ECU dead or something else?

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tucker1
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ECU dead or something else?

#1 Post by tucker1 » Wed Mar 22, 2017 9:47 am

The car wouldn't start this morning. Turning over but no lights on the LPG indicator which suggests something electrical is to do with the system.

It's an Aldesa system that's about 8 or 9 years old now and worked fine throughout.

On one past occasion it did the same thing and the issue I found was the main LPG fuse from the battery had broken to bits in the holder. I removed it and the car ran on petrol. A replacement fuse and it was back to normal.

I have the same symptoms but removing the fuse makes no difference and doesn't seem to allow it to run on petrol.

The car is as though the immobiliser is preventing it starting. The lack of any power on the LPG display makes me think the LPG ECU might have died or something?

Can anyone suggest a possible cause or solution?

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Re: ECU dead or something else?

#2 Post by Brian_H » Wed Mar 22, 2017 8:20 pm

Any idea where the swtiched live for the lpg ecu is being taken from?

What car and any idea which Aldesa system it is may help, would take what you've said above to mean its a multipoint.

If its fed off the petrol injectors feed its possible that the wiring has a problem there, I'd check that before going straight to the ECU personally. It might be worth doing a fault code scan if the car supports doing so as that may give a clue where the problem is.

I'd suspect theres a chance the feed to the petrol injectors isn't working as it should do if thats where your ecu is fed from, could be a broken wire, blown fuse etc.

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Re: ECU dead or something else?

#3 Post by LPGC » Wed Mar 22, 2017 8:25 pm

Seems to be petrol related not LPG related, like Brian says.

Aldesa does have one difference that may have potential to prevent petrol from working if the LPG ECU is fried. it has a built in immobiliser that can be programmed by the installer. But still, would expect the Aldesa switch to light when ignition was on if the petrol system was working (the switched live Bri mentioned). The immobiliser works by disconnecting petrol injectors while not connecting LPG injectors. Only a very small chance that ECU is fried in a way that doesn't leave petrol injectors connected though. The lack of switch lights is more telling.

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Re: ECU dead or something else?

#4 Post by tucker1 » Wed Mar 22, 2017 10:39 pm

Thanks for the replies.

I got it recovered to my local garage and the issue was the fuel pump. To many occasions where the petrol level has been low no doubt.

However, my luck hasn't improved. As the car came off the truck the front spring went and snapped.

I also have a damaged lpg temperature sensor so it's no longer switching automatically.

The aldesa is the multi point and parts in the UK very hard to come by.

I need to find a suitable temp sensor. Most of the ones I have seen seem to be m5 or m6 threads but mine looks a bit bigger.

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Re: ECU dead or something else?

#5 Post by Brian_H » Wed Mar 22, 2017 11:56 pm

At least you have an answer - its not that uncommon to happen, best keeping minimum of 1/4 tank to avoid it happening!

You might be better to look at a different type of sensor - like this one that goes in the pipework > http://tinleytech.co.uk/shop/lpg-parts/ ... with-plug/

I don't know what the resistance your system expects to see is, but if you can find out then you should be able to find something suitable.

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Re: ECU dead or something else?

#6 Post by tucker1 » Thu Mar 23, 2017 12:31 am

Thanks.
That sensor is interesting. So that goes into the lpg pipe after the reducer? Or is it fitted to the water pipe that heads into the reducer?

I assumed that the one fitted to the reducer picks up the water temp to determine to kick the solenoid open?

I can find photos of the reducer I have fitted but very little spec about it.

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Re: ECU dead or something else?

#7 Post by LPGC » Thu Mar 23, 2017 11:12 am

I don't know the spec of Aldesa reducer temp sensors but you'll need one of the same electrical spec (resistance response). Whether or not it is fitted in the reducer or inline won't make much difference but try to find electrical spec is compatible before buying.

Unusual that a broken fuel pump would prevent engine live from coming on (your switch didn't light) but I suppose a broken pump could cause the fuse for engine live and pump (same fuse on a lot of vehicles) to blow. I'd be asking the garage for evidence of changing the pump rather than just changing a fuse or relay though :roll:

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Re: ECU dead or something else?

#8 Post by tucker1 » Thu Mar 23, 2017 1:14 pm

I will try and see if I can find any Turkish website that give the electrical spec. From memory there is very little on the web about it.

I saw the old fuel pump that had come out of it, so it has definitely been changed.

The live switch orange light didn't come on when I was cranking it over. I thought it did normally when the key was fully turned. However, I checked a number of fuses myself and when I removed and replace one under the dash the orange light came on but went out when I tried to start her. I don't know if the fault codes locked something off as it generated P0261, P0264, P0267, P0270 and P0444.

When the garage got in in they removed the petrol fuel line and turned it over and nothing came through.

However, he said after fitting the new pump fuel was flowing but initially it still wouldn't start until he cleared all the codes off and disconnected the LPG temporarily. I think that's where the temp sensor has been knocked as it's perched on the top of the reducer and probably easy to catch.

Zavoli appear to do one the same thread size, but I need to check the spec is ok.

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Re: ECU dead or something else?

#9 Post by LPGC » Thu Mar 23, 2017 4:08 pm

Those codes are for petrol injector circuits 1 through 4 and evap purge control solenoid open circuit respectively, they could all have been caused by blown pump pump fuse and/or blown pump relay if same fuse/relay sends 12v to the engine loom and fuel pump.

If you now measure the fuel pump electrical resistance and it's not shorted, the jury will be out as to whether you just paid for changing your fuel pump unnecessarily. There is the chance that if pump resistance is normal, which may be a couple of ohms, it could still have been broken and not working.... Engine shouldn't start at all if you disconnect the LPG ECU, LPG ECU wouldn't disable the evap purge valve but removing Aldesa ECU could potentially effect a fix if the ECU had crashed somehow and Aldesa has that built in immobiliser facility (could have crashed and turned on it's built in immobiliser). I'd be connecting my old pump up to a battery to see if it works and if it does would have to wonder if swapping a fuse/relay or just temporarily disconnecting the LPG ECU was the real fix :lol:

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Re: ECU dead or something else?

#10 Post by tucker1 » Thu Mar 23, 2017 5:20 pm

I'd checked the fuses Inc the one for the pump relay and they were all intact.

My had mechanic said there was power to the pump but the pump was dead.

I am not entirely sure what he did to get it running once the new one was in but he's disconnected the lpg ecu at some point. He thought the petrol injectors were closed off from the lpg, although he's not an lpg guy so admittedly he wasn't sure how the lpg side might have had any bearing.

Still it's back up and running now other than the temperature switch, which appears to be an m10x1 thread.

I am hoping to find something that size otherwise it will have to an inline one.

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Re: ECU dead or something else?

#11 Post by LPGC » Thu Mar 23, 2017 5:30 pm

What a coincidence though - pump dies at exactly the same time engine wouldn't run even if pump was good, one necessary cure was to replace the pump, other thing necessary was to unplug the LPG ECU and plug it back in. Unless he said pump wouldn't run when he re-connected power to it, which would explain a blown fuse which would explain lack of LPG system lights.

There are a few temp sensors with M10 thread, not sure if M10 x 1 or if electrical spec is same as Aldesa though. Other ways around it - there are plenty installs where a temp sensor is fitted into a different bolt hole replacing the bolt in a reducer / could fit a smaller temp sensor and just seal it in place with some type of heat conductive paste that sets, drill and tap an M10x1 bolt through the middle to work as an adaptor. See if you can pick up an Aldesa spec one first?

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Re: ECU dead or something else?

#12 Post by tucker1 » Tue Mar 28, 2017 10:27 pm

Thanks Simon

I have found a zavoli sensor with exactly the same thread size.

Alternatively, the existing M10 bolt is hollowed out and could be tapped to have an M6 or maybe a bit bigger thread inside it to take another sensor and screw it into that as a make shift option.

The problem is there is absolutely no info on the web to confirm the Ohms of the Aldesa one. My multimeter has died of death (not that I was much cop at using it), but once I replace it, can I measure the Ohms from the existing wiring to determine the correct electrical spec?

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Re: ECU dead or something else?

#13 Post by Brian_H » Wed Mar 29, 2017 9:14 am

You should be able to. You'd need to heat it and check resistance/ohms value at known temperatures and compare to what detail is available for your replacement one. Provided you can get a connection to both sides of the old sensor

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Re: ECU dead or something else?

#14 Post by LPGC » Wed Mar 29, 2017 11:10 am

Potential cache22 though, if the resistance of the existing temp sensor can be measured using a multimeter why won't it work on the car? Unless it still functions but won't physically fit where it's supposed to?
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Re: ECU dead or something else?

#15 Post by tucker1 » Wed Mar 29, 2017 3:39 pm

No, the sensor is no more. The part that sat in the bolt recess has come out and detached from the wiring. All I have is the existing wiring that went into the sensor.

I take it without the sensor I can't find out that way?

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