vapor lock or bad fuel pump

[billofdurham]

The chances of hearing the in-tank pump whilst you are driving are as likely as my celebrating my 21st birthday again!

A quick check for the fuel relay is to put your finger on it then switch on the ignition. You should feel a click. Do that two or three times.

To listen for the in-tank pump you need an assistant. Remove the fuel filler cap and put your ear as near as possible to the hole. Your assistant should now switch on the ignition, without starting the engine, and you should hear, momentarily, a buzz from the pump. Once it has primed the system it stops until the fuel in the pipe between that pump and the main pump needs to be replenished.

To replace the pump is fairly easy as the nice people at Volvo have made it accessible from the luggage area. Remove the carpet and you will see an access cover.

This 240 is a 5 speed too, I wonder how many of them they made.

A large number as the manual transmission was standard in the UK and, as far as I know, Europe.

Bill.

[cgreygoose]

well it's been sitting in my driveway for the last week, starts up fine idles fine and will stay running for an hour at times while other times it stalls out in 10 mins. I installed a new fuel pump relay with no change and I'm replacing the fuel filter later today and if need be the fuel pump that is in the fuel tank. I dont' ever hear the rear tank operating unless the car is running and I go back and listen inside the the fuel tank. I'll have to have my son turn the key to the on position while I wait to listen. if there is no noise, replace pump? if there is a short hmm till it primes leave it alone? I've been reading tons of posts about this very frustrating problem and it seems over whelming to think I will be able to fix it on my own. The wagon is in reallly nice shape and I only paid $550 for it but that doesnt' mean I have time and money to sink into it in order that I can drive it to work each day. I'll replace the pump as it wasn't really that expensive but what is my next step after today if she doesn't want to stay running? FYI, with the new fuel pump relay it stalled out quicker than ever before. Should I put the old one in? thanks for your time in helping me solve this problem.

[billofdurham]

If you can hear the in-tank pump running whilst the engine is running it would seem to be OK. However, if it stalls out try the listening test with the ignition switched on only. It may be that the pump is starting to fail and cutting out from time to time.

The new relay shouldn't cause it to stall out so I suspect there is another problem. One thing that is often overlooked now is the sock filter which is fitted to the in-tank pump. At one time this was a service item but was taken off the list. This filter did have a habit of disintegrating allowing little bits of filter to pass into the main filter. When it did disintegrate it also allowed any other pieces of rubbish in the tank to pass to the main filter. It may pay to check the sock filter for integrity, especially if you are changing the main filter. The main filter doesn't last very long if the sock filter has failed.

Bill.

[cgreygoose]

i checked for power at the pump and I've got it at the connection point but when I connect the pump connector to it I dont' get any reading beyond that connector. somehow power is not passing thru that connector. does that sound possible? am I doing something wrong? perhaps there is a ground that's loose that i can't see but that would make sense since I don't hear the pump coming on with the key in the on position. this isn't making sense to me. any guidance on what to do next? I checked the fuse panel and they all look fine. the car starts up like normal too with these connections NOT connected. that must mean that the other pump is doing all the work. I almost forgot, when I pulled up the lid to where the pump is, it's been repalced as it's all brand new so someone has been in there trying to fix the same problem that I now have. bizarre. Please help. I'm going to lose my head.

[billofdurham]

If you have power at one side of a connector but not the other the connector is suspect. It may be badly corroded inside. I suggest that you cut the wires either side of the connector and do a temporary join to determine if you now have power to the pump. If that cures the problem you can make it a permanent join by putting in a replacement connector. They are inexpensive and easy to fit. If it doesn't cure the problem you will already have disconnected the pump if you do decide to take it out.

A tip on checking fuses - don't just look at them and say they are OK. Check them with a multimeter for continuity. I learned this the hard way about 40 years ago when I had a problem with one of my cars. The fuses looked good but an auto-electrician found the problem within 2 minutes by checking the fuses, as he put it, properly.

Bill.

[cgreygoose]

well I got the power issues resolved, user error. Here is a recap. Continues to stall with no consistency, idled in driveway yesterday for an hour. turned engine off went to sons soccer game came back started right up but stalled within 10 mins. the volvo has a new intank pump, new fuel filter, new pressure regulator, new fuel pump relay. the exterior pump looks to be original and I was thinking that I should replace that today. I can't hear the pump while the key is on the on position but once car is running I can a nice hum coming from tank. I will check for continuity at the fuse panel. Should I buy the secondary pump or take it to my volvo garage and let someone with more experience handle it from here? I think this will be my last part to buy without knowing if it's the real problem. It kills me as when it's running the car is awesome but having it stall at 70mph or at the stop light is too stressful. Been late to work a few times already and the fear of being stranded outside my 5 miles AAA limit will be a costly tow.

[cgreygoose]

I crawled under the car today with a new pump ready to swap and the secondary pump works fine. Nice low pitch hummm. it could now be working and not staying on once i'm underway and then it stalls out dunno. I didn't check for continuity since the pump's were both humming nicely. the car idled nicely too and I took it around the block and it drove great but my luck tomorrow on my commute I will stall out. What does it say that once I spray starting fluid in the intake it will resume driving well? something is preventing the fuel from keeping the car running or could it be a NON fuel issue. ignition or electrical. Go figure. I'm done for the night.

[cgreygoose]

replaced the exterior pump and now it hums nicely all the time. ran great for 4 days with no stalls then it stalled on me yesterday at stop light again. it always starts up when I spray ether into the throttle body. not sure but perhaps I'm not getting full power to it at all times? I don't hear either when I turn key to the on position (not running). I dont] know if I"m just not hearing it from all the other external sounds going on but that could be part of my problem if it's not kicking on right away. it's weird and frustrating. until I figure out another way to fix it this I will always have my ether with me.