New problem. Engine stumbles

[Rversteeg]

According the wiring diagram of the 97-98 series LPT the RSR (2/12) is no longer mounted near the cooling fan relay, but closer to the top of the nearside strut zssembly. Also the drawing indicates two different relays; the cooling fan relay having two coils (two speed fan) and RSR a single.
I never did a thorough search on my 98 LPT, but I can’t remember having seen an RSR when I had the battery removed.
By the way, the RSR also feeds the ignition coil, so with a failing RSR you also loose ignition. The rpm gauge will probably not be affected as it is powered via the power stage.

Rob

[mhuk]

Originally Posted by Laird Scooby

It's possible the relay you've found was the cooling fan relay in that case - where was it?

Also tell me more about this "low impedance mod" for the injectors?

Can you also give the Bosch part numbers of the injectors you're currently running?

I'm hoping that what you've done so far (which will have cleaned the raly connectors, fuses and holders) may have sorted the problem but i didn't realise there were modifications to the original wiring. This may be the source of the problem and possibly explain the abscence of the RSR relay.

Hi,

From the post after your's the chap says fan has 2 coils inside the relay so looks like it's the fan I found.

The injectors are BOSCH 918600 off S70R I think. They been working fine last year. The mod was done by last owner.

Found this online and this is how it looks too...

(All of the wires terminate together into a single round crimp, but have spade connectors at the other end to go back into the harness. As there is no resistance you'll be able to use the high impedance injectors)

AND

(All LH2.x ECU's have high impedence injector drivers. N/A cars also have high impedence injectors. On the other hand, turbo cars use low impedence injectors, hence the use of a resistor pack. As you've been told, find the resistor, it should be on inner fender between headlight and strut tower, on the intake side of the car, near ignition module. Just unplug it and put wires like described above - they get current from central wire to other four wires to the injectors. Leave the resistor pack hanging there in case you ever want to go back to lowZ injector)


It looks to me like a plug with some terminals all connected to each other. It looks OK connection wise.

[mhuk]

Originally Posted by Rversteeg

According the wiring diagram of the 97-98 series LPT the RSR (2/12) is no longer mounted near the cooling fan relay, but closer to the top of the nearside strut zssembly. Also the drawing indicates two different relays; the cooling fan relay having two coils (two speed fan) and RSR a single.
I never did a thorough search on my 98 LPT, but I can’t remember having seen an RSR when I had the battery removed.
By the way, the RSR also feeds the ignition coil, so with a failing RSR you also loose ignition. The rpm gauge will probably not be affected as it is powered via the power stage.

Rob

OK so looks like what I found on passenger side wing (buried) is the fan relay. I looked on the strut yesterday and can not see anything well apart from a relay I fitted for the charge coolers water pump and water injection. I will look again. Just a real PITA that it's getting dark quickly when I get home! Grrrr

Thanks guys!!!!

[Laird Scooby]

Originally Posted by Rversteeg

According the wiring diagram of the 97-98 series LPT the RSR (2/12) is no longer mounted near the cooling fan relay, but closer to the top of the nearside strut zssembly. Also the drawing indicates two different relays; the cooling fan relay having two coils (two speed fan) and RSR a single.
I never did a thorough search on my 98 LPT, but I can’t remember having seen an RSR when I had the battery removed.
By the way, the RSR also feeds the ignition coil, so with a failing RSR you also loose ignition. The rpm gauge will probably not be affected as it is powered via the power stage.

Rob

Very true Rob but we don't know what year this car is. I was looking at the wrong diagram, that for my 760 (which being the facelift is very similar to most 9xx models) where the ignition coil is fed directly from the ignition switch. I'm fairly sure some early 9xx models shared this layout though.

The modification for the injectors is where i suspect the fault lies, yes there are problems with Volvos wiring sometimes and age does it no favours but that can be said of all makes (some are a lot worse than others though!) but on the whole, it's fairly reliable.
We don't know what standard the modification work was done to or even if it has been correctly done so to my mind, that would be a good place to start looking once the basics such as dirty fuses are covered, which they have been now.

Hopefully we'll have more info on it later!

[Laird Scooby]

Originally Posted by mhuk

The injectors are BOSCH 918600 off S70R I think. They been working fine last year. The mod was done by last owner.

Found this online and this is how it looks too...

(All of the wires terminate together into a single round crimp, but have spade connectors at the other end to go back into the harness. As there is no resistance you'll be able to use the high impedance injectors)

AND

(All LH2.x ECU's have high impedence injector drivers. N/A cars also have high impedence injectors. On the other hand, turbo cars use low impedence injectors, hence the use of a resistor pack. As you've been told, find the resistor, it should be on inner fender between headlight and strut tower, on the intake side of the car, near ignition module. Just unplug it and put wires like described above - they get current from central wire to other four wires to the injectors. Leave the resistor pack hanging there in case you ever want to go back to lowZ injector)


It looks to me like a plug with some terminals all connected to each other. It looks OK connection wise.

It should be a 10-digit Bosch number, usually starts 0 280 but putting that in front of 918600 doesn't come up with anything. Maybe that's the Volvo number?

This is what the part number looks like on the injectors :



Those are my injectors (the update/upgrade) but found this on fleabay for S70R injectors :



You can see the Bosch number on them.

Also have you got a link to that mod?

[mhuk]

Mine are the blue ones above. From the PO his said 'Uprated injectors – ME7 Blues (resistor pack modded)'

I could not find a real guide but from this "the ballist resistor is bolted to the right hand side flitch by the battery .all you have to do is cut off the resisters and solder all the wires together and then you can use me7 blue injectors"

That's just what it looks like. Pictures are dead online since photobucket decided to charge and killed a lot of good forum posts off. I'll get some pics.

Cheers

[Laird Scooby]

Originally Posted by mhuk

Mine are the blue ones above. From the PO his said 'Uprated injectors – ME7 Blues (resistor pack modded)'

I could not find a real guide but from this "the ballist resistor is bolted to the right hand side flitch by the battery .all you have to do is cut off the resisters and solder all the wires together and then you can use me7 blue injectors"

That's just what it looks like. Pictures are dead online since photobucket decided to charge and killed a lot of good forum posts off. I'll get some pics.

Cheers

Blue ones? I know i'm slightly colour blind but i would have said they were green?

The guide you quote from sounds very much like butchery to me, easier, quicker and more reversible to simply create a small link loom to link the resistor pack out then unplug the resistor pack and plug the link loom in.

Some pics will be good, maybe i can spot something dodgy that you've not spotted for whatever reason.

[mhuk]

yes green more then blue.

here is a video of what it does.

https://youtu.be/zJQPg4WEZkM

This afternoon I did this

unplugged the maf. Runs

unplugged the tps. Runs

changed the crank sensor.

unplugged the fuel regulator vacuum hose no change
found a earth wire from the fuel injector look was not connected. put back and no change.

I know for a fact there is another earth and it won't run without that connected to the inlet manifold.


found that relay must be the rsr and car won't run without out and under the head light is a massive 2 speed fan relay.


I'll get a pic of the mod.

[TonyS9]

Not sure this is relevant, but a missing speed signal can cause reving issues, especially if you use full power without a speed signal. The ECU will punish you with high idle. It does reset when you switch off though.

Problem sounds very regular, its like an air leak and when it cycles the mixture it dies through weakness, when you open the throttle it enriches the mixture from open loop mode.

Try disconnecting the TPS and seeing if it makes any difference.

[Laird Scooby]

Originally Posted by TonyS9

Not sure this is relevant, but a missing speed signal can cause reving issues, especially if you use full power without a speed signal. The ECU will punish you with high idle. It does reset when you switch off though.

Problem sounds very regular, its like an air leak and when it cycles the mixture it dies through weakness, when you open the throttle it enriches the mixture from open loop mode.

Try disconnecting the TPS and seeing if it makes any difference.

Originally Posted by mhuk

yes green more then blue.

here is a video of what it does.

https://youtu.be/zJQPg4WEZkM

This afternoon I did this

unplugged the maf. Runs

unplugged the tps. Runs

changed the crank sensor.

unplugged the fuel regulator vacuum hose no change
found a earth wire from the fuel injector look was not connected. put back and no change.

I know for a fact there is another earth and it won't run without that connected to the inlet manifold.


found that relay must be the rsr and car won't run without out and under the head light is a massive 2 speed fan relay.


I'll get a pic of the mod.

Tony - he's already tried disconnecting the TPS ^^^^^

No change it seems.



Try unplugging the Knock Sensor and see what happens. Also have you read the codes?