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troubleshooting : melodic clicking fuel pump relay Volvo 244 (1985)

Cybernesia

Cybernesia

Member
Joined
Jan 26, 2022
Location
Portland OREGON
Hello all at TurboBricks!

I have a melodic clicking sound from the fuel pump relay (which I made sure was good still).

I had it towed to my mechanic a month ago and worked on (for this issue) but it came back.

Last thing that helped was a pin or two to the ECM was cleaned up and that helped. After getting it back, it stalled while I was on the road and somehow I bumped a wire in the engine bay and it cleared up for the ride home. Probably something shorting out but any suggestions on how to help would be great!

Ive done some searching online and haven't found a issue like this. Maybe this is just under the general electrical issues area but don't know. Oh used cars..


https://youtu.be/GDF-k1FSXUI
 
It looks like your car has the original main engine wiring harness and some poorly repaired connectors on the firewall near the dipstick.

My advice is to replace that first.
 
Google for: biodegradable wiring site:turbobricks.com
For example, here's what the door lock actuator looked like in my '85:
IMG_0957a_central_locking_lock_rod_switch.jpg


Your engine-to-cabin harness may have similar problems. You can post in wanted for a good harness, or 240turbo.com has new replacement harnesses. If you want to try to isolate the problem, find the ECU in the passenger footwell and trace the harness through the firewall to the engine compartment. When it's clicking, try wiggling the harness in the engine compartment and see if the clicking stops.
 
Thanks for everyone that responded.

I am super happy there are replacements for the old horrible harness (that look plug and play for the most part). Anyone not a mechanic go at this and what was the outcome? I love tinkering but not a mechanic, i'm more into computers. I have inspected some bare wires but what should I do to fix the issue? Any troubleshooting at the ECU I can do?

Was fortunate to get this car for free and it ran great for 6 months. I started getting the clicking randomly and now it wont start at all. The last time I drove it the senor hole plug popped out of the radiator and with that I think it cashed out my head gasket. Just want to get it up and running to see how bad the head gasket is before I replace the harness.

Ugh the mess of issues but boy what a lovely looking car.
 
I've replace wiring harnesses in a couple rigs.

Be patient, methodical, and logical.

It just takes some time, don't be intimidated.

Consider labeling.
 
Cybernesia said:
Thanks for everyone that responded.

I am super happy there are replacements for the old horrible harness (that look plug and play for the most part). Anyone not a mechanic go at this and what was the outcome? I love tinkering but not a mechanic, i'm more into computers. I have inspected some bare wires but what should I do to fix the issue? Any troubleshooting at the ECU I can do?

Was fortunate to get this car for free and it ran great for 6 months. I started getting the clicking randomly and now it wont start at all. The last time I drove it the senor hole plug popped out of the radiator and with that I think it cashed out my head gasket. Just want to get it up and running to see how bad the head gasket is before I replace the harness.

Ugh the mess of issues but boy what a lovely looking car.
Click to expand...

honestly, sell the car to a turbobricker and move on
 
Thanks for the comment and suggestions Mr. V.

@apachechef
Yeah, probably makes more sense for someone to sell a car like this and move on but I do like a challenge and willing to put some work into it. Just wish I didn't move so far from my mechanically inclined friends. I get that a head job is serious but if anything, doing it or trying it will gain me confidence either way.
 
You gotta do basic troubleshooting with a test lamp to figure out if it is the ECM, a poor ground circuit, or power cutting in/out.

It could just be a corroded fuse holder in the engine bay. I would start there. That fuse goes to the relay and powers up the entire EFI system.


I would backprobe the terminals at the fuel pump relay with an incandescent test lamp, NOT A METER, and see if I were getting good solid power to the power wires. Then connect one end of a lamp to a known good power source (such as the wires you just checked) and then backprobe the relay control circuit to the ECM and see what you get. Key on.
 
If you can't do a head gasket yourself, it's not worth keeping the car. The cost will far exceed the value. You can do (or have done) a leak down & compression test which will indicate whether you have a blown head gasket. Why not do that first? Then you can decide whether it's worth chasing the electrical gremlins or not.
 
Thank you Zvolv for your advice. I am going to pick up a test lamp today to try and diag it more.

I definitely am looking to do a leak down & compression test on it asap. Thanks lookforjoe!
 
electrical troubleshooting

And back.

So i have started out troubleshooting with a test light and now know the fuel pump relay is getting power. I am lost and wondering if there is some write up on using a test light to help troubleshoot an issue like this. I have searched around and just get super basic explanation on how to use it and wondering if anyone can provide any assistance.
 
Ok the test light will help you figure out whether there is power and if it's enough to power the circuit. By lighting the bulb the test light will show that. There are three very important terminals on the relay to check. Terminal 30, 87 and 15. Terminal 30 is constant power and should light the test light solid with the key off. It is the large red wire. Next is terminal 15. This is switched power to the relay to tell it to turn on and it should light the test light when you turn on the key. Terminal 87 with the large red/yellow wire is the output to the fuel pump. Once you crank the engine over it should light solid and stay on with the engine running. Keep it connected to this terminal while the engine is running and if the relay is clicking see if the test light flickers. If it does you also want to check the other terminals to see if they flicker. If the flickering is only out of terminal 87. Then the relay is the cause. If the flickering is on terminal 15 you may have a bad ignition switch or melted fuse. Lastly if the flickering is on the terminal 30 wire that is the power feed for the relay and may mean fuse box damage or a bad connection in the engine compartment.
 
results in..

thanks @dl242gt

I have constant power on the 30 pin, my relay doesn't have a 15. Looks like the options are 30 / 85 / 86-1 86-2 / 87-1 and 87-2. I grounded the one side of the test light and put the other in the slot where 87-1 is and it started but didn't stay running (no clicking at all). I tried again and it struggled to start.

Shall I try to jump the relay to see the outcome? is the 15 pin known as something else? Here is a picture of my relay. Thank you for your help.
8PlqydgMAwUJCgFe-b00K8WcQYoL_aSoKycKyk2uUc7VXFzFT2O7OhR0CjQ5k0FfrzTA0DfkyfzqOmpFl69LOcdJLMAoEppcGYi24BfRS9Z5XafFrXcGOzbjRdT4OwgCtYN3SDA7uwiEfiwe_36XJS5RsWHeYjZl_Uug_eCZjaRbIQT_1PuYbGrg45e5Gig2RqLXXBj6ZjdBBO5q_cUIaIdRXth6lHbCAKLVKwc_vhH7rp8AW0c9buSoQ8i5-yQhuecCsjk6rmmocng7R9kH0_6r3M5VVLawrW2rza6V7r5vKZJdyicpozNtGh1GksUeDzTGoelJ_0QkQcmQNSp0BrFqA5aWq8ZAe3DjT8olLpMGvD28J0fiC2wYxIXgTQtHJkrPLkQw-IAVuPPh8klCV7PyBpYtr69h73Ch9VTT3V2hshombgwKB5ezCE8oGIjYFyhyb9REayGQw1LGnj8PgUECCYTertbQw4jfmavr7kQi5zKyEA_BcjPlg1-BpC86eM9J6pvcrxsDtdwWSjYd4njr8s5qjEIvih2rDIcHoqHzgat29yAqrkopwa3Dej9CEm6PvUfHrEBsOJ-kLyAFGvO67-l1SGH-d9OMXfo1lGjjhKsNma1Co6Y-53UVV21qNGBdYk54l3FMoYET0pEQaQcczza2FW4hN-oBSLytFuBuu1IzuFAVXt-FJhG1aZ_56fTEw-rfvWRV_LtxzunUjgo=w1252-h939-no
 
OK terminal 15 is switched power with the key. So you can use the test light on each wire and figure out which terminal switches with the ignition key. There should also be a a 31b terminal that gets grounded by the computer to turn on the fuel pumps. The switched power wire may be a blue or blue/red wire. The main thing is you want to see that the power isn't interrupted causing the clicking.
 
I ran the test light on the 6 pins where the relay sits and found beside the big red wire (30) nothing else shows light either off or with key enabled. Will I have to crank the car over for the light to show? I also dont have a blue or blue/red wire connecting to it.

It sounds like it wants to turn over and start when the relay is out though. It just doesn't seem to get enough gas.. How do I make sure the ground is good, to rule that out?
 
The relay is grounded out by the fuel computer. You can test the ground by connecting the test light to 12v. Then probe the ground wire and try to start the car. The fuel computer should ground the wire and turn on the test light. No light means the computer is not grounding the circuit.

You should also definitely have ha key on power wire. The relay won't turn on if it's missing the switched power feed.
 
ECU bad most likely.

I found help and we troubleshoot with the test light that the wires were good between the ECU and injectors and we saw that the power was going through both sides of the injectors so the ECU is most-likely faulty.

Opened the ECU and nothing looked burnt but there was a weird clear dried liquid on half the board. Tried to clear it up as much as possible but no dice. Going to swap ECUs then if that doesn't help it, ill probably sell to a bricker and move on.
 
Cybernesia said:
I found help and we troubleshoot with the test light that the wires were good between the ECU and injectors and we saw that the power was going through both sides of the injectors so the ECU is most-likely faulty.
Click to expand...
The ECU grounds the injectors to turn them on. When unenergized, you'll see +12v on both sides.

Cybernesia said:
Opened the ECU and nothing looked burnt but there was a weird clear dried liquid on half the board. Tried to clear it up as much as possible but no dice. Going to swap ECUs then if that doesn't help it, ill probably sell to a bricker and move on.
Click to expand...
The clear stuff is "conformal coating" (see wikipedia) and is there to protect the circuits from dirt&moisture.

Does it still do the weird clicking when you turn it on? If so, I'm guessing that the ECU tries to turn on the main relay / fuel pump relay but something is shorted out, the voltage drops, the ECU and relay eventually shut off due to low voltage, voltage recovers once the relay opens, and the cycle repeats.

When clicking, try wiggling every wire&bundle in the engine compartment that are near the rear bulkhead to see if you can find one that changes the clicking. If you find one, inspect it carefully for missing insulation and shorted wires.

If you haven't found a copy already, you can find a 1985 greenbook wiring diagram at ozvolvo.org/archive/
 
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