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Discussion Starter #1 (Edited)
Hi, about 2 weeks ago I had the engine replaced in my 09' VTi (95 bhp, 1.4) as the piston rings were damaged. The replacement VTi engine came from a Pug 08' write off & is the same spec in all respects.

I have been driving it around ok up until yesterday but today it suddenly won't start. It turns over ok just like it did before but won't fire up. If the door is opened with the key still in then yes, it does beep. No faults appear on the dash either.

A few things i noticed since the engine was fitted:

- A slight noise coming from the top end when idle & i am told it could be the hydraulic tappets.

- A slight boomy noise at certain revs, like the exhaust is blowing slightly.

- The temp gauge does not work properly as it barely moves.

I still have the old engine for parts.

Any thoughts much appreciated before I try to find someone to come over & plug in a tester ?

Thanks

EDIT: Reading through here on the forum I see there are some basic electrical checks I could carry out as I have a multimeter & some basic tools - Water ingress in fuse box, blown fuses < anything else I can check ?
 

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Discussion Starter #2
After a bit of research it looks like the coolant temp sensor could cause a non start & considering mine is obviously a bit dodgy then this will the first place ill check tomorrow. Fingers crossed :notsure:
 

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Discussion Starter #3
Ok so I disconnected the temp sensor & after a few seconds it started! The fan then went on to full speed though as it thought it was too hot as the sensor was disconnected, had to disconnect the battery to stop it.

I then took the sensor out & did an ohms test which seemed ok, resistance was around 22k ohms & went up with heat applied (water in a source pan test). The sensor plug & socket had a load of green gunk on it which I cleaned off as best i could with a file & contact cleaner. However plugging it back in it won't start again.

So, looks like the sensor is still the problem.

Or, have I fixed the sensor but there are codes that need clearing ??

Thanks for any help... anyone ?
 

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Coolant sensor should not stop it starting unless it recording high temps so fueling is too weak for a cold start.

Often if you start car with sensor disconnected the BSI will log a fault and temp will go to high and fans will run you have to clear the BSI fault when sensor is fixed/replaced as it does not auto clear
 

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Discussion Starter #5
Coolant sensor should not stop it starting unless it recording high temps so fueling is too weak for a cold start.

Often if you start car with sensor disconnected the BSI will log a fault and temp will go to high and fans will run you have to clear the BSI fault when sensor is fixed/replaced as it does not auto clear

Thanks. However, it did start when I disconnected the sensor ?

HELP!! Big problem now is that I decided to do a BSI reset & now after this its gone into economy mode!! The window is wide open & to activate the window you have to be able to start it, which I can't. So the car is outside on the drive with the window stuck open. What to do ???!!!
 

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Try locking car with key and hold key in lock position. Autoclose on windows should work in eco mode.

As above check the ecu plugs for coolant ingress, faulty sensor killed my daughters ecu (its also how i found you need to clear BSI sensor fault with planet to get coolant sensor working properly again).

One of the symptoms of the daughters car ecu fault was car would intermittently not start (no starter and no sound of fuel pump priming when ign switched on)
 

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Discussion Starter #10 (Edited)
Thanks for all the help. Before I saw your post I managed to close the window by unplugging the sensor again, this allowed me to start the engine & close window.

I think I'm getting to the root of the problem now but still not sure. The o ring that seals the sensor in must be knackered as when all is in place you can squeeze the radiator hose & coolant comes out around the sensor, so its not sealed properly! This would explain why the plug was getting corroded. Have just connected the good sensor from my old engine but it still won't start. (I forgot to pick up the good o ring as well though, the other engine is stored a few miles away from here)

My thinking is that because the sensor was not sealed properly initially, the BSI saw a fault somewhere either with pressurisation or something else related & stopped it from starting.

Still, when i disconnect the sensor it appears that this overrides this particular fault somehow as it starts, hmmmm!?!

I'm assuming now though that once I replace the o ring then get the codes cleared by someone with a planet, then it should be ok ?
 

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also water may be getting through the sensor and not past the o ring, then running up the inner wires, if corroded this can give false readings to the ecu.


pull plugs from ecu and fusebox.


 

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Sensor will leak coolant INTERNALLY as stated so getting a reading at 1 end ie the sensor does not mean the signal is getting to the ecu.

Unplugging the sensor does put coolant fan on this is normal as the ecu sees a hot engine so puts fans on full to try and cool it down

As windy says a faulty sensor should not stop it starting but it seems in your case it is so i would be looking closely at the wiring from the sensor for a break in it or fusebox/ecu plugs as already said.
 

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Discussion Starter #14 (Edited)
Thanks for the replies, much appreciated.

Having spent a night last night reading through all the posts on water/coolant ingress its now obvious I should have looked first at the ECU & heeded your advice! I have checked the BSI plugs & the PSF1 box & they are spotless. All fuses check ok too.

How do i get to the ECU properly so I can inspect it. Its tucked away tightly, is there some instructions somewhere to get it out, I can't find any ?

Cheers
 

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Discussion Starter #15
So I thought the ECU was the BSI & vice versa :nono:. Tit.


Anyhow, if anyone is still in the room then looks like it's a bit of a mystery still as I have no corrosion at the ECU or PSF1 box.

Did I read correctly somewhere that there are hidden fuses underneath the fuses in PSF1 box? Perhaps also the sensor cable has been corroded. Can I bell it out, does it go directly from sensor>ECU ?

Thanks
 

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i think i would first be doing what windy said before, read and reset with planet/lexia, before going further.

and yes the fusebox has as much in it as a modern tv, not like the old days when your ford capri had a fag box fusebox.

 

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Discussion Starter #17 (Edited)
Since my initial posts Ive had to go away & learn as much as I can about how things are working. I have a better understanding now.


ECU plugs & ECU sockets are clean, no coolant or water ingress as far as i can see.

Diagbox shows only one code P0118, ECT fault - open circuit or short to positive. Variables are reading -40 degrees, no rpm. There were an array of BSI faults as well but these were cleared with a BSI reset.

With the new ECT sensor disconnected & ignition on I am getting 3.3v across the ECT signal & ground, not the expected 5v ref. I also tested the signal with a known good ground, still 3.3v.

With everything disconnected I checked the integrity of the wiring & all checks ok with continuity & resistance (1.3 ohms end to end on signal & ground wires). Infinite resistance across signal & ground, so no short here.

So far it's pointing to an ECU fault but am struggling to see how this has happened as all I have effectively done is replace the ECT sensor & its plug.

thanks
 

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Coolant sensor open circuit will show -40 on diagnostics so it must be open circuit i cant see it being the ecu to be honest unless you had water ingress

I have a 307cc here and the roof was not working i checked it all and it all seemed fine only fault showing was no outside temp signal the sender for this is in the passenger mirror which had been replaced with non powerfold type plugged in correct type mirror and roof now works !!

It really is amazing how complex things can be and something insignificant can stop them dead !
 

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Discussion Starter #19 (Edited)
Thanks. Yeah your right although the replacement sensor & plug came from my other working engine, I've tested it at ambient temp & it reads about 5k ohms, not open. Im not sure what the correct specs should be here though.

One thing I haven't done is volt drop the cables, there may be some resistance there when under load, coolant may have degraded them. If there was voltage drop on one of the cables this would throw the sensor reading out of range which would also throw a P0118.

Driving me nuts
 
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