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Unread 03-30-2012, 07:23 AM   #151
augiedoggy
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Quote:
Originally Posted by rooster51 View Post
Zander, thanks for doin this write-up and for putting up w/ all these dweebs with their illiteracy and comparing jeeps to dodges to camrys. I dont know how your head doesnt hurt when you read some of these posts. Your a better man than me.
I'm actually comparing Chrysler 5.2. and 5.9's to different year Chrysler 5.2 and 5.9's... Since the they dodges and jeeps used the same engine and transmissions at the same time period with different programming and fuel pressures.
People have mentioned differences but not what they are besides the starter being on the other side of the engine.. The injectors are from other vehicles so yeah some might mention them for size reference (which actually doesnt mean much)...I think this comparison can be beneficial especially if we learn that some thing really is different and how..this can effect parts swaps and effectiveness of them in different enviroments (For example will a dodge fuel pump fit and work in a jeep).. I would think Sean at sct would know if the programming is really completely different since he wrote the tunes for both right? Didnt he recommend the 19lb injectors to someone for their jeep?

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Unread 03-30-2012, 10:47 AM   #152
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I had a similar experience as Augie (I used the 703 injectors), but this was in my 95 Jeep GC 5.2L. During both open and closed loop, I was running extremely rich. I have since pulled my plugs, and none of them were fouled out, so I can be pretty sure that there was no leaky injector. I still need to get to Lowes to get some hose to make sure the injectors are not leaking, but at this point I am pretty certain the 703 injectors were dumping just too much fuel for the motor to handle, and the PCM to compensate for.

Also, not sure how much it matters, but I do have the Mopar Performace PCM installed in my rig. Maybe it is managing the fuel tables differently than the stock PCM. Or another possibility might be that the 95 Jeep PCM in general can't handle the 703 injector flow. I know that there are differences between the 93-94 PCM and the 95 PCM, but not sure what they are.
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Unread 03-30-2012, 11:07 AM   #153
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Quote:
Originally Posted by sebian
I had a similar experience as Augie (I used the 703 injectors), but this was in my 95 Jeep GC 5.2L. During both open and closed loop, I was running extremely rich. I have since pulled my plugs, and none of them were fouled out, so I can be pretty sure that there was no leaky injector. I still need to get to Lowes to get some hose to make sure the injectors are not leaking, but at this point I am pretty certain the 703 injectors were dumping just too much fuel for the motor to handle, and the PCM to compensate for.

Also, not sure how much it matters, but I do have the Mopar Performace PCM installed in my rig. Maybe it is managing the fuel tables differently than the stock PCM. Or another possibility might be that the 95 Jeep PCM in general can't handle the 703 injector flow. I know that there are differences between the 93-94 PCM and the 95 PCM, but not sure what they are.
Can you tell us the stock injector model number you had? For some reason on rockauto 95 had a different model number than all the rest which I posted in the OP, wanted to make sure it was accurate.
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Unread 03-30-2012, 12:17 PM   #154
sebian
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I will check them later this afternoon when I get back home. I will grab the full model number off the injector.
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Unread 03-30-2012, 04:20 PM   #155
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It was kind of a funny angle looking at the injectors to see the model number, but this is what I got; Model Number 53030262.
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Unread 03-30-2012, 04:35 PM   #156
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That part number sounds right for a '95. The stock '95 injector, AFAIK, was rated to flow more fuel than the 703s. I don't think injector flow rating is the problem here, it's something else entirely. Did you reset the computer after installation?
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Unread 03-30-2012, 05:53 PM   #157
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Quote:
Originally Posted by CatSplat
That part number sounds right for a '95. The stock '95 injector, AFAIK, was rated to flow more fuel than the 703s. I don't think injector flow rating is the problem here, it's something else entirely. Did you reset the computer after installation?
Yup...how odd I wonder why 95 was the only year to have those and had the highest flow...
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Unread 03-30-2012, 07:41 PM   #158
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Yup...how odd I wonder why 95 was the only year to have those and had the highest flow...
So I was right about the 95's with the chart I posted earlier (same as the dodges BTW)... I though only the 95 5.9's came with those injectors though...either that of the pcm throttles them down to the 18.x lb flow yours actually uses... The thing is again like I mentioned earlier the stock injectors were timed to fire on the back of the hot valve to turn it to a vapor just as the valve opened... All the pros who I spoke to about this said you have to retard your fuel syc with a machine and by turning the distributer to get optimal timing for these new atomized spray injectors vs the stream ones...

So they should have worked in your just like they should have in mine.... Wonder why they didnt?... I still have mine sitting here along with like three sets of 19-20lb ones to test for the seller I bought them from... he said he had never sold the 703's for a magnum engine before ..only the older 2nd gen injectors modded for 4 hole spray flow...

Here's a post from a guy named HankL who really researched his answers...Notice he mentions the computer must be changed or reprogrammed...

begin quote:

"I read the following from the Q&A section of the official Chrysler publication April 2001 Mopar Performance News:

Q(5) I'm working on a fuel-injected combination and my dyno program
shows I could benefit from more injector delivery. What can you tell me
about flow rates of the injectors in your catalog? Also, if you have
the factory injector rates would be very helpful.


A(5) You should step up the injectors in something like only 25 percent
increments. The production V-8 is 24 - the MPP package is 30! Remember
that you must change the computer if you change the injectors; at the
least, it must be reprogrammed with the new injector values. Injector
rates are not as easy as one might think, but they go something like
this:

Engine Years Flow rate in lb/hr
Neon ( All) 23.9
2.5 Magnum 91-95 17.4
2.5 Magnum 96-01 23.2
4.0 Jeep 91-95 21.4 (Equivalent to Lucas 5207013 )
4.0 Jeep 96-01 23.2 (Equivalent to Lucas 5208005 )
5.2 Magnum 92-95 18.2
5.2 Magnum 96-01 23.2
5.9 Magnum 93-95 24.5
5.9 Magnum 96-01 23.2 (Seimens/Chrysler P/N 53030778)

---end quote---

Note that about 1996,
when the engine PCM computers went to the OBD-II standard,
all the Dodge fuel injectors went to a 'common calibration' of 23.2 lb/hour.

There is another article about different makes of fuel injectors I
read at:

http://web.archive.org/web/200106101...ectioninfo.htm

If you have a modified 1996+ Magnum engine and you feel you need to 'bump up'
the fuel injectors just a bit, the model year 1993-1995 5.9V8 fuel injectors
are about 6% larger at 24.5 versus 23.2, and Neon injectors are 3% bigger.

For Junkyard hunting
here is a very large list of injectors used in past engines:

http://autospeed.drive.com.au/cms/ar...ml?&A=0102

or, if that page doesn't load
in the Google internet archive:

http://web.archive.org/web/200108012...flow_rates.htm
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Unread 03-30-2012, 07:49 PM   #159
sebian
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Quote:
Originally Posted by CatSplat View Post
That part number sounds right for a '95. The stock '95 injector, AFAIK, was rated to flow more fuel than the 703s. I don't think injector flow rating is the problem here, it's something else entirely. Did you reset the computer after installation?
My battery was disconnected the entire time I did the injector swap. More from a safety stand-point than needing to reset the PCM, but it served the same the purpose of resetting the PCM at the same time.

Only other thing that I can think of as the reason my swap didn't work is the possibility of a leaky injector or two.
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Unread 03-31-2012, 12:19 AM   #160
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Quote:
Originally Posted by sebian View Post
My battery was disconnected the entire time I did the injector swap. More from a safety stand-point than needing to reset the PCM, but it served the same the purpose of resetting the PCM at the same time.

Only other thing that I can think of as the reason my swap didn't work is the possibility of a leaky injector or two.
After resetting the pcm, the pcm collects data from the next 50 start up cycles to adjust fuel trim.
Are you past 50, or not yet?
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Unread 03-31-2012, 12:12 PM   #161
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Quote:
Originally Posted by augiedoggy View Post
The thing is again like I mentioned earlier the stock injectors were timed to fire on the back of the hot valve to turn it to a vapor just as the valve opened..
Certainly a good theory, and one that's indeed the "ideal" way to atomize fuel and used in many modern injector designs. The CBR600RR, for instance, has an injector that outputs twin pencil beams to hit both intake valves.

With the Magnum intake designs, it really doesn't work as well as theory suggests. Unlike the CBR, for example, the Magnum injects the fuel perpendicular to the intake runner air flow, rather than reasonably parallel to it. Thus, the pencil-beam fuel flow is disrupted the instant it leaves the injector and begins to atomize, albeit poorly compared to the EV3 injector spray patterns. When you consider that, along with the valve location in the Magnum heads, the EV1 injectors really don't do a great job of atomizing the fuel using the intake-valve heat atomization method, nor do they do a good job of misting the fuel like the EV3s.
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Unread 03-31-2012, 01:21 PM   #162
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Originally Posted by rooster51 View Post
After resetting the pcm, the pcm collects data from the next 50 start up cycles to adjust fuel trim.
Are you past 50, or not yet?
ok the pcm is supposed to be able to adjust the fuel trim enough after a few minutes of driving at speed in closed loop mode to not dump so much fuel it floods into the engine oil .... I may have bad injectors or one that was leaking while the truck was off.... I plan on pressure testing them for leaks...
bottom line I rest the pcm and put in the stock injectors and it never ran anywhere near as rich and after about 15 20minutes of driving after warmup the pcm had adjusted fuel trim well...I can see it while driving throught the torque software and an elm327 adapter which gives me much of the real time data from the pcm...
fifty startups??..... The pcm learns in closed loop mode AFTER WARMUP... it runs on preprogrammed fuel trim tables and has no way of adjusting or knowing what injectors are installed until it reaches closed loop mode...Thats my whole point!
you could start it a 100 times and it will still flood the engine just as much until it reaches closed loop operation when warmed and the pcm starts paying attention to the 02 sensors to adjust...This is why the pcm has to be reprogrammed for a different size injector... If I'm wrong someone please clarify how..
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Unread 03-31-2012, 02:34 PM   #163
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Originally Posted by rooster51 View Post
After resetting the pcm, the pcm collects data from the next 50 start up cycles to adjust fuel trim.
Are you past 50, or not yet?

As Augie mentioned, the PCM would have adjusted the fuel trims once it got into closed loop. I could definitely tell a difference after it went into closed loop as there was less smoke, but it still looked like I had just Seafoamed my engine. I ran it for a good 20 minutes, at varying RPM's to try to get it to adjust further, but the PCM could not back the fuel trims back enough to eliminate the rich condition. I also did not go on a test run on the roads with it, smoking as bad as it was, and even just reversing from the garage to the driveway, it was running really poorly. I didn't want to risk damage to the motor, or stalling somewhere in BFE Texas.
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Unread 03-31-2012, 03:44 PM   #164
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So now we have a 95 running too rich and a 98 Dodge ram running too rich...and one 98 Jeep running just fine. Is there a difference in how the injectors are aimed between the truck and the Jeep that could account for this?
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Unread 03-31-2012, 07:20 PM   #165
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Originally Posted by zander21510 View Post
So now we have a 95 running too rich and a 98 Dodge ram running too rich...and one 98 Jeep running just fine. Is there a difference in how the injectors are aimed between the truck and the Jeep that could account for this?
Nope, same manifolds and same engine. As mentioned, my '94 with a swapped 5.9 runs them just fine.
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