1994 850 No start, no spark

1994_850_owner · Post by **1994_850_owner** » 09 Mar 2010, 10:12

OK, here goes.

I have a 1994 850 non-turbo with 132,000 miles. The timing belt was changed at 70,000 miles and the car has been kept up with over the years by the original owner, always getting the work done at the dealer. Everywhere I look and touch it is all OEM Volvo parts down to the plugs and wires.

I have read 32 pages of forums here and have gotten many ideas. I have also posted on SwedeSpeed. I have also downloaded the 850 manual. It is great. Thanks again for making that available.

My car started doing this a couple of years ago. I would go out to start it and it would just not start- winter or summer. After waiting 15 or 20 minutes it would start and I'd go about my merry way. Recently, it started dying on me while I was driving. Then after awhile it would start again and be fine. This last time I got about 2 miles from home and it quit. I went back 2 hours later and it still wouldn't start. So, I went back in the morning and it started right up. I turned it around and started for home. Just as I was getting to my driveway it died again and hasn't started again.

I pulled the codes and I got 314 for the CMP sensor. No other codes in position 6- ignition, nor in posiotn 2- EFI. I even tried position 7 and no codes were there either. I decided to go ahead and change out the plugs, wires, rotor, distributor cap, and coil. I have a new battery and I tightened all of the cables going to the battery. I checked all of the grounds at the ground point in front of the battery and they all check out ok too. I put in the CMP and it still won't start. I checked and both cams are turning when we try to start. I then put in a new crankshaft positioning sensor. Still no start or spark. I checked all of the fuses. I am getting fuel to the rail but checking with the NOID light I am not getting a pulse. I replaced the main EFI relay- the one by the radiator. I have ordered a fuel pump relay and it should be here today. I did not do the jumping trick between pins 15 and 87. I checked the resistance on the coolant temperature sensor and it was within limits. I went ahead and ordered a new one as well as an OEM thermostat (192) and it's due in today also. I checked the voltage at the CMP and I am getting 12 volts on pin 1, 5 volts on pin 2, and 0 volts on pin 3 with the key in the on position. While cranking I get the same readings- no pulse. I checked the ground, pin 3, and it was 0 ohms to ground. I have not had out the ignition ECU yet. I even tried starting it in neutral but still no joy. Thinking that maybe I had a bad CMP I took it back and got a new one, to no avail. I don't have a scope to see if I am getting a good square wave or not. And my DVOM does not have a dwell setting on it.

I don't know what else to try. I have stumped all of the mechanics that have looked at it.

Does anyone have any other ideas??? I would appreciate any other thoughts here. I really don't want to have it towed to Volvo to fix the problem. I've been working on this for over a month now and I am getting a little frustrated. It's a good thing that I have another car or I would be really pulling my hair out...

Appreciate it. Thanks, Don

Post by **jblackburn** » 09 Mar 2010, 11:21

Well, first of all, welcome to the site!

I wish I had an answer for you, but the truth is I'm stumped too. You've definitely done your research on this, and have already done everything we typically suggest to try. I think at this point the signal may not be coming from the ECU itself. You may be able to fault-trace the wiring between all associated sensors to the ECU box, and back to the ignition coil and see if there are any breaks in associated wiring. If you're not getting any continuity problems there, it may just be the ECU itself is dead. A rare occurrence, but it can happen.

Hopefully some others will have ideas as well.

Post by **charlyW** » 09 Mar 2010, 12:32

Try the speed sensor we had a truck at work which wouldnt start sent it the techs tried everything no codes from the array of computers turned out the speed sensor was duff

Post by **confused_al** » 09 Mar 2010, 15:00

How is your PNP? Got any code(s) from A1?
A bad PNP switch would prevent you from start, but put gear in "N" will overcome that.

1994_850_owner · Post by **1994_850_owner** » 09 Mar 2010, 15:32

I put in the new volvo fuel pump relay and still no start.

I checked the codes at A1 and got "124" and "134"

I haven't seen anything before about checking for codes in A1. There is not any mention of them in the Haynes manual or anywhere else that I have read. What do they mean ???

Maybe we are on to something here...

Post by **confused_al** » 09 Mar 2010, 15:46

Here is DTC library link:
https://www.matthewsvolvosite.com/forums ... hp?t=10758
Also, you can find DTCs in the AUTO TRANS DIAGNOSIS part of the service manual (p18).
Looks like you are on it.

Post by **jblackburn** » 09 Mar 2010, 15:59

134 Faulty load signal from ignition control module

Well, that's what it is causing the no spark. I've never seen that code come up before, though. Computer issue? I don't know. Not very descriptive, is it?

I'll try to do some research for you when I've got a chance tonight...I definitely can't find anything on a quick search here or by google.

1994_850_owner · Post by **1994_850_owner** » 09 Mar 2010, 16:12

what about the 124 code???

124 Mode selector faulty or short circuit to ground

what does that mean???

where do I check, any ideas???

Thanks

Post by **confused_al** » 09 Mar 2010, 16:28

On page 27 (AUTO TRANS DIAGNOSIS part of the service manual):
"DTC 124: SHORT TO GROUND IN MODE SELECTOR SWITCH CIRCUIT
1) Turn ignition off. Carefully pry driving mode selector
switch from center console. Ensure controls for selector operate
smoothly and do not stick. Ensure "W" button does not stick in
depressed position and operates smoothly without catching. Shake
driving mode selector to see if there are loose parts in the switch.
Replace as necessary. If driving mode selector is okay, go to next
step.
2) Disconnect driving mode selector connector. Put switch in
mode "E". Connect ohmmeter between selector terminal Brown/Green and
Black wires. Put switch in mode "S". Connect ohmmeter between
Green/Orange and Black wires. Ensure "W" button is up. Connect
ohmmeter between Green/Orange and Brown/Green wires. If ohmmeter reads
infinite resistance for all tests, go to next step. If ohmmeter does
not read infinite resistance for all tests, replace driving mode
selector module.
3) Disconnect TCM. Connect ohmmeter between TCM side of
selector terminal Brown/Green and Black wires. If ohmmeter reads
infinite resistance, check for short circuit to ground in Green/Orange
wire. If ohmmeter does not read infinite resistance, check for short
circuit to ground in Brown/Green wire."

On page 28:
"DTC 134: INCORRECT LOAD SIGNAL
1) Load signal from ECM provides information to TCM on torque
being delivered by engine. If TCM does not register an incoming load
signal when RPM sensor on transmission gives a signal that input shaft
RPM is greater than about 600 RPM, DTC 134 will set.
2) If DTC 134 is set, check for poor terminal contact in
connectors between TCM and ECM. Also check for an open, short circuit
to voltage, or short circuit to ground in signal wiring between ECM
and TCM. If all circuits are okay, connect scan tool to DLC. Ensure
engine is warm, transmission is in neutral, and A/C is off. Select
SCROLLING VALUES. Load signal should be about 35. If load signal is
okay, replace TCM. If load signal is not okay, replace ECM."

Post by **jblackburn** » 09 Mar 2010, 16:47

Cool, thanks Al. So it looks like it IS the computer, but it sounds like it may just be a connection issue.

Often times, the 124 code can be taken care of without taking out the switch simply by mashing the buttons back and forth a few times to clean the contacts. Clear that one & see if it comes back again.