Hey gang,
Well, the car committed the cardinal sin. I'll give any car a second chance if it breaks down, but after a second time it is time to move on. However, before I can sell this thing I need to get it running again.

I was driving home tonight and the car was running fine... right up to the point it wasn't. I started accelerating from a traffic light when I heard a faint "puff" and the engine cut out. I cranked it, but got nothing more than the occasional stumble and a rotten egg smell. As a precaution I replaced the FI fuse, but that didn't help. There was too much traffic for me to hear whether the main pump was running or not. I didn't get the feeling that the timing belt broke, as that would have made expensive noises. Would a fuel pump just go like that? Any other ideas? It was dark by the time I got home so I wasn't able to do any diagnosis.

Thanks,
Jim

 

BANG.... rattle, rattle, rattle..(silence),is an expensive noise. I'll wait for the experts to comment but fuel pumps can fail, but they usually start dragging first.

 

You should do the usual, check for spark, check for fuel, check timing belt, etc. Go to www.stepbystepvolvo.com for free guide to 740 no-starts. Techniques may help with your 240.

 

I'll have to do that today. I know where was no rattle-rattle-rattle-BANG, and the car still turns over and even attempts to pops/stumbles a bit, like its getting whatever residual fuel is left in the system. I too have never had a fuel pump just up and quit like this, and it was recently tested and found to be within spec.

 

Check out my "Real-Life Volvo Quiz" on my website. The problem could be electrical. Also, change the air fiter.

 

I'll check out your site. All filters are new (oldest is 3 months old). I did some quick checks and I found:

- I checked the fuse and none are blown.
- I am getting spark, and with a plug out for this test I was getting what seemed to be fuel puffing out of the plug hole on the compression stroke.
- I am hearing a fuel pump after removing the #4 fuse for the transfer pump.
- The distributor rotor is turning
- I didn't see any obvious big vacuum leaks that would cause the engine not to run.
- Both transfer and main pumps were tested within the last month or so and both were given a clean bill of health.

I'm going back out after dinner with a second set of hands to see if I can confirm ignition timing. It seems odd that something would just break on initial tip-in like this without any warning.

Thanks,
Jim

 

Something appears to be up with the distributor, but I'm not sure exactly what. I confirmed that the ignition timing was close, but not exactly right. I also noticed that the connector for the distributor harness was hitting up against the timing belt cover. For giggles I loosened the distributor and moved it a bit while my wife cranked the car. The car fired up and ran. I set the timing, but I noticed that when I first attempted to rev the engine it shuddered and tried to jump out of the engine bay, then would rev normally (more or less) I also noticed a random stumble at idle. I was going to record it and post the video but when I tightened the distributor I must have moved something because the engine died and is back to not starting.

The part that appears to be messed up is the Hall switch or its connector. I'm not thrilled with the cost of a new unit ($154 from NAPA) so I need to perform a few more tests to make sure that is the problem. I'll let you know what happens.

Jim

 

Could be a cap/rotor/plug wire/plug issue. The hall sensor is difficult to replace and the connector breaks easily, but it would be a good idea to clean-up the connections and make sure its getting good voltage. It might be a bad connection at the ignition ECU side, or at the coil.

 

Not to mention expensive. The cap and rotor, while not new, look to be in good shape. I can't see all the ignition wires going bad at once. When I pulled the #1 plug to check for spark the plug looked old but servicable. I talked to my mechanic today and I will also check the harness that rusn from the ECU, under the engine and up to that Hall connector. If that is still intact I'm going to pick up a used but known good distributor and swap it in.

Thanks,
Jim

 

Before I get into my possible screw up, I did find something. While tracing the wires from the ECM to the distributor, I discovered that the wire to what I think is the knock sensor is severely damaged, but connected. I don't think this would prevent the engine from running, but I need to fix it nonetheless.

Tonight I started tinkering with the distributor. When I started the engine would turn over, wouldn't start, but pop/stumble slightly when I released the key. I pulled the connector from the distributor, and using a test light (since there was no voltage spec) I checked Terminal 1 on the harness and there was voltage. It wasn't full battery voltage (the light wasn't as bright) but there it did light up. Now, while fumbling with this I briefly touched the test light (grounded on the intake manifold) to the middle terminal in that connector. When I did that I heard an electrical snap. Since I did this, the engine turns over but I am no longer getting that pop/stumble when I release the key. Apart from going to Terminal 5 of the ECM, I don't know what this terminal does. What did I fry and how much more expensive did this become?

Thanks,
Jim

 

I would check for spark again but chances are the hall sensor is fried.

The hall sensor is powered by the ECU on pin #1, 12VDC. It outputs 5VDC pulses back to the ECU on the center pin. Pin 3 is the sensor ground. I would use a volt meter instead of a test light.

The ignition ECU connector has pin "sleeves" and are a known source of electrical connection probelms.

There are a couple different BOSCH distributors out there so make sure the part numbers match, sometimes you have to tap them with a hammer to break the seal to get them out.

With the key on and the new distributor plugged in I would spin the drive gear and check for spark before you install it. And having the old one lined up to plug #1 would make it easier to install ...

PS - sorry for the small attachment - file size limits on this board ...

 

Thanks for the info. It didnt' appear I was getting 12v to terminal 1 but I will check 1 and 2 tomorrow with my DVOM.

Jim

 

I own an 85 240 and several years ago I got stuck at a gas station with a dead airmass meter. A defective airmass meter is the main cause of a nostart condition. AIrmass meter is on front driver side, just behind the battery. Try to not buy new. Check scrapyards for good replacements.
There are easy ways to check the meter. The first test isx to simply disconnect the connector that goes to it. Leave the meter in place, just diconnect it and try to start.
If it starts , it will run rough and very rich. It is just an emergency mode. Not to run for la long time. I think you can get to a mechanic with this trick but that's it. So, if does start with the meter disconnected, then, it is most likely the airmass meter going bad.

Hope this help.
If you find this useful, I can dig in my books to find how to test those meters in search for a good one. New meters are priced at around 400.00
The good news is that it is very easy to install.

Good luck

 

Richard,
Thanks for the info. I did try this but the car still wouldn't start. I'm 99% convinced the Hall sensor is bad. The car is back to stumbling a bit when I release the key from cranking. I pulled out my multimeter and I'm getting 12v to the Hall switch. The coil primary and secondary resistance is also within spec. The Hall connector is broken off the side of my distributor. While the wires appear to be intact and my mechanic said that he's had many Volvos run fine with that connector broken, I'm wondering if either a wire did come loose or if some moisture got in there and messed things up. I'm on the road all this next week so this will have to be tabled until I get back.

Thanks,
Jim

 

So much for being 99% sure. I installed the replacement distributor and... nothing. It is still doing exactly what it was doing before. I guess it could be fuel related. I might drizzle a little gas into the intake and see if its enough to get the car to at least pop. If it does then I know that a humming fuel pump isn't necessarily a working fuel pump...

Thanks,
Jim

 

This is definitely not a fuel-related issue. First of all I started pulling spark plugs and each one was gas fouled. Further, I cheated and sprayed a little ether down each plug hole before replacing the plugs and apart from a slight pop, nothing. It should have caught with a little ether.

I'm beginning to wonder if the timing belt jumped a tooth. It is the one thing I can't 100% vouch for. The crankshaft and the distributor seem to line up properly and everything is turning as it should, but I didn't pull the cam cover to confirm complete alignment. The other thing I'm noticing is that when I crank the motor it sure is rocking from side to side. I know that this is an interference motor, and at no time did I hear anything metallic to indicate that I had valve to piston contact. It isn't a Diesel, so I assume that jumping one tooth wouldn't necessarily mean disaster.

This whole thing is a nuisance.

 

Its non-interference. Are you sure you have spark?

 

I thought I read somewhere that this was an interference motor so I'm glad to hear that it isn't. Early on in this process I tested for and was getting spark. I also know the cam is turning because while I was checking the engine actually started, spraying oil from the open filler cap. At that time I was even able to set the base timing with a timing light. The violent shaking when turning over and the occasional pop when I release the key tells me that things are happening, just not at right time. I replaced the distributor thinking that there was an intermittent spark issue.

Thanks again,
Jim

 

See attached ... I would double check the wires are in the correct order.

 

Thanks for the image. I have a Bentley and I've done timing belts on other cars before. If you are referring to the ignition wires they haven't been moved since the car was last running. Seems like a cheap thing to take everything apart, confirm the timing marks are still lined up, and throw in a belt as a precaution.

Thanks,
Jim