I'm looking to replace the aging vacuum hoses in our 740... and the "new"
'87 240 while I'm at it.

The question I have is that both have vacuum hoses from the manifold for
engine load info to either the FI (Regina) or ignition (Volvo-Chrysler). In
both cases, the original hose is a skinny, almost see through, plastic
hose/tube with fat rubber "boots" on each end vs. the plain-jane vacuum
hose typically used for things like the fuel pressure regulator.

Can I use normal vacuum hose to go the Regina manifold pressure sensor and
Volvo/Chrysler ICU, or do I have to use tubing identical to what is already
there?... which I imagine is a specific Volvo part. Anyone BTDT?

Thanks!
-Ryan
--

Athens, Ohio
1987 245 DL 312k
1990 245 DL 133k M47, E-codes
1991 745 GL 290k (Girlfriend-mobile)
Buckeye Volvo Club

Ummm...
Why are you replacing the nylon lines?
They last forever, AND, the one to the ignition unit needs to be plugged anyway.

I see.... I figured while I was at it and had some spare hose I'd just do it. The rubber ends were pretty ugly on my old '90 745.

So I should just plug the ignition system hose on the 240? Any fuel economy or emissions hits?

Thanks!

-Ryan
--

Athens, Ohio
1987 245 DL 312k
1990 245 DL 133k M47, E-codes
1991 745 GL 290k (Girlfriend-mobile)
Buckeye Volvo Club

Fix the rubber ends.
There's a huge emissions hit due to plugging the line: you'll likely pass.

So basically, plugging the hose in the 240 tricks the computer into not retarding the ignition under load?

As for the nylon lines lasting forever.... a mouse seems to have found the hose very appetizing. Sigh...

Thanks!
-Ryan
--

Athens, Ohio
1987 245 DL 312k
1990 245 DL 133k M47, E-codes
1991 745 GL 290k (Girlfriend-mobile)
Buckeye Volvo Club

Pluging the vac line to the Volvo/Chrysler CU can make a significant reduction in NOx, assuming the other numbers are within limits. I've recorded 6 or 7 success stories since first posting on it.

For a technical description, see my original post
--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks Bruce!

That's a great and very interesting description. We don't have any sort of vehicle/emissions inspection here in SE Ohio, but I like to do my part keeping the 240's running clean.

I'll plug up the hose... the other advantage is that now unused nylon tubing from the 240 can replace the mouse eaten one for the 740's MAP sensor. :-)

Cheers,
-Ryan
--

Athens, Ohio
1987 245 DL 312k
1990 245 DL 133k M47, E-codes
1991 745 GL 290k (Girlfriend-mobile)
Buckeye Volvo Club