Volvo 760 2.3 turbo - power issue

[lessertegasi]

good afternoon everyone and thank you for the responses.

the mechanic has checked and there is no air leak between the MAF and the throttle body.
there was leak before which caused an erratic idle that would always run at 2000+RPM even when stopped but this has now been solved.

the car has a Lambda Sond system
the fault code that comes up is 2 3 1

please follow this link https://drive.google.com/file/d/1jkV...ew?usp=sharing to an image of what I hope it's the air flow meter



also the engine is a B230FT

all the best

[Laird Scooby]

Originally Posted by 360beast

There is an ecu labelled motronic 1.0 and a motronic powerstage in the engine bay too Dave at least there was on the 1987 and 1988 ones I broke.

I've got two lots of Motronic stuff and a flywheel for it to convert my 360 to a B230ET but I haven't looked at the stuff for years now as the project won't be going anywhere soon.

You're right it is an old style flap Air flow meter not an air mass meter like LH2.4.

The Motronic thing is all down to marketing really Luke, both the fuel and ignition ECUs as one combined unit mean they can say it's more sophisticated which then means if one part goes wrong, they both have to be renewed as one. More profit!

Cynical old git, aren't i?

Originally Posted by lessertegasi

good afternoon everyone and thank you for the responses.

the mechanic has checked and there is no air leak between the MAF and the throttle body.
there was leak before which caused an erratic idle that would always run at 2000+RPM even when stopped but this has now been solved.

the car has a Lambda Sond system
the fault code that comes up is 2 3 1

please see attached an image of what I hope it's the air flow meter



also the engine is a B230FT

all the best

That fault code relates to the Lambda sensor. You'll need a new one and then pull fuse #22 to reset the ECU afterwards.

Yours should be the Motronic 1.8 aka LH2.4, as per the link i provided earlier.

Yes, that is the MAF in your pic, not to be confused with an AFM (Air Flow Meter) which has a flap inside that moves in response to air flow. The MAF is a hot wire airflow sensor and uses the cooling effect of air movement over a hot wire to sense air flow.

The symptoms you're getting fit with a Lambda sensor so hopefully that's all that's wrong with it. However it might pay (now the air leak between MAF and throttle body has been fixed) to pull fuse #22 for a few minutes and then give it a test drive - it may still be holding the "fault" caused by the air leak (that would put the Lambda sensor out of limits) and responding accordingly.

Try that first then if no joy, get a new Lambda sensor.

[lessertegasi]

Just got back from the diagnostics centre.
The mechanic said the ECU appears to not trigger fuel relay.
He tried to bypass the issue but it did not work.
He suggested changing the ECU.

Also the pins inside it were corroded. He cleaned them and replace the worst ones but this did not seem to solve the problem either.

Any thought on that?

And how easy / costly is to get another ECU?
The model is :
BOSCH Jetronic
0280000563
3517370

Thank you in advance.

[classicswede]

That ECU number makes it a LH2.4.1 but you can still plug in and use the later LH2.4.4 ECU's

Is it just the pins on the ECU or is it the wiring loom that has corroded? In teh late 80's Volvo did use biodegradable wiring and the engine looms tend to just crumble and fall apart

[TonyS9]

"no leak between maf and throttle" - Leaks can occur at the manifold gasket, especially if its been tightened unevenly.

If the fuel relay is not triggered the engine won't run, if there is an intermittent problem is could well be the relay, they are known to fail. Usually a thump or knock on the relay will change the status.

Fuel relay is controlled by ECU based on input from the crank or cam sensor. I think you probably have a crank sensor so he can check its resistance while moving the cable around.

Fuel pressure maybe ok when the fault isn't occuring, its harder to monitor it all the time. The pump or prepump maybe faulty.

What he said about the air may not be correct. The idle air valve and general leakage of the throttle control the air for idle. Unless the valve is sticky (which is rare, everyone blames idle valve for idle problems but its rarely the case), its more likely to be a fuel problem caused by low pressure, faulty injectors, faulty MAF etc.

You may also have a cold start injector, try blocking its fuel feed with a clamp.

2 3 1 is fuel too weak or too rich in part load. It is decided from the O2 sensor, but does not mean the sensor is faulty.

[lessertegasi]

Originally Posted by classicswede

That ECU number makes it a LH2.4.1 but you can still plug in and use the later LH2.4.4 ECU's

Is it just the pins on the ECU or is it the wiring loom that has corroded? In teh late 80's Volvo did use biodegradable wiring and the engine looms tend to just crumble and fall apart

Hi,
Thank you for the response.
Wiring loom has been checked and cleaned.
The pins were mainly corroded.
Do you happen to know which other ECU numbers would fit that model (it's a turbo)
Do you know where can I get that part?

I really appreciate your help.

All the best

[Laird Scooby]

Originally Posted by lessertegasi

Just got back from the diagnostics centre.
The mechanic said the ECU appears to not trigger fuel relay.
He tried to bypass the issue but it did not work.
He suggested changing the ECU.

Also the pins inside it were corroded. He cleaned them and replace the worst ones but this did not seem to solve the problem either.

Any thought on that?

And how easy / costly is to get another ECU?
The model is :
BOSCH Jetronic
0280000563
3517370

Thank you in advance.

If you've got corroded pins on the ECU, you've got a water ingress problem, or at least have had in the past. Have a look at this, might give you a few ideas.

https://www.volvoclub.org.uk/faq/Eng...lCircuitRepair

There are other ways round getting the fuel pumps to run when they should as well.

[TonyS9]

You can a replacement ECU from ebay, many direct ad at the moment but like £100 from the US. Other 940/740 ECU going in UK/EU for about £40 (this is more a fair price).

Usually many cars being broken on ebay, so try to find an early turbo 940 with the 563 computer. I'm not sure if other versions will work, you maybe able to rechip it use the chip in yours to change a later model version to work.

If you research around you can find the information. Try the 940 tuning chip sellers on ebay, they will know the difference between each version, usually happy to chat to you.

[Laird Scooby]

Originally Posted by lessertegasi

Hi,
Thank you for the response.
Wiring loom has been checked and cleaned.
The pins were mainly corroded.
Do you happen to know which other ECU numbers would fit that model (it's a turbo)
Do you know where can I get that part?

I really appreciate your help.

All the best

Someone else had an ECU problem about 9 months back, he got it repaired at :

https://www.atpelectronics.co.uk/

Cost wise he had to pay a test fee which was somewhere around £40-50 and the repair fee was somewhere around £300 but the test fee was discounted off the repair which has a lifetime guarantee. As they also repair/upgrade the common failure points it means the whole thing is guaranteed for life.
If memory serves correctly the person who had the problem sent it off on a monday and had it back by the thursday. He'd already tried a supposedly good ECU bought via ebay but found it was DOA - a common fault where something inside fails due to power surges - what i'm not entirely sure but it is quite common.

If budget is a problem, there is another way to get the fuel pump to run, it involves adding a cheap (about a fiver) relay and bypassing the ECU control on the fuel pump. While this doesn't sound like a major problem, in the event of an accident, even if the engine is stopped, if the ignition is still on the fuel pumps will be running. It should therefore be used with caution!

[lessertegasi]

Hi everyone,

I sent my ECU for testing at ATP and they came back to me saying that the fuel pump output is failing.

They remanufactured it and send it back to me today.
I installed the ECU did about 20 miles and although there was no lambda indication anymore, no fuel smell and idling was steady at 1000rpm, suddenly the car started stalling again, lambda light came on flashing and eventually switched off.
The exact same issue I had when I first started the thread.

I don't know what other options I have really. It is really sad.

Thank you