182 Hesitation and poor idle. Solution in progress.

[Wobba]

Car: 2004 Renault Clio 182 FF Cup Pack

Symptoms:

Low idle
Hesitation
Poor power delivery
Kangerooing

Waffle:

I picked the car up about 4 weeks ago knowing it needed a dephaser and cambelt change as it sounded like a diesel. Parts and tools ordered.

It also had a poor idle and was too low at about 600RPM but drove fine under open throttle.

Before I had time to do the belt and pulley the car showed a non-flashing emissions warning light. Car was fine.

Replaced MAP sensor, slight improvement but then faded back to poor.

Crank sensor replaced. No change.

Spark plugs changed. No change.

Coolant temp sensor changed. No change.

HT leads checked. No change.

TB cleaned. No change.

Pre-Cat lambda changed. Much more linear power delivery, but idle unaffected.

Checked alternator and battery. Both supplying correct output.

Not long after, and probably related, the emissions light started flashing and there was a misfire on piston 4.

Garaged car. Took it apart. Replaced dephaser and timing belt. Tool bent. Redid timing and triple checked it.

Car was noticeably a lot quieter.

Injector 4 replaced. Misfire gone.

Still, poor idle and hesitation remained.

Compression test results came back good in case timing was out.

MAP sensor test: turn car off, unplug sensor, start car and test drive. No more problem.

Conclusion: Wiring loom and/or plug connection at fault.

Next action will be to trace wiring and check plug to the MAP sensor.

Lesson: replacing parts can help diagnose things but never forget the wiring or plugs themselves can be at fault.

Pics to follow.

 

[Ianboom]

Was reading an older thread on here this morning about a similar problem that was down to water damage in the plug under the washer bottle.

Well found!

 

[Wobba]

Yea lol I read that too

I have seen loads of people with this same problem, which I will post up pics of how I correct, hopefully tomorrow

 

[milotron]

Hi I have the exact same problem, my car has a stutter in low revs and is doing my head in, where is the map sensor located, is it easy to find? Thanks ste

 

[Wobba]

The MAP sensor is under the plastic engine cover, to the left on the oil filler cap. It's a rectangular shape, with a grey/black plug going into it.

They are quite cheap to replace, but first try pulling the plug off and starting the car and go for a drive. Ignore the error messages on the dash.

 

[Wobba]

Typically, having now tested the MAP sensor plug and loom all the way back the the ECU plug I cannot find any issue with it!

Multimeter test showed no problem from the pins of the MAP sensor blug to the feed to the ECU at all...so perhaps I've just been really unlucky and had two bad MAP sensors in a row? There could be signal interference with the engine running of course, but I doubt it...

Having now plugged in the original OEM sensor again it feels much better. Perhaps these non-OEM sensors are to blame?

 

[bloke]

The MAP sensor is under the plastic engine cover, to the left on the oil filler cap. It's a rectangular shape, with a grey/black plug going into it.

They are quite cheap to replace, but first try pulling the plug off and starting the car and go for a drive. Ignore the error messages on the dash.

thought they are around £100 or so?