I recently installed a new fuel pump relay because the old one just about disintegrated in my hand. Car is running great. I also changed the idle air control valve. So much better! But...the car seems to be running rich. I'm wondering if I possibly crossed the two red wires to the relay? I tried looking for schematics on line and have the manual, but it's a mess to read. Hoping someone knows. Thank you.

 

Relay 2/23 in the 103 position? How would you swap wires?

 

Thank you. When I spliced in this replacement unit, I may have crossed these two red wires, by chance. I'm trying to figure out if that's the case. Hoping someone might know if that would cause the car to run too rich. Thank you.

 

That’s not the fuel pump relay - what does that power?

 

Thank you kindly for your assistance. The unit disintegrated in my hand one day when I was changing the air intake control unit. I found another on Ebay and it's listed as "Volvo 850 Fuel Pump Control Relay Fuse 3545803." Unfortunately, that's all I know at this point.

When you open the hood, it's straightaway right there, very visible, near the intake control unit. Whatever it is, the red leads to it are always hot/on. Thanks, if you happen to know what it is. I may have to start tracing some wires to see where they go. Was hoping someone would recognize it straightaway and have a bit of info.

 

Is that a fuel injector relay?

 

I'm sorry if this photograph is too big. I took another one to show the position of the unit. I"m not sure where those wires go. They disappear into that black tube. Thanks if anyone recognizes what it is. It seems very important. The car will not start or run without that little bitty unit installed.

 

There is to show the position of the unit. It is directly in front of the fan and held by a wee clip. It's hard to see the unit, but it's just above the rainbow of spliced wires. Thank you if you know what that little unit is.

 

On 850s, the fuel injector relay is a gray box by the radiator. The fuel pump relay is in the relay box atop the firewall.

 

Thanks, mt6127. It looks like you've named the part, that's great!

 

That's what I said.

 

Sorry if I didn't give credit where it is due. Thanks so much for helping to name the unit.

Does anyone know where the two red wires go? I want to make sure I didn't cross them when I spliced the new unit on. Car seems to be running a bit rich and I notice a couple of stumles into a bit of high idle.

Thanks Volvo peeps!

 

That’s the injector pulse relay.. the wires go Into the harness down between the ac compressor and passenger headlight.. PIA to get to.. if those wires were crossed I don’t think it would start at all… if running rich you need to look towards up stream 02 sensor and coolant temp sensor and mass air flow sensor.Those send the signals to control the AF ratio…iv Ben in that boat before and would look towards the MAF sensor.. I actually Instaled a Bremi brand Maf And it lasted year now I got that stumble and high idle once in a while again… damn

 

Great info, thank you so much. I was careful to take pics while changing that injector unit, so I doubt I crossed the feed wires there. I'll check the MAF sensor. Thanks for your good help.

 

Well, I took the car to get the diagnostic codes for the engine light and, unfortunately, there was no power to the unit they hook the diagnostic device to. Will work on that and update y'all in a couple weeks. Thanks!

 

Where did you get that plug? Just about every 850 needs that plug replaced.

I'm not too sure about the wires being crossed, but that is a little worrisome. There are pins on the PCM apparently powered by that thing, as well as the injectors. I don't really think that's your problem, but I admit it's just complex enough to make you wonder.

 

This guy has a variety on his website

https://www.prancingmoose.com/blackvinyl.html

 

Thanks!