No Start

familyman · 2017-08-30T09:09:22+00:00

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

familyman

I couldn't find one. The car has August 1990 on the compliance plate, but the rego papers list the car as 1991. And apparently in 1991, they moved the function of the 25A fuse into the fuse box. So I don't know which one is true: if my car has it but I can't find it - or it never had it.

I'm going to try to power the in-tank pump with an external power source - then connect 4 & 6, and try and start the car. (Because I know the in-tank was working from an external power source before.) But I have to find online which wire it is again, because I've forgotten. :-(

familyman

FREEEEEZZING

familyman

Powering the tank pump externally (by itself first, so I can hear it running), and bridging 4 & 6 - to make the main pump run - doesn't start the car.

I was going to test if fuel is reaching the injector rail. But it must be... Because when the 1L bottle of fuel emptied - surely it wasn't all sent into the pistons - so it must have been returned to the tank, right?

What would cause those 3 things:

a. Injectors not operating
b. Main pump not running
c. Tank pump not running when 4 & 6 bridged (Edit: IGNORE - both run)

Time to cart the computer back inside and look at circuit diagrams.

jamesinc

If the injectors aren't firing, that sounds like faulty CPS

familyman

Man, there ain't no way in the world I'm getting that fuel inlet line apart to check fuel is reaching the injector rail. And I'm using decent-grip split ring spanners too. King kong must've tightened it. The return line looks far easier, but I wanted to check things in a logical order. [Sigh]

familyman

Ok, fuel must be reaching the injector rail when both pumps artificially powered. ('Cause it squirts out the back of pressure regulator quite ok.) :-)

DW42

I couldn't find the 25A fuse in the engine bay of my June 1990 240, also registered as a 1991. Turned out that someone had replaced it with an aftermarket fuse located nearby -- I simply didn't recognise it as such until an expert looked at it.

Slowbrick

Yeah it should have the fuse. It's the 93 cars that lost it and had box fuses on the battery terminals.

I think amongst all of this we have a few stand out points.

1. Your car doesn't prime the pumps when you turn the key. It should prime the pumps each time you turn the key. If this is not happening then something is up with either the relay, the ECU or your injector grounds.
2. Your pumps run when you force them. This is a good sign. I think troubleshooting can stop at this part.
3. Your car runs on lighter fluid. This means you are getting spark. Means your EZK and CPS are probably working correctly.

Based on what I can see, and remember this is over the internet, I think you have a problem with your ECU getting power. If it isn't cycling the pumps then that's a good indicator your ECU isn't doing what it's supposed to be doing.

familyman

IPD says: https://www.ipdusa.com/products/10621/122077-fuse-holder-25-amp-240

"For owners of 1982-89 non-turbo 240 series Volvos with LH fuel injection. With the Bosch® LH fuel injection system, current is supplied from the battery to an exposed blade style fuse. The fuse is located about a foot behind the battery on the driver’s side inner fender."

DW42;117425 wroteTurned out that someone had replaced it with an aftermarket fuse located nearby

This site: http://cleanflametrap.com/emfuse.html says:

"Since 1983 and LH2.0, 240's with EFI through 1990 models have the fuel system (computer, fuel pumps, idle valve, injectors, air mass meter) all powered through the engine wiring harness (thick red wire) fused near the battery and originating at a battery junction box on the left inside fender wall."

"However, in 1991, the engine and main cabin harness underwent big changes, moving this fuse out of the weather being among them."

And has a picture of its location:

So maybe we got all the wiring harnesses they already had made up, but gave the USA a new batch. I'll try and find it again.

So it should come directly from the battery +ve, or from a wire on that junction rail, right?

familyman

I cannot locate that fuse. Even removed power steering reservoir to check it wasn't hiding.

Positive lead goes from the battery, into some black conduit, under the battery tray. Cannot see where it goes from there. But moving it shows one thick wire branches off from under the back of the battery tray, up to the junction rail. Then it feels like the rest of the conduit goes through a hole in the engine bay wall. Obviously it goes off to the starter motor at some point. Tracing back the other way from the starter motor - its cable is inside heatshrink/harness - so the conduit changes at some point I can't see.

Tried to record video under the battery tray using my phone, but I can't see where the conduit goes. And it can't focus on anything else under there (like a missing fuse).

The 1990 wiring diagram shows the fuse. The 1991 diagram omits it. Maybe sometime between June and August they removed it - swapping it's function into the fusebox area.

@DW42 - where is your fuse physically located/wired to/from?

* While poking around I measured the orange supply wire on the AMM with ignition on. Measures 9.4V - is that normal? (The circuit diagram shows that AMM orange wire also goes off to one side of all the fuel injectors and start injector, and also to the ECU and fuel pump relay. I don't know if fuel injectors have any internal resistance, but that orange wire has to go through a diode and a couple of coils inside the fuel relay - which should drop at least 0.6V - but is 9.4V too low at the AMM?)

Major Ledfoot

Wait a minute....

familyman;117349 wroteGuys, when you read off diagnostic codes... If I plug the probe into socket 6, the LED glows very dimly, push button 2 seconds, it flashes off 1-1-1.

Socket 6 is the EZ-K. So your EZ-K is all right.

But if I test #2, the LED is on bright - all the time. Is that normal?

Eh? No way. If socket #2 is doing that, something to do with the fuel ECU is cactus.

https://www.volvoclub.org.uk/faq/EngineOBDCodes.html#FuelInjectionandIgnitionDiagnosticCodesi

Slowbrick

You have a multimeter? Think it's time to get specific and start checking for voltage and continuity.
http://www.volvowiringdiagrams.com/volvo/LH%202.4/LH2.4%20ECU%20Pin%20Out.jpg

Slowbrick

Also according to the diagram for the 91 240 it gets its ECU power from fuse 6. So going by that if you apply power to 6 then turn the key you should get your relay to close and the ECU should power up and prime the pumps. Also I've made a mistake and in 91 the intank is powered from fuse 4 and not 6.

The diagram is here.
http://www.volvowiringdiagrams.com/?dir=volvo/240%20Wiring%20Diagrams

familyman

bgpzfm142;117465 wroteIf socket #2 is doing that, something to do with the fuel ECU is cactus.

@Slowbrick LOL, that is just hilarious... I was just watching a youtube video, guy put the probe in #2 on a 1990 - and I noticed it didn't light up. Then I thought, wait a minute... one LED is for the EZK, the other is for the ECU... Maybe an always-on LED indicates an ECU fault. Then I came back here to read that /\.

I was just about to search online for where it's located. Is it the one behind the glovebox?

familyman

Grr... Battery is flat for some reason! (Edit: Oh - left the doors open all night. But I replaced the interior bulb with an LED - that shouldn't flatten the battery in 12 hours, unless they draw far more current than I thought.)

Yes, removing fuse 6 and powering fuse 4 externally turns tank pump on.

DW42

Here's the altered FI fuse on mine (marked with a red arrow). The wires go to the battery and into the harness.

familyman

Thanks.

* Thought for a minute there I'd killed the main pump. So I bridged 4 & 6, heard pump/s running, went to boot and unplugged tank pump, heard it drop out, but main pump stayed on.

Slowbrick

Have you tried applying 12v to fuse 6 and bridging to 4 and turning the key to see if it primes?

familyman

Sort of did that a little while ago, but I'll do again in a sec... (One aligator clip on my patch lead broke. Waiting for soldering iron to heat up to fix it.)

Some mechanic online wrote to disconnect the battery before unplugging the EZK/ECU. So I just unclipped it (still plugged in though) to try and read off the part number, to be sure I've got the right module... Anyway, I felt to try the key after unclipping it (in case it's just a broken wire, etc. and moving it was enough to reconnect). The car was much closer to starting - nearly every cycle around it was spluttering trying to start, instead of one short splutter and nothing like it has been. Still no pumps for fuel of course. So I'll resolder the patch lead, run the pumps manually, and try to start before doing what you asked again to be sure.

familyman

That didn't work. Ok...

Slowbrick;117472 wroteHave you tried applying 12v to fuse 6 and bridging to 4 and turning the key to see if it primes?

* Just bridged 4 & 6 again - both pumps run - crank - no start. Then remembered the relay visibly unlatched itself before, when cranking with the key, so...
* Bridged 4 & 6 and applied external 12V to both. No start.
* Fuel came out of the rear of the fuel pressure regulator last night when I removed the hose.

So I assume these three means the injectors have fuel primed ready to go?

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