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  #1  
Old 02-11-2016, 02:41 PM
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Mystery Transmission Line: 1972 280 SEL 4.5

Hello Peachparts! I have a second request regarding my 1972 280 SEL 4.5:

Thanks to Tom, it looks like we might have an answer to my prior thread regarding vacuum signal to the Manifold Pressure Sensor. We do however have a new mystery!

Please note that the car had it's 4.5 removed and replaced with a 3.5 out of a 300 (1970ish). This means that the car now has the four speed automatic and 3.5 engine. We're in the process of connecting everything, and I have absolutely no idea what this line does, or where it goes.

The line appears to go back to the Automatic transmission. I do not know if it is looking for vacuum, or if this is oil, or.....? It appears to almost join up where the nipple supplying signal to the Manifold Pressure Sensor lives - but not quite.

The pictures below illustrate the pipe in question (outlined in yellow); the photos are of the back of the 3.5, with the firewall just behind.

Once identified, it looks like I'm also going to need the banjo bolt as well that goes through the banjo, as that is nowhere to be found.

Many thanks,

-James





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  #2  
Old 02-11-2016, 03:37 PM
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The pics are so tiny I cannot make them out, but this is a vacuum line for the transmission and it does not connect where the MAP connects. The MAP uses its own dedicated vacuum source line. There is also a connector for the brake booster, which IIRC has its own dedicated line. The transmission one, if memory serves, uses a connector that bolts it to the manifold but also supplies vacuum for the central locking system.

If you need that piece, I can tell you it wasn't attached to my manifold - only the MAP nipple was.
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  #3  
Old 02-11-2016, 03:48 PM
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Bigger pics

Tom,

Thank you again. Let's see if I can put in a handful of links to bigger pictures. I figured that the large spigot at the back of the manifold fed the brake booster; that's good to get confirmed.

Warning, the pics these link to will be quite large. I'm very curious as to where the banjo secures in order to find signal. As they are the originals, the Banjo Transmission Line is not marked in Yellow, but should be in exactly the same position as the smaller pictures.

Best,

-James





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  #4  
Old 02-11-2016, 05:31 PM
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It does look like you have the proper location for that line, in the lower manifold. But the MAP connects on the other side.
Maybe these will help. In the PDF, the part in my other picture, the MAP nipple, is 30. You are missing 28 (And presumably 29) to attach the transmission vac line, and if memory serves, 28 also has another nipple that attaches to it for the door locking system. Someone who has a 108/109 3.5/4.5 that can take live pics may be able to help show the system when setup.

Attached Files
File Type: pdf 09-400.pdf (189.0 KB, 38 views)
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Current:
2018 Chrysler Pacifica Limited
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Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
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  #5  
Old 02-12-2016, 02:13 PM
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Tom,

Absolutely fantastic. Thanks to your documentation, I was able to find the correct mount point for both the Manifold Pressure Sensor and the Transmission Vacuum Signal. I also correctly deduced that the bung on the passenger side of the back of the manifold was for the coolant temperature sensor.

Having combed through the parts that came with the car, I am missing the Banjo Bolt for securing the transmission vacuum signal line. Would you happen to know where I might be able to find one?

Best,

-James
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  #6  
Old 02-13-2016, 07:37 PM
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Someone with EPC access may be able to get you the part number. I take it that your lower manifold did have the MAP piece attached? It'd be odd to remove it.

As an aside, you sure you have a 3.5 engine? You have 4.5 injectors.
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Current:
2018 Chrysler Pacifica Limited
1999 Chrysler 300M - 214,141+ miles

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
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  #7  
Old 02-16-2016, 10:52 AM
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Hello Tom!

Huh. That's good to know. The injectors that are on the car are the 'horrid' ones that I found in a bag of parts - most of the insulators are damaged. I was able to find the 3.5 Brain that came with the car (and ran the part number to make sure). However, as the engine came with no injectors or fuel rails, I was forced to source a set of 4.5 fuel rails and injectors (which have yet to be installed).

Hopefully there's no difference between the ohm rating for the 3.5 / 4.5 injectors, and that the 3.5 brain will be able to fire them.

Best,

-James
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  #8  
Old 02-17-2016, 03:50 PM
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The 3.5 ECU can fire 4.5 injectors (All DJet injectors have the same ohm specs) but the 4.5 ones flow a LOT more. So your mix will be WAY off and you may not even want to run with them at all.
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Current:
2018 Chrysler Pacifica Limited
1999 Chrysler 300M - 214,141+ miles

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
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