lasercowboy
Wonderful 240 experts, I need some electrical advice please!
I went to start the 240 yesterday, and when I turned the key to second position, there was a click, and no fuel when I cranked. It sounds like the fuel pump relay isn't engaging, but the rest of the electrics work, and it turns over fine.
In initial diagnostics, I have 12V at the main fuel pump fuse (#6), but the voltage at the pins of the relay seems a bit dodgy: 1-2 V at the first pin (the thicker red wire), and 0.25 V at pins 2-4 with ignition in second position. The relay looks ok inside, but I appreciate that visual inspection is not a good test!
What should I be looking at to diagnose this?
Many thanks in advance.
Vee_Que
Held it locked in and seem if it works?
lasercowboy
Sorry, not getting what you mean?
tbro
lasercowboy
The bit I'm not sure about is whether it's the relay, or something in the wiring before the relay. Does anyone know what voltage I should be getting at the relay pins?
lasercowboy
So from a bit more googling, it looks like bypassing the relay by jumping fuse 5 to fuse 7 seems like a good way to test if that's what the problem is. I'll give this a crack when I'm back home on Friday and report back :)
lasercowboy
Hmmm so if I jump fuse 4 to fuse 6, the fuel pumps run fine with the battery connected... so no problems with the pumps themselves - phew!
I have no idea what's up with the electrics though. The relay seems to be fine, but it's just not getting power. I guess I need to delve into the wiring diagram. Any thoughts?
tbro
First off, did it start with the fuse jumped? If so then relay or high resistance maybe at the fuse holder.
If it didn't then test test test sorry!!
lasercowboy
@tbro good point! so I just tried starting it with the fuses jumped, and got nothing. It turns over, but not firing.
With the fuses jumped, the pumps are REALLY loud (especially the main pump under the car) and there is an audible noise in the engine bay.
Any suggestions? I'm at a complete loss. I have a feeling it's a piece of electrics somewhere else that has failed and is causing these symptoms, but the wiring diagram isn't giving me much to go on...
lasercowboy
Ok, so it looks like the ECU may be at fault - the code reader thingy is not giving me the 1-1-1 that it's supposed to if I push the test button. The LED comes on when I push the button, but no codes out...
tbro
Sorry mate, I only know K-jet, ain't I lucky.
Go with the basics, do you have spark, if not work your way backwards leads,cap, rotor .
Major Ledfoot
lasercowboy;97919 wroteOk, so it looks like the ECU may be at fault - the code reader thingy is not giving me the 1-1-1 that it's supposed to if I push the test button. The LED comes on when I push the button, but no codes out...
Checking LH 2.4
- put jump connector into Socket 2
- Ignition on
- push button for between 2 and 5 seconds, LED will stay on steadily while button pushed
- release button, LED should go off
- codes should then display after about 2 seconds.
See
https://www.volvoclub.org.uk/faq/EngineOBDCodes.html#FuelInjectionandIgnitionDiagnosticCodesi
Putting the jump connector into Socket 6 tests the EZK116.
Still no codes getting flashed to you?
lasercowboy
Still nothing, including with a different ECU. No fuel pumps, and no codes.
I'm totally lost for where to start looking now.
Major Ledfoot
Have your tried changing the ECU relay? And, is the ECU getting juice?
lasercowboy
There's an ECU relay? Where is it?
There is definitely 12V getting into the ECU (and some lower voltages on other pins apparently).
There is 12V also getting to the main red wire into the fuel pump relay. The bit i don't get is why i don't get starting even when the fuel pumps are running...
Thanks for the help by the way - it is much appreciated! Determined to get to the bottom of this...
lasercowboy
Humph. Looks like no spark either, so there is something seriously fubar with the electrics.
Major Ledfoot
There's an ECU relay? Where is it?
Whoops! Had my 700 hat on, sorry. The ECU and fuel pump relay is one and the same.
240 hat on. Okay, so, he's an 89 model.
http://www.volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/Volvo%20240%201989.pdf
Page 19
Fuse #4 is all good?
Yellow-black wire from the relay to pin 21 of the ECU is all good?
Major Ledfoot
Looks like no spark either
You should see 12v at pin 5 of the EZK (red wire) and pin 4 of the ECU (also a red wire). These are fed from the battery.
lasercowboy
We have 12V at the EZK,
We also have 12V at the ECU,
There is continuity on the yellow-black wire from the relay to the ECU,
If i hold the relay pins open, that should cause the fuel pumps to run, right? I'll try that next.
This still doesn't explain the lack of spark issue though, unless I was testing it wrong... There is definitely 12V at the coil.
tbro
I know with K-jet there can be no spark if the fuel relay fails , its cuts power to the ign module, maybe same??
