No Start

familyman · 2017-08-30T09:09:22+00:00

YM 1990 will be LH 2.4. Have you checked for codes?

familyman

Just found the CPS does have a crack in the outer insulation but that's up at its the top plug. But even if faulty, the CPS wouldn't stop the fuel pumps running at key turn-on, correct?

This is the same ECU: http://www.ebay.com/itm/401167908722

Time to wash up, walk to the takeaway for something to eat before coming back. Nearly out of money, nearly out of food... LOL.

carnut222

There must be somebody near you who could offer to swap out their known working ECU and also fuel pump relay...I'd offer but in country Vic. The fuel ECU with pink label...I think 561...is prone to fail. Fuel ECU is located behind trim panel next to the accelerator pedal. There is no fuse in the engine bay on 91 240. There's a good troubleshooting for LH2.4 in the Bentley blue Volvo 240 workshop manual, and it includes what pins on the fuel ECU to check for power etc. I have one somewhere but not sure where since we moved...maybe somebody else can scan and upload the image.

Major Ledfoot

familyman;117484 wroteJust found the CPS does have a crack in the outer insulation but that's up at its the top plug. But even if faulty, the CPS wouldn't stop the fuel pumps running at key turn-on, correct?

Incorrect. The fuel ECU detects an 'ignition on' status and latches the fuel pump relay on briefly to prime the rail.

When the starter motor is engaged, the fuel pumps operate via the starter circuit. LH 2.4 provides 2 injections per revolution in start mode.

When the engine starts, the ECU provides the fuel pump relay with the means to stay operated.

familyman

carnut222;117487 wroteThere must be somebody near

Slowbrick is closest I think, and he's giving enough valuable help. :-)

carnut222;117487 wroteThere's a good troubleshooting for LH2.4 in the Bentley

I read about that Bentley list, haven't looked for it yet.

Ok. (Other) panel off. Found it (again, LOL).

familyman

bgpzfm142;117491 wroteIncorrect. The fuel ECU detects...

But if the crank position sensor were broken, it measures engine rotation, yes? So even if it were faulty, it won't stop the fuel pumps priming when the key is first turned to dash lights on position, will it? (Because the engine hasn't been cranked yet, but the pumps turn on.)

familyman

Fuel ECU part number is: 0 280 000 561

Slowbrick

561 is pink label I think. Where are you located familyman?

jamesinc

$40 + post

familyman

See PM James. (When I type it, LOL.)

I've been doing a lot of reading...

* Yes, my 561 has a pink label. Made in Germany. Apparently the common fault is the integrated circuits are coated in a silicon, that allows moisture in to cause corrosion. I wish I could find more info on this part of it, because I have some experience with electronics, and it makes little sense what they're referring to. (Corrosion on the pins, moisture actually entering the chip internally!?)
* White 561s are better, but have also been known to fail.
* You can also buy remanufactured units that have had the ICs replaced. Sometimes they give you the same ECU number, sometimes they don't (see next point).
* A '0 280 000 561' can be replaced by a few different numbers, but '0 280 000 951' is the most common people swap in. However the original 561 has provision for "cold start valve operation", whereas the 951 does not.

Q: What is a "cold start valve" (is it the "cold start injector"?), what is the effect of losing that feature, and what would need to be done to deal with that?

jamesinc

The cold start valve is basically an extra injector that comes on when the car needs to go rich AF. I forget what temperature it comes in at, but it's extremely cold, like -10°C.

familyman

Feels like that now out here, LOL. I can't feel my feet.

familyman

Ok, removed rear of ECU wiring plug. Now to work out if I can test using that picture, or if I can find this Bentley troubleshooting guide.

jamesinc

You can test some voltages using this guide:

Slowbrick

Pink label ECUs fail in some very strange ways and are by far the most notorious of the bunch. 9xx series ones are the pick of the bunch and I've never heard of one failing. White label ones are better than the pinks but not hugely. If you replace it then get a 9xx if you can and if not then get a white. Don't get another pink one. They are too unpredictable.

lasercowboy

Do check for the pre-fuel pump fuse/wiring. I had a similar set of symptoms with my 240 recently, and tried a different ECU, EZK, pump relay, etc.

It turned out that the wiring for the pre-fuel fuse had too high resistance, so even though it showed continuity (and generally correct voltages in the right places) it wasn't letting enough current through.

EDIT: here's the thread: https://ozvolvo.org/discussion/5873/240-electrics-no-juice-getting-to-fuel-pumps#latest

lasercowboy

Actually, reading the first few posts of that thread back (reminding myself of the symptoms) it sounds very similar to what you're experiencing.

familyman

@lasercowboy - I'm reading through it now. You mean the 25A spade fuse? It seems my year model doesn't have it.

Note 1: My diagnostic position 2 LED is already on bright before I press the button. Then press the button and the LED stays on (it never changes even for that split second as you press the button) - and of course, displays no codes. Whereas the position 6 LED glows very dimly with probe in, and displays codes as it should.

The #2 LED being either always on - or dead - is what I'd expect to see from a device with fried integrated circuits.

Note 2: You had no spark, whereas mine does.

Note 3: Noting this comment from @tbro :
"I know with K-jet there can be no spark if the fuel relay fails , its cuts power to the ign module, maybe same??"

... Now when I was reading about faulty ECUs, I found an old comment that said that same thing... That green fuel pump relays used to control/kill spark, but white relay cars move that function into the ECU! That other guy then quoted someone else HE read somewhere, who claimed a possible fix was to use a green relay, but only after swapping the pins in the relay socket around to suit - thus the green relay has the required circuitry that dies in the white relay car's ECU...

... And in another thread I saw, an electronic technician built his own circuit based on a 555 timer to replace a pulse that dies in the ECUs - which feeds the EZK I guess(!?) - I forget the details now - but that page turns up constantly during searches.

So these again point to the ECU.

I'm just waiting for some email replies now, about different numbered ECUs - to decide which one to use.

familyman

LOL. I was just looking at the circuit diagram... Take note of fuse 6! Anyone have any idea what they're on about there? 2x circuit lines, 2x fuses, both connected to the same point at the dot. (Why not just one line, one fuse - like fuse 4 just above it!?)

jamesinc

I would assume you satisfy the current requirements of that circuit, rather than using one thicker wire.

familyman

What's going on with terminal 22 on that pic on the previous page? (It has 2x terminal 22s on the list.)

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