850 GLT automatic 1995 #3 cylinder /dead

ddixon · Post by **ddixon** » 05 Feb 2009, 19:08

My 95 850 GLT has the interior OBD connection. My volvo dealer tells me this means the car has the OBD II diagnostic system.
Is this correct? My OBD II reader shows 2 codes.
Po303 listed as Cylinder 3 Misfire Detected. DUH!
P1310 No listing under volvo. Ford lists it as Ionization Misfire Detection Module Fault.
I am an experienced back yard mechanic. #3 cylinder is completely dead, but there are no unusual noises. There is hot spark. Plugs are Bosch, replaced 1500 miles ago, wire set is excellent, boots have no cracks. I pulled off the fuel rail, I didn't measure the pressure, but it looks good. & the #3 injector seems to have a good spray pattern. (I also use injector cleaner about every 3 tanks of gas). The only thing I didn't check is the electrical circuit feeding #3 injector. Is there a correct check procedure? Thanks for any help.

Post by **Ozark Lee** » 06 Feb 2009, 07:24

Welcome to MVS,

On your '95 you have OBD-II with OBD-I functionality via the A/B test ports under your hood.

I find the codes from Port A-2 to often be more accurate than the P codes from the OBD-II port. Here is how to read them:

http://volvospeed.com/CheckEngine.php

We also have a factory service manual pinned here that will help you run the problem down.

https://www.matthewsvolvosite.com/downlo ... vo_850.zip

See the appropriate test with codes.pdf after you unzip the manual.

...Lee

ddixon · Post by **ddixon** » 13 Feb 2009, 14:11

THANKS FOR YOUR HELP! I pulled the codes out of the under hood diagnostic unit, using the #A2output socket, Then #A6 output socket. #2 had 4 codes, #6 had no codes.
The codes were 453, 543, 545, 553. I cannot find any information in the PDF Manual on any of these codes. In addition upon going into Test mode #2 & #3 (on both socket#2 & socket #6) the system activated the fan circuit low & high speeds, & the intake manifold solenoid valve. Should I erase the codes & start over? Your input is greatly appreciated in what is turning out to be a very stressful situation. Thanks ddixon

Post by **Ozark Lee** » 13 Feb 2009, 14:51

All 4 codes are misfire codes, two of them indicate a misfire on one or more cylinders and the other two indicate a misfire on #3 cylinder.

My bad, I should have directed you to the tests with codes turbo.pdf file. It goes through all of the procedures for dealing with the misfire codes. Most of the procedures can be done without special tools but there are a couple of tests that need a Volvo Scan Tool to get the readings.

...Lee

ddixon · Post by **ddixon** » 09 Mar 2009, 10:12

Finally got a chance to work on the 850, not much success, is there a way to check out the fuel injectors without a breakout box? (Just using a VOM meter). If not, where can I get a Breakout box? thanks Don

Klausc · Post by **Klausc** » 09 Mar 2009, 13:51

If you are getting spark on #3, I suggest a compression test is in order. The failure rate for fuel injectors is very low.

Post by **Ozark Lee** » 09 Mar 2009, 15:21

is there a way to check out the fuel injectors without a breakout box?

You can check the signal with a VOM but that won't necessarily tell you if the injector is actually firing. I'm with Klausc that the next step is a compression test. When gasoline got so expensive a lot of people started running 87 Octane in their turbos and wound up with burned exhaust valves.

...Lee

ddixon · Post by **ddixon** » 10 Mar 2009, 09:37

ok! first my 850 is non turbo, Second Spark is fine, so is compression. therefore I think it is either injector wiring, & or The ECU. forgive me for not being clear enough in my question, but what I want to know is there any way I can check out the connections between #3 cylinder injector, and the ECU, without a Breakout box? For example how do I check whether I even have voltage to injector #3,what that voltage should be? perhaps resistance? or is that circuit grounded or broken?
I would much prefer to make this check without stoning the ECU.
Thanks for any help Don

Post by **Ozark Lee** » 10 Mar 2009, 12:36

On a 95 N/A model it has multiport fuel injection. All of the injectors fire from a common source. If it starts and runs the line from the ECU is good. Unplug the #3 injector and another injector and check for continuity between the green wires on each and the grey wires on each. If you don't get good continuity between the green wires you need to check the branching point shown as 23/11 if there is not good continuity between the grey wires check the branching point at 23/3.

Underhood harness.pdf

...Lee

ddixon · Post by **ddixon** » 12 Mar 2009, 13:32

OK! I checked the continuity on not only #3 injector but just about any combination of injectors that you can think of.
Results: ALL the grey wires have good continuity, none, absolutely none, of the of the Green wires have any continuity with any other green wire. Does this tell you anything? And also, what should I look for at 23/11? Is this a terminal point with perhaps a connector? Thanks Don