"Driving along in my Automobile". Red light turns green goes two feet and stops. Cranks, but no start. Checked fuel pressure. Ok. Relays clicking but no hum from the fuel pump. Great! Clever me just happen to have a new spare pump. Called BCAA. At home installed the new pump turned the key heard the pre prime, YES! turned it over and over and nothing. Checked for codes only one (111) interesting, although I had disconnected the battery. Perhaps that cleared the faults. Clever me just happen to have a new cam sensor. Installed it. No start. Checked and cleaned all fuses. All work, all ok. Swapped relays. No go. Did both tests on two relays. checked out ok. Alright, Check for spark. No spark. Wow, pull plugs and wires and check resistance. All is well. Just happen to have a spare new coil. Installed it and still no spark. Time to check timing belt and tensioner. it was replaced less than a year ago. All timing marks lined up perfectly. Looked just like new. Now I am baffled. Checked for hall sensor in the distributor. Don't see one. At this point I am "Dazed and Confused". Trying as it may be, I love my Volvo and will not ever give up. I welcome anyone that can shed some additional information to help me put my Volvo back on the road where it belongs. Regards, P51.

 

Yes - disconnecting the battery will reset all engine codes. Said you replaced the "cam sensor". I'm wondering what you may have replaced since there is no cam sensor. Perhaps you replaced the crank position sensor?

Your vintage 940 has either LH2.4 or LH3.3 fuel injection and uses a crank position sensor to provide the timing information for spark and fuel injection. The hall sensor provided the timing information on earlier versions of the LH fuel injection system - thus explaining why you don't see a hall sensor.

Check the basics - do you have spark when cranking the engine? If you look in the oil cap when someone cranks the engine do you see the cam moving? Do you see pulses at the fuel injector while someone cranks the engine?

 

I have pulled the plugs and did the spark test. still no spark. And yes it is the crank sensor, my apologies. It's a 2.3L LH.

 

Same question as earlier - Turbo, non turbo, bosch or regina? The turbo cars have a relay that provides power to the coil. Both bosch systems have an ign amplifier that can stop working or have a bad connection. What kind of engine/fuel system and we can give you some more exact suggestions.

 

It is a non turbo regina fuel injected redblock.

 

I trust when you say there is no spark there is fuel pressure and injector pulse tested with a noid light. If you had a bad flywheels speed sensor you would have no injector pulse. The only fuse related to the ignition system is #1. You should be able to find 12v at terminal a on the amp 4/26 that the coil is mounted to. 4/42 is the ignition control unit. Have replaced several bad coil/amp combos on rex cars but never a control unit. But I would check connections to it - control unit is mounted next to the passengers right foot.

 

Thank you very much. I will let you know how this goes. I'll have to purchase a noid light. Schematic is great, again thank you.

 

I have a '93 940 Turbo Wagon It cranks but won't start. Initially the problem was intermittent. It seemed to start fine most of the time when it was cold. But after it warmed up, it wouldn't start after it was shut off. When it wouldn't start, I wasn't getting spark out of the coil (new coil along with cap and rotor) and I noticed the tachometer didn't bounce when cranking. So I replaced the crank position sensor and now my intermittent problem has become permanent. Any suggestions on next steps in diagnosing this issue? I am pretty sure this model and year only came with the Bosch LH 2.4 electronic fuel injection system. I am the original owner. Not sure if this is relevant but Lowjack was installed when it was new due to theft of previous car. The alarm still works when Lowjack switch is activated so I don't think that is a factor but not sure. This is the only custom wiring ever done to the car.

I am a newby at diagnosing electrical issues so I will likely need some basic instructions.

Thanks in advance for any guidance.

Jeff

 

When you replaced the crank position sensor what brand did you use? I would stick with either Bugicord or Volvo branded crank position sensors.

 

thanks for the response. I got the Crank Position Sensor from IPD. the box says: MTC #VR645. Not sure of the manufacturer.

Also, when use the ODB 1 diagnostic and use diagnostic test mode #2 to test the RPM sensor (which I assume to be the crank position sensor) I get the 1-4-1 code which indicates it's working. Am I correct in assuming the RPM sensor is the same thing as the crank position sensor? If yes, is there another way to test the crank position sensor?

Sorry for all the basic questions. It's a daily driver so I'm in a hurry to get it on the road so I can stop borrowing another car.

Thanks,
Jeff

 

First thing. you know how to use the obd1 self diagnostic box - are there any codes stored in the ign or fuel control units?
If the car has spark - your speed sensor is working - let's focus on the fuel system. Do you hear the fuel pump buzz when you try to start the car? (bump key to the start position and return to the on position - the pump will buzz from under the car under the drivers seat area for 1 second. Open door stick head under car, bump starter and listen.) Is there gas in the tank? Do you have any way to check fuel pressure?
If the fuel pump is making noise - common electrical things that prevent the fuel system from working are highlighted below. Fuel pump and injector relay - cracks form in solder joints on the circuit boards inside those. Cracks create resistance, resistance creates more heat - eventually no current will flow when the cracks are large enough. The injector relay under the hood is the worst for no starts. Most normal humans need a magnifying glass to see the cracked solder joints. And talented people can re-solder those relays. Ballast resister for the injectors - the 6 prong connection gets very corroded sometimes. You could use your 12v test light to check for power at the green wire on any injector. The ECU grounds the injectors to fire them. I trust you have checked all the related fuses (shown below) You can easily test for injector pulse with a $10 noid light (but not with a normal test light)

 

My bad. I forgot to mention I am still not getting spark out of the coil since replacing the crank position sensor. I do hear the fuel pump when I turn on the car. I replaced both the in tank pump and the high pressure pump under the drivers seat a couple years ago. No codes flashed (other than 1-1-1) when in diagnostic test mode 1 with cable in socket 2. I checked fuse 1 and 11 and they were fine.

I am at work now but will check some of the other fuel system items you mention later today. I do not have a Noid light but I have a harbor freight nearby sells one that works on Bosch PFI or Bosch2. Will one of these work on my car?

are there other things I should check bro see why I am not getting spark?

 

Don't know why honk is sending you down the fuel system path since you stated that you don't have spark. It would be useful to see if you have pulses on the injectors though since the CPS provides the signal to both the fuel injection and the ignition systems. If you don't have a noid light you can maybe borrow one from and auto parts store. Many lend out tools.

Have you checked to see if you have spark coming out of the coil? I would work my way backwards from the spark plugs to the ECU to see where the signal is lost.

I see that the CPS you purchased was the cheap MTC one. I generally avoid those cheap aftermarket brands as their quality is sketchy and since replacing the CPS made and intermittent problem permanent I would be suspicious.

 

Ok - What codes are in socket 6 (for the ignition system)?

The fuel pump relay turns on 2/12 the ignition/injector relay - the black relay under the hood that develops cracked solder joints, or bad connections with the round electrical terminals. Check for 12v on one side of the coil with the key on. That power comes through relay 2/12. The ignition amps go bad - I never found a good test for those other than swapping them out if everything else checked out. Sometimes there's a a bad connection at the ignition amp also, wiggling the connector might bring it back to life temporarily.

 

I can confirm that I am not getting any volts to the coil with the key in position 2. I am not sure I can locate the part you are calling the Ignition/injector relay (2/12 in the diagram). From the diagram, it appears to be on the front of the drivers side strut tower. Is that where I should look? I see something that could be it that is in the neighborhood. It is behind the battery and in front of the driver side front wheel well, below the ABS unit. It has 4 wires going into it - red, black, gray and yellow/blue. (volvo part #1323592-1) but I was told that is the "aux suppression relay." Is this the part I am looking for? If not, can you give me a better idea where under the hood I should look and maybe what other part is close by for reference?

I will test for codes in socket position 6 again. I didn't get any before changing the CPS but I'll test again.

I am going to pick up a NOID light tomorrow morning from harbor freight. they have one that works on Bosch PFI or Bosch2. Is this what I need? If not, I'll try a loaner from autozone.

Thanks again guys. I really appreciate it.

Jeff

 

Yes that's called a noise suppression relay sometimes. The wire colors match up with the diagrams - you should have 12v on the red (it goes straight to the battery), and 12v on the blue and yellow when cranking or on (power comes from the fuel pump relay) The black wire is ground and the grey wire goes to the hot side of the coil and the injector ballast resister. On the EZK wiring diagram grey wire from the 2/12 relay - there is a bold notation 20/15:2 That means that wire goes to component 20/15 (the ballast resister in the Injection diagram) terminal 2. On some cars the small red wires where attached to the positive battery terminal come loose/get a poor connection and prevent the engine from running.

Pry the cover off the relay if not working and check for cracked/melted solder joints - or some reason current will not pass.

 

I’m getting 12 volts from the red wire and from the blue/yellow wire. Both are getting power with the ignition key off. Can I bypass the relay by jumping a wire from the red to the gray? Then If I get spark to the coil I would know the noise suppression relay is the problem???

thanks,

jeff

 

Some good news, I hope. I jumped a wire from the red wire going into the Noise Suppression Relay (2/12 on the above wiring diagram) to the gray wire coming out of this relay and the car fired right up. As I was handling the relay with the key in the on position, I heard and felt it click several times so before I order the part, I'm going to confirm I don't have a cracked wire or a corroded/deteriorated connector before order the part from IPD.

By the way, before I jumped the red to the gray wire and got it to run, I tested the injectors with a NOID light (Autozone for $25) and none of the injectors were getting flashes. I could used them as a loaner and returned them but I'm going to keep these lights for future use.

I have a few questions for this group of geniuses before I stop bugging you:

1. Am I taking a victory lap too soon on this? Is there something else it could be? Let me know what else I should test to confirm it's the Noise Suppression Relay.
2. Would it be safe to drive the car temporarily (about 40 miles round trip per day) with the Noise Suppression relay bypassed with my jump wire?? If it's just for noise suppression, I can get by without it until the part comes in but I don't want to chance it if this relay serves other safety related purposes
3. IPD has a Volvo OEM part for $78 and an aftermarket (AMR?) for $19. Is the extra $$ worth spending for OEM on this part?
4. Check me if I'm wrong but from what I learned through this process this part is also known as Aux Suppression Relay on IPD's website or the Ignition/Injector Relay and is Volvo part #1323592-1. Can anyone confirm all these names refer to the same part? I just want to make sure I know what people are talking about when I see these various terms in other posts.

Many thanks to Hoonk and Act1292 for bearing with me as I sorted this out. The wiring diagrams were very helpful too. If you're ever in South Carolina, let me know. I know where all the good BBQ is.

I really appreciate it.

Jeff

 

You could try re-flowing the solder on the little circuit board of the relay. I'm not familiar with the RSR (I only had 240s and it didn't have this relay) but found that the typical problem with other relays on these Volvos was cracked solder joints on the little circuit board in the relay. If you're handy with a soldering iron just pop the top off the relay and resolder all the joints on the circuit board. Usually the ones that crack are the joints that hold the solenoid of the relay. I would do this instead of running a wire.

 

Thanks for the tip. I will pick up a soldering gun from a friend and give it a try. I haven't soldered anything since I was a kid so there's a better than average chance I will screw it up given the circuit board is so small. But the new part is due to arrive in a few days so it's worth a chance.

Thanks again for all the help.

Jeff