Volvo 850 1996 / Tranmission or PNP or what? Topic is solved

[DennisCA]

I believe that indicates a possible issue with the PNP switch as it's apparently what controls the reverse lights on the autos. So if you have a no-crank condition and issues with reverse lights maybe it's time to prioritize that.

This site has a guide on how to repair it
viewtopic.php?f=1&t=29930

I hope you have somewhere under a roof to be when it comes time for the PCV job, I recommend a flex head ratchet (I had use of both a flex) to get at some of the bolts under the intake that support the intake.

I suppose working on the PNP switch is best done when you also do the PCV job. Then you can also double check and clean the starter motor connections and test if the solenoid and motor work by giving them 12V.

[BeerDeer]

I believe that indicates a possible issue with the PNP switch as it's apparently what controls the reverse lights on the autos. So if you have a no-crank condition and issues with reverse lights maybe it's time to prioritize that.

This site has a guide on how to repair it
viewtopic.php?f=1&t=29930

I hope you have somewhere under a roof to be when it comes time for the PCV job, I recommend a flex head ratchet (I had use of both a flex) to get at some of the bolts under the intake that support the intake.

I suppose working on the PNP switch is best done when you also do the PCV job. Then you can also double check and clean the starter motor connections and test if the solenoid and motor work by giving them 12V.

Thank you! But couldn’t a bad battery also cause a no-crank issue? My previous battery was 5 years old, so I replaced it with a new one just to be safe.

Unfortunately, I don’t have a covered space to work on the PCV system, so I’ll need to do it in these cold conditions. I also don’t want to pay a shop for this repair—it’s an old car, and I’m concerned they might overcharge me significantly.

I’ll check the PNP switch when I work on the PCV system—it seems like a good idea to address that as well.

Do you have a guide or resource on how to safely double-check and clean the starter motor connections or test the solenoid with 12V? I want to avoid damaging any electrical components during this process. As a student with no formal experience in mechanics, I’m relying on guides to help me handle these repairs step-by-step.

Thank you for your help!

[DennisCA]

Yes it very well could, but did I misunderstand that you, I thought you had replaced the battery and it didn't make a difference? Or have you not installed the new battery yet?

You should definitely check that first if so before messing with the starter if you don't have to. If it was me, and I am no expert I want to add, I would have removed the starter motor from the car and hooked it up to a 12V source on my bench. I would check if the motor was working by giving it 12V on the small spade connection, putting 12V on that one should close the circuit and activate the starter, If that didn't make the starter come alive I would probably not bother going further but just replace the whole thing.

I am not sure it's a good idea to attempt the above inside the engine bay. I would replace the battery first if you haven't done so, then look for the ground points on the motor and clean them from possible corrosion secondly. Then visually inspect and trace the cables going to the starter by following them backwards from the starter motor for any obvious damage if the first two steps didn't work. But maybe someone else has a better idea?

Perhaps this is worth reading on the starter motor replacement:
https://volvo850wagon.wordpress.com/201 ... placement/

[Sveedy]

I have found that the best way to test a starter out of the car, is to put it on the ground and hold it with your foot while using jumper cables to activate it. If it's good, it should not just turn on and spin, but kick ( or at least try to ) itself out from under your foot.

[BeerDeer]

Yes it very well could, but did I misunderstand that you, I thought you had replaced the battery and it didn't make a difference? Or have you not installed the new battery yet?

You should definitely check that first if so before messing with the starter if you don't have to. If it was me, and I am no expert I want to add, I would have removed the starter motor from the car and hooked it up to a 12V source on my bench. I would check if the motor was working by giving it 12V on the small spade connection, putting 12V on that one should close the circuit and activate the starter, If that didn't make the starter come alive I would probably not bother going further but just replace the whole thing.

I am not sure it's a good idea to attempt the above inside the engine bay. I would replace the battery first if you haven't done so, then look for the ground points on the motor and clean them from possible corrosion secondly. Then visually inspect and trace the cables going to the starter by following them backwards from the starter motor for any obvious damage if the first two steps didn't work. But maybe someone else has a better idea?

Perhaps this is worth reading on the starter motor replacement:
https://volvo850wagon.wordpress.com/201 ... placement/

Yes I installed a new battery, and so far, the "no crank" issue hasn’t returned. However, today, with temperatures around -11°C, it took two attempts to start the engine. On the first attempt, it cranked but didn’t start. I powered off, tried again, and it started right away. After that, the car ran smoothly without any issues.

Now my question is: if it were the fuel pump or fuel pump relay, wouldn’t I also experience problems while driving, such as stalling or power loss? None of that happens—the car drives smoothly once it starts.

Could this be caused by a sensor, such as the camshaft sensor, MAF, or O2 sensor? Or could it even be related to the rotor wires? I recently replaced the distributor cap and spark plugs (Bosch), but not the rotor arm itself. The ignition coil was also replaced, along with the battery.

What else could cause this behavior? It seems isolated to the cold start, and once the car is running, it’s completely smooth and operational. I’d appreciate your thoughts on this!

[BeerDeer]

I have found that the best way to test a starter out of the car, is to put it on the ground and hold it with your foot while using jumper cables to activate it. If it's good, it should not just turn on and spin, but kick ( or at least try to ) itself out from under your foot.

I think my next step needs to be further testing, as I’ve already replaced the following components:

Battery
Ignition Coil
Spark Plugs
Distributor Cap (Rotor Cap)

Today, despite these replacements, the car still took two attempts to start. On the first attempt, it was cranking but didn’t start. On the second try, it started immediately without any further issues. Once started, the car ran smoothly with no power loss or stalling.

I’m unsure if the problem could be related to the fuel pump or fuel pump relay, since there are no issues while driving—no stalling or loss of power. Could the starting problem still be related to fuel delivery, or should I investigate other potential causes?

I’d appreciate any advice or guidance on what to test next!

[DennisCA]

If the starter is cranking the car I do not think it is the issue anyway, seems like the new battery fixed that.

As for the cold start issues I do not really know what could be the cause for that.

[BeerDeer]

If the starter is cranking the car I do not think it is the issue anyway, seems like the new battery fixed that.

As for the cold start issues I do not really know what could be the cause for that.

Could the issue be the fuel pump relay, camshaft sensor, or fuel pump? My understanding is that if the fuel pump were defective, the car would likely stall mid-drive or experience power loss right? Since that’s not happening, I’m unsure if the pump is the problem?

To test the fuel pump, is the correct method to:

Turn the key to the second position and listen for the fuel pump running?
Or, should I try turning the key just short of starting the engine and listen for the pump?

Additionally, could this issue be related to the spark plugs? I replaced them with Bosch Super Plus FGR7DQE. https://www.motonet.fi/tuote/bosch-supe ... earch=true

The previous owner used NGK plugs. I wonder if the change could have introduced any compatibility or performance issues.

Any advice on diagnosing these possibilities would be greatly appreciated!

[coop]

The fpr issue in my experience is only when the engine is cold. When I had the issue it was only really an issue when starting the car in the morning. If it ran that day it usually cranked right up

[erikv11]

One very common problem is failed or failing check valve at the fuel pump. When this happens, after you turn the Carr off the fuel pressure leaks down over time. Then it takes a few turns of the key to get the fuel pressure back up, and it starts.

Here's one easy way to test for bad check valve at the fuel pump:
1 let car sit overnight
2 turn key to position II until all dash lights illuminate but do NOT crank the starter
3 wait 2-3 seconds until fuel pump stops running
4 repeat steps 2-3 again
5 repeat steps 2-3 again
6 repeat steps 2-3 again
7 now can the starter, does it start more quickly now?

If it doesn't start any better after priming the fuel pressure then look elsewhere, but this is one way to check.

You can also monitor fuel pressure at the rail and see if it leaks down when you turn off the car, how quickly it creeps back up during steps 2-6, etc.

It can be difficult to hear the fuel pump in position II. Easier to hear if someone else turns the key and you are back near the pump, especially easier if the cover is removed in the trunk/cargo area.

This does not sound like a fuel pump relay problem, but you can always jumper it to test that.

This does not sound like a problem with the new spark plugs.

If this were my car I would not try to troubleshoot any minor startup problems until the cam seals and the PCV were fixed.