The car is a 1990 Volvo 240 DL. Standard 5 speed M47. Yesterday I noticed the car was hard starting. It would spin over and after about 10 seconds it would start.
When I got home I popped the hood and noticed vacuum line to the Fuel Pressure Regulator had came off. So figured while I was there I would replace the vacuum line. I replaced it and the car fired up just fine and I drove it to the store and ran and started perfectly. I was like finally had an easy fix.

Well this morning I went to leave for work and the car would not start. I popped hood and made sure vacuum line was still on and it was. So I pulled Fuel pressure regulator off another volvo 240 I have that runs. But still no luck. Then I changed out (with other volvo 240 that runs) Fuel pressure regulator with no luck. So I got test ligiht out. Went to the main fuel pump, it has not power to it. I checked the fuse #6 its showing power with key off? So Im asking for help. I did remove the main fuel pump and it works?

I missed work today. Hoping to get this fixed this evening but not sure what to do next. Thanks for any help.

 

I forgot to add that it has spark and will run for a few seconds with healthy dose of WD40.

 

check and see if you have spark at the coil when you crank it. If you do not - fix this issue first. If you do, then there is a problem between the relay (if it is working properly) and the fuel pump. I did have a 240 once that the fuel pump harness plug came loose on the drivers side under the dash near the brake pedal or so if I remember right. Good luck

 

Coil is fine and have power to it. I checked the fuel pump relay and it is clicking like its working. Tomorrow after work I will try and trace wire for the relay to fuel pump.

 

First check your fuel pump relay. Just cause it's clicking doesn't mean it's working. Usually they fail intermittently prior to a hard failure. They develop cracks in the solder joints on the little circuit board in there. I usually just resolder them and keep a spare in the car.

If that doesn't help, you might want to check your ECU as well. There were early versions of the LH 2.4 ECUs that had a pink label and have a part number that ends with the digits 561. These ECUs were known to develop problems in the fuel pump circuit. They can be replaced with a white label ECU (I forget the last 3 digits) from later cars with the LH 2.4 fuel injection. I had thought that the last of the pink label ECUs were in '89 but perhaps some '90 cars had them too.

For full diagnosing of fuel pump issues, check our Art Benstein's site: In the Tank - 240 Volvo Tank Pump and Sender

 

First my ecu ends with 951 and white label. I swapped fp relay from another volvo i have that runs. It didnt change anything. I checked the intank pump its not getting power either. I disassembled and cleaned the fuse and holder by the battery. With no change. Kinda stumped now. Fp relay has power on 30 terminal. I really dont want to bypass everything and install a switch. My car is pretty nice.

 

the fuel pump relay plug has power to terminal 30 the rest are dead with the key on. So I am thinking it the ECU. Which is bad news. I have 2 other volvos but they are 86 models which are different I believe?

 

If you hot wire the FP does the car run.

 

Without a wiring diagram in front of me to go by I would try to figure out why you don't have power to pin #86 without the relay plugged in and find out where that 12v comes from,

 

yes, the car runs if I put a jumper on 4 and 6 fuse. I have replace the fuse holder under the hood by battery with new 25 amp fuse. Yes, the old one looked rough but I was getting power thru it. I have tried 2 other fuel pump relays. That I know w.o. doubt that are good. With no result. The plug for the Fuel pressure relay has the other signals coming from the ECU. Which I believe only work if the engine is turning over. I could install an aftermarket relay and bypass the ECU safety stuff but hate too. Im running out of time have a barrowed car and it goes back tomorrow. My wife is out of town with our other car. Im about to do some test on the ECU to verify its bad. The online info isnt to great? Thanks

 

ugh, the copy of the 1990 LH2.4 diagram in the OTO DVD is awful quality.




ahhh, the 1991 version is a much better scan.



should be virtually identical to your car.

 

anyways, when you switch on the ignition, the fuel pump relay should only come on for about 1 second, then go off again until you crank the car over. when you crank the car over, the Ignition CU sees the crank position sensor pulses and sends them to the ECU (fuel injection CU), which in turn restarts the fuel pump. if the crank position sensor pulses stop, then the fuel pump is shut off, this is largely as a safety measure, to stop engine fires in crashes and such.

note that fuel pump relay is TWO relays in one. one half of it switches on the ECU and auxilliary stuff, and comes on with the ignition. the other half runs the fuel pump.

 

Yes, with the exception of the wiring between battery and terminal 30 on the fuel relay. And according to OP's statements here, that's where the trouble was.

For the rest of you finding this thread, the test looking for power at the AMM (system relay switched) is very useful to determine the integrity of the often-crusty wiring under the hood for that red wire and blade fuse in the 83-90 cars. The key to that test's success is providing a load. Without that load, a bit of crusty corrosion can fool a test light or meter.

 

long story short. Yesterday I drove the car with a jumper on the f.p. relay. Ran fine after work had to make a couple of stops. The last stop it wouldnt start. I reached over the put relay back on and checked fuses again. Still no luck. I grabbed the relay and all of sudden the car started. I could turn and twist the relay and it would die or start.

Well I made it home and I pulled all the black tape off the f.p.relay wire harness. Looks like somebody replaced the f.p. relay plug and harness and did a shotty job. That is where the short was. So I built my own harness and while I was at it I added a relay using Dave Burtons info at volvo 240 Mods and Fixes

Its up and running and is running smoother and fire up better than it ever has. I also ran new wire from the relay to the pumps. I appreciate everybodys help and realize that this volvo is challenging to me. I hate wiring, lol. But willing to figure it out. Thanks again.

 

ohgawd, I totally forgot to mention. 1986 is smack dab in the middle of Volvo's failed experiment with biodegradable wiring... it runs from 1982 or 83 to mid year 1987. the wiring harnesses on these cars crumble with age and heat. The only cure is a complete replacement of the entire harness, all under-hood wiring. I doubt replacement harnesses are available from the factory anymore, so that means rolling your own, and Volvos connectors aren't that friendly towards rebuilding

 

yep, I have one 86 as a parts car and another 86 wagon. Both the wiring looks realy rough. One of the these days like to replace the battery cables etc. under the hood. Just got home from work all was good today. Thanks again.

 

bad wiring harnesses will cause all sorts of random behavior, nearly impossible to debug until all the bad wire is replaced. intermittent shorts between signal wires midway down the harness where its all wrapped up and invisible... ugh!

 

Im hoping that there isnt any more cobbled wiring but afraid there probably is somewhere. When I first got the car I was working 2 jobs; so I had a local garage work on it a couple of times. Seeing their attitude towards my volvo I started working on my own car. Its a learning process but I understand the car and mechanics. Only thing Im afraid to tackle is the heater fan. LOL. Thanks for all your help.