Vovlo busted, any suggestions?

[Ratdat]

I am going to try and interrogate the signal at the injectors today, see what that tells me.

It's most likely the power is supplied to the injectors (possibly fvia a dropping resistor pack) and then earthed by the ECU.

[Mr_Bo11ox]

The above is correct, the ECU completes the earth side of the circuit to fire the injector. I just borrowed a scope from work and attempted to test the duty cycle of the injectors while cranking, but the fuggin battery was 90% flat after yesterdays efforts, and got to 100% flat before I got a meaningful reading out of the fuggin scope. I will try that again tomorrow when the battery is charged.As for disconnecting the wiring, I removed the earth lead from the battery whilst the engine was idling, I didnt disconnect owt at the alternator. The logic was, if the alternator is fooked the engine will die as it has no source of electricity for the spark plugs, injectors etc. If the alternator is working the engine will keep running as the alternator is providing the electricity. I have done this for years and never once had a problem, however i've always had a nagging doubt in my mind that it cant be the best way to treat an ECU! Ah well looks like I have now experienced the 1% of cases where this causes BIG PROBLEMS! You live and learn etc.

[shite_meister]

Well we all make mistakes at some time in our lives-I had to adapt a flasher relay upside down this week and forgot to reverse two connections as it was arse-uppards and now I have £16 worth of little plastic box reminding me to check connections properly At least your car should be cheap to get secondhand parts for if you can diagnose it and it won't need to be coded like a 'modern'

[andrew e]

Mr_B did you reach for the swan vestas in the end? Or have you driven off into the sunset?

[Mr_Bo11ox]

No, this car is well stuck for the time being. I need to find a new ECU for it, I have found one at Lakes Volvo but its £70 so I will continue looking for a cheaper one for a bit longer before desperation sets in. If anyone sees an old RWD volvo in their local scrappy, do us a favour and check the Jetronic box (under the kick panel by the drivers right ankle). I need one with part number 0 280 000 936, fitted to assorted early 90's 2.0 non-turbo 240, 740 and 940 models.I am having to go everywhere in the fuggin Pony so I will have to get it sorted soon... 400+ miles a week is too much for it (and me).

[Guest]

I told you before, beaded seat covers! Not just for decoration.Will be at a yard this weekend, I'll scribble down the number. If I see anything (doubt it) I will drop you a line.

[Volksy]

I got the turbo for my Volvo from Salvo. They were top notch when it came to service, and gave 3 months warranty on the part.Might be worth a try..

[FredTransit]

I will see what I can do Mr B, keep hassling me!

[Mr_Bo11ox]

The Volvo is back in business as of last night! R-R member Lankytim sorted me out with an ECU off a 940 with the same 2.0 engine, for my favourite price of £0. DIfferent part number, but I plugged it in and the engine started almost straight away. It ran terribly though and threw out clouds of whitte smoke (must have been drinking the contents of its sump via the breather system) So I emptied the sump and refilled it with new oil, and the Volvo immediately started and purred like a kitten. LOVELY.Moral of the story is - do not disconnect your battery with the engine running! D'oh! An initially knackered alternator quickly turned into a shafted ECU, non-running vehicle and a sumpful of petrol.

[seth]

Glad to hear its running again

[michiel]

Excellent! What's good for the Volvo, is good for the Pony.

[dollywobbler]

Excellent. That tall Tim chap sounds like a top bloke!

[retrogeezer]

Great news..

[FredTransit]

Good news! I will take your advise though.....

[Mr_Bo11ox]

So does anyone know, what is the right way to check an alternator is doing the biz then? You can't just put a voltmeter on the +ve output terminal cos thats 'hardwired' to the battery so presumably you'd end up just testing battery voltage by doing that.

[fiatdaft]

I always do it by measuring the battery voltage with the engine running,14 volts ish is good.i think

[gallondrunk]

.

[dollywobbler]

Does your Volvo not have a charging light Mr B? Many cars do. Voltage across the battery is right though - somewhere around 14v with the engine running, dropping down to 12ish when not charging - and much lower once it starts losing its juice!