No fuel delivery (EDIT: No start)

Post by **rgk** » 20 Oct 2011, 14:13

No voltage to fuel pump. Ran a jumper cable across the proper fuel pump relay terminals as directed by the Haynes Repair Manual, and received voltage to fuel pump, showing that the relay is bad. However, even with proper voltage to the pump, I am still not receiving fuel to the engine. In fact, the pump does not appear to be running at all, even though it and the filter are brand new. Should I feel a vibration in the pump when the ignition is turned to the ON position? Should that vibration persist?

I was cleaning the throttle body and accidentally got cleaner in the plastic throttle body electric sensor. But this wouldn't cause the fuel pump not to run, would it? Shouldn't the fuel pump always deliver fuel on start, regardless of whether the throttle body is open or even attached?

There is some fuel in the tank. Not a whole lot (I'm in the red), but the gauge definitely rises when the car is turned on. I suppose it's possible the pump was DOA. Maybe I'll remove it and take it to the auto parts store for testing. Now that I think about it, I'm going to try to dig up the old fuel pump and see if that might work.

Any help is appreciated, thank you.

Post by **rgk** » 20 Oct 2011, 15:37

I removed the fuel pump and ran a jumper cable directly into its leads from the car battery. Much to my surprise, the pump activated and shot out fuel. I jumpered the relay leads and plugged the pump directly into its specified leads. It worked. It seems that my jumper cables are not fitting into the relay leads that well, and providing intermittent power.

However, when I jumper the 87/2 and 30 leads and plug the fuel pump in, there is power being provided to the pump regardless of whether or not the key in the ignition switch is set to ON. Is this normal?

There is fuel reaching the engine, but I'm not quite sure whether it's sufficient. Also, the primer pump is not working and the main pump is running loud. Is this because I am jumping the 87/2 and 30 relay leads? Should I first get a good relay and then try to test the fuel pressure? Or should it not matter that the primer pump isn't working? Shouldn't the main pump provide enough fuel to start the car on its own?

I suppose another thing I can do is check for a spark at the spark plugs. If anyone has any other advice, I'd appreciate it.

Thanks.

waynej · Post by **waynej** » 21 Oct 2011, 10:48

It's much easier to skip the jumpers at the relay and just go to the fuse panel. Get a test light, ground it to the seat bolts and find one of the larger amp fuses that is hot and then run a jumper from that to the fuel pump fuse. Both pumps should run.
Always check for spark first thing. Fuel pump relay will not close without ignition pulse. Use a test light on the coil. One side should be steady on and the other should be pulsing on and off (flashing) when cranking or running.

Post by **rgk** » 21 Oct 2011, 19:02

Thank you, I will try that and check for spark. I've been reading http://cleanflametrap.com/transferPump.htm and am interested in how power to the right side of the fuel pump fuse runs the tank pump, whereas power to only the left runs the main pump.

waynej · Post by **waynej** » 21 Oct 2011, 19:20

Is the fuse blown?

Post by **rgk** » 23 Oct 2011, 15:08

I checked for spark, no spark.

I then jumped the B and C inputs that go into the distributor together, per Haynes instructions. Received a spark. I checked for voltage at the C input, received voltage. There is also voltage at the blue wire going into the computer.

I put everything together and lo and behold, the car started immediately and ran for about ten seconds. It then died and continued the same original symptoms: start, then die immediately. I suspected the fuel pump after all, so I decided to run relay tests. I have two fuel pump relays, so I tried the other one. Same symptom. I then tried removing the fuel pump relay, and the car wouldn't start. This leads me to believe that the relays are fine. I'm not reading voltage to the fuel pump, but I suppose this could be due to human error. I then tried jumping the 87/2 and 30 relay inputs WHILE starting the car, and that caused the car to not start at all anymore.

Haynes says that if there is voltage at the C input AND there is a spark, to replace the pickup coil. A little bit of research shows that this is located in the distributor. God help me if I have to remove the distributor. I am going to try putting the spark plug back in the car and see if its starts (and dies) again. Maybe at the least I should buy a new relay and some spark plugs and see what happens.

By the way, the #4 (fuel pump) fuse was not blown, but it did seem to be dead when I checked for resistance, so I replaced it. It has not blown since.

Post by **rgk** » 23 Oct 2011, 16:42

UPDATE:

I don't know what I did to make it happen (maybe scrub clean ground connections very well?), but I now have spark directly at the plug when cranking.

Still, however, no start. Not surprising, considering that the fuel pump has NO power being delivered to it. It would be simple to assume that I need a new fuel pump relay, but here is what is confusing me: I have two relays, one from this car, and one from an older Volvo. That relay worked fine when the older Volvo was laid to rest. And just today, when the car started and ran for a little bit (then died on its own), it was the application and removal of those relays that made a difference in the car's behavior (see above post).

This leads me to believe that the relays are good, and the lack of power going to the pump is situated somewhere else.

I also thought that maybe I fried my ignition module (I mistakenly called it the computer in the above post). I don't think that I would have spark at crank, however, if this was the case.

I also have a spare ignition module from the older 240, and thought that I fried the first one because the car started up when I switched them out. I thought perhaps I fried it by trying to start the car while powering the fuel pump through the 87/2 and 30 inputs at the relay terminal.

So what do you guys think? Get it over with and buy a new relay? Also, my backup relay was pulled from an older model 240 and has a different number stamped on it. However, when I see relays for sale on ebay, they show extended compatibility. Does the replacement relay have to be an exact match?

I suppose I should also check voltage to the primer pump.

Post by **rgk** » 23 Oct 2011, 18:45

one more thing which perturbs me is that any time I jump 87/2 and 30, it operates the fuel pump, regardless of whether or not the ignition is in the "ON" position. should it behave this way? I'm not sure if it always has...

Final update of the weekend:

nearly ten volts going to the primer pump, not sure if that's enough. cleaned leads for a little voltage boost. full voltage coming out of "30" at the fuel pump relay terminal, while nothing at 87/2, not even with either of the two relays attached. best thing to do at this point is to get a spare relay and see what happens. I also discovered that jumping 30 with 87/2 causes the voltage at the primer pump to be nonexistent, explaining why the main pump then runs so loud, but not explaining why jumping these cables and trying to start the car causes everything to implode. til next time. i'm tired! but had a good sunday working on and learning from the car. good night everyone.

Post by **rgk** » 05 Nov 2011, 10:13

Received a replacement fuel pump relay. It's doing the same thing: no voltage to the fuel pump. When checking the voltage at the relay, I received a very weak signal and, upon moving the voltmeter's negative lead around on the seat frame, received a slightly higher voltage. The beeping that comes on when your key is in the ignition and the door is open came on. For the longest time it would come on for about exactly four beeps, then shut off, but now it's staying on.

I tried cranking the engine. It came on, then died immediately. I tried a couple more times, with the same result. I could definitely hear the fuel pump operating for a couple of seconds, then dying. After a couple tries the car would not start at all. It definitely seems as if it's got a bad ground somewhere or something, but I've checked everything that I know of, and cleaned what I could find. I suppose I could replace the back of the ignition switch, but replacing the actual lock assembly seems formidable.

Any ideas?

waynej · Post by **waynej** » 05 Nov 2011, 12:28

Have you ever replaced the 30 amp fuse and holder for the fuel system. It sits about 8 inches aft of the battery (white fuse holder). Volvo recommends replacing every 30k. The holder has copper contacts and the cheap fuses have aluminum contacts. You get corrosion from the 2 dissimilar metals. Since it won't even crank for long it sounds like you have a weak battery. Have you checked the voltage at the battery?