Occasional loss of power.

[Laird Scooby]

A guess on my part would be the RSR - Radio Suppression Relay. I don't think this brings any codes up usually but can cause the signal to be lost from the MAF because on some models (like mine) it feeds the MAF as wel as the injectors and fuel pump relay.

Depending which model you have, it will either be by the coolant tank or on the passenger side inner wing.

Could certainly cause these problems and others similar like bad starting. Worth a look.

[Delta66]

Thanks, I'll pass that on as a suggestion, starter for 10 to the mechanic.

[Delta66]

Originally Posted by Laird Scooby

If the rev counter was still registering something until the engine physically stopped turning then it's fair to say the CPS is probably ok.

This is a bit of a hunch based on a recent bit of experience but worth a try.



First, check the relay in position "E" as shown on the diagram is pushed fully home.

...

Turns out that was the cause of the fault. The mechanic found the relay was only partially working, as in one of the two switches inside was Ok and the other was not always opening and closing as it should. When he phoned Volvo to get a new relay apparently they just said "its the white one" and did not need a parts number because they are supplying lots of them due to failures and intermittent faults.

[Laird Scooby]

Glad you got it sorted and at least one of my suggestions helped!

[Stephen Edwin]

Have I missed this. What is the relay in position E please?

I can just about see a title on the diagram. LH Jetronic Relay. Hmmmm ....

Is it a relay particular to that car/engine system, or?

Does it have a more generally known, more informative, name?

[Laird Scooby]

Originally Posted by Stephen Edwin

Have I missed this. What is the relay in position E please?

I can just about see a title on the diagram. LH Jetronic Relay. Hmmmm ....

Is it a relay particular to that car/engine system, or?

Does it have a more generally known, more informative, name?

Fuel Pump Relay. That is on a 7/940 though, whether your 240 will be anywhere near the same/similar or not is another matter!

Just to put that into perspective, middle green relay at the top :



That's my Fuel Pump Relay, not even mounted in the same plane! The internals are turned through a right angle to cope as well.

Yes, they come in a variety of colours too! Green and white are the usuals for Volvos.

[Stephen Edwin]

Oh yes the 240 fuel pump relay. EEK.

Upstairs, the 240 section has advice about connecting a wire to basically by-pass that relay to see if that is the fault, and to get home. And advice about e.g. fitting blade fuses for the relay to avoid problems with the old ceramic fuses. Most so called ceramic fuses nowadays are plastic bodied and alluminium fuse metal .... leading to corrosion against the brass contacts, heat, melting, failure....

I'm not aware of it being reported as cutting out except at low speeds. One notorious incident was on a very busy roundabout in a rush hour. Apparently a breakdown service moved the car double quick pronto. And fortunately for the driver, the patrol realised the fuse problem and sorted it out there and then, in a safer place.

[Laird Scooby]

Originally Posted by Stephen Edwin

Oh yes the 240 fuel pump relay. EEK.

Upstairs, the 240 section has advice about connecting a wire to basically by-pass that relay to see if that is the fault, and to get home. And advice about e.g. fitting blade fuses for the relay to avoid problems with the old ceramic fuses. Most so called ceramic fuses nowadays are plastic bodied and alluminium fuse metal .... leading to corrosion against the brass contacts, heat, melting, failure....

I'm not aware of it being reported as cutting out except at low speeds. One notorious incident was on a very busy roundabout in a rush hour. Apparently a breakdown service moved the car double quick pronto. And fortunately for the driver, the patrol realised the fuse problem and sorted it out there and then, in a safer place.

The "Continental" fuses as they were often known because they came here from the Continent (Europe in other words) were a huge PITA and any auto-electrician worth his salt used to keep a 1/4" drill bit in his tool box as the "weapon of choice" for a non-functioning circuit on cars with continental fuses. Next to the 1/4" drill bit was a length of emery tape.

The drill bit was used between the fingers to spin in the fuse receptacle and the emery was used to clean the fuse end caps - this was before the plastic body and aluminium fuse links! That was when they were still brass contacts in the receptacle and fuse end caps and real ceramic for the fuse body.

Blade fuse upgrades are a definite improvement, fuseboxes can be bought inexpensively to cover as many ways as the existing continental fusebox has and usually more for the same physical area. In many case it will be "plug'n'play" in as much as Lucar (1/4" male/female push on connectors) connectors were almost certainly used to connect to th fuse box so can be unplugged from the old one and onto the new one.

If you're wise, you will separate the circuits coming off each continental fuse so more protection is afforded and individual circuits can be fused so that a failure in the reversing light circuit for example doesn't render the indicators and stop lights inoperative.

[Stephen Edwin]

It becomes a question of how far one goes in updating which parts of the 240.

The fuel pump fuses are widely recognised as wise to change to blade fuses.

[Laird Scooby]

Originally Posted by Stephen Edwin

It becomes a question of how far one goes in updating which parts of the 240.

The fuel pump fuses are widely recognised as wise to change to blade fuses.

That's the ultimate question isn't it? How far do you go?

If it's just one or two circuits, say fuel pumps and heated rear window, i'd probably go for a pair of interlocking blade fuse holders and have done. If there were several circuits, i'd go for a complete upgrade.

Given the age of yours, a blade fuse upgrade fusebox could easily be considered a "period upgrade". Even adding a CD player would.

Depends how important originality is for you.

However, if you consider things like reliability, ease of maintenance etc then a full balde fuse box would be a good period upgrade. If you wanted a CD player, it would obviously have to look right in the car but that would be considered a period upgrade too - especially as there were cars from 1986 onwards with factory fit CD changers - not many but i know of one or two.
By the mid 90s though, CD players were much more widely available and the original head units on cars from the late 80s were generally getting tired so would have been changed by second or sometimes third owners of cars from say 1988.

Even fitting LPG can be considered as a period upgrade. Although not widely available, even in the mid 70s, cars were converted to run on CNG and/or LPG with some manufacturers making prototypes.
A school friend of mine whose dad worked for Calor Gas as a rep had a Mk4 Cortina company car that ran on CNG, converted by Calor presumably but i also know BL made a prototype Allegro with LPG and something else as well, a Maxi i think.

All depends what you want and how far you're prepared to go.