no start problem. Low voltage supply to injectors

[peanut]

has anyone experienced this fault and found the culpret ?
Everything checks out ok spark fuel delivery etc but the voltage at the injector connections is scarcely 1v+ ?
Voltage at DME terminal 30 is 12v+

When i jumper the DME terminals 30 -87 -87b the pump runs normally and the engine coughs a couple of times but doesn't start.


Is there possibly a problem with the ECU ? maybe it is not earthing the injectors properly ?

any ideas are welcome . Its my only transport at the moment and it hasn't run for a month

 

[zcacogp]

I have had a similar problem on a 928. The relay board (i.e. one relay) supplied +12v to the injectors, which were grounded in turn by the ECU. The relay had failed, so the injectors weren't being given enough juice to turn them on. It would be worth checking this on your car. Either way, you have some good, solid diagnostics, and I would have thought that knowing you only have +1v at the injectors would mean yuo are pretty close to finding the solution. Best of luck. Oli. P.S. Only transport and hasn't worked for a month? What have you been doing - walking?

 

[peanut]

Hi Olli crikey you had a reply before I'd posted my question ...amazing How the devil are you ? hope your beast is running well. I think you are right I'm close but working out in the cold and rain sure hinders clear thinking []

 

[zcacogp]

Peanut, Not true - you had posted the question otherwise I wouldn't have known what you were asking! You must be nearly there. Most 'non-start' problems posted on here are "My car won't start. Why not?". You have a clear diagnosis (not enough volts at the injectors) and just need to work out why this is so. So, check the relay, there may be a common earth point on the ECU which needs looking at, check for broken wires to the injectors, perhaps try swapping the ECU with a known-good unit if this all fails. I know exactly what you mean about cold and wet not helping diagnosis. It's when your fingers get too cold to feel anything, and too stiff to move, that you really have problems ... thick boiler suit helps. As does a woolly hat. And some latex gloves (and thin cotton ones underneath them if the latex ones are big enough.) My beast needs driving. It was being used for 40-ish miles a day, and thrived on it. Now it's going about 10 miles a week, and is a lot less happy for it. These things need to be driven, and hard .... Oli.

 

[robwright]

ORIGINAL: zcacogp These things need to be driven, and hard .... Oli.

Will second that mate. My turbo gets used 7 days a week and she loves it. Never misses a beat. I don't even think oif her as being old now. Just a normal car. Well not normal she is special [] Why isn't everyone beating depreciation and driving 21 year old Porsches???

 

[zcacogp]

ORIGINAL: robwright Will second that mate. My turbo gets used 7 days a week and she loves it. Never misses a beat. I don't even think oif her as being old now. Just a normal car. Well not normal she is special [] Why isn't everyone beating depreciation and driving 21 year old Porsches???

Two reasons. 1. Status. In the UK, cars are seen as status symbols; more so than almost anywhere else in Europe. Having a new car is essential to keep up with the Joneses, and having an old car is only for poor people. A car that is 21 years old? You must be practically on the breadline! 2. Perceived reliability. Everyone knows that old cars are unreliable and break down a lot. All the car manufacturers tell us that. A 21 year old car must spend more time in pieces, being repaired, than on the road. 3. (Yes, OK, a third. Although a minor one.) Safety. New cars are much safer. And given the driving standards of most people on the roads today, safe cars are a good thing ... They certainly do thrive on regular use. I can never understand the mentality of some people who pop up on here, declaring that low-mileage cars which are driven once in a blue moon are the best examples to buy ... every car I have ever owned has improved with driving, and has been sold in better condition than I bought it in ... Oli.

 

[robwright]

Well I feel like I have far better status driving my 21 year old Porsche than I would a brand new Mundano. And my girlfriend loves her too, which helps a lot []