Problems after 12 hole injection upgrade

[alexgalexg]

98 XJ 4.0
Today I upgraded to 12 hole fuel injection from ksuspension. When running it runs great! Foot to the floor and your head is pulled back, idle is lower and runs much smoother. But having some issues.
Late start
Runs suspiciously quiet for a flowmaster exhaust
Seems to be consuming more fuel than it should
Does not pass readiness test (pic supplied below)
It's important to note that I did not reset the ECU because in my experience it takes many hours for it to actually reset after pulling the battery cables. I simple let the engine adapt.

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[RCP Phx]

Need more info on the injectors, but late starts are usually from losing pressure in the system. As far as using more fuel, what are your long/short fuel trims?

 

[alexgalexg]

Need more info on the injectors, but late starts are usually from losing pressure in the system. As far as using more fuel, what are your long/short fuel trims?

Injectors are 12 hole fuel injectors from ksuspension. Major performance upgrade. There was no leak prior to the upgrade and I ha e checked the I injectors to find no leak now. I left the battery disconnected overnight and will also perform the reset with the headlights in a minute here after reconnecting the battery before work

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[RCP Phx]

I was referring to - "X" lbs/hr @ "Y" psi . Have you put a pressure gauge on it to see if it's "bleeding" down after you shut it off?

 

[alexgalexg]

My pressure gauge leaks. I know it has proper 49psi pressure when running. Also after letting the computer reset overnight I started it this morning and it fired right up. However it still seems to be using a lot of fuel

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[RCP Phx]

What are your fuel trims?

 

[alexgalexg]

What are your fuel trims?

Unfortunately I am at work until 8pm. I will update tomorrow with fuel trims

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[trippled]

What are you basing your fuel consumption off of?

 

[lazyxj]

Your scanner shows the evaporative system and O2 heater tests have not passed.
Neither is dependent on the injectors.

I have tried different injectors in several stock XJs.
IMO, most of the improvement people feel is the result of clean injectors, with a good spray pattern, compared to the old, dirty injectors they replace.
The factory supplied injectors are the right size for a stock engine.

It would be interesting to do side by side dyno comparisons between new, stock injectors and the newer injectors, with more holes.

Larry

 

[alexgalexg]

Basing my fuel consumption off the gauge which has been accurate every day. Tomorrow I have a day off I will deal with fuel trims and look at timing. I have a light miss as well so something is up. I suspect that it's a bad connection between the injector and the connector but I'm working on that.

So far problems aside I have noticed the engine runs smoother, quieter and has a lot more power

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[Heavyopp]

What kind of gas mileage are you getting?

My XJ is pretty disappointing mileage wise -- best I've done is just under 14 MPG around town

I have upgraded injectors -- from a Ford Mustang, don't know the number at the moment -- 2000 cherokee


XR3E-A4B New Multi Port Injector CM4956 Set (6) for 99-01 Ford Mustang 3.8L. These are the injectors I used.

 

[sinat01]

If you cant figure it out, shoot raffi at Ksuspension an email. he will help ya figure it out

 

[alexgalexg]

I talked to him. Hes sending me a new set of injectors. In the meantime I'm going to make sure that something's not wrong on my end. I'll update shortly with fuel trims. I'm pretty sure it's the injectors though... didn't have a miss prior to installing them

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[alexgalexg]

What kind of gas mileage are you getting?

My XJ is pretty disappointing mileage wise -- best I've done is just under 14 MPG around town

I have upgraded injectors -- from a Ford Mustang, don't know the number at the moment -- 2000 cherokee


XR3E-A4B New Multi Port Injector CM4956 Set (6) for 99-01 Ford Mustang 3.8L. These are the injectors I used.

Cant say for sure what my mileage. But I can literally watch the needle move since I put these in. My commute is 10 mins and the needle drops half a notch each way. Used an entire notch yesterday...

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[alexgalexg]

Fuel trims
https://youtu.be/S8smQtBR1_4

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[dktool]

Used an entire notch yesterday...

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I haven't spit coffee on the keyboard lately but that one did it, thanks !

I will use that reference next time someone asks me how much gas it took in my rv towing the boat.........."I used right at 437 notches to get here."

 

[alexgalexg]

I haven't spit coffee on the keyboard lately but that one did it, thanks !

I will use that reference next time someone asks me how much gas it took in my rv towing the boat.........."I used right at 437 notches to get here."

Haha! You know what I mean though. I dont have the overhead console so I just go by the gauge

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[RCP Phx]

When doing any data logging it has to be done under a load to be of real value.
Everything that I have found suggest they(0280156161) are to large. They are meant for earlier XJ's that run lower PSI.

 

[alexgalexg]

When doing any data logging it has to be done under a load to be of real value.
Everything that I have found suggest they(0280156161) are to large. They are meant for earlier XJ's that run lower PSI.

Excellent point however these have been installed on hundreds of xj's including 97+

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[RCP Phx]

:roflmao: :roflmao: :roflmao: says who? The guy you bought them from sells them out of his house!