Fuel pump on a 1998 Volvo S90

anbran123 · Post by **anbran123** » 19 Mar 2018, 10:18

I'm in the process of ordering a fuel pump for my 1998 S90. The parts guys are saying that there are TWO fuel pumps on my car....An "internal" and "external" one.

Is this correct??

I only am aware of the one in the fuel tank...

Thanks,

Mike

Post by **RickHaleParker** » 19 Mar 2018, 16:46

Only one fuel pump. However on the '98 S90 they did do a midyear change on the fuel pump so there two part numbers listed for the fuel pump on the '98 S90. Fuel pump part number 9438003 was replaced by Fuel pump part number 9438756.

Combined tank unit, complete (Sender and pump) 9142959 was replaced by 9180931.

If you can get the part numbers from him, perhaps we can figure out what going on with that guy.

My bet is he seen two part numbers for the fuel pump and concluded there are two fuel pumps. Why a parts guy would do so is beyond me.

'97 - '98 S90/960 there are four five changes to the fuel delivery system for them years that I'm aware of, and all four five are midyear changes. Navigating it can make a person's head spin.

anbran123 · Post by **anbran123** » 23 Mar 2018, 10:23

I've seen pictures of the "external" pump that they are talking about. It's attached beside the fuel filter underneath the car. I believe that the earlier models had 2 pumps.

I guess the only way ascertain the correct internal pump is to remove the old one and take it from there based on what it looks like?!

Some of the pumps that are listed for my S90 show two wire connectors on the pump and some others have a plastic plug in connector...

Anyone have a picture of their pump from an S90 (or late 960)?

Thanks

V-Jet · Post by **V-Jet** » 26 Jun 2018, 12:33

Volvo’s 1998 “New Car Feature” manual (which they published every year to detail all the minor running changes they’ve introduced for that model year) mentions that a new type of fuel pump was introduced on the S90 & V90 in 1998, it is an impeller pump which is quieter and provides a more even fuel flow compared to the older gear pump. It then states only this newer type of fuel pump will be stocked as spare parts as this is a direct replacement for the older pump from 1995 960 onwards.

The connectors are different on the 1998 fuel pump but if you purchase a genuine Volvo pump, it will come with connetor & wiring terminals to convert the connectors on the -97 sender for the 98 pump.

I suspect the updated fuel pump was necessary as part of the returnless fuel rail system introduced in 1998, whereby excess fuel is returned to the fuel tank from the fuel pressure regulator, so any fuel that flows past the fuel pressure regulator to the fuel rail only goes to the injectors. Previously up to 1997 the excess fuel is returned to the fuel tank from the fuel rail.

Post by **RickHaleParker** » 26 Jun 2018, 15:09

Previously up to 1997 the excess fuel is returned to the fuel tank from the fuel rail.

Some of the '97s had no return fuel rails and some did not, midyear changes. There is quite a number of different fuel rails for the '97 and at least two for the '98 because they had trouble with the end cap leaking.

V-Jet · Post by **V-Jet** » 26 Jun 2018, 15:39

RickHaleParker wrote: ↑26 Jun 2018, 15:09 Previously up to 1997 the excess fuel is returned to the fuel tank from the fuel rail.

Some of the '97s had no return fuel rails and some did not, midyear changes. There is quite a number of different fuel rails for the '97 and at least two for the '98 because they had trouble with the end cap leaking.

The different fuel rails in ‘97 was because 960 to S/V90 itself was a mid year change. Original 960 fuel rails had the long bracket while the S/V90 fuel rails did not, instead they had long supporting bolts.

Return-less fuel rail on the other hand was not introduced until ‘98 which I’ve confirmed through parts diagram (listed as only for ‘98) and it was also mentioned in the 1998 “New Car Features” manual as one of the features introduced on the 1998 model year.

‘98 got a complete fuel system overhaul, I believe the main objective is the introduction of fuel vapour leak detection system for the North American (USA & Canada) market. Although cars outside North America didn’t get the fuel vapour leak detection system, they still got a lot of updated parts as a result such as a different fuel tank (with additional port for the fuel vapour sensor, sensor not fitted outside North America), relocated & different shaped charcoal canister, different fuel delivery lines (with different connectors for the fuel filter, ‘98 got quick release type fuel filter) etc.

Post by **RickHaleParker** » 26 Jun 2018, 17:20

The different fuel rails in ‘97 was because 960 to S/V90 itself was a mid year change.

The 97-98 S90 badge is just a marketing ploy. The only difference is the badge. My '97 S90 is titled as a 960.

Return-less fuel rail on the other hand was not introduced until ‘98 which I’ve confirmed through parts diagram

See screenshots

V-Jet · Post by **V-Jet** » 28 Jun 2018, 07:57

Saying the S90 is exactly same as a 960 and the badge is just a marketing ploy is like saying the S70 is exactly same as an 850. While one evolved from the other, and the S90 wasn’t as heavily redesigned from the 960 as the S70 was from the 850, the fact still remains that there is a lot more difference than just the badge!

The most noticeable difference between the 960 and S/V90 is the redesigned centre console, with different seat heater switches, automatic shifter unit, handbrake lever & armrest / cup holder. Under the skin, the S90 & V90 has much larger rear brakes (increased from 265mm diameter & 10mm thickness on a 960, to 277mm diameter & 12mm thickness on a S/V90) with different rear brake calipers too. The newer style brake calipers on the S/V90 also meant the brake pressure reduction valve on the 960, found in the engine bay just under the brake master cylinder, is no longer required & deleted from the S/V90. Volvo actually published two 1997 “New Car Features” manuals, one at the start of 1997 model year & contains information on the 850 & 960, then a mid-1997 “New Car Features” manual which contains information on the S/V70 & S/V90.

There’s a lot of other minor differences between 960 and S/V90 which most people aren’t aware of. For example the wiring on the starter motor relay is different for automatic cars, the PNP switch for starter motor is on the positive (live) side of the relay on 960 but on the negative (ground) side of the relay on S/V90, therefore you can’t use a 960 engine wiring loom in a S/V90 or vice versa - unless you swap the entire interior wiring loom of the car as well.

As for the electronic parts diagram in VADIS / VIDA, I’ve found over the years that there are numerous errors on the ‘97-98 S/V90, I imagine this is because around this time Volvo introduced VADIS and someone did a pretty lousy job of transferring all the paper data onto a digital system. For example if you start your search with ‘97-98 S/V90 and try to find parts for the automatic gear shifter unit (shift knob etc), depends on which link you followed you may end up looking at a 960 one instead. Another example is if you try to find the steering column plastic cover in OAK (interior colour only found on S/V90) you won’t find it on the digital system, but you can on the old paper catalogue. Therefore for parts on S/V90 I tend to refer to the old paper catalogue, which I find a lot more accurate than the digital system.

dm635 · Post by **dm635** » 15 Jul 2018, 07:46

Interesting the difference between the 960 and the S-V/90. Had no idea. Although I did notice the shifter difference earlier this year while looking for the knob on my 960. The whole center console was different on the V90 I was looking at.

I've wondered why the early '97 is 960 while apparently the later '97 is a V or S90. When was the change? Sounds like quite a few differences between the 2. I was totally unaware.

V-Jet · Post by **V-Jet** » 19 Jul 2018, 07:08

dm635 wrote: ↑15 Jul 2018, 07:46 I've wondered why the early '97 is 960 while apparently the later '97 is a V or S90. When was the change? Sounds like quite a few differences between the 2. I was totally unaware.

I don’t know the exact date but I believe it is around the end of 1996 calendar year, the factory Volvo “New Car Features” workshop manual I have which details all the difference between the 960 and S/V90 was printed in December 1996. As you probably know, 1997 model year was produced from August 1996 to June 1997. I’ve heard somewhere that the production line workers get a month off in July while factory tooling is changed over in preparation for the next year model.

850 evolved into S/V70 at the same time, hence just like the 960 and S/V90, there’s also ‘97 850 and ‘97 S/V70.