Tuscan S injector trouble
Discussion
My 2002 Tuscan S passed its MoT after a year laid up with no advisories. The tester did point out a slight coolant leak.
I topped up the fuel tank and a couple of days later started it in my garage and looked underneath for any sign of the leak.
To my horror, fuel was dribbling out under the car; subsequent investigation showed it was coming from cylinders 4-6 cat exhaust joint.
The injectors were way overfueling and it was all going through the engine and out the exhaust joint.
I've spent 2 months trying to sort it with no success. Had all injectors cleaned and rebuilt. When the electrical plugs are removed the injectors
don't leak. But with any of 4-6 injector electrically connected the connected one sprays fuel from when the pump is initiated to when it cuts out.
It doesn't start, understandably, but if it did I think the injectors would just spray continually.
So for some reason it seems the MBE ECU is telling that bank of injectors to open and stay open.
I have renewed the RAM chip and have a new pressure regulator to fit but don't think that's the issue. Have used the diagnostics program to reset the adaptive settings. Again no improvement. I have cleaned up the injector loom earth to the bellhousing but it looked ok anyway.
Have also taken the injector loom multiplugs apart and used contact cleaner on those.
Have any of you experienced this problem? Or perhaps have an idea where the problem lies?
I can't even get the car to APM TVR as my garage is in the back garden so breakdown recovery almost impossible.
Any good suggestions would be very much appreciated.
I topped up the fuel tank and a couple of days later started it in my garage and looked underneath for any sign of the leak.
To my horror, fuel was dribbling out under the car; subsequent investigation showed it was coming from cylinders 4-6 cat exhaust joint.
The injectors were way overfueling and it was all going through the engine and out the exhaust joint.
I've spent 2 months trying to sort it with no success. Had all injectors cleaned and rebuilt. When the electrical plugs are removed the injectors
don't leak. But with any of 4-6 injector electrically connected the connected one sprays fuel from when the pump is initiated to when it cuts out.
It doesn't start, understandably, but if it did I think the injectors would just spray continually.
So for some reason it seems the MBE ECU is telling that bank of injectors to open and stay open.
I have renewed the RAM chip and have a new pressure regulator to fit but don't think that's the issue. Have used the diagnostics program to reset the adaptive settings. Again no improvement. I have cleaned up the injector loom earth to the bellhousing but it looked ok anyway.
Have also taken the injector loom multiplugs apart and used contact cleaner on those.
Have any of you experienced this problem? Or perhaps have an idea where the problem lies?
I can't even get the car to APM TVR as my garage is in the back garden so breakdown recovery almost impossible.
Any good suggestions would be very much appreciated.
Two thoughts. For engine related matters, Joolz of Kits and Classics should be able to advise. Also, while I am not sure if he does the MBE ECU, but Paul smith of pselectronicsolutions.co.uk is very helpful for all electrical related matters; I have used him to discuss an issue and then repair my Dash ECU and he turned around that repair very quickly.
Also if that amount of fuel is going into the engine, there is a good chance some will find its way into the sump and hence the oil. I would suggest you will need to do an oil change, once you have solved the problem and before you run the engine.
,Good luck
Also if that amount of fuel is going into the engine, there is a good chance some will find its way into the sump and hence the oil. I would suggest you will need to do an oil change, once you have solved the problem and before you run the engine.
,Good luck
Sounds like a lot of fuel has gone through that engine !
If it's not a wiring issue, then you're looking at an ecu issue .. if it's an early ecu (single big plug) you might struggle getting one (they can change hands for 500-750 pounds used!) .. if it's a later ecu (3 smaller plugs plug) you stand a better chance of finding one.
If it's not a wiring issue, then you're looking at an ecu issue .. if it's an early ecu (single big plug) you might struggle getting one (they can change hands for 500-750 pounds used!) .. if it's a later ecu (3 smaller plugs plug) you stand a better chance of finding one.
S3Dave and Spitfire thank you for your suggestions and I will follow them up.
I have got quite concerned about the fuel.. When checking if I was getting anywhere just by switching ignition on and pressing key fob to energise the pump, I had the plugs out. Only the cyiinder with its inlet valve open was getting fuel into it ofc. A lot - I could rock the car and see it swirling around on the piston!! So I'd pipette it out and have another think. It looks like an ECU rebuild/replacement is called for and it is the later one with the three multiway plugs. You're both absolutely right, a lot of fuel has gone into and through and if I can fix the fault and not hear the injectors spraying all the time the pump runs, I will change the oil before attemtping a start. Thanks again for your support - I don't feel so lonely !!
I have got quite concerned about the fuel.. When checking if I was getting anywhere just by switching ignition on and pressing key fob to energise the pump, I had the plugs out. Only the cyiinder with its inlet valve open was getting fuel into it ofc. A lot - I could rock the car and see it swirling around on the piston!! So I'd pipette it out and have another think. It looks like an ECU rebuild/replacement is called for and it is the later one with the three multiway plugs. You're both absolutely right, a lot of fuel has gone into and through and if I can fix the fault and not hear the injectors spraying all the time the pump runs, I will change the oil before attemtping a start. Thanks again for your support - I don't feel so lonely !!
As you've proven, the cable that is supposed to pulse the injectors isn't pulsing them, it's keeping them permanently supplied
spitfire4v8 mentions.....If it's not a wiring issue
Excuse me for possibly asking a stupid question but it does matter, could save much effort and money, have no idea what you have and haven't done
Have you disconnected the ECU and tested the loom to prove there's no short anywhere that's keeping a permanent negative on the problematic injectors
Had to ask yet do feel I've failed miserably on this one
spitfire4v8 mentions.....If it's not a wiring issue
Excuse me for possibly asking a stupid question but it does matter, could save much effort and money, have no idea what you have and haven't done
Have you disconnected the ECU and tested the loom to prove there's no short anywhere that's keeping a permanent negative on the problematic injectors
Had to ask yet do feel I've failed miserably on this one
Sounds like easy to find when you know where it is. Wiring or ECU.... never had an injector spraying full time before.
Sure you know but this is a bomb now, caution please. Mate of mine trying to extract injectors on a late Ford soaked them over night with brake cleaner/release oil, came in next morning and thought I'll splash a bit heat around that after trying to extract and failing.... was deaf for two days, new roof panel to workshop, plastic sump blown to bits, lucky not to be seriously hurt.
Sure you know but this is a bomb now, caution please. Mate of mine trying to extract injectors on a late Ford soaked them over night with brake cleaner/release oil, came in next morning and thought I'll splash a bit heat around that after trying to extract and failing.... was deaf for two days, new roof panel to workshop, plastic sump blown to bits, lucky not to be seriously hurt.
The injectors are driven using some power mosfets in the ECU. They basically pull one end of the injector coil hard down to ground. The top of the injector coil is straight to 12V iirc with no current limit (could be wrong on that). I also seem to recall there is one mosfet per injector despite them being driven in batch mode (so 2 lots of 3 which go at the same time). *If* one injector went dead-short then only one mosfet would burn out and the other injectors would most likely work as intended on that same back...but sounds like they are all squirting on that bank? Please confirm.
Footnote: Hi Sagi Badger! Sort of missing theTuscan but (prepare for swearing and abuse) the Boxster GTS 4.0 is absolutely awesome!
Footnote: Hi Sagi Badger! Sort of missing theTuscan but (prepare for swearing and abuse) the Boxster GTS 4.0 is absolutely awesome!
Well I'm makling a bit of progress - I think! Learning a lot anyway..... including the posting quirks of Pistonheads.
Sagi Badger - thank you for that cautionary tale. I've heard of a few incidents of petrol igniting accidentally and they all went off like gunpowder.
I feel very lucky that it wasn't pouring fuel out the exhaust joint during the MoT!
So I've been investigating the electrickery. I've peeled back the rubber boots on the injector connectors so I can get probes in and measure what's going on without running the pump and putting fuel in.
Polly Grigora.....I had already tried to test the loom. But only a day or two before your post so actually a very good suggestion.
I have a storage 'scope but as I'm not trying to see pulses a DVM is proving adequate. What has confused me is the wiring diagrams......I've done continuity checks from the 32 way connector (in the engine bay under the scuttle on the driver's side) to the injector connectors. I found each injector has its own line to the plug so they must be ganged together further back whereas the multiway connection diagram from tuscaninfo shows just one line for each bank. Perhaps I'm looking at a different multiway. Anyway, none of the lines went to earth and there was continuity between connector pin and multiway.
By playing around with connectors I've established:-
With all injectors disconnected and ignition on, I see 12V on both Pin 1 and 2 on them all. Which I think is as it should be.
With all injectors connected, injectors 1-3 still have 12V on Pin 2 but 4-6 have just 2V. Hence the continual spraying.
The rogue line seems to be 5. With that disconnected, there's 12V to 4 and 6. So No 5 is dragging the other two down.
PetrolHeadPete.... thank you for enlightenment re the ECU. Yes, all on that bank are squirting together but the rogue seems to be 5 pulling the others down. I wonder if it has a faulty Mosfet which is doing it. Can't quite figure why it's only when the injector is connected but maybe the current through that coil is affecting it. The resistance of that injector coil is same as the others btw at 16ohms.
I had the ECU out with some hopes of replacing components (I have the necessary temperature controlled hot gun) but couldn't figure how to get the board out with those three connectors seemingly moulded in. So put it back in the car and just looked at the voltages on the injector connectors.
And now as is often the way, life is what happens while I'm planning. I'm away to my son's for a week so the Tuscan will have to sit in suspense....literally as it's 3 legged on an axle stand so I can connect and disconnect the battery.
I'll be posting on this again ofc. Thanks again guys for your thoughts. Roger T6TVR
Sagi Badger - thank you for that cautionary tale. I've heard of a few incidents of petrol igniting accidentally and they all went off like gunpowder.
I feel very lucky that it wasn't pouring fuel out the exhaust joint during the MoT!
So I've been investigating the electrickery. I've peeled back the rubber boots on the injector connectors so I can get probes in and measure what's going on without running the pump and putting fuel in.
Polly Grigora.....I had already tried to test the loom. But only a day or two before your post so actually a very good suggestion.
I have a storage 'scope but as I'm not trying to see pulses a DVM is proving adequate. What has confused me is the wiring diagrams......I've done continuity checks from the 32 way connector (in the engine bay under the scuttle on the driver's side) to the injector connectors. I found each injector has its own line to the plug so they must be ganged together further back whereas the multiway connection diagram from tuscaninfo shows just one line for each bank. Perhaps I'm looking at a different multiway. Anyway, none of the lines went to earth and there was continuity between connector pin and multiway.
By playing around with connectors I've established:-
With all injectors disconnected and ignition on, I see 12V on both Pin 1 and 2 on them all. Which I think is as it should be.
With all injectors connected, injectors 1-3 still have 12V on Pin 2 but 4-6 have just 2V. Hence the continual spraying.
The rogue line seems to be 5. With that disconnected, there's 12V to 4 and 6. So No 5 is dragging the other two down.
PetrolHeadPete.... thank you for enlightenment re the ECU. Yes, all on that bank are squirting together but the rogue seems to be 5 pulling the others down. I wonder if it has a faulty Mosfet which is doing it. Can't quite figure why it's only when the injector is connected but maybe the current through that coil is affecting it. The resistance of that injector coil is same as the others btw at 16ohms.
I had the ECU out with some hopes of replacing components (I have the necessary temperature controlled hot gun) but couldn't figure how to get the board out with those three connectors seemingly moulded in. So put it back in the car and just looked at the voltages on the injector connectors.
And now as is often the way, life is what happens while I'm planning. I'm away to my son's for a week so the Tuscan will have to sit in suspense....literally as it's 3 legged on an axle stand so I can connect and disconnect the battery.
I'll be posting on this again ofc. Thanks again guys for your thoughts. Roger T6TVR
Getting the PCB out I found to be near impossible so I neatly cut the plastic case to expose the board from t'other side and when finished in neatly glued it closed again with black rtv.
Could you have a trapped loom wire? Have you taken the cam cover off recently? That's a favourite to trap wires and ground them. If all coils measure the same then sounds like its pointing back to failed ECU
Could you have a trapped loom wire? Have you taken the cam cover off recently? That's a favourite to trap wires and ground them. If all coils measure the same then sounds like its pointing back to failed ECU
Does the ecu have 6 injector drivers or just 2 Pete? On my emerald conversions I run 6 injector drivers on the later cars as the wiring supports it back to the ecu plug (on the cars ive seen so far, it's tvr after all) , but unsure if inside the ecu itself it goes down to 2 drivers and the wires are internally linked in 2 batches of 3. I can't see how one driver going faulty could cause all 3 injectors to fire unless they were internally linked in the ecu .. ?
RVSPyestock said:
Polly Grigora.....I had already tried to test the loom. But only a day or two before your post so actually a very good suggestion.
Ok then, was a thought...Reading through your latest post, something is telling me that you're possibly using the incorrect diagram
Have sent you a personal message (you should see it in your email inbox), once you reply to my message I will email you something that may be of some help
You'll need to disconnect all ECU Plugs and all injector plugs to test the engine loom for a possible short
Best tests being - Ignition off or better still positive battery lug disconnected
1) Multimeter - Set @ Ohms - Check for there being no continuity between battery (or engine block negative) and every injector cable (both cables at each injector)
2) Multimeter - Set @ Ohms - Check for there being no continuity between any of the injectors signal cables and also no continuity between any of the injectors positive supply cables and there signal cables
Slowly check every possible combination when carrying out the above - between - Injector 1 cables & injector 2 cables - then - Injector 1 cables & injector 3 cables and so on - Every possible combination
The above is the only way of being 100% sure that the loom is good or bad
Please accept my apology if you know about all the above tests
Edited by Polly Grigora on Thursday 7th September 13:08
spitfire4v8 said:
Does the ecu have 6 injector drivers or just 2 Pete? On my emerald conversions I run 6 injector drivers on the later cars as the wiring supports it back to the ecu plug (on the cars ive seen so far, it's tvr after all) , but unsure if inside the ecu itself it goes down to 2 drivers and the wires are internally linked in 2 batches of 3. I can't see how one driver going faulty could cause all 3 injectors to fire unless they were internally linked in the ecu .. ?
I'm going off memory here but I think there are 6 mosfets but the drive to them is ganged into 2 groups of 3. So the fact they all squirt seems to imply that one fault has brought the entire bank with it. Kicking myself that I seem to have deleted the photos of the ECU internals that I took !Oh man, I should know this. The MOSFET (S) would only pull all three injectors down full time if all three went short or were switched together incorrectly.
The fact this seems to be full time fuel with ignition on, if I understand correctly, as soon as powered up, we either have a very odd loom fault (like unlikely) or an ECU goofing. The MOS's would be switched in banks of three, if there are 6 which makes sense, but if one went down then the other two be safe, right?? I am looking for Petrol Head Pete to confirm as it is long time since I was in the industry and have limited knowledge of the ECU internals. Away at the mo without my PC with TVR stuff on..
So my gut feel is the MOS's are being switched as a trio incorrectly, so an ECU fault.
Footnote Pete I have a Maloo now, a works vehicle as Mr Khan forced me to sell old faithful, the Sag is being treated to some new bits and the Tuscan is an ongoing project... had some new cam blanks ground to my spec.... Yes money pit... yes I am mad.
The fact this seems to be full time fuel with ignition on, if I understand correctly, as soon as powered up, we either have a very odd loom fault (like unlikely) or an ECU goofing. The MOS's would be switched in banks of three, if there are 6 which makes sense, but if one went down then the other two be safe, right?? I am looking for Petrol Head Pete to confirm as it is long time since I was in the industry and have limited knowledge of the ECU internals. Away at the mo without my PC with TVR stuff on..
So my gut feel is the MOS's are being switched as a trio incorrectly, so an ECU fault.
Footnote Pete I have a Maloo now, a works vehicle as Mr Khan forced me to sell old faithful, the Sag is being treated to some new bits and the Tuscan is an ongoing project... had some new cam blanks ground to my spec.... Yes money pit... yes I am mad.
A delayed update.
I did a thorough check on the wiring loom with the much appreciated help of Polly Grigora.
With the battery negative disconnected, the ECU removed, I checked for any continuity between each injector pin to engine casing and injector pins to injector pins. Also checked each bulkhead multiway pin. All open circuit.
The injector positive pins puzzled me at first as they all showed resistance (80ohms iirc) but that went to the expected open circuit once I had removed the injector supply fuse. Probably a component on the ignition supply circuit was giving the 80ohms.
So my conclusion was - no fault on the wiring loom.
I'm back to looking at the ECU.
I thought I would try desoldering all the multiway connector pin joints on the board. I hope the board will then lift up from its fiendishly designed plastic chastity belt and enable the hidden side of the board to be examined.
Desoldering....hah....very slow and laborious and I'm not there yet. Tricky, as everyone says, even with the resources of soldering iron, desoldering braid, hand vacuum desolder pump and relatively cheap desoldering heating iron. Plus hours of youtube browsing for inspiration.
If I get disenchanted with this approach I'll resort to cutting the plastic case open. Thank you for posting that PetrolHeadPete as I'll feel less of a vandal. I can't figure the best way to do that so any further detail you can remember would be helpful.
So no final solution but at least posting will reassure you all that my silence didn't mean I'd entered a suicide pact with my much loved Tuscan.
I did a thorough check on the wiring loom with the much appreciated help of Polly Grigora.
With the battery negative disconnected, the ECU removed, I checked for any continuity between each injector pin to engine casing and injector pins to injector pins. Also checked each bulkhead multiway pin. All open circuit.
The injector positive pins puzzled me at first as they all showed resistance (80ohms iirc) but that went to the expected open circuit once I had removed the injector supply fuse. Probably a component on the ignition supply circuit was giving the 80ohms.
So my conclusion was - no fault on the wiring loom.
I'm back to looking at the ECU.
I thought I would try desoldering all the multiway connector pin joints on the board. I hope the board will then lift up from its fiendishly designed plastic chastity belt and enable the hidden side of the board to be examined.
Desoldering....hah....very slow and laborious and I'm not there yet. Tricky, as everyone says, even with the resources of soldering iron, desoldering braid, hand vacuum desolder pump and relatively cheap desoldering heating iron. Plus hours of youtube browsing for inspiration.
If I get disenchanted with this approach I'll resort to cutting the plastic case open. Thank you for posting that PetrolHeadPete as I'll feel less of a vandal. I can't figure the best way to do that so any further detail you can remember would be helpful.
So no final solution but at least posting will reassure you all that my silence didn't mean I'd entered a suicide pact with my much loved Tuscan.
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