Seat ibiza injector fault
Discussion
Hi, got a problem where one of my injectors is permanently on, full.
I understand injectors are negatively switched.
However where would be best to start looking? are there relays that can be changed (if faulty), or is injection direct powered and controlled by the ecu?
I'm going to buy a mutlimeter and check for shorts tommorow, (will unplug the relevant bits of loom to isolate them from each other). But if its likely to be a simple relay, then obviously that will be my first port of call.
Is there anywhere i can get a wiring diagram for my car? 1999, 1.4 8v?
Any pointers will be very much appreciated.
I understand injectors are negatively switched.
However where would be best to start looking? are there relays that can be changed (if faulty), or is injection direct powered and controlled by the ecu?
I'm going to buy a mutlimeter and check for shorts tommorow, (will unplug the relevant bits of loom to isolate them from each other). But if its likely to be a simple relay, then obviously that will be my first port of call.
Is there anywhere i can get a wiring diagram for my car? 1999, 1.4 8v?
Any pointers will be very much appreciated.
Are you saying it is electrically on or jammed open?
In operation each injector has power and is earthed by the ECU. In some cases the injectors are earthed in banks rather than individually.
With the ignition on there should be 12v on one pin of each injector plug.
With ignition on the other pin of each should not have continuity to earth. If there is then unplug the ECU and test again. If it still has continuity then you have a short in the loom. If not then I suspect a short circuit in the ECU.
Steve
In operation each injector has power and is earthed by the ECU. In some cases the injectors are earthed in banks rather than individually.
With the ignition on there should be 12v on one pin of each injector plug.
With ignition on the other pin of each should not have continuity to earth. If there is then unplug the ECU and test again. If it still has continuity then you have a short in the loom. If not then I suspect a short circuit in the ECU.
Steve
orangesrule said:
It is electrically on, for example, you prime the fuel pump and petrol sprays out of injector 1. Will do some further investigations today, thanks.
That isnt quite clear.If you prime the pump only, and provide no electrical power to the injector, then it is mechanically stuck open.
So are you just turning on the ignition, hearing the pump prime and assuming it is electrically held open, or actually tested.
I guess most simple way, unplug the injector and key on to prime the pump and watch what happens.
orangesrule said:
Well i was convinced the injector was dead, so bought a used one...and had the same issue. I then swapped them about, and petrol still sprays from injector number 1 and no others.
Then you are back to tracing the short circuit.Do you have info on what pin numbers do what on the ECU, known as the 'pinout'?
If you do then cut the injector 1 wire a couple of inches from the ECU and run a new wire from the injector to the ECU.
If this works you can either strip the loom and find the short or just tidy your bodge and live with it. The only downside is that whatever caused the short is likely affecting other wires as well and more faults will develop in time.
Steve
Hi, I would recommend using VCDS, once known as VAG-COM, plug it into the car and take a passenger out with you and data log the car and see whats it doing. If you believe it's an injector related fault then monitor the correct measuring block for injector quantity. If the vehicle is a petrol, remove injectors and test them on the ASNU machine. The ASNU machine we have will test injector inductance; flow rate at different pressures and RPM, spray pattern test at different pressures and RPM and if needed it has an ultra sonic bath to clean the nozzles.
Edited by Enginostics on Sunday 6th January 20:01
I have looked for the ecu pinout, but to no avail.
Had a gander at the ecu, which was soaking. so have unplugged it, removed from the car and removed the breather valve. Its now in the house drying out (although didn't really look wet inside through the breather).
This evening i traced through the ground cable from the injector to the ecu plug, i can't seem to find an earth fault with the plugs unplugged....which is pointing me towards the ecu.
I'll give it till tuesday to dry out, plug it back in and see how it goes.
Had a gander at the ecu, which was soaking. so have unplugged it, removed from the car and removed the breather valve. Its now in the house drying out (although didn't really look wet inside through the breather).
This evening i traced through the ground cable from the injector to the ecu plug, i can't seem to find an earth fault with the plugs unplugged....which is pointing me towards the ecu.
I'll give it till tuesday to dry out, plug it back in and see how it goes.
After letting the ecu dry for a couple days, i plugged it back in this morning; and the bleddy thing, fired on all cylinders straight away.
Quickly made a cover to stop water dripping in off the wiper mechanism right onto the ECU. Water now, drips onto the box and flows into the gutting.
Quickly made a cover to stop water dripping in off the wiper mechanism right onto the ECU. Water now, drips onto the box and flows into the gutting.
Edited by orangesrule on Tuesday 8th January 14:09
SuperchargedVR6 said:
Interesting. Bosch ECUs are normally very well sealed against water ingress. Are all the seals intact?
You sir are correct, driving to work yesturday and the fault reappeared. I ripped the ecu out before i started work, and split the casing, which was very well sealed, and was bone dry inside, with no signs of water ingress.Soooo back on it this morning, wiggling the loom near the ecu plug, made the car go from 3 to 4 cylinders on idle. I removed 2 inches of wrapping on the loom to find a twin core screened cable, the outer insulation was removed for the last inch or so, with the screen slightly exposed. So i insulated the screen and then re wrapped this part of the loom.
So far i can't make it go down onto 3 cylinders, so basically it looks like water ingress into the loom lowered the insulation resistance and an earth path was tracking through the screen. (fingers crossed this was it, but i'm not holding my breath now)
Edited by orangesrule on Wednesday 9th January 10:48
orangesrule said:
.......(fingers crossed this was it, but i'm not holding my breath now)
Nor would I.That screen is unlikely to be the problem as in order for it to work it should be earthed at one end or the other (but not both).
I think you still have the problem in the loom (which is better than in the ECU) you have just disturbed it for the time being.
Steve
Was working fine, till driving home from work at midnight last night, then the fault reoccurred.
Had another look around the ecu and loom plug, and it all looked good. traced the loom back another 6 inches, and under a bit of opaque perspex which covered the window wiper motor, you could clearly see the issue. The loom had been ran hard up against the corner of the motor casing. Which over time has worn into the loom causing this fault. Obviously messing with the ecu and plug disturbed it enough, to work temporarily. But now very confident this was the source of my problems.
Had another look around the ecu and loom plug, and it all looked good. traced the loom back another 6 inches, and under a bit of opaque perspex which covered the window wiper motor, you could clearly see the issue. The loom had been ran hard up against the corner of the motor casing. Which over time has worn into the loom causing this fault. Obviously messing with the ecu and plug disturbed it enough, to work temporarily. But now very confident this was the source of my problems.
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