CEL 2-3-1 - fuel pressure at 35lbs.. What now??!

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 12:13

Just checked fuel pressure at the Schraeder is 35 lbs. What should I be checking next. I've changed the fuel filter, at 300,000 k's I'm thinking it could be fuel pump. But is there anything else that I should be considering first?

Advice appreciated. Thanks.

FYI car is a 94 850 2.3 Turbo wagon.

icelandic · Post by **icelandic** » 10 Apr 2009, 12:18

If memory serves me right, pressure should be above 41 pounds. Next thing to check is the vacumm operated fuel regulator valve in the fuel rail. Its a diaphragm valve, with a vacumm line that goes from it to the TB. Two possibilities: the vacumm line is faulty, or the valve is faulty.

Icelandic

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 12:43

Alright. With no vacuum to the regulator there is 45psi. However, I checked the vacuum out of the tb and it was at 20 in lbs of vacuum, what is it supposed to be?

Post by **Ozark Lee** » 10 Apr 2009, 12:51

The low fuel pressure can indeed cause the 2-3-1 CEL. Try pinching off the fuel return line and see what the pressure does. It should jump up - try to keep it under 55 lbs.

If the pressure does jump up with the return line pinched then the fuel pump itself is OK and I would focus on the fuel pressure regulator.

...Lee

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 13:07

After car is shutoff and key removed. After 2 minutes pressure begins to climb... After 20 mins pressure now at 43 psi.

Hmmm. Feeling a little stumped here.

You are right I disconnected the vacuum line to the fuel pressure regulator. At that point fuel pressure jumped to 45 psi. When it was readded pressure dropped to 36psi.

Post by **Ozark Lee** » 10 Apr 2009, 13:34

Try taking a pair of pliers and squeezing the actual fuel return line. 44 PSI is the normal operating pressure - it should jump well above that.

...Lee

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 13:45

As soon as I pinch the line the pressure jumps immediately to 55psi and I'm sure it would go higher if I left it.

Now what? Do I replace the regulator? Can it be repaired? What's best. If I should replace the regulator. Whatshould I be expecting as a cost?

Post by **Ozark Lee** » 10 Apr 2009, 14:22

I think that is were I would go next. They are kinda pricey, FCP has them for around $107.00. They are not a high failure rate item so you might want to try one out of a junk yard.

...Lee

Mike-Halewai · Post by **Mike-Halewai** » 10 Apr 2009, 23:30

Well before I replace that I have one last question re: whether my issue could be related to a vacuum leak or something...and it is outlined in the questions in this link...

https://www.matthewsvolvosite.com/forums ... 618#p83618

Post by **MadeInJapan** » 11 Apr 2009, 07:04

Answered that question in that link- hopefully it will help.
Good luck figuring all of this out- you will eventually.