I apologize for posting about an existing subject but I've read the forums and I am stumped.

Only issue is intermittent no start. Upon turning the key through positions, the car chimes, dash lights glow, engine tries to start but cannot. I cannot work on the vehicle myself (health issues) and mechanic is unsuccessful in finding a diagnosis (I understand intermittent issues are difficult to diagnose). When it would not start, I couldn't hear the in line fuel pump engaging nor the relay so I figured we had a good idea of what the issue was. There are no other issues, and when it starts, it runs perfectly.

So far, we've changed the in line fuel pump, the fuel pump relay, and the crank position sensor. I also bought an ignition switch, which is going to be changed today. Another idea I have is the main fuel pump. (It's getting expensive!)

Any other ideas? I am throwing a lot of money to potential fixes because my mechanic doesn't seem to know how to diagnose the issue. The next idea is to take the car back and find a Volvo savvy mechanic as he's had my car for a month now. Desperate!!

Thank you.

 

Changing the ignition switch is a good idea, could be your problem.
If not, when the no-start occurs spray some starting fluid in the intake and see if it fires up--that will tell if it's fuel or spark problem.
It's always better to have a savvy Volvo mechanic. More and more specialization is driving this business. But it should be an older Volvos mechanic--newer Volvos are nothing like a 240 or any Red Block. As cars age they develop issues that sometimes defy even the best techs as wiring, sensors, and many parts which normally last "forever", fail.

 

Stop replacing parts you can't prove are bad (unless they are returnable) (that includes the ignition switch that won't fix it!)

For an erratic problem - you need to determine first what system is not working when the car does not start. I trust the engine spins over it just does not catch. - Do you think you can duplicate the problem on a regular basis? If so you will need a couple of 12v test lights and a fuel pressure gauge hooked semi permanently to the car to determine what system does not work. What makes the engine start again after you have a no start episode? Are there any self diagnostic codes stored indicating an out of spec condition/component? Does your tech know about the OBD1 self diagnostic system and how to use it? Here's a link, there are better guides out there than this https://www.2carpros.com/articles/vo...e-1983-to-1993

Engine spins over does not start - is there fuel pressure ? (look at the already connected fuel pressure gauge)
If not is the test light connected to the fuel system relay lit up indicating power is going to the fuel pump/s?
Does the test light connected to the pulsed side of the coil flash when the engine is running or trying to start? If so you should have spark at the spark plugs. What does it look like inside the distributor cap?
Attach a $5 noid light to one of the injector wires - does it flash when the engine is spinning over indicating the ECU is firing the injectors?

As mentioned a Volvo specialist, especially an old one is needed. Most cars have not had distributors or spark plug wires for over 20 years - if you have a 30 year working on the car he may have never seen a system like that and be aware that those 2 little dusty black lines inside the distributor cap is what can make a car not start if it is humid outside. Or a similar line on the rotor button (or even spark plugs/wires) Or that little fuzzy line around the end of the fuel system fuse is preventing enough current to flow to the pump. Problems like this tend to end up being very simple - if you have someone familiar with older technology methodically looking at known failure points. Everything today is code driven - no code? Techs sometimes have no clue what to do.

If someone has had your car for a month they are probably in over their head and they may have other work they will get paid for them to do. Everybody works on commission - and it's hard to charge a customer with a car/problem like yours for the real amount of time spent on it - making your current service provider even less likely to spend time to solve your problem. Techs get satisfaction from FIXING things -

 

Since the problem is intermittent you will probably have to do some diagnosing yourself. Your statement about not hearing the fuel pump run when it is not starting is the first step in diagnosing. When you turn the key from off to the II position (not cranking) you should hear the fuel pump run for approximately 1 sec and then shut off. From there proceed to try to start the engine. If you only hear the pump run in the cases where the engine starts and don't hear it when it fails to start then the problem is usually one of 3 components:

1) Fuel pump relay
2) 25 Amp Fuse
3) Main fuel pump
4) ECU

The fuel pump relay is normally the cause but you mention that it has been replaced.

The 25 amp fuse under the hood is also a typical failure point in older models of the 240 but I noticed that yours is a '93 and I believe the '93 models had relocated the 25 amp fuse so it doesn't have the water infiltration problem earlier models had. Check it anyway. Clean the fuse and put some dielectric grease on it. There is a smaller wire that goes from the positive battery post to the 25 amp fuse. This fuse runs the fuel injection.

The main fuel pumps last a long time on these cars unless the in-tank pump fails and is not addressed.

There are cases where the ECU fails and causes these sorts of failures. However, those tended to be related to "pink label" ECUs which were mainly limited to '89 models. Search the threads here to find out how to identify the pink label ECU. I have read of a white label ECU fail in this manner as well but that seems to be an exception rather than the rule.

 

I thought I had followed up with the resolution but I hadn’t. A hearty thank you to everyone who responded.

The problem ended up being discovered once the dash was pulled out. The wires leading to the fuel pump relay had been chewed by a mouse.
I guess I should have considered that upon dealing with a 30 year old car.

Solved and thank you.