406oc.co.uk

Hello everyone.

Few days ago, I noticed that my Peugeot 406 2.0 HDi 110 tends to jerk forward. Sometimes while I just start moving, sometimes during driving open road I feel the car jerking forward a little, it doesn't work smoothly. I don't know how to explain it better since English isn't my native.

What can this be? Bad, leaking injector? How hard is to DIY to replace one? Should I stop driving ASAP or is it fine to drive short distance every day, like 10-15km a day?

It doesn't have check engine light on or any error.

I don't think those are the normal signs of injector problems - uneven idling, rough running at low engine speeds and possibly poor starting if the problem is serious are more typical.
I would not consider injector replacement unless you have more evidence this is the problem.
A leak-off test may help in confirming injector wear.

You could also try running with the mass airflow sensor disconnected to eliminate that as a possible cause.

I would also look for sensor connection problems, poor earth connections etc.

Thank you.

It's starting fine, idle is fine, but like I said, sometimes at low speeds and at normal crusing speeds where I keep throtthle at same position, I notice jerking forward and RPMs tend to oscilate a little, I even notice it on the dial.
It seems that fuel consumption has increased, but I'm not completely sure on this one.

You can check to see if your throttle position sensor is clean, and you're throttle cable isn't too tight.

Have a look here, it shows the throttle cable and how to remove the sensor.

https://youtu.be/4fYHo7voyx0

Could be speed sensor on gearbox if its only doing it when the car is moving. Had that issue a few years ago and its an easy fix

Jerking forward is now even more noticed while driving.

I removed MAF to see if it's dirty, and now I get anti pollution fault with check engine light on.

Tried driving it with MAF unplugged, check engine light still on and it shows anti pollution fault when starting.

Jerking with MAF unplugged is still there, but it seems like not as a much, but maybe it's just in my head.

Having the MAF unplugged will put the light on, but on the 90 it's still okay to drive but the other engines will run rough.
If your running is largely unaffected by the MAF unplugged then it isn't faulty as such, maybe a clean with contact cleaner will help.

MAF connected or not, I still get Anti pollution fault and check engine is always on.
I even tried to clear it with that cheap OBD2 diagnostic, but that doesn't do anything.

I bought EGR cleaner and sprayed it in air intake while keeping the car at 2000 rpms. Connected back MAF sensor and the light is still on, but car seems to be running better. Maybe it's in my head, maybe because it's warmed up. Will try to take it for a drive later.

The warning light will normally go out after completing a few journeys with all the sensors connected, may take a few days but don't worry about it.

If you could read the error description it would almost certainly report the MAF disconnected as an intermittent fault. 3 - 5 cylces of running the engine then turning it off/keys out/doors shut for say 10 minutes to ensure the ecu shuts down fully will clear the warning light unless the fault condition is still present.

The cause of the jerking is likely to be a poor electrical connection to one of the sensors, the engine ecu, or a bad earth somewhere and can be really difficult to find. It may help to unplug, examine and reconnect all of them carefully a few times, together with the ecu wiring harness connector(s), battery connections and all engine earths.

Remember to allow all the ecus to shut down BEFORE disconnecting the battery, see this link: viewtopic.php?f=10&t=13431

The sensor list and locations:
https://catalogs.ssg.asia/peugeot/?lang ... aWVyPT0%3D