I have a Volvo 740 which has been running perfectly. No performance issues, no start problems. But a couple a days ago the car just wouldn’t start. The start engine is running, but that’s it.
I’ve checked out the ususal stuff to no avail. My suspicion is now focused on the coil. But how can find out if it is dead? I’ve tried Google but didn’t find anything. I remember my father doing the “blue sparkling light” test many years, but I don’t remember how he did it. I have a voltmeter, but not an ohmmeter.
A standard old-fashioned test is to pull a sparkplug, lay it on the engine (so that its body is grounded) with wire connected, crank the engine and see if you can observe a spark. If you can, the coil is exonerated - indeed, at this point you suspect that the only possible remaining ignition problem would have to do with timing.
But does your car have a coil? (Some recent ones don’t.)
BTW, your use of “start engine” may tend to make some readers conclude you are not all that experienced in dealing with this sort of problem - the common term is “starter”.
You could try replacing it. Because the great car mechanic William Shakespeare always advocated shuffling off the mortal coil.
But stupid puns aside, it is true that if you draw the spark plug, you should be able to see a spark. Usual warnings apply – don’t touch the spark plug while you’re doing this and make sure there’s not a lot of gas or other flammable vapors in the air.
What other stuff have you tried? Wet ignition wires or distributor (if you have one) can cause those symptoms. A quick test is to spray with WD-40.
Remove the “center” spark plug cable (the one connecting the coil to the distributor) and carefully examine the metallic electrode inside each boot. If one electrode is corroded, the cable could be the culprit. (Twice in the last 2 years I have had cars that would not start. In both instances, a corroded electrode in the center spark plug cable was the problem.)
If the center spark plug cable looks O.K., reinstall it. Then hook a timing light (with inductive pickup) to one of the spark plug wires and crank the engine. If the timing light flashes, it is pretty certain the ignition system is O.K. If the timing light does not flash, check another spark plug wire. If it still doesn’t flash, there’s probably a problem somewhere in the ignition system.
Let’s see if I got this right: I unplug on of the plug wires, keep the plug in and put it on the engine (ground), right? But if I don’t get a spark, it could just as well be something wrong with the distributor, couldn’t it? Could I unplug one of the wires from the distributor to the plugs, keep the plug in and lay it on the engine, then a put the other end in the coil and start the engine? (Just want to get this right.)
I’ll got WD-40 laying around somewhere. I’ll find it and apply it to the connection points.
I don’t have a timing light. Can I build one easily?
As for the car, it’s an old car, a 1985 model with a 230E engine. The reason why I want to test it is because the car has an electronic fuel infusion system (now that Xema has taught me that it’s called a starter, not a start engine, in English, fell free to tell me the proper term here). So I cannot use a standard coil. My local car parts dealer don’t have the one I need so they will have to order one for me. It would cost $150 and I can’t return it.
I’m not all that knowledgeable about cars, and my “Dummy’s guide to getting a car running in 21 days or get fried trying” was only talking about measuring the resistance.
I’ll go and test it now, I’ll be back later.
(btw, what is the top of the distributor and the spinning thing on the inside called in English?)
Volvo master technician and technical instructor here.
First off what year 740? Turbo or non turbo?
About coils. In about 20 years of dicking around with Volvos I can count the number of bad coils I have seen on the fingers of one hand and have several fingers left over. So while it might be a coil, the smart money says it is not a coil.
Here are some tests I would like you to do.
In a quiet area leave the driver’s door open, push the door chime switch closed with your left hand and turn the key to the on position. (It might help to have the radio off) Do you hear a buzz from under the car for about 1 second?
Next turn the key to start, and watch the tach on the dash. does the needle jump slightly, or does it just lay there dead at zero?
Next and most importantly, does the car have gas in it? Are you sure? Are you sure you are sure? I don’t care what the gauge says, are you sure?
Rick’s experience and advice will probably be most helpful in this matter.
But back to the original question, first you want to see if you have spark (the “blue sparkling light”). The simplest thing to do is to remove the coil wire (the thick wire from the coil tower to the distributor cap) from the cap and position it so it’s about 5mm from a grounded (earthed) part of the engine or chassis, in a place where you can see the gap between the end of the wire and the metal ground while you turn the key to the start position. Crank the engine and watch for repeated sparks jumping from the wire to ground.
If you have spark, the coil (and all of the ignition primary system) is functioning. Next test for spark coming out of the distributor cap by doing the same thing with a spark plug wire. If you still have spark (on all cylinders), you have faulty spark plugs, a fuel injection problem, or an engine mechanical problem.
If you don’t have spark, you might have a faulty coil, but as Rick mentioned the problem could be some other part of the ignition primary system. The testing for that is more involved, but much of it can be done with a voltmeter.
You don’t need a timing light to test for spark, and I think it would be difficult to build one. You only need a timing light to measure and set the ignition timing. This is almost certainly not an issue unless the distributor housing has been rotated.
I forgot to include: If you have spark from the coil, but not at the ends of the spark plug wires, the fault is in the distributor cap, rotor, or plug wires.
You can not run the engine with a spark plug hooked directly to the coil. That would only provide spark to one cylinder, which would not be enough for the engine to run on.
If you don’t have spark from the coil, make sure the coil wire is okay and its connection in the coil tower is in good shape. If necessary, substitute a good insulated wire to test for spark from the coil.
Your questions: 1. In a quiet area leave the driver’s door open, push the door chime switch closed with your left hand and turn the key to the on position. (It might help to have the radio off) Do you hear a buzz from under the car for about 1 second?
I’m not sure I understand. Do you mean like a door alarm? Apparently I don’t have such a thing, I never hear a sound when I jump out of the car speeding. Anyway, I tried to push the door switch closed while keeping the door open, turned the key to on-position, but I didn’t hear a thing.
2. Next turn the key to start, and watch the tach on the dash. does the needle jump slightly, or does it just lay there dead at zero?
The needle jumped slightly. What does it mean?
3. Next and most importantly, does the car have gas in it? Are you sure? Are you sure you are sure? I don’t care what the gauge says, are you sure?
He-he. Yes, I’m sure. I added 25 liter to whatever was left just two days before this happenned.
Did the problem just happen one day when you went out to start the car, or did the car die on the road, and not restart?
The car was in the garage. What makes this strange is that the car was running great until this happened. No indications of any problems at all
Allright, I have some more information:
First, the test: I made use of one of the wires from the distributor, and put a spare plug in the other end (3 plug wires connected to the distributor with plugs as normal, and 1 wire connected to the distributor and with the plug on the engine). So, first I put the plug on the engine, turned off the lights and started the car. I didn’t see a thing. Then a moved the wire and put it next to the windshield right in front of me. Turned on the engine, and this time I saw a very weak blue light for just a split of a second. When I did it again I couldn’t see anything. I also tried it with a different wire and a different plug, but didn’t see anything either. I’m sure I saw the weak blue light the first time, because the garage was all dark and the raised hood shielded me from much of the head lights.
But this was a wire coming from the distributor. Can I do the same thing with a wire coming directly from the coil??
The car itself is a Volvo 740 GLE with a 230E engine, 1985. No turbo. This is what I’ve done so far to fix the problem.
Replaced the old plugs with new ones. The old plugs looked all right, ie. it didn’t look like the engine was about to die.
Replaced the distributor cap (?) and that spinning thing on the inside with new ones
Replaced all 4 wires from the distributors to the plugs, and the high voltage wire from the coil to the distributor.
Replaced the battery with a spare one, which was almost new
Checked all fuses (well, there should be two more somewhere. But I believe those two safeguard the ABS system)
Checked every wire and connection point in the engine room for loose connections and possible meltdowns.
Air filter looks ok
No visible oil leaks, and the engine has oil.
Remaining on my list are:
Fuel system/fuel pumps. I haven’t checked this because the engine room smell of gasoline when I try to start the car, and the plugs are wet. Also, when I try to start the car I hear a buzz sound from the engine for a second which I think is the pump running.
Carburetor. I haven’t touched this and I would prefer not to since it’s an electronic fuel infusion system.
Distributor. I have opened it up and cleaned it, and I’m fairly sure I was able to put it together the why it was. If true, timing shouldn’t be an issue (unless that’s the problem in the first place).
So, what do you guys think it could be? Coil, distributor, something else?
I’m pretty sure that’s the buzz he meant, and I’m pretty sure it is the fuel pump.
I’m pretty sure it means that certain parts of the ignition primary are functioning.
This indicates that the coil responded to the ignition being switched on. The weakness of the spark might indicate that the coil is weak, but that’s not a certainty. If you just get a single spark from turning the key to on, but not a series of sparks when the starter is cranking, that suggests that another part of the ignition primary is not working. The two main suspects are the ignition pick-up coil, inside the distributer body, and the ignition module/amplifier.
Absolutely, and it’s a better place to start testing.
This suggests that fuel delivery is okay and that no spark is getting to the plugs.
A car has either a carburetor or a fuel injection system, not both. You may be thinking of the throttle body, which is not a suspect for the symptoms described.
It’s very unlikely – in fact, virtually impossible – that timing was the problem, and it would not have changed unless you loosened the distributor body clamp screw and rotated or removed the distributor (and even then, if you were careful to get it back exactly where it was it wouldn’t change).
At this point I would say the most likely suspects are the ignition pick-up coil and the ignition module. Rick could probably offer some wisdom about this.
I hope this is true, I’m not sure testing the ignition system is something I’m ready for.
Thanks. Now I’ve tested the coil both by placing the distributor’s end of the coil-to-distributor on (metal slightly above) the chassis, and I’ve used a plug wire with a plug connected in one of the ends. I got zero. Absolutely nothing. Checked the coil tower, looked allright. So I guess we’re down to the coil or parts of the ignition system then?
I’ll see if I can get somebody to drive me to the car graveyard tomorrow, maybe I can pick up a used coil cheap. Rick, if you’re coming back, can you (or anybody else) tell me how test the ignition pick-up coil and the ignition module?
Fuel injected Volvos run the electric fuel pump (located under the floor between the front and rear seats) for one second when the key is turned to position II (run) Your not hearing it means that either it isn’t working or you did not hear it. Generally if the pump does not run when the key is turned to position II this is the cause of the no start (no pump = no start) however later on you say the plugs are covered in gas. This indicates that the pump must be running. You might want to repeat the test with someone else inside the car, while you bend down between the driver’s and rear door. The pump is located under the left side floor at about this position.
It means that the ignition primary is working. This is a good thing.
Ah any chance you put diesel in? (got my ass kicked for a full afternoon on an old Volvo that would not start, turned out the car had been filled with Diesel)
the wire or plug has to be attached to a ground for the spark to jump and be seen.
Great, a non North American varrient. :smack: If my memory is correct, a B230E is a fuel injected engine with Bosch K jetronic or Bosch LH, I’m not sure about the ignition system used on this engine. Question do the fuel injectors have electrical connectors on them, or no electrical connections on the injectors?
Never hurts
also can’t hurt. Two questions 1. Is the distributor mounted on the back of the cylinder head, or near the front of the block near the power steering pump? 2. Is there any chance you got the HT leads from the distributor to the plugs mixed up when you replaced them? BTW the little spinny thing is called a rotor.
probably not the problem, but again it can’t hurt.
all the fuses you need are located in the center console, infront of the ash tray. No other fuses elsewhere that I can recall
Good idea
not the problem, but again can’t hurt.
This smell of gasoline bothers me. You should not be smelling gas even if the engine does not start.
*As Gary T mentioned you don’t have a carburetor, your car is fuel injected (not infusion, but it does get your meaning across)
*Distributor, if yours is front mounted, the cap is held on with two clips, if rear mounted, it has three small screws (8mm?) holding the cap on. The rotor (spinny thing) is a push fit on the shaft. NOTE: There is a keyway on the distributor shaft, to locate the rotor correctly. make sure the rotor is installed correctly on the shaft.
Is there any way for you to take a picture of the engine compartment and e mail it to me? This would verify which injection system is on your car, and make my life easier. E mail addy is in my profile.
Next I would like you to go look at the battery. Attached to the postive (red) cable are several smaller wires that attach to the battery clamp. Are these wires still attached, and are the battery terminals clean?
Are all of the air tubes from the air filter to the engine attached, and no air leaks?
Starting to sound that way. Do you have a voltmeter or a testlight? Check for voltage at the two small terminals of the coil wth the key on. Are these connections tight? Can you tell me what the connector for the distributor looks like? Is it a 2 pole connector or a 3 pole connector? Again is the distributor in the front or rear of the engine?
I repeated the test and this time I did hear something, but it was more like a clicking sound, not that unlike the sound I got when I turned the key. (??)
Now, you have burned that image into my brain … No, I don’t think so because I used the same gas-only pump as I normally do. But it doesn’t hurt to check [Alien wanders off to find a hose]
The B230E in the 1985s uses what the manual refers to as Inspr. CI. I have a book that calls it [translated] a continouos injection system. Note: This book also warns that the information made public on the fuel injection system on the 230E is, qoute, “limited and contradictory”.
The system: There are 4 black hoses coming from something that I believe is the fuel distributor. There are also 4 big metal pipes (grey) right beneath these hoses.
(I prefer the old fashioned cameras, so no digital, but I could probably call someone and arrange for a picture if it helps.)
The distributor is at the rear (point of view standing in front of the car: the distributor is on the other side of the cylinder block, closest to the windshield. The cap is mounted with 3 screws).
The HTs are ok, I’m sure about that (different lengths). I did completely remove the distributor to clean it, but I made markers on the cylinder head, the distributor, and the spinning base of the rotor. I was careful not to move the rotor in any direction. I put the rotor back in facing the same way as it was when I opened it up.
To elaborate, I only smelled gas the first time I popped the hood, after I had almost drained the battery.
No problem with the battery, no loose wires, and I’ve cleaned them all (when I replaced the battery with my spare). No loose air tubes detected.
Yes, I have a voltmeter (analogue, old and cheap). No testlight though.
I could not detect any voltage on the two low voltage connection points on the coil, key in on-position. On the distributor there are 3 low voltage wires bundled together. There’s a plastic thing mounting these wires to the distributor and this is broken (no damage to the wires) so it was kind of a dangling in the air from the wires going into the distributor. This was the reason I removed the distributor in the first place. I could be hard to test these wires without removing the distributor again, so if you want me to do that, can I be boring and remove the isolation or just cut them in two and re-wire them later?.
BTW, I didn’t find a coil at the car graveyard. I will have to order a new one, but I would like to avoid that intil I’m sure it’s the coil that’s the cause of this.
… No, I don’t think so because I used the same gas-only pump as I normally do. But it doesn’t hurt to check [Alien wanders off to find a hose]