Help with injector selection

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Cheromaniac
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Re: Help with injector selection

Post by Cheromaniac »

If you divide the projected crank HP number by 10, that's a good approximation of the flow in lb/hr that you'll need from each injector on a Jeep I6. It'll be close enough that the ECU would only have to make small adjustments to the short term fuel trims.
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Re: Help with injector selection

Post by SkylinesSuck »

And if it's already pretty close, a map adjuster or a piggy back like an SAFC (which is basically a map adjuster with multiple rpm adjustment points) can suffice. You will still of course need a wide band O2 sensor to see how to adjust it. I think I still have my SAFC2 sitting around somewhere.
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Re: Help with injector selection

Post by HCE »

Before going on the op should pop his hood and verify what ecm system is on his jeep. 2000 should have coil on plug this would be a Chrysler system. Most the post seam to be offering help for the renix system. There is very little information out there on strokers in the later system. A Chrysler system has limited room to install another bung between the dual manifolds and mini cats. One solution may be to use a wideband sensor that outputs an emulated analog signal to the ecm. https://www.plxdevices.com/ProductDetai ... 7346002726.
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Re: Help with injector selection

Post by SkylinesSuck »

Everything I said was directed at OBD2 compliant JTEC ecu's ('97+).
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Re: Help with injector selection

Post by HCE »

I stand corrected on the renix. Around 2000 there are some differences with coil on spark plug and stereo oxygen sensors. Are the ecm strategies the same even though they are both jtec? On the 2004 ecm does not act as constrained as what has been described by others with older swaps.
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Re: Help with injector selection

Post by Cummins90 »

Thread jacking? Not sure what's up here.

I'm better versed in the XJ series and the timeline should be similar for other models with the 4.0. In terms or fuel injection renix lasted to 1990. In 1991 the SBEC2 ecu from Chrysler was used. In 1996 the OBD2 compliant JTEC ecu was used until 1999. Then the JTEC 2 was used until the 2001 year. The JTEC 2 continued in 4.0l vehicles until 2004. 2005 and 2006 TJ recieved the NGC PCM.

To the best of my knowledge the SBEC1 and SBEC3 where never used for the 4.0l. All of this info is just what I have come up with and there are others with much more knowledge than I do.

I have tried to piggyback the JTEC and it can be done but it's a learning process that takes some time.
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Re: Help with injector selection

Post by lazyxj »

HCE wrote: January 15th, 2019, 8:34 am A Chrysler system has limited room to install another bung between the dual manifolds and mini cats.
There is enough room to add two bungs for A/F sensors on a 2000-2001 dual cat manifold.
No reason why you can't do the same .


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