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1994 940 Turbo FI Relay Location 900

posted by tedv on Sun Mar 31 18:42 CST 2013
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last visit: Sat Oct 18 10:51 CST 2014

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Anyone can shed some light on ALTERNATE FI Relay location on some 1994 940Ts? Apparently NOT on the relay tray where they normally are...

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1994 940 Turbo FI Relay Location 900 1994

posted by lucid on Tue Apr 2 09:06 CST 2013
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last visit: Fri Oct 24 12:31 CST 2014

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Ted, do you have a Blue or a Green "cube" relay in the relay rack front row, second from the end (M position) on the right side? If so, it's the "new" Pump relay formerly housed with the FI System relay inside the White case (left side E position).

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

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1994 940 Turbo FI Relay Location 900 1994

posted by tedv on Tue Apr 2 09:39 CST 2013
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last visit: Sat Oct 18 10:51 CST 2014

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Thank you, I guess normally on earlier models the M position is unused?
I don't have the car in question, all mine are "normal". It is a discussion which left some unanswered questions and that's why I was asking...

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1994 940 Turbo FI Relay Location 900 1994

posted by lucid on Tue Apr 2 09:59 CST 2013
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last visit: Fri Oct 24 12:31 CST 2014

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"I guess normally on earlier models the M position is unused?"

My '93 diagram green book shows "M" used for Rear Foglight (not USA).

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

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1994 940 Turbo FI Relay Location 900

posted by HillBilly on Tue Apr 2 07:10 CST 2013
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last visit: Thu Oct 16 08:26 CST 2014

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On some models there are two seperate fuel relays.
My 94 Model 940 with Bosch Injection has two.
The first one is on the relay terminal behind the ash tray. It's a small square cube type relay (blue) and it's on the front row second from left.

The other fuel relay is located under the hood on the passenger's side. It's on the inner fender beside the coolant expansion tank. It's black and is the same size as a conventional Volvo fuel relay.
This under hood relay is called the "Radio Suppresion Relay", but it is a fuel system relay.

Hope this helps
steve

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1994 940 Turbo FI Relay Location 900

posted by HillBilly on Wed Apr 3 11:33 CST 2013
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last visit: Thu Oct 16 08:26 CST 2014

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I've been scrutinizing the electrical schematics for the 94 model 940, and noticed a few things that weren't clear to me before.

I said yesterday that some of the 940's there are two seperate fuel relays....one under the dash on the relay terminal and one under the hood near the coolant resevoir.
This is true. My 94 model with Bosch LH 2.4 injection has two.

One (the Fuel Pump Relay) is on the relay terminal located behind the ash tray.
This small blue cube relay powers both the intank and Main fuel pumps.
The 12V power supply to this relay comes directly from fuse #1 (25 amp) and remains constantly energized.
This relay is operated (on-off) by a (negative) ground signal from the Jetronic Module (terminal 9).
The 12V secondary output from this relay powers the Main fuel pump directly (thru the 25 amp fuse) and also powers the in-tank fuel pump and fuel level sensor, and the oxygen sensor thru fuse #11 (15 amp).

The second relay (Radio Interference suppression) is located under the hood near the coolant resevoir.
This relay is rectangular and black.
The 12V power supply to this relay comes directly from the battery and remains constantly energized.
This relay is controlled (on-off) by a (negative) ground signal from the Jetronic Module (terminal 21).
The output supplies 12V power to the fuel injectors, the Mass airflow meter and the Idle air control valve.

The fuel injectors and idle control valve are operated by a (negative) Ground signal from the Jetronic Module.
Fuel injectors...terminal 18.
Idle Control Valve...terminal 33.
The Air Mass meter is also operated by the Jetronic Module.

I also own a 93 Model 940 with Regina Fuel injection and it only has 1 fuel relay located behind the ashtray. This is the conventional relay that I am used to seeing on the Volvo 240's with LH 2.2 and LH 2.4 injection that I've owned.

If any of this is incorrect I'm sure that I'll hear about it

The electrical schematics that I reference are from "Mitchell Repair Information Company".

Hope this helps

steve

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1994 940 Turbo FI Relay Location 900

posted by lucid on Wed Apr 3 13:18 CST 2013
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last visit: Fri Oct 24 12:31 CST 2014

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Steve, I don't mean to step on your toes here, but some things you've described don't match what' I see in the OE diagram. I do agree with much of your post, but offer the following because I think it helps the reader to distinguish a relay's Coil voltage from it's output ("relayed") voltage. I'm addressing the RSR first because in operation it gets energized first (like the older System relay in the White case, which it now replaces). I'm using a 1995 OE diagram, which shows just the single "Main" pump. [I think the '94 is the same, but that's a guess.]

The Radio (Interference) Suppression Relay (RSR)is located under the hood near the coolant resevoir. This relay is rectangular and black. The 12V power to this relay's Coil (and to it's input switched voltage) come directly from the battery and remain constant. This relay is controlled (on-off) by a (negative) Coil ground signal from ECU 21, [when the Ignition Key is turned On, putting 12v on ECU 35]. The RSR output terminal 87 (3) supplies 12V power to the fuel injectors, Mass airflow meter, Idle air control valve, ECU 9, and Fuel Pump relay Coil+ side terminal 86 (2).
[The Pump relay's ground side 85(4) will be controlled by ECU 20, when Ignition timing pulses are detected at ECU 1.]

The Pump Relay is on the relay terminal rack located behind the ash tray. This small blue cube relay powers both the intank (if present) and Main fuel pumps. The constant 12V power to this relay's Coil comes directly from fuse #1 (25 amp) . This relay is operated (on-off) by a (negative) ground signal from ECU terminal 20). The 12V switched output from this relay powers the Main fuel pump directly (thru the 25 amp fuse) and also powers the in-tank fuel pump (if present) and the oxygen sensor heater thru fuse #11 (15 amp).

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

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1994 940 Turbo FI Relay Location 900

posted by HillBilly on Thu Apr 4 14:12 CST 2013
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last visit: Thu Oct 16 08:26 CST 2014

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"Steve, I don't mean to step on your toes here, but some things you've described don't match what' I see in the OE diagram" (Lucid).

That's OK Lucid, this is not a classroom and you are not my teacher.
I stated where I got my information.
If you have a schematic that shows something different I'm not suprised.

I suppose that the only thing to do is trace the circuits and see exactly where the wires actually connect if you're curious.

One thing that I do know for sure.
I've had 35 years experience drawing and reading electrical schematics...both power and control, so I'm pretty sure what my schematics show.

As far as the difference in relay terminology, I've found that there is a lot of difference from region to region in this country about the terminology and exactly what it describes.
That's out in the trenches of course....with the great unwashed.

It's much easier to show a circuit in schematic rather than trying to describe it verbally, that's why I didn't go further than I did in my descriptions. It's very easy to add too much information and muddy the water.

JUst my opinion
steve

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Correction to yesterday's post above 900

posted by lucid on Thu Apr 4 07:33 CST 2013
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last visit: Fri Oct 24 12:31 CST 2014

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I goofed in describing how the 5-pin cube Fuel Pump relay works.

In the 3rd paragraph (Pump Relay description) the following sentence is wrong:
"The constant 12V power to this relay's Coil comes directly from fuse #1 (25 amp)."

It should be replaced with:

The Fuel Pump relay's coil voltage to terminal 86(2) comes from the energized RSR relay's output terminal 87(3). So the corrected paragraph reads as follows:

"The Pump Relay is on the relay terminal rack located behind the ash tray. This small blue cube relay powers both the intank (if present) and Main fuel pumps. The Fuel Pump relay's coil voltage to terminal 86(2) comes from the energized RSR relay's output terminal 87(3). This relay is operated (on-off) by a (negative) ground signal from ECU terminal 20). The 12V switched output from this relay powers the Main fuel pump directly (thru the 25 amp fuse) and also powers the in-tank fuel pump (if present) and the oxygen sensor heater thru fuse #11(15 amp).

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

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