14 PM
Seems to run good now, with the 037 ECU back on. drove a couple miles till it started to HAIL and I had to scoot back home...
Looks like I just wasted some money on an 044 ECU, Still don't understand why that one ran so lean.
Still saw a couple lean moments but for the most part it ran as it did before. Probably should have left well enough alone.
Posted by: cgnj Feb 17 2019, 06:50 PM
Did the idle mixture adjustment have any effect? These ECUs are pretty bullet proof.
Posted by: Olympic 914 Feb 17 2019, 07:28 PM
Did the idle mixture adjustment have any effect? These ECUs are pretty bullet proof.
I did try the idle mixture on the 044 ECU to no effect that I could see.
Again the top range of the AFR gauge is set at 16.0 I may have been able to notice a difference if I had adjusted the top AFR setting to something like 20.0 or whatever the top of the range is.
as it was, revving the engine in the driveway it remained solid above 16.0 and I didn't want to venture down the street not knowing how lean it was and risk cooking something.
Posted by: tmessenger Feb 17 2019, 08:00 PM
Did the idle mixture adjustment have any effect? These ECUs are pretty bullet proof.
I did try the idle mixture on the 044 ECU to no effect that I could see.
Again the top range of the AFR gauge is set at 16.0 I may have been able to notice a difference if I had adjusted the top AFR setting to something like 20.0 or whatever the top of the range is.
as it was, revving the engine in the driveway it remained solid above 16.0 and I didn't want to venture down the street not knowing how lean it was and risk cooking something.
Lean is not hot. Stoichiometric (14.7 a/f) with petrol is where the most heat is produced, if you are running around that range then you need to be concerned.
Tim
Posted by: r_towle Feb 17 2019, 09:30 PM
The heads flow better, so it will run more lean than stock.
The 037 always ran rich, so you may have a decent setup.
Posted by: Olympic 914 Feb 18 2019, 07:35 AM
The heads flow better, so it will run more lean than stock.
The 037 always ran rich, so you may have a decent setup.
I was not aware the 037 ECU ran richer. So its possible that the 044 ECU I have is OK, just not optimal for my application.
I'll put a few more mile on it and see how it runs . basically its the same setup I had.
The fuel pressure is at 28, so another possibility is to bump that up a little and then dial back the idle mixture on the ECU
I was looking to get the most out of these heads and cam and thought the 044 ECU may have been a step down that path.
I have a vacuum gauge, but haven't hooked it up. mainly because of the plumbing involved. but that might help tune the MPS because then I would know what vacuum the MPS was seeing when it went rich or lean and give me a better idea of where adjustments may be needed.
Or I may just be chasing unicorns.
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)