The Definitive Injector Swap HOW TO - Page 12 - JeepForum.com

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post #166 of 675 Old 03-31-2012, 08:30 PM
augiedoggy
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But the 94 used different fuel flow numbers than the 95... so the pcm could be programmed completely different..

and I have a 96 5.9 not a 98.

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post #167 of 675 Old 04-03-2012, 06:52 PM
augiedoggy
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Ok so some of the data on witch hunter is not entirely accurate...apparently there are lots of errors...
I am going to be installing 0280155712 injectors first which are actually 16 ohm not 2.1 ohms like the site has listed... also the injector guy says the 20lb "710" injectors are actually higher flow than stated on witch hunter... he says a lot of guys actually use them to replace the stock injectors in vettes all the time and they are rated at 20lb at 39psi not 43... and will flow quite a bit higher at 49psi.. (22.5lb)
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post #168 of 675 Old 04-04-2012, 11:10 AM
CatSplat
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Quote:
Originally Posted by augiedoggy View Post
also the injector guy says the 20lb "710" injectors are actually higher flow than stated on witch hunter... he says a lot of guys actually use them to replace the stock injectors in vettes all the time and they are rated at 20lb at 39psi not 43... and will flow quite a bit higher at 49psi.. (22.5lb)
That could very well be, but I have no idea if anyone has used 710s in a Jeep or why they would want to.

I don't know why you'd say there are "lots" of errors on Witchhunter. 2.1 ohms looks to be a typo and "the injector guy" has shown no test data to invalidate their numbers on the 710s. If anything, I find Witchhunter more accurate than most injector flow tables; the 703 is routinely listed as a 16lb injector, which it most definitely is not. Witcherhunter's number for the 703 is quite correct and I have verified it on my own flow bench.

1994 5.9L ZJ, retrofitted UC package, NP242 swap, 17" JK Moabs with 32" BFG MT KM's.
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post #169 of 675 Old 04-04-2012, 07:58 PM
augiedoggy
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Quote:
Originally Posted by CatSplat View Post
That could very well be, but I have no idea if anyone has used 710s in a Jeep or why they would want to.

I don't know why you'd say there are "lots" of errors on Witchhunter. 2.1 ohms looks to be a typo and "the injector guy" has shown no test data to invalidate their numbers on the 710s. If anything, I find Witchhunter more accurate than most injector flow tables; the 703 is routinely listed as a 16lb injector, which it most definitely is not. Witcherhunter's number for the 703 is quite correct and I have verified it on my own flow bench.
I spoke with a guy who runs a business rebuilding them and he said the flow numbers there are not all rated at 43psi... many of them are actually different flow rates than posted there..like many of the ford injectors which were rated at 39 psi not 43. He said many others just copy and paste info from other sites so he rely s on his own flow tables he created from his tests and found some there to be inaccurate... maybe most are correct but I've found three different sets of numbers for the same injectors at different sites so I'm just saying it shouldnt be taken as gospel... this is the same guy that sent me 4 different sets of different size injectors to test out including the 703's that ran too rich...

BTW I installed the Bosch "712" injectors and they work great so far...drove it around a bit today and my fuel trim levels hover above and below 0 and dont go to either extreme.. there are rated at 21lb or 225cc at 43psi? from what I've been told by witch hunter...which would make them flow just under 23lb at 49psi..

and yes the yellow injectors like the 710s are the most widly sold gen 3 upgrade for 95 and older magnums according to many of the sites like the one I linked earlier here... and ebay.. because all the 92-95 except the 95 5.9l flowed at 18.2 lbs baseline at 39psi and the pcm did the rest of the work the downside to the yeelow injectors is they have no slots for clips... you would use them for the same reason you would upgrade from any generation 2 injector to a generation 3 style
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post #170 of 675 Old 04-09-2012, 07:56 PM
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Lots of information, numbers, and thought put into this thread! I just want to verify, I have a 97' ZJ 4.0L, I would want to go with these -
Bosch 0280155715; 23.1lb/hr @ 39psi & 25.9lb/hr @ 49psi

Thanks!

1998 Jeep Grand Cherokee 5.9L
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post #171 of 675 Old 04-10-2012, 08:30 AM
Tbone18
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I have a 1997 Jeep Grand Cherokee TSI, 4.0. I swapped out the old stock injectors for the higher flow ford 715 injectors and have big problems. Initially it ran great and had noticably faster acceleration and fuel mileage gains. After about 200 miles the check engine light came on and it began to idle very rough and sputter. It does this now constantly while idling or driving. There are bad vibrations from the rough idle and it does this while driving at any speed. When i floor it it still sputters and bearly gets up to 65mph on the highway. The codes are 43, 12, and 27. I sound dumb here but could it be the spark plugs fouling out because of too much fuel now compared to the stock injectors? Help please! Maybe i should have installed the bosch 703 injectors instead of the ford 715's.
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post #172 of 675 Old 04-10-2012, 08:41 AM
BoostinChick
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^ Did you disconnect the battery when you did the injector swap? Have you tried manually clearing the codes again, recently? 27 usually means something is up with the injector itself or the PCM. You didn't happen to accidentally snag the injector harness when installing? Those things are pretty brittle.

1998 Jeep Grand Cherokee 5.9L
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post #173 of 675 Old 04-10-2012, 10:19 AM Thread Starter
zander21510
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yeah I would check to see if your plugs are fouled up. I would bet only 1 or 2 of them are fouled up and you have a bad injector that went bad when it started sputtering.
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post #174 of 675 Old 04-10-2012, 04:15 PM
augiedoggy
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Quote:
Originally Posted by Tbone18 View Post
I have a 1997 Jeep Grand Cherokee TSI, 4.0. I swapped out the old stock injectors for the higher flow ford 715 injectors and have big problems. Initially it ran great and had noticably faster acceleration and fuel mileage gains. After about 200 miles the check engine light came on and it began to idle very rough and sputter. It does this now constantly while idling or driving. There are bad vibrations from the rough idle and it does this while driving at any speed. When i floor it it still sputters and bearly gets up to 65mph on the highway. The codes are 43, 12, and 27. I sound dumb here but could it be the spark plugs fouling out because of too much fuel now compared to the stock injectors? Help please! Maybe i should have installed the bosch 703 injectors instead of the ford 715's.
If you didnt reset the pcm it might have been running off the pcm adjustments from the old injectors and now that its attempted to adjust parameters for the new ones it has failed to be able to do so and its running rich... the 715's are much larger than stock (or the 703's) and overkill for the 4.0 they may be too large for the pcm to throttle down. Its also mentioned in this thread it can take up to 200 miles for the pcm to relearn... this is also why jet chips only work for about 200 miles before the pcm relearns to compenstae for their changes and then the jet chip does nothing for performance until the pcm is reset again... (jet chips are garbage for these pcm's)
Its awful funny that so many people in this thread have had "bad injectors"
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post #175 of 675 Old 04-10-2012, 04:54 PM
BoostinChick
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Thanks for partially answering my question, I was going to go with the 715's but after reading this I may just stick with the 703's.

1998 Jeep Grand Cherokee 5.9L
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post #176 of 675 Old 04-10-2012, 11:54 PM
AndyLegg96ZJ
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I have a 96ZJ 4.0...after reading thru this whole thread I'm assuming my best bet is to go with the 703's..Does anyone have a spare set? maybe 7 or 8 incase 1 or 2 of em end up not holding pressure. Shoot me a PM!!

Unless anyone knows who has em.. tell me who to PM
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post #177 of 675 Old 04-11-2012, 11:43 AM
AlphaLorde
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I've been following this for a while to see if I should do this mod.

Now with more info about the flow rates, I'm still on the fence.

Would 3lbs/hr more fuel be too much my zj?
I not sure if it needs more fuel. Mild mods, mostly bolt ons.

At what point with mods should the injectors be increased?

1998 ZJ Laredo 5.2L 139k 231 w/SYE artec trussed 8.8 4.25"F/5"R lift
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post #178 of 675 Old 04-11-2012, 11:59 AM
augiedoggy
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Quote:
Originally Posted by AlphaLorde View Post
I've been following this for a while to see if I should do this mod.

Now with more info about the flow rates, I'm still on the fence.

Would 3lbs/hr more fuel be too much my zj?
I not sure if it needs more fuel. Mild mods, mostly bolt ons.

At what point with mods should the injectors be increased?
most pros suggest only upgrading injectors when going with a supercharger or turbo with decent boost.(or when boring to a bigger engine displacement).. stock injectors are not at their full capacity at all (most are at 80% flow capacity ideally at WOT) which is why going bigger has no benefit... the benefit is going from an older pencil type single stream injector to a newer 4 hole generation 3 injector with a fine fuel mist spray pattern... this is why its possible to see slight mpg increases as the fuel is burned more efficiently...
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post #179 of 675 Old 04-12-2012, 07:02 AM
KyBoy1991
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Quote:
Originally Posted by augiedoggy View Post
most pros suggest only upgrading injectors when going with a supercharger or turbo with decent boost.(or when boring to a bigger engine displacement).. stock injectors are not at their full capacity at all (most are at 80% flow capacity ideally at WOT) which is why going bigger has no benefit... the benefit is going from an older pencil type single stream injector to a newer 4 hole generation 3 injector with a fine fuel mist spray pattern... this is why its possible to see slight mpg increases as the fuel is burned more efficiently...
I've not chimed in, as I've been reading, learning, and thinking...but this statement by augie is exactly the sole purpose IMO. Think about this, you can fill a 5 gallon bucket almost to the rim, and are able to put out a lit cigarette in the liquid fuel....AS LONG as you stay out of the fuel vapor when sneaking up the side of the bucket. That's the crude simpleness of this swap....you're going from a fat stream to a fine mist. You get that cigarette in the vapors the entire bucket blows....you sneak up the side and are fast enough you can put it out in the gas.....I've seen this done...my dad is a dumba$$ and showed this to me as a kid.

4.0 guys IMO after following this entire thread should ONLY go with the 703's and to better that put on a 99+ intake. Unless you've got a 4.0 that is wildly modified, i think anyone is going to run into the same issues many have talked about here.

Awesome thread, awesome input from lots of folks with tons of knowledge.....
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post #180 of 675 Old 04-12-2012, 07:41 AM
rb2biker
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Did I miss something related to the intake? Why 99 or later?
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