308 Erratic idle

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Tam
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308 Erratic idle

Post by Tam »

Good evening folks!
Trying to help my son out with a newly acquired Pug.
When idling it sounds as if it's "Missing" but is ok when driving or revving it a bit above idle, the eml is on also. He put an obd reader on and it showed 2 codes:
P0354 for which he replaced coils which hasn't helped.
P1340 is the other code but unsure what this relates to.
Can anyone shed some light please?

308 (T7) 5 DOOR SALOON 1.6 VTi 16V 120 (EP6) Manual gearbox 5

VF3**************[VIN obfuscated, can be read by forum staff]

Thanks in advance

Tam

wheeler
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Re: 308 Erratic idle

Post by wheeler »

Is it the BMW engine by any chance?
P1340 seems to relate to a camshaft sensor fault, the BMW engine is fairly common for the timing chains/tensioners wearing which can cause a cam sensor fault to be logged.
What state were the spark plugs in ?
Why PSA moved from their own engines to the BMW pieces of junk I don't know?

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xantia_v6
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Re: 308 Erratic idle

Post by xantia_v6 »

I think it is the EP6 120 engine.
Were all the ignition coils replaced or just 1? If only one was replaced, was it the correct one? I think that number 4 is at the gearbox end of the engine.
Did the same fault codes come back?

Tam
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Re: 308 Erratic idle

Post by Tam »

Thanks for the replies guys!
All coils and plugs were changed, plugs were in a bad shape(Oily) and the rubber sleeve was cracked on one.
it is the EP6 120 engine.
These codes are showing now after the coils and plugs have been changed as he didn't have an OBD reader prior to changing them. Symptoms are still the same after replacing them.

Thanks

Tam

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Huskyxantia
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Re: 308 Erratic idle

Post by Huskyxantia »

Maybe sticky valves ?
Did read somewhere a 308 with similar problems and they used seafoam and after adding half of the product to half tank of fuel it worked .

If the valves don't close properly it can cause a poor idle and a missing sensation.

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xantia_v6
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Re: 308 Erratic idle

Post by xantia_v6 »

If this engine has not previously had the timing chain and tensioner replaced, then I would think it likely that this is the cause. Does the engine have a top-end rattle when started from cold? if so, how quickly does it go away?
Last edited by xantia_v6 on 10 Apr 2020, 09:14, edited 1 time in total.
Reason: Removed misleading info.

Tam
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Re: 308 Erratic idle

Post by Tam »

Will ask the question and get back to you-Thanks

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Huskyxantia
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Re: 308 Erratic idle

Post by Huskyxantia »

Crank case ventilation issue ?

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xantia_v6
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Re: 308 Erratic idle

Post by xantia_v6 »

Huskyxantia wrote:
10 Apr 2020, 08:05
Crank case ventilation issue ?
I don't think that the naturally aspirated 120 HP version has an issue with crankcase ventilation in the same way that the turbocharged ones do.

The 120 HP has conventional port injection, not direct injection despite what I said earlier), so carbon clogging of the ports should not be an issue.

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GiveMeABreak
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Re: 308 Erratic idle

Post by GiveMeABreak »

There is a known issue with these, where the Engine Management Light is showing and where one or more of fault codes P1337, P1338, P1339 & P1340 are showing.

Basically the TSB concerned the pollution of the valves or valve seats caused by driving short distances or using the car without heavy load of the engine.

However, others with this engine and problem checked the intake valves and channels with an endoscope, but these showed clean - others had gone down the replacement route of the electronics to no avail, but ultimately, it was worn / broken piston springs. The engine was replaced.....

The actual P1340 fault as it relates to this Engine specifically is:

Fault: A non-characterised combustion misfiring on cylinder 4. Ignition misfiring (with possibility of damage to the catalytic converter).

Condition for Fault:
  • Engine Management ECU in main triggering phase
  • Engine Speed above 500 RPM and below a threshold defined in the engine ECU
  • Torque below a threshold defined in the ECU
  • The Crankshaft and Camshaft are synchronised
Condition for Disappearance of Fault: Clearing is impossible (after a pre-defined driving cycle)

Downgrade Modes whilst fault is active:
  • Cutting of cylinders if fault persistent
  • Deactivation of richness regulation
  • Deactivation of checking of the canister purge
Symptoms of Fault:
  • Starting impossible
  • Starting difficult
  • Unstable idling
  • Idle speed too high
  • Lack of power
  • Engine hesitation
  • Emissions outside the norms
  • Excessive fuel consumption
Suspect Areas:
  • Sparking plugs
  • Fuel injectors
  • Electrical harness
  • Engine ECU
The P0354 Fault for this engine:

Fault: Detection of ignition misfirings on cylinder 4: Coherence. Detection of a failure on the power stage of the ignition coil of cylinder 4. Coil diagnostics by measurement of the spark time

Condition for Fault:
The following conditions have to be met
  • Engine management ECU in main triggering phase
  • Engine running
  • No "multiple ignitions" mode activated
  • Cutout condition in passive deceleration
  • Voltage between 12 and 15 V
  • No crossing of "coil charge time signals" detected by the diagnostics
  • Engine speed between 400 and 1500 rpm
Condition for Disappearance of Fault:If no error is found, the fault counter is decremented (whether or not misfirings are detected at the same time). When this counter reaches 0 and the number of ignitions is over 250.

Downgrade Modes whilst fault is active:
  • Engine torque changes to "uncertain" status
Symptoms of Fault:
  • Unstable idling
  • Lack of power
  • Emissions outside the norms
Suspect Areas:
  • Ignition Coil
  • Connector
  • Engine ECU

Tam
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Re: 308 Erratic idle

Post by Tam »

Thanks Marc!
An update, he took it to have the codes read at a garage next to him.
At cyl 4 There is no spark and no compression either after doing a compression test, he reckons a piston ring or whatever but it will need a strip down and loads of money.
He has decided to cut his losses and scrap it when they reopen.

Thank you all for your input, it is much appreciated.

Tam

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GiveMeABreak
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Re: 308 Erratic idle

Post by GiveMeABreak »

No Problem at least fore warned is fore armed. I hope he has better luck next time with whatever he decides to get.