855r no power at a26 and a27

[AndreasJJ]

Hello hello,
I finally got the car running becuse i realised that i missing power to a26 and a27 pins to the ecu soo i jumped does 2 wires to the battery and the car runs.but now to the ”problem” wierd thing is that the car starts sometimes without those wires to battery.

But the thing im wondering is why? Anyone had the same problem? And those wires should always have 12v If im looking at the wiring diagram but If im leaving the wires connected to battery the iac valve stays buzzing..and the times the car starts without them on the battery its as it should iac turns on when ignition is on etc etc

And earlier i could remove the wires from the battery and the car would stay running but today If i removed the the car died..soo i had to leave them on for it to stay running

Also the car is manual swaped like 10 years ago by someone and yes it has worked since then.sorry for bad explaining

[WhatAmIDoing]

Sounds like you have broken wires in the harness that are intermittently connecting and/or shorting out. Unfortunately, you'll probably have to trace the wires to find the break. Normally 90deg bends or where the wires pass through a cutout are the prime suspects. Follow the wiring diagram and check any switches, relays, or fuses that control those wires.

Perhaps someone with more knowledge on the ECU can comment, as I don't have a wire diagram nor do I know what either of those wires control.

[Chuck W]

A26 and A27 Both get power from the battery, but indirectly.

A26 is fed from the battery through splice 23/0. That battery lead also feeds the main Fuel System relay coil (2/32) (The relay mounted above the radiator). Again, through this splice (23/0). If you don't have A26, you won't have A27. That battery lead feeds the 12V+ to both the coil and the power side of that main FI relay (2/32)

Your failure is somewhere between the battery and that splice 23/0. Looking at the wiring PDF that splice in the power line is located somewhere in the main harness that is located in the wiring raceway on the front of the engine. Rough guess is where it makes the turn down.

How are you feeding power to those pins?

[AndreasJJ]

A26 and A27 Both get power from the battery, but indirectly.

A26 is fed from the battery through splice 23/0. That battery lead also feeds the main Fuel System relay coil (2/32) (The relay mounted above the radiator). Again, through this splice (23/0). If you don't have A26, you won't have A27. That battery lead feeds the 12V+ to both the coil and the power side of that main FI relay (2/32)

Your failure is somewhere between the battery and that splice 23/0. Looking at the wiring PDF that splice in the power line is located somewhere in the main harness that is located in the wiring raceway on the front of the engine. Rough guess is where it makes the turn down.

How are you feeding power to those pins?

First of all so on the right path..what means with 23/0 etc etc?

But yes i kinda know where the wires go and to what ”parts” but not where the wires go trough the loom If that makes sense..and when it comes to the Main fuel relay everything has power that should have power atleast last time i checked,im just using one of those wire spilce connector thing don’t know what they are called

Im going after this diagram (If the picture worked)

[Chuck W]

The "23/0" is a factory wire splice. It's located in the plastic wire loom that runs across the front of the engine.

Search Google for "1996 volvo 850 wiring diagrams pdf" (Or send me a message with an email) to see a better factory diagram, and also get locations of the splices, etc. Your diagram doesn't ID any of the splices.

A27 is fed from the main relay through 2 other splices (23/6 and 23/11, which are both also in the wire loom, closer to the battery side of the engine).

You should have 12V at pins 2 and 4 of the main FI relay (The two RED wires in your diagram) with the key in the "ON" or "II" position. This is the feed from the battery and also to A26. (Through splice 23/0). If you have power to both of those pins, but no power to A26, your issue is at splice 23/0.
If you have 12V at those 3 places, then you should have 12V on pin 3 (GREEN wire) on the main FI relay, which also powers the injectors. If the wiring is good from there, you should have 12V at A27

If you don't have power at pin 3 of the relay, the relay is bad. If you have power at pin 3 of the relay, check check the green wire of the EVAP valve on the fan shroud. If you don't have 12V there, check splice 23/6. If you do, check the green wire on the IAC. If you don't have power there, check splice 23/11.

You applying 12V power to both locations is back-feeding the system, which is why it starts. Seeing as it doesn't start like that all of the time, you have a break in one of your power splices mentioned above.

I'm guessing something failed in whatever work the previous owner did when the manual swap was done. It could also be something as simple as the needed splice when the PNP switch is removed from the system for the auto trans (a GN/RD wire), which is also contained within the wire loom.

[AndreasJJ]

The "23/0" is a factory wire splice. It's located in the plastic wire loom that runs across the front of the engine.

Search Google for "1996 volvo 850 wiring diagrams pdf" (Or send me a message with an email) to see a better factory diagram, and also get locations of the splices, etc. Your diagram doesn't ID any of the splices.

A27 is fed from the main relay through 2 other splices (23/6 and 23/11, which are both also in the wire loom, closer to the battery side of the engine).

You should have 12V at pins 2 and 4 of the main FI relay (The two RED wires in your diagram) with the key in the "ON" or "II" position. This is the feed from the battery and also to A26. (Through splice 23/0). If you have power to both of those pins, but no power to A26, your issue is at splice 23/0.
If you have 12V at those 3 places, then you should have 12V on pin 3 (GREEN wire) on the main FI relay, which also powers the injectors. If the wiring is good from there, you should have 12V at A27

If you don't have power at pin 3 of the relay, the relay is bad. If you have power at pin 3 of the relay, check check the green wire of the EVAP valve on the fan shroud. If you don't have 12V there, check splice 23/6. If you do, check the green wire on the IAC. If you don't have power there, check splice 23/11.

You applying 12V power to both locations is back-feeding the system, which is why it starts. Seeing as it doesn't start like that all of the time, you have a break in one of your power splices mentioned above.

I'm guessing something failed in whatever work the previous owner did when the manual swap was done. It could also be something as simple as the needed splice when the PNP switch is removed from the system for the auto trans (a GN/RD wire), which is also contained within the wire loom.

Okey okey huge thank you i will bring out the multimeter AGAIN to see what i can find and i will give u a update..i mean i don’t have a problem to just put the wires on a switch (would be a great anti theft system hahaha) but just becuse of peace of mind i wanna figure it outAlso sent you a message about the pdf didn’t seem to find it

And also don’t remember If i mentioned it but sometimes i can disconnect the wires and the car would keep running but not know...really wierd but yeah i guess its an intermittent issue

[Chuck W]

I sent you a link to the PDF.

You don't want to run 12V to BOTH of those locations on a switch.

[abscate]

Thanks for that help Chuck. If you know a good Indy in dee Indy Kasha could use a reference in her cold start problem. See thread here

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