1991 240 Won't start

[faof2]

This is a question to help me understand what happened to my car, a clarification of what the repair shop did, what I should do now, and an attempt to help prevent the problem from recurring. I have no complaints about the repair shop’s work. However, I do not sufficiently understand what happened, and I would like to understand what happened .
I’ve organized it by topics.
PRELIMINARIES:
1991 Volvo 240 station wagon with 98,000 miles. Runs smoothly, no engine performance issues until this incident.

THE INCIDENT:
One morning, I went out to run errands and when I turned the key, the engine turned over fast but would not start. Not even a hint of starting. Not having any clue of what could be wrong, I opened the hood to see if anything looked amiss. I saw nothing out of order. I tried starting again, no luck. I then examined each ignition related wire, primary and secondary, to see if any were broken, cut, disconnected,etc. The only thing I noticed was that there was a small amount of corrosion in one of the distributor cap towers. I fiddled with each distributor wire, knowing I wasn’ t really solving anything. I went back to trying to start the car frequently as I did this. Then, about the seventh attempt, it fired right up. (Later, I will ask your opinion as to why it started that time.)
Against my better judgement, I decided to go out on the road. The only thing I noticed was that it very briefly cut out a few miles down the road at freeway speed, maybe for one-half a second. After my errand, as I started to go home, it fired up normally and I was on my way UNTIL it just stopped running while going about 65 mph on the freeway. I pulled off and tried in vain to start it, then called a tow truck. The tow driver said I was not getting fuel. How he derived this conclusion, I don’t know. He was not a mechanic.


REPAIR SHOP:
At the repair shop (AAA approved , specializes in Volvos, and the shop which has serviced this vehicle), the service manager(who happens to own/drive a 1980’s era Volvo) showed considerable concern when I pointed out the corrosion in one of the distributor towers. Here is what he wrote on the invoice:
“ CAR TOWED IN
Labor service – $92.00
no start…cranks…no start…check for spark and fuel pressure…no spark…replace suppressor relay and ignition fuse. Test operation. ok
NOTE: we advised customer to replace corroded distributor cap and ignition rot…or as well as wires…not replaced at customer request…no guarantee on this repair without the replacement of these additional components.. PAR
New fuse genuine copper fuses $3.57
New 35 23 608 Fuel pump relay $62.47”

QUESTIONS:
1. The suppressor relay – Does it control both the ignition AND the fuel pump? Help me understand this interplay. Does it sound realistic that both fuel and ignition failed at the same time?
2. What caused a fuse to blow, and which one likely would it be?
3. In a phone call (but not on the invoice), he recommended having the fuse box terminals cleaned at a cost of $45. I figured I could do this myself. I believe he said I could do this with WD-40. What is your opinion of the need to clean the fuse box terminals?
(I also decided I could replace the cap, rotor, and wires myself rather than spending the $120 the shop would charge)
4. About the “no guarantee”. Am I to conclude that he believed the corrosion in one distributor tower could cause this problem to happen again? When I asked if I should maybe carry a spare relay, he said no, the existing one lasted for almost 20 years, no reason to believe it is subject to failure.
5. Do you think I should carry a spare suppressor relay “just in case”?
6. How about carrying an extra fuse? Is a “genuine copper fuse” any better than a regular fuse?
7. Where exactly is this relay located? I looked in my “Bentley’s Volvo 240 Manual” and could not locate this relay. Does it go by a different name perhaps?
8. Why do you suppose it wouldn’t start, then did, then wouldn’t again permanently?
9. Any thoughts on preventing something like this happening again? The prospect of the car suddenly losing power on the freeway is frightening.
10. If we were back at the morning it wouldn’ t start, what procedures would I follow to determine the cause of it not starting?
11. I have not yet done the recommended work. I imagine you will recommend I do so. However, the car runs smoothly. My other vehicles are non-Volvo older cars. I am used to cars giving warning signs before failing.

MY LAST QUESTION:
If I have a followup question, how do I submit my followup question?
Thanks in advance for your help

[billofdurham]

1. The radio suppression relay is actually a fuel injector relay. The pre 1986 injectors were supplied constant + power to one terminal and supplied a timed ground to the other terminal via the ECU. The constant + power used to come from the fuel pump/injection system relay. In 1986 Volvo decided to isolate the fuel injector circuit because of some radio interference created by the pulsing circuit. The solution was to energize the radio suppression relay with the pump/system relay feed instead of using it to power the injectors directly.

However, the relay that was replaced on your car was the fuel pump relay not the suppression relay. I have been through all my books and can find no mention of the radio suppression relay for the 240, but it is mentioned on the 740. Wiring diagrams for the 240 have no suppression relay but for the 740 there is one. A copper fuse is just a more expensive fuse which is usually used on integrated circuits.

The part number quoted on the invoice is definitely the fuel pump relay.

2. Fuses are there to protect the electrical system from damage in the event of a faulty component. They can blow for a multitude of reasons. One reason could be a faulty relay that caused a short circuit. As to which fuse it was, there is no ignition fuse listed for your car. The nearest I can get is the fuel injection fuse which is mounted next to the ignition coil.

3. Are the fuse box terminals that bad. Have a good look at them and decide for yourself. As for cleaning, WD40 would be a possibility with a fairly soft brass wire brush. Obviously the battery would need to be disconnected to avoid short circuits. However, in all my years of driving/maintenance I have never known a fuse box that is mounted inside the car to need a total clean. Fuses in the engine compartment, like the fuel injection fuse, may need their housing terminals cleaned as they are subject to moisture and heat. However, for that I would replace the holder.

4. I think the corrosion in the distributor is unrelated to this incident. It will cause a slight degrading of the current to the plug but, in my opinion, would not cause a total failure of the ignition system. I can agree with him on one point, it isn't necessary to carry a spare relay.

5. Answered in 4.

6. By all means carry a spare fuse. You should have enough spare fuses to cover the whole range fitted to your car. A copper fuse is more expensive but is not specified for the fuel injection system. Just make sure you have one of the correct rating. As I said above you should really carry spare fuses of each rating fitted to your car. Many a motorist has been put back on the roads because my former colleagues and I always carried fuses when we were at work.

7. There is no listing for a radio suppression relay for your car. The fuel pump relay is under the left side of the dash.

8. Relays can stop and then start again for no apparent reason. Whenever I suspect a relay isn't working I give it a good hard flick with my finger. In a lot of cases this kicks it back to life. It is then either replaced or opened up to see if there is a bad solder joint.

9. Unfortunately, a relay stopping working is something that can't be foreseen. No amount of preventative maintenance will cover that type of breakdown.

10. You would need to check for spark and fuel. The fuel side is easy. Listen for the fuel pumps starting up as you switch on the ignition. If you miss that then take out a spark plug after you have tried to start the engine. If fuel is flowing the tip of the plug will be wet. To check for a spark have a spare spark plug handy. Take off one of the plug leads, put the spare plug in the connector, hold it about 1/8" from the engine block, preferably using electricians insulated pliers or thick rubber gloves, and have someone try to start the engine. If there is a spark you will see it jump the gap.

11. It depends on how bad the corrosion is but the distributor cap, rotor and plug leads should be changed as part of your service schedule. Volvo don't set any time on this but I usually look at 3 years or 36,000 miles. No matter the make of the car if a relay suddenly fails then you will get no warning signs.

If you have any follow up questions post them here.

The opinions given above are mine and have been reached after years of experience. An experienced mechanic may disagree with them.

Bill.

[faof2]

Bill of Durham,

I want to thank you for taking the time to help me understand the "no start" problem I had. Your response to each question was appreciated.

One issue I still wonder about - Why did the car have no spark and no gas at the same time? Was that because the fuel pump relay problem caused the fuse to blow, and the blown fuse was causing a "no spark" situation?

Also, where might I find instructions on where to find the fuel pump relay in case I ever have to replace it?

Thanks again,
faof2
91 Volvo 240

[billofdurham]

Why did the car have no spark and no gas at the same time?

On re-reading my previous reply I missed that one! Looking at the wiring diagram the in-line fuse also feeds the ignition ECU. When it blows - goodbye to fuel and spark.

The location of the fuel pump relay can be found by using this link.

There is also a main fuel system relay behind the right side of the dash.

Bill.