RRC Starting Problem
Discussion
Thought I'd try and pick the brains of the RRC experts here 
You might recall, I bought a 3.9 Vogue a month or so back, knowing that it had a starting problem. The issue is, sometimes it will start immediately, but other times it just churns and churns over, occasionally catching a single fire but not starting. A further symptom is that often, when this happens, it will fire when you release the key.
So, basics first, I replaced the dist cap and rotor arm. Cap says it is Lucas but I remember something about Lucas-branded stuff now being some Italian import? Anyway, either the original or replacement items have made no difference.
It has had all manner of possibly-related parts replaced before I bought it (including airflow sensor, stepper motor and throttle position sensor, it has also had a new distributor, which is free and moves under vacuum, and new plugs and leads although from looking at receipts I'm not sure the plugs are premium-quality). I have also put a brand-new battery on (because on a cold day, inching the original one out of the battery well with my fingertips, it slipped and fell to the floor with obvious consequences
)
Then I wondered about vacuum leaks. Have checked all over the place and also sprayed carb cleaner all around the vacuum system but nothing from that.
Next thing was engine earths. I stuck a jump lead from the battery to the water pump and lo, it started instantly. Bingo, I thought, but then it went back to doing the same thing even with the jump lead in place.
Then I wondered whether the ignition switch was faulty and was cutting the coil feed when you turn to the start position. Jumped a 12v live straight onto the coil and lo, it started instantly. Bingo, I thought, but then it went back to doing the same thing even with the jump lead in place.
It has to be something ridiculous and simple, because sometimes it will start fine, and once it's running, it runs fine (although does seem a little down on power, but we can come back to that another day!).
I'm wondering about ECU earth, since that is under the seat and the floor in the driver's footwell is poorly. I'll have a look at that.
Failing that I guess I'm into a full diagnostic of all the injection system, but as I said, I sense it may be simple. Anyone got any other ideas/had anything similar?
TIA.
You might recall, I bought a 3.9 Vogue a month or so back, knowing that it had a starting problem. The issue is, sometimes it will start immediately, but other times it just churns and churns over, occasionally catching a single fire but not starting. A further symptom is that often, when this happens, it will fire when you release the key.
So, basics first, I replaced the dist cap and rotor arm. Cap says it is Lucas but I remember something about Lucas-branded stuff now being some Italian import? Anyway, either the original or replacement items have made no difference.
It has had all manner of possibly-related parts replaced before I bought it (including airflow sensor, stepper motor and throttle position sensor, it has also had a new distributor, which is free and moves under vacuum, and new plugs and leads although from looking at receipts I'm not sure the plugs are premium-quality). I have also put a brand-new battery on (because on a cold day, inching the original one out of the battery well with my fingertips, it slipped and fell to the floor with obvious consequences
)Then I wondered about vacuum leaks. Have checked all over the place and also sprayed carb cleaner all around the vacuum system but nothing from that.
Next thing was engine earths. I stuck a jump lead from the battery to the water pump and lo, it started instantly. Bingo, I thought, but then it went back to doing the same thing even with the jump lead in place.
Then I wondered whether the ignition switch was faulty and was cutting the coil feed when you turn to the start position. Jumped a 12v live straight onto the coil and lo, it started instantly. Bingo, I thought, but then it went back to doing the same thing even with the jump lead in place.
It has to be something ridiculous and simple, because sometimes it will start fine, and once it's running, it runs fine (although does seem a little down on power, but we can come back to that another day!).
I'm wondering about ECU earth, since that is under the seat and the floor in the driver's footwell is poorly. I'll have a look at that.
Failing that I guess I'm into a full diagnostic of all the injection system, but as I said, I sense it may be simple. Anyone got any other ideas/had anything similar?
TIA.
paintman said:
ECU is earthed by wire in the loom, not through its casing.
Have a look at this, includes a couple of links:
http://forum.lro.com/viewtopic.php?f=65&t=9450...
Cheers paintman, just heading out now, I'll have a read when I'm back.Have a look at this, includes a couple of links:
http://forum.lro.com/viewtopic.php?f=65&t=9450...
Had a hectic couple of weeks and finally got a few minutes to look at this again today.
So, with the ignition on, I can't hear the fuel pump running (bear in mind that once started the car runs fine!). It looks as if the pump has been replaced at some point, it looks new and clean and the pipe unions are shiny. it also has some weird lashed-up connection; originally 3 wires (black blue and green) spliced into a little extra harness with 4 wires (2 black, 1 blue, 1 green).
Disconnected this and found that with the ignition on and the pump disconnected, I only had about 5v at the connector. I then tried putting 12v across the pump and still couldn't hear it running (bear in mind that once started the car runs fine!
). If I start the car and then pull the pump connector, the engine dies in <1 second. So, somehow the pump must be running (maybe it was replaced with the new silent-running version 
) Picture of the pump and connectors below.
I still have a suspicion about the ignition switch. Does anyone know how it is supposed to deliver power when turned to the start position as opposed to the run position? The reason I say this is that if I turn the key hard over to the start position, the engine turns but doesn't start. If I carefully, gradually, back the key off towards the run position, when it gets to the point where it is just about to stop turning the starter, the car often fires into life. I could of course be completely imagining all that and it may be coincidence! For the sake of £18 I might try replacing it though.
Your thoughts and expertise welcome as ever!
So, with the ignition on, I can't hear the fuel pump running (bear in mind that once started the car runs fine!). It looks as if the pump has been replaced at some point, it looks new and clean and the pipe unions are shiny. it also has some weird lashed-up connection; originally 3 wires (black blue and green) spliced into a little extra harness with 4 wires (2 black, 1 blue, 1 green).
Disconnected this and found that with the ignition on and the pump disconnected, I only had about 5v at the connector. I then tried putting 12v across the pump and still couldn't hear it running (bear in mind that once started the car runs fine!
). If I start the car and then pull the pump connector, the engine dies in <1 second. So, somehow the pump must be running (maybe it was replaced with the new silent-running version ) Picture of the pump and connectors below.I still have a suspicion about the ignition switch. Does anyone know how it is supposed to deliver power when turned to the start position as opposed to the run position? The reason I say this is that if I turn the key hard over to the start position, the engine turns but doesn't start. If I carefully, gradually, back the key off towards the run position, when it gets to the point where it is just about to stop turning the starter, the car often fires into life. I could of course be completely imagining all that and it may be coincidence! For the sake of £18 I might try replacing it though.
Your thoughts and expertise welcome as ever!
Had another go at this and here's the latest.
I connected a voltmeter across the blue & black to the pump and got the following readings:
1. Ignition off: 0v
2. Ignition on: Initial volt spike as expected to prime the pump (approx 10.5v, but a digital meter doesn't catch up that quickly) then drops away to something like 3-4v
3. Ignition cranking: 7-8v. This doesn't seem enough. From the g33.co.uk page which paintman listed above (great site, thanks!) there should now be 12v at the pump, as the ECU should turn the pump on
4. Using my "backing the key off" technique above, which strangely seems to be the most reliable way of actually getting the car to start, once it's running the voltage at the pump is 12v or thereabouts, as it should be.
So, I'm not sure what's happening in step 3 above. Somehow the ECU is not delivering the full 12v to the pump. Anyone got any thoughts on that? Despite my ignition switch theory, it seems that the ECU, and not the ign switch direct, should be powering the pump, so the ign switch is not a factor?? Or perhaps is the switch not delivering 12v somewhere it should be and that's the issue? I don't want to throw new parts at it willy-nilly but I'm tempted to go for a switch at £18 if only to rule that out?
Actually I think I next need to power up the pump directly (as was suggested above) to see if I get an instant start. If I do that with everything connected (by baring back a section of the insulation on the wiring harness as I have done to take voltage readings), is that going to back-feed the ECU and nuke it? Or should I just disconnect the pump completely and power it up that way?
Thanks for sticking with this! It's quite interesting for me and I sense I'm closing in on it.
I connected a voltmeter across the blue & black to the pump and got the following readings:
1. Ignition off: 0v
2. Ignition on: Initial volt spike as expected to prime the pump (approx 10.5v, but a digital meter doesn't catch up that quickly) then drops away to something like 3-4v
3. Ignition cranking: 7-8v. This doesn't seem enough. From the g33.co.uk page which paintman listed above (great site, thanks!) there should now be 12v at the pump, as the ECU should turn the pump on
4. Using my "backing the key off" technique above, which strangely seems to be the most reliable way of actually getting the car to start, once it's running the voltage at the pump is 12v or thereabouts, as it should be.
So, I'm not sure what's happening in step 3 above. Somehow the ECU is not delivering the full 12v to the pump. Anyone got any thoughts on that? Despite my ignition switch theory, it seems that the ECU, and not the ign switch direct, should be powering the pump, so the ign switch is not a factor?? Or perhaps is the switch not delivering 12v somewhere it should be and that's the issue? I don't want to throw new parts at it willy-nilly but I'm tempted to go for a switch at £18 if only to rule that out?
Actually I think I next need to power up the pump directly (as was suggested above) to see if I get an instant start. If I do that with everything connected (by baring back a section of the insulation on the wiring harness as I have done to take voltage readings), is that going to back-feed the ECU and nuke it? Or should I just disconnect the pump completely and power it up that way?
Thanks for sticking with this! It's quite interesting for me and I sense I'm closing in on it.
Weirdly even if I power the fuel pump direct, I can't hear it running; would have thought I would. But it obviously runs because the car can be driven.
If I disconnect the pump from the loom, put power to it, and try and start the car, nothing happens, but if I reconnect it then with my key technique it starts. It's almost as if the ECU knows the pump is missing, but I didn't think it was that intelligent.
I've got access to a wiring diag but only a copy in front of me. I'll pore through it.
If I disconnect the pump from the loom, put power to it, and try and start the car, nothing happens, but if I reconnect it then with my key technique it starts. It's almost as if the ECU knows the pump is missing, but I didn't think it was that intelligent.
I've got access to a wiring diag but only a copy in front of me. I'll pore through it.
Edited by CAPP0 on Monday 23 February 22:55
V8 Fettler said:
You have a 3.9i and you've mentioned the stepper motor, therefore you probably have a hotwire EFi (14CUX), does your wiring diagram look something like this?
http://www.gomog.com/allmorgan/HotWireEfiWiring.jp...
Fuel pump is 8
Yep, that's the one http://www.gomog.com/allmorgan/HotWireEfiWiring.jp...
Fuel pump is 8
However, it looks like the fuel pump relay is solely responsible for fuel pump power regardless of the engine state? In which case the relay is either going to be in or out, which doesn't account for the difference in voltage at the pump when cranking or running?
I tried running the pump from a separate battery, otherwise unpluggeed from the car, and the car wouldn't start at all,not even reluctantly. That was what prompted my earlier pondering about whether the car knows whether the fuel pump is present or not, ie, an open circuit back to the ECU stops something else from functioning? I don't want to power the pump up withthe harness connected as I suspect that might fry something else.
Additional earth I can try. I just looked back through the hiostory with the car and it had a new fuel pump fitted 6 months ago.....so, someone else has been on this track but didn't solve it.
Additional earth I can try. I just looked back through the hiostory with the car and it had a new fuel pump fitted 6 months ago.....so, someone else has been on this track but didn't solve it.
No wading from me, although I've only had it a couple of months; who knows what happened in the past. It doesn't LOOK like a car which has seen much other than tarmac.
I also keep erring towards the fuel pump relay, my only hesitation being that this relay drives the fuel pump regardless of where the signal to do so is coming from - correct?? In which case how come it runs fine? If it's not the relay then I am starting to wonder whether the ECU is not feeding the relay/pump correctly during cranking. I believe you can get the ECU tested? Or maybe it would be easier to try and borrow a known-working one and try that.
I also keep erring towards the fuel pump relay, my only hesitation being that this relay drives the fuel pump regardless of where the signal to do so is coming from - correct?? In which case how come it runs fine? If it's not the relay then I am starting to wonder whether the ECU is not feeding the relay/pump correctly during cranking. I believe you can get the ECU tested? Or maybe it would be easier to try and borrow a known-working one and try that.
Well the mystery thickens a little more.
Took the cover off the fuel pump relay and managed to monkey-arm the key from the back seat So, when I turn the ignition on, sure enough the relay closes for a second or two as expected, then releases. Then when I crank, the relay closes again. Which suggests that the relay, the ECU and the coil pulse are all doing their thing correctly. Somebody may have been in there before, the relay is a brown plastic Bosch and not the tin-can one I expected??
If you recall from a post of mine above though, the voltage at the pump blipped up to 10+ for the ignition-on priming sequence (I guess it made 12v although the DMM didn't catch up quickly enough) but it was much lower, 7v I think, during cranking. Candidates for that, well, maybe the starter is dragging the voltage down, although it's a new battery (perhaps could do with a charge now) and the engine turns over happily enough. A bad earth? A bad connection somewhere between the relay and the pump? Maybe I need to jumper from the relay to the pump and see what that does. Or maybe a new relay anyway, perhaps the contacts are not allowing full current to flow?
I. Am. Almost. There.
(I think…..)
ETA - I did indeed jumper 12v onto the relay output, and for the first time ever, I heard the pump run, although clearly it has run before as I have driven the car 50 miles or so. Sooooo, now I am thinking there is an issue with the power supply going onto the relay (contacts, not the switch side). The brown cable feeding power to the relay comes from the ECU - and that ECU pin also feeds the ignition switch, according to my wiring diag. So maybe I am full-circle back around to the switch itself. If not then I need to check the power output at the ECU, pin 15.
Just rambling away here, I guess I'm either hoping that writing it down will give me a eureka moment, or that someone will recognise the symptoms and advise what they did to cure it themselves!
Took the cover off the fuel pump relay and managed to monkey-arm the key from the back seat
So, when I turn the ignition on, sure enough the relay closes for a second or two as expected, then releases. Then when I crank, the relay closes again. Which suggests that the relay, the ECU and the coil pulse are all doing their thing correctly. Somebody may have been in there before, the relay is a brown plastic Bosch and not the tin-can one I expected??If you recall from a post of mine above though, the voltage at the pump blipped up to 10+ for the ignition-on priming sequence (I guess it made 12v although the DMM didn't catch up quickly enough) but it was much lower, 7v I think, during cranking. Candidates for that, well, maybe the starter is dragging the voltage down, although it's a new battery (perhaps could do with a charge now) and the engine turns over happily enough. A bad earth? A bad connection somewhere between the relay and the pump? Maybe I need to jumper from the relay to the pump and see what that does. Or maybe a new relay anyway, perhaps the contacts are not allowing full current to flow?
I. Am. Almost. There.
(I think…..)
ETA - I did indeed jumper 12v onto the relay output, and for the first time ever, I heard the pump run, although clearly it has run before as I have driven the car 50 miles or so. Sooooo, now I am thinking there is an issue with the power supply going onto the relay (contacts, not the switch side). The brown cable feeding power to the relay comes from the ECU - and that ECU pin also feeds the ignition switch, according to my wiring diag. So maybe I am full-circle back around to the switch itself. If not then I need to check the power output at the ECU, pin 15.
Just rambling away here, I guess I'm either hoping that writing it down will give me a eureka moment, or that someone will recognise the symptoms and advise what they did to cure it themselves!
Edited by CAPP0 on Thursday 26th February 17:55
I know you're all waiting for today's episode, so here goes!
Yes, if I shunt straight onto the white/purple off the relay, the pump runs continuously. But, the Rangie still demonstrates the same (failure of) starting issue.
I haven't shunted 12v to the relay input for fear of back-frying the ECU? However, I have monitored the voltage there, and this is where it gets interesting. Ignition on, engine not running, not cranking, I have 12v (or thereabouts, 12.8 earlier) at the brown relay power input. But if I crank it, bearing in mind that the brown power feed is fed direct from the ECU, the voltage drops to around 8-9v. I tested the battery voltage during cranking and it "only" drops to around 11.5. which I'd probably expect.
So, something is dragging the ECU output volts down when the engine is cranking. And given that the car still didn't start when I shunted the pump direct, I wonder what else is having it's voltage dragged down when the car is cranking. I have already tried flying an earth lead (jump lead) from the battery to the engine, to give a stronger earth. Am I back to whether the ign switch is the root of all this? It still only ever seems to fire the millisecond I release the key. Round and round in circles….
Yes, if I shunt straight onto the white/purple off the relay, the pump runs continuously. But, the Rangie still demonstrates the same (failure of) starting issue.
I haven't shunted 12v to the relay input for fear of back-frying the ECU? However, I have monitored the voltage there, and this is where it gets interesting. Ignition on, engine not running, not cranking, I have 12v (or thereabouts, 12.8 earlier) at the brown relay power input. But if I crank it, bearing in mind that the brown power feed is fed direct from the ECU, the voltage drops to around 8-9v. I tested the battery voltage during cranking and it "only" drops to around 11.5. which I'd probably expect.
So, something is dragging the ECU output volts down when the engine is cranking. And given that the car still didn't start when I shunted the pump direct, I wonder what else is having it's voltage dragged down when the car is cranking. I have already tried flying an earth lead (jump lead) from the battery to the engine, to give a stronger earth. Am I back to whether the ign switch is the root of all this? It still only ever seems to fire the millisecond I release the key. Round and round in circles….
Well once it starts (which it did 5 mins ago) it runs fine, sounds nice, not missing anywhere. There's definitely fuel and spark once it's running. I just think something is dragging voltages down somewhere during the cranking phase and that's stopping it from having enough grunt to start.
It's a 91 3.9EFI VSE. I think some had a schrader valve on the fuel rail to check the pressure with but this one doesn't seem to have.
It's a 91 3.9EFI VSE. I think some had a schrader valve on the fuel rail to check the pressure with but this one doesn't seem to have.
Well, I'm losing the will to live with this one! After all the above, I have now cleaned the battery posts, the starter motor live, and the live post which is on the bulkhead fed from the starter, which puts power inside the car. Problem still exists.
I shaved back some insulation from the brown (pin 15) cable to the ECU and took some readings. It sits at 12v+ with the ignition on, but drops to approx 8v when cranking. However, the battery voltage itself, and the voltage up to and including the bulkhead live post, only drops to 11-point-something. Once the engine has started, this immediately goes back up to 13.8v as would be expected. So, something is dragging the voltage to the ECU down when cranking, and I believe that will be affecting both the fuel pump voltage and the injectors? Just looking at the wiring diag and that same power feed to the ECU also looks like it feeds the main relay and the fuel pump relay - so that bears that out, the pump and injectors are not getting 12v when cranking. I don't know whether they would operate at 8v - guess not.
The wiring is not in good condition on the car, someone/someones has been at it in several places and there is indication of previous overheating under the lower dash panel (melted plastic) although what that was, or when, or what was repaired, I'll never know.
One other point, the heavy black cable to the ECU should be earth but it isn't. I'm getting no continuity from that cable (again, insulation shaved) to the body. Even if I short that cable to earth, the car still doesn't start properly. Can/does the ECU get it's earth from elsewhere?
I'm still at the point where the engine only really starts once you have cranked it for a while and when you back the key off. I now don't think it is the ign switch itself, I have jumped that and it still doesn't start.
I have also used jump leads to put an earth straight from the battery to the alternator, and then another to go onto the water pump for the block, to make sure I have a decent earth. Thinking about it I may put one to the body and see whether that helps; perhaps I have either missed an earth to clean, or there is one not present somewhere?
Last thing I can find in the wiring diag is something called the "main connector" which looks, amongst other things, to supply that brown ECU/relay power. Item 12 in the Haynes manual on the dedicated fuel injection wiring diag. Does anyone know where that lives - I'd check it for cleanliness etc.
Other than that, over to you guys for any ideas where/how to look next?
I shaved back some insulation from the brown (pin 15) cable to the ECU and took some readings. It sits at 12v+ with the ignition on, but drops to approx 8v when cranking. However, the battery voltage itself, and the voltage up to and including the bulkhead live post, only drops to 11-point-something. Once the engine has started, this immediately goes back up to 13.8v as would be expected. So, something is dragging the voltage to the ECU down when cranking, and I believe that will be affecting both the fuel pump voltage and the injectors? Just looking at the wiring diag and that same power feed to the ECU also looks like it feeds the main relay and the fuel pump relay - so that bears that out, the pump and injectors are not getting 12v when cranking. I don't know whether they would operate at 8v - guess not.
The wiring is not in good condition on the car, someone/someones has been at it in several places and there is indication of previous overheating under the lower dash panel (melted plastic) although what that was, or when, or what was repaired, I'll never know.
One other point, the heavy black cable to the ECU should be earth but it isn't. I'm getting no continuity from that cable (again, insulation shaved) to the body. Even if I short that cable to earth, the car still doesn't start properly. Can/does the ECU get it's earth from elsewhere?
I'm still at the point where the engine only really starts once you have cranked it for a while and when you back the key off. I now don't think it is the ign switch itself, I have jumped that and it still doesn't start.
I have also used jump leads to put an earth straight from the battery to the alternator, and then another to go onto the water pump for the block, to make sure I have a decent earth. Thinking about it I may put one to the body and see whether that helps; perhaps I have either missed an earth to clean, or there is one not present somewhere?
Last thing I can find in the wiring diag is something called the "main connector" which looks, amongst other things, to supply that brown ECU/relay power. Item 12 in the Haynes manual on the dedicated fuel injection wiring diag. Does anyone know where that lives - I'd check it for cleanliness etc.
Other than that, over to you guys for any ideas where/how to look next?
Thanks for the suggestions above. Answers in sequence…
There's a spark when cranking, I haven't checked a plug for wetness though, that'll have to be next.
I don't have access to any fault readers which would work with this. I guess Rovergauge is the cheaper option although would have to work out the "make your own cable" task. Mind you at this rate I imagine an investment in ECUMate might save a lot more hair-tearing.
Is the diag connector the blue 3-pin under the steering column?
Unfortunately I don't know anyone locally with the same car to test another ECU. However there is a good indy not too far from me, who has worked on my L322, so I might have a chat with him.
Mine doesn't have lambda sensors fitted (although it does have the plugs on the harness). I did check with the previous owner and he said they were never there when he had the car,
Never mind scattergun, flame gun is starting to sound like an option!
Thanks again for sticking with me on this lengthy saga and offering suggestions chaps, I do genuinely appreciate this. Looking forward to nailing it now.
There's a spark when cranking, I haven't checked a plug for wetness though, that'll have to be next.
I don't have access to any fault readers which would work with this. I guess Rovergauge is the cheaper option although would have to work out the "make your own cable" task. Mind you at this rate I imagine an investment in ECUMate might save a lot more hair-tearing.
Is the diag connector the blue 3-pin under the steering column?
Unfortunately I don't know anyone locally with the same car to test another ECU. However there is a good indy not too far from me, who has worked on my L322, so I might have a chat with him.
Mine doesn't have lambda sensors fitted (although it does have the plugs on the harness). I did check with the previous owner and he said they were never there when he had the car,
Never mind scattergun, flame gun is starting to sound like an option!
Thanks again for sticking with me on this lengthy saga and offering suggestions chaps, I do genuinely appreciate this. Looking forward to nailing it now.
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