Tuning the RX4's Fuel Injection - Page 2

wheelbender6 · 04-21-2022, 10:59 AM

The reason I am horning in on your thread is because I may buy a Genuine G400C, and it has Delphi EFI.
I’d like to own an RX4, but the seat height concerns me since I have only a 29” inseam. I ride in a lot of stop and go traffic and tall seats make that more difficult.

Boatguy · 04-21-2022, 11:14 AM

Quote:

Originally Posted by pyoungbl

You might find this interesting...from Zongshen....

Ah! A new weapon for the EFI/carb wars! Lolol.

wheelbender6 · 04-21-2022, 11:56 AM

Great bedtime story.

pyoungbl · 04-21-2022, 12:32 PM

The Delphi ECU is used on many small engines. They probably have similar (if not identical) sensors but the actual map is going to be modified to work with the specific engine model, exhaust and intake setup. As a purely academic exercise I'd like to know how the various sensors feed into the base map and how they interact. Check the throttle body size for that Genuine 400. On the RX4 it's a 45mm TB.

JFOlivier · 04-21-2022, 01:17 PM

If you take a look at the IAP sensor on the x-pect it is between the throttle valve and the intake manifold so how does that give you the atmospheric pressure when it is working from almost a vacuum to near atmospheric pressure depending on the throttle position and the engine load. I sort of felt that that pressure sensor was sort of an advance warning to the EFI system as to where the RPM's were in relation to the throttle valve so as to supply more or less fuel. With RPM's rising on a flat road throttle valve will be closing and pressure in the inlet manifold will be dropping into more of a vacuum where Rpm's dropping on a hill with the throttle valve opening would be increasing the pressure to the IAP. So does this sensor really do anything about altitude or is altitude just handled by the O2 sensor in a closed loop.

pyoungbl · 04-21-2022, 01:34 PM

x-pect?

wheelbender6 · 04-21-2022, 02:04 PM

The G400c makes a little over half of the hp of the Rx4, so it will have a much smaller throttle body. The rest of the EFI components should be very similar.

Bob Kelly · 04-22-2022, 12:23 AM

Quote:

Originally Posted by pyoungbl

Adjusting the resistance leaves one with the same problem as before, the ECU will respond with more fuel across the entire rpm range. A good ECU map will try to maintain the mixture at a steady state but, in reality, many maps go from lean to rich and back to lean. This means that your 'fooler' might take care of a lean condition on parts of the map but a super rich condition elsewhere. The only way to know what's going on is to put the machine on the dyno. I have seen some very talented tuners who were able to build a map to flatten the mix but this is not something the average garage tuner can accomplish. If the Delphi ECU was used in large numbers of motorcycles we might see tuners stepping up to create a better map but that's not the case right now.

Personally, I do not have a problem with the fueling on my RX4. I'm keeping it stock, along with the intake and exhaust.

But the problem is that the bike Runs too lean from the get go !!! it could handle more fuel throughout the entire band ! .... the question is how much resistance is needed and where do I put it ? LOL I'm willing to add a resister in line to richen up my bike I don't think a bike should have a white plug in it...but that is how they are set up... !
.....
Bob.....

Bob Kelly · 04-22-2022, 12:36 AM

Quote:

Originally Posted by wheelbender6

The reason I am horning in on your thread is because I may buy a Genuine G400C, and it has Delphi EFI.
I’d like to own an RX4, but the seat height concerns me since I have only a 29” inseam. I ride in a lot of stop and go traffic and tall seats make that more difficult.

I own a 2021 RX4 and I lowered it 2" front and rear super easily
1.) i took out all the pre load and ran the nuts up to the top of the shock in the rear and locked them there... that dropped the rear almost exactly 2" (EDIT# I discovered that this is not the thing to do as it bottoms out the rear shock. I made a longer lower link instead to get it 2.5" lower)
2.) I loosened up the pinch bolts and raised the fork tubes in the triple trees up 2" and that lowered the front.... However to do that I had to buy some handle bar risers to fit the handle bars and move the handle bars back away from the fork tubes.... i got the 2" riser type that pivot in the original handle bar clamps
it worked real good I have a 30" inseam and can flat foot both feet at a stop.
.....
Bob.....

wheelbender6 · 04-22-2022, 06:55 AM

Thanks Bob Kelly. RX4 is back in the running for me.

JFOlivier · 04-22-2022, 08:58 AM

When I get some time I will take a look at my air temp sensor and try to measure its resistance. Then raise the temperature and see if the resistance increases or decreases which will give me some idea where to aim for. Right now spring in the bee yard is keeping me a little busy. I would guess that the colder the air temperature the more fuel added.

pyoungbl · 04-22-2022, 03:55 PM

Quote:

Originally Posted by Bob Kelly

But the problem is that the bike Runs too lean from the get go !!!
.....
Bob.....

And you know this how? Did you check with an O2 sensor or some other tool, or are you saying so because "Everyone knows"?

JFOlivier · 04-24-2022, 09:46 AM

I removed and tested the Intake Air Temperature sensor and checked its resistance and at around 70 degrees F it read 1.8K ohms and at about 35 to 40 degrees F about 2.2K ohms.
So this thermistor has a negative coefficient and the higher the temperature goes the lower the resistance so to lower the temperature reading you will need to add some resistance in series with the thermistor. I would try no more than 100 ohms at a time or if you can find a 200 or 300 ohm potentiometer you could work from zero increase up to 300 ohms increase in steps. Measuring any changes is the challenge, however I just filled my tank with mid grade gas and feel there is a difference in power and acceleration on my Lifan e-pect so maybe the RX guys will be able to feel a difference. Looking at setting up ECU hacker I need to find some of those flat pins they use in the China Bike plugs so that I can make up a plug to fit the ECU port, any idea where I could find those.

Bob Kelly · 04-24-2022, 06:18 PM

Quote:

Originally Posted by pyoungbl

And you know this how? Did you check with an O2 sensor or some other tool, or are you saying so because "Everyone knows"?

LOL Your right I don't know for a fact ! but I trust my instincts and my 60 odd years of experience with motorcycles it feels lean throughout the entire power band..... and if I could add a resister to ritchen it up I most certainly would
to the gas mileages demise !
I have not seen a single Fuel injection system that gave you a tan sparkplug
they are all white.... and white is lean and hot.... you don't want that on a motorcycle period...even if it is water cooled tan is much better and a closer proximity to the desired 14:1 air to fuel ratio you should be getting
.... their probably set at 12:1 for all I know but it's certainly a ways away from the 14:1 sweetspot.
do a color check and see what I mean....the porcelain is white not tan or brown!
.....
Bob.......

Lukas · 04-24-2022, 06:40 PM

I do not know if you have understood my thread about ecu is quite chaotic and I think to complete it with this content, http://www.chinariders.net/showthrea...t=29467&page=2 how to connect to hod ecu hacker, how to change maps and add what I did not describe, ie adding patch to the map which is quite convenient, because it allows you to change parameters without interfering in the map I changed the parameter of the cylinder capacity and maximum engine speed I think, But to tune the map I sent the map file to https://oldskulltuning.com/and for 30 euro they make tuning of fuel injection time and ignition I wanted to have straight-line map and it worked before changing cylinder I bought a camera and I would like to record how my bike runs.

04-21-2022, 10:59 AM	#16
wheelbender6 Join Date: May 2015 Location: Houston area Posts: 1,902	The reason I am horning in on your thread is because I may buy a Genuine G400C, and it has Delphi EFI. I’d like to own an RX4, but the seat height concerns me since I have only a 29” inseam. I ride in a lot of stop and go traffic and tall seats make that more difficult. __________________ "Its not WHAT you ride; its THAT you ride"
	0

04-21-2022, 11:56 AM	#18
wheelbender6 Join Date: May 2015 Location: Houston area Posts: 1,902	Great bedtime story. __________________ "Its not WHAT you ride; its THAT you ride"
	1

04-21-2022, 02:04 PM	#22
wheelbender6 Join Date: May 2015 Location: Houston area Posts: 1,902	The G400c makes a little over half of the hp of the Rx4, so it will have a much smaller throttle body. The rest of the EFI components should be very similar. __________________ "Its not WHAT you ride; its THAT you ride"
	0

04-22-2022, 06:55 AM	#25
wheelbender6 Join Date: May 2015 Location: Houston area Posts: 1,902	Thanks Bob Kelly. RX4 is back in the running for me. __________________ "Its not WHAT you ride; its THAT you ride"
	0

04-21-2022, 12:32 PM	#19
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	The Delphi ECU is used on many small engines. They probably have similar (if not identical) sensors but the actual map is going to be modified to work with the specific engine model, exhaust and intake setup. As a purely academic exercise I'd like to know how the various sensors feed into the base map and how they interact. Check the throttle body size for that Genuine 400. On the RX4 it's a 45mm TB.
	0

04-21-2022, 01:17 PM	#20
JFOlivier Join Date: Nov 2020 Location: Northern Neck of Virginia. Posts: 164	If you take a look at the IAP sensor on the x-pect it is between the throttle valve and the intake manifold so how does that give you the atmospheric pressure when it is working from almost a vacuum to near atmospheric pressure depending on the throttle position and the engine load. I sort of felt that that pressure sensor was sort of an advance warning to the EFI system as to where the RPM's were in relation to the throttle valve so as to supply more or less fuel. With RPM's rising on a flat road throttle valve will be closing and pressure in the inlet manifold will be dropping into more of a vacuum where Rpm's dropping on a hill with the throttle valve opening would be increasing the pressure to the IAP. So does this sensor really do anything about altitude or is altitude just handled by the O2 sensor in a closed loop.
	1

04-21-2022, 01:34 PM	#21
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	x-pect?
	0

04-22-2022, 08:58 AM	#26
JFOlivier Join Date: Nov 2020 Location: Northern Neck of Virginia. Posts: 164	When I get some time I will take a look at my air temp sensor and try to measure its resistance. Then raise the temperature and see if the resistance increases or decreases which will give me some idea where to aim for. Right now spring in the bee yard is keeping me a little busy. I would guess that the colder the air temperature the more fuel added.
	0

04-24-2022, 09:46 AM	#28
JFOlivier Join Date: Nov 2020 Location: Northern Neck of Virginia. Posts: 164	I removed and tested the Intake Air Temperature sensor and checked its resistance and at around 70 degrees F it read 1.8K ohms and at about 35 to 40 degrees F about 2.2K ohms. So this thermistor has a negative coefficient and the higher the temperature goes the lower the resistance so to lower the temperature reading you will need to add some resistance in series with the thermistor. I would try no more than 100 ohms at a time or if you can find a 200 or 300 ohm potentiometer you could work from zero increase up to 300 ohms increase in steps. Measuring any changes is the challenge, however I just filled my tank with mid grade gas and feel there is a difference in power and acceleration on my Lifan e-pect so maybe the RX guys will be able to feel a difference. Looking at setting up ECU hacker I need to find some of those flat pins they use in the China Bike plugs so that I can make up a plug to fit the ECU port, any idea where I could find those.
	1

04-24-2022, 06:40 PM	#30
Lukas Join Date: Jan 2021 Location: A small Polish empire Posts: 244	I do not know if you have understood my thread about ecu is quite chaotic and I think to complete it with this content, http://www.chinariders.net/showthrea...t=29467&page=2 how to connect to hod ecu hacker, how to change maps and add what I did not describe, ie adding patch to the map which is quite convenient, because it allows you to change parameters without interfering in the map I changed the parameter of the cylinder capacity and maximum engine speed I think, But to tune the map I sent the map file to https://oldskulltuning.com/and for 30 euro they make tuning of fuel injection time and ignition I wanted to have straight-line map and it worked before changing cylinder I bought a camera and I would like to record how my bike runs.
	0