Are there any obvious hidden things that one can check off,

 

Unclear what you are asking. If you have braking issue please describe it in more detail so maybe someone can help you.

 

forgive me please, it’s an engine cutting out/stalling issue that doesn’t appear to be anything other than electrical.
the rev counter will stop working and then it may fire back up again, but every now snd then once the rev counter cuts out the charging light will come on and the vehicle may or may not start again.
touch wood, I’ve never had to have it old boy towed home as yet.
is there a relay or common issue that appears as these vehicles hit a certain age. I believe this vehicle has travelled in excess of 400,000 kms.
I have clocked up over 10,000km in this vehicle and this issue has only surfaced recently, causing my local mechanic a lot of embarrassment.
any ideas on the subject would be truly valued, it old boy seems just to good to be sent off to the scrappers.

 

'86 240 has a Hall effect sensor in the distributor. This sensor and associated wiring to it may be responsible. The fuel injection relay may be faulty.
These years are notorious for disintegrating wiring (the insulation rots) also, and if that is the case, then then there are no easy solutions.
Any 400K kms car has to be subject to extra care, it doesn't owe you anything.
Have you had a "professional" opinion?

 

thanks plenty for your input.
I brought the vehicle off and Volvo serviceman that had owned the car for ten plus years as a lone vehicle for his clients.
it had sat for maybe a year before it was sold to me, he did though replace the under bonnet wiring loom with a second hand one, he replaced radiator, cam belt and a few hoses.
Since I’ve had it, I’ve replaced the radiator expansion bottle (twice), the master cylinder, engine and gearbox mounts, the distributor with a second hand one, by-passed the heater as it was losing water and the rear passenger floor was getting wet. The air conditioning was rebuilt by the mechanic I brought it off, but that has failed badly also.
The mechanic, because it’s an intermittent issue has never had it play up on him.
If it stopped and wouldn’t start again, I’d be happy to walk away from it, but it does start again.
when driving it at moderate speeds, it looses power and the rev counter drops to
”0”, and if it’s in a good mood, it’ll
kick back into life again, but if wants to show me who the boss is, the alternator light comes on and I’m forced to park up so that I can place it into park to restart it again.
I’ve cleaned earth wires, cleaned battery terminals, replaced the distributor, replaced the computer by-passed fuse because the spring inside had become rusty and lost its tension.
it starts again a lot easier nowadays but it still cuts out. I can’t put it down to heat, ad this can happen when it’s still cold and it can happy after it’s been running for an hour.

it appears you have have a little bit to do with these lovely older models Volvo’s and if you could maybe give me a list of try this, replace this, I’d be happy to throw a few dollars at it Ali g with a few hours or two.

even if I am/was yo give the cat away, I’d like to think the next owner wouldn’t have to live through what I’ve lived through with it.

the leg cramps, the tense shoulders, I’m sure you can get an idea of where i’m going with this.

 

suppose i would first check the distributor cap and rotor, and as lev has said fuel pump relay.

 

really appreciate your input here

A new cap and rotor were added when the second hand distributor were installed by the mechanic.

Would the fuel relay cut in and out intermittently without any clear patent at all?

 

fuel relay yes it could, if your mechanic has a spare lying around you could swap it out to check

 

I'd still be looking at the distributor Hall sensor and associated wiring based on the symptoms and history even though the distributor was already replaced with a used part. Check the cable from the sensor onto and into the wiring loom.
And you can always blame the ECU, aka the computer, for mysterious electronic behavior.

 

The distributor has an O ring to try to stop the crankcase Vapor’s from oiling the distributor but o I’ll get there eventually

Yes the fuel pump relay can go and you should check that swap it or clean the contacts to get it working You can also jump the relay temporarily. I cut one open and put a fuse in so I can plug that to test but it should be able to unlatch to be permanent. I’m trying to think where it is located exactly

I think on a 740 it’s below the radio on the drivers side under the Center console left cover

on a 240 it might be either under the carpet left of drivers feet or on the right side above passengers feet near the ignition computer Others can verify better?


if you pull the distributor swap it with another old one
or
if you can buy just the sensor you need to rivet it to the sensor plate in the distributor

I’ve bought the plate before along with a new sensor tgen no rivetingneeds to be done but you need to take apart the distributor


the connector on the distributor or the sensor may be oil soaked or wires may have bad insulation

I bought a cheap made in China distributor with cap and rotor for 100 bucks.. cheap new, but you get what you pay for , you are probably better to use an OEM distributor but I was having trouble buying the sensor so it’s an option too, even just as a part for troubleshooting you can simply swap I it and then look for an OEM one if that was the issue.

careful about the relationship of parts if you take apart the distributor it’s not hard but it might be possible to get something out by 180 degrees. I’d mark the gear and make sure you get it back the right way around
take pics use punch location marks use red paint to keep things in order etc

I’d set the engine to TDC and note where the rotor is pointing

I think it should be pointed to cyl 1 on TDC on cyl 1 after it’s on it’s compression stroke.. remove plug 1 feel for air coming out then at TDC on crank

id mark the distributor location and try to get it back the same

I guess you can use a timing light after , to adjust the distributor position but the computer seems to control a lot of that, the computer does not control where the rotor is pointed, that is a mechanical adjustment.. if you put it back close, your car should at least start and run someone else can describe how to set that timing perfectly and properly with a timing light later if you upset that adjustment,


the flame trap can plug up and that may cause extra crankcase pressure I bought a used 740 that wants to push its dipstick out and spew oil
if it has that issue maybe it pushes more oil into the distributor
The sensor does not like being oil soaked and that can cause no starts and side if the road frustration. And intermittent no start issues



When you crank you should see the tach bounce, if it does not then that’s a sign that the engine is not seeing the TDC pulse.


A mechanic can check fuel pressure or if you don’t have a gauge you can open the line from the pump where it connects to the fuel rail and put it in a jar and don’t crank for long it will fill the jar or overfill it quickly so you have to think about fire , don’t start it unplug ignition coil
a fire is very possible and there are safer ways to check that Any little spark lighting off a jar of raw gas will cause a fire that you aren’t putting out without a catastrophe so be very careful and that is not going to be a “recommended practice” make sure you have an appropriate extinguisher and don’t do this inside your shop and not a hot engine and no sources if ignition People trip into trouble lights and things and can cause a really serious situation. fans and motors can cause sparks Be super careful if you even think of doing this because it can be a stupid thing you regret so easily ..

When I replace a fuel pump I also started connecting a tiny 12v bulb in parallel with the pump . I put the lamp in the engine compartment
after that I just look and if the lamp is on my fuel pump has power. If I have relay issues I can tell.. it’s just to help me solve these issues more easily, that’s all . Tiny grain of wheat bulb. very small amp draw. On when fuel pump has power.