Peugeot 207 Vti crank no start ongoing issue

[MikeT]

Engine was able to start using signal from the cam sensor?

Exactly that. Diagnostic (and rev counter) showed 0 engine speed yet it started and ran well but it came back from the manufacturers as suspected timing chain. There were other faults he found too including air leak from open-ended breather pipe, fuel trims maxing out, unable to go into closed loop running etc.

I quite enjoyed that educational class.

[max1]

Thanks for the replies

That ECU connector that we unplugged to test the ECU pins directly was the connector that had all the other sensors on it as well - pretty sure anyhow & would need to confirm this somehow? So if this is the case this would have eliminated any other sensor pulling the voltage down.

Any thoughts on this ? Pretty sure when we looked at the wring diagram it showed all other sensors were wired to this connector.

[darbuck]

does this car have a seperate throttle position sensor because if it is reading high it could be causing flooding preventing start try cleaning throttle body. These are normally linked to ECTS and also check for a vacuum leak or blocked PCV , as has previously been said the parasitic draw on the system could be causing mayhem in the ecu .A bad ects is more likely to cause erratic idle.

[MikeT]

Thanks for the replies

That ECU connector that we unplugged to test the ECU pins directly was the connector that had all the other sensors on it as well - pretty sure anyhow & would need to confirm this somehow? So if this is the case this would have eliminated any other sensor pulling the voltage down.

Any thoughts on this ? Pretty sure when we looked at the wring diagram it showed all other sensors were wired to this connector.

Not all, max. Some even wire through more than one of the three connectors.

[max1]

Ok understood. Without trying to sound too defeatist Im starting to think we are getting in above our heads now. As you said a lot of the sensors are inaccessible as they are under the car, testing for rouge resistance at the connector end is doable but we don't know what resistances to expect to start with.

We can narrow it down a bit more with a few more tests but there will still be lots of areas we don't have proper knowledge of, electrically wise. Im wondering what else we can do now that will narrow the search down considerably more than where we are at now. What do you think ?

[max1]

does this car have a seperate throttle position sensor because if it is reading high it could be causing flooding preventing start try cleaning throttle body. These are normally linked to ECTS and also check for a vacuum leak or blocked PCV , as has previously been said the parasitic draw on the system could be causing mayhem in the ecu .A bad ects is more likely to cause erratic idle.

Thanks, there is a throttle motor position sensor, not sure what it is reading though.

[darbuck]

It should be at zero at startup and idle, it essentially measures throttle pedal position which is directly proportional to butterfly valve angle in the throttle body. I would be checking the crank and cam sync is correct and that your crank is showing rotation before anything else, also make sure your in tank pump is priming on startup, but I read somewhere recently that there is a known issue on Magnetti Marelli ecu's where a wire breaks going into the ecu causing a non start condition you will have to google it though. I know I am throwing a lot of possible causes but I think its better to have as many variables as possible but you seem to be methodical in how your working through them. I am not great on electronics but just going by past experience's.

[MikeT]

Ok understood. Without trying to sound too defeatist Im starting to think we are getting in above our heads now. As you said a lot of the sensors are inaccessible as they are under the car, testing for rouge resistance at the connector end is doable but we don't know what resistances to expect to start with.

We can narrow it down a bit more with a few more tests but there will still be lots of areas we don't have proper knowledge of, electrically wise. Im wondering what else we can do now that will narrow the search down considerably more than where we are at now. What do you think ?

Not at all max, I take my hat off to you given the backstory.
Yeah, a quick buzz around the ECU plugs sounds a reasonable alternative imo and there shouldn't be a problem viewing live data, clear the fault codes etc.

[max1]

Thanks Mike but I think you misinterpreted my question or I wasn't clear. Basically I think we have hit a dead end here & I'm not sure if there is much more we can do that is accurate enough to give us anything meaningful moving forward, perhaps you disagree?

The sensor voltage is either being pulled down by another component on the car somewhere & finding this without accurate info on what other component values etc should be is very difficult, not to mention gaining access to them. Or the ECU is faulty but then what has caused it to fail is vital to find out if it has to be replaced. Catch 22.

Baring in mind how much time i've been off the road now, how much I have spent on it & how much it would cost for a Peugeot dealer to look at it, I am seriously having to consider selling it for spares or repair.

[darbuck]

your definitely not getting an immobiliser fault Max are you

[MikeT]

Thanks Mike but I think you misinterpreted my question or I wasn't clear. Basically I think we have hit a dead end here & I'm not sure if there is much more we can do that is accurate enough to give us anything meaningful moving forward, perhaps you disagree?

The sensor voltage is either being pulled down by another component on the car somewhere & finding this without accurate info on what other component values etc should be is very difficult, not to mention gaining access to them. Or the ECU is faulty but then what has caused it to fail is vital to find out if it has to be replaced. Catch 22.

Baring in mind how much time i've been off the road now, how much I have spent on it & how much it would cost for a Peugeot dealer to look at it, I am seriously having to consider selling it for spares or repair.

No, you're good max, I think we're on the same page.

In respect of a definitive daignosis, I agree that probing for a potentially obviously low resistance is sort of pissing in the wind without the data for each circuit/component. Alternatively you could disconnect each other sensor/actuator circuit and see if the 5v magically re-appears.... but that requires a lot more yoga, as you say.

That's the last option I can come up with at this point.

Equally, all the prior suggestions including to read live data is only valid if you see any value in fixing your car, but also happy to help if I can. I think it's a nice enough car and a pity to get shot of after all you've invested in it, given the only definitive evidence we have of it being a non-runner so far is bad ECT data.

[darbuck]

If I can just say one thing I took my c5 off the road last october and have two cars since both of which broke my heart one nissan and one saab, I was having problems with C5 turbo and injectors and decided I was going to scrap it nearly 12 months on I have the c5 running again and I am glad I didn't scrap it. maybe take it off the road until you can get back to it and buy a banger thats running until you can. I do have the advantage of a lot of driveway that you might not have. obviously only if you like the car. was the ECTS you replaced genuine and did you test the resistance in it at ambient temperature and over heat the new one gradually in a pot of water using a pliers up to approximately 90c. this video should help.

[max1]

Thanks Mike but I think you misinterpreted my question or I wasn't clear. Basically I think we have hit a dead end here & I'm not sure if there is much more we can do that is accurate enough to give us anything meaningful moving forward, perhaps you disagree?

The sensor voltage is either being pulled down by another component on the car somewhere & finding this without accurate info on what other component values etc should be is very difficult, not to mention gaining access to them. Or the ECU is faulty but then what has caused it to fail is vital to find out if it has to be replaced. Catch 22.

Baring in mind how much time i've been off the road now, how much I have spent on it & how much it would cost for a Peugeot dealer to look at it, I am seriously having to consider selling it for spares or repair.

No, you're good max, I think we're on the same page.

In respect of a definitive daignosis, I agree that probing for a potentially obviously low resistance is sort of pissing in the wind without the data for each circuit/component. Alternatively you could disconnect each other sensor/actuator circuit and see if the 5v magically re-appears.... but that requires a lot more yoga, as you say.

That's the last option I can come up with at this point.

Equally, all the prior suggestions including to read live data is only valid if you see any value in fixing your car, but also happy to help if I can. I think it's a nice enough car and a pity to get shot of after all you've invested in it, given the only definitive evidence we have of it being a non-runner so far is bad ECT data.

Thanks Mike. Yes of course Id love to get it fixed & I'm very appreciative of your help no question. Im just getting a bit weary as I've been without a car for 6 weeks now & need to think about my options.

I suppose reading live data will eliminate whether the ECU is seeing the engine crank or not. It would be good to find the MAP sensor as suggested elsewhere to read its voltage as well. As for unplugging all other sensors, this seems difficult as like you said they are accessed from under the car & I don't have suitable jack. Of course we haven't checked for spark yet either.

[max1]

If I can just say one thing I took my c5 off the road last october and have two cars since both of which broke my heart one nissan and one saab, I was having problems with C5 turbo and injectors and decided I was going to scrap it nearly 12 months on I have the c5 running again and I am glad I didn't scrap it. maybe take it off the road until you can get back to it and buy a banger thats running until you can. I do have the advantage of a lot of driveway that you might not have. obviously only if you like the car. was the ECTS you replaced genuine and did you test the resistance in it at ambient temperature and over heat the new one gradually in a pot of water using a pliers up to approximately 90c. this video should help.

Cheers yeah have checked all this

[max1]

your definitely not getting an immobiliser fault Max are you

Not that i know of, keys are recognised still ok. Fuel is getting dumped into the engine on crank due to the ECT sensor not being recognised, I can smell it.

3.3v here where 5v should be is the problem, finding out whats causing it is the headache.