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Fuel consumption change after injector swap

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Old 09-28-2015, 10:47 PM
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Default Fuel consumption change after injector swap

Recently installed a set of 703's, filled the tank and reset trip meter to drive it through once this week out of curiosity on fuel economy vs before injector swap fuel economy.

Initially around town driving w/o using a/c fuel economy seemed to be doing better than before swap. However, the wife and I drove it over to Dallas last weekend (much to her chagrin. lol!) on the highway ~70-75 mph w/ a/c on and it really seemed to suck the fuel down noticeably. I was very surprised. I've only put ~ 200 miles on it and it's almost at 1/4 tank. That's well below what it was prior to swap.

Has anyone else experienced this after an injector swap? I don't seem to find any extensive data about it. If it's normal, I'm ok with it since it's not driven much at all. Just wondering...

Also, no codes, no cel's, no leaks, etc. Everything about it is meticulously maintained so I can't really find fault with any other parts of the systems and I'm very happy with the performance and how it runs.

Last edited by 4WD4EVER; 09-28-2015 at 10:48 PM. Reason: Add info
Old 09-28-2015, 11:14 PM
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If its not a renix did you reset the computer and put it into quick learn more? It would tend to run rich i believe with the upgraded injectors without.
Old 09-28-2015, 11:16 PM
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No toaster, I did not since it wasn't exhibiting any of the symptoms that required a reset. Maybe I should anyways? I don't see how it could hurt...
Old 09-28-2015, 11:21 PM
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Originally Posted by 4WD4EVER
No toaster, I did not since it wasn't exhibiting any of the symptoms that required a reset. Maybe I should anyways? I don't see how it could hurt...
I've gotten into the habit of doing it every time I change anything that might remotely effect fuel mixture.
Old 09-28-2015, 11:22 PM
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Lol! I understand. 'preciate the feedback.
Old 09-28-2015, 11:23 PM
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No problem. We're here to bounce ideas off each other. You have saved me many times and probably will a many more.
Old 09-28-2015, 11:27 PM
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I agree. Glad I helped somehow.
Old 09-28-2015, 11:29 PM
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Have u ever considered Volvo 746 injectors?
Old 09-28-2015, 11:30 PM
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Originally Posted by XJwonders
Have u ever considered Volvo 746 injectors?
The 703 is the part for older xj's while the 746 is for the later years. Different connector for almost exactly the same injector I believe.
Old 09-28-2015, 11:34 PM
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Originally Posted by XJwonders
Have u ever considered Volvo 746 injectors?
No Wonders, I haven't. Can you give me a quick synopsis on the differences (other than the connectors toaster mentioned)?
Old 09-28-2015, 11:40 PM
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Originally Posted by toasterknight
The 703 is the part for older xj's while the 746 is for the later years. Different connector for almost exactly the same injector I believe.
Volvo injectors are better suited for renix years 87-90. 703 injectors perform better on 91-98 engines. Then the connectors changed, and they use 784's on 99-06 engines.

People DO run 703's on renix engines. I don't know what the differences between 703's and 746's but I have read plenty of posts where people who switched to 746's from 703's and engines ran better.
Old 09-28-2015, 11:41 PM
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Originally Posted by XJwonders
Volvo injectors are better suited for renix years 87-90. 703 injectors perform better on 91-98 engines. Then the connectors changed, and they use 784's on 99-06 engines.

People DO run 703's on renix engines. I don't know what the differences between 703's and 746's but I have read plenty of posts where people who switched to 746's from 703's and engines ran better.
Oops I think I was confusing part numbers.
Old 09-28-2015, 11:47 PM
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I looked into a bit more and it appears the 746 is 19#/h while the 703 is 23#/h that's about the only difference I can find in my quick search.
Old 09-28-2015, 11:48 PM
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Originally Posted by toasterknight
I looked into a bit more and it appears the 746 is 19#/h while the 703 is 23#/h that's about the only difference I can find in my quick search.
thanks. I wasn't sure myself.
Old 09-28-2015, 11:49 PM
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Thanks fellas, I'll look into it more. Like I said, I don't drive it much and I'm not concerned about fuel as much as performance and that part I'm satisfied with.


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