Lack of power. Like really sloooow.

[Tom]

Hi guys, My uncle has a 307 estate 2.0hdi not sure if its 90 or 110bhp. Now i havent drove it, but he says theres a huge lack of power, but the catch is its only occasionally. Some times its absolutely fine and drives as it should. But other times he says its dead slow, like 3rd gear foot flat cant over take a lorry slow. So im going to have a look over the weekend and see what i can make of it just wanted some advice before i go into it.
Im thinking perhaps an issue with the maf? Or some other sensor or some dodgy wiring somewhere? Thanks everyone

[Toms306]

TPS or MAF is my guess...

[Tom]

Oh shit yeah completely forgot they have a TPS, thats on the pedal yes?

[Toms306]

Umm, I don't know on a 307. On the 306 HDi it still has a cable and is mounted on the airbox for no apparent reason lol.

The other thing is, is it actually slow as in revs restricted, or is it the clutch slipping lol?

[Midnightclub]

If it's the 110 it's boost control is done by the ECU via a vacuum solenoid, another possible cause of it being slow.

Second thoughts, didn't the 307's have massive problems with DPF's getting blocked and causing mega poor performance?

[Toms306]

Good point, the DPF should bring up a fault light though. Are there any lights on Tom? And do you have any diagnostic equipment to plug in and test?

[rd070707]

It will be in limp mode, many different things can cause it so no point guessing like it will be maf, it will be blocked dpf, turbo control solenoid, wiring etc etc, diagnostics is needed or you will waste a lot of time trying to sort it out.

Is the eml lit?

[Dum-Dum]

Either vac leak on the line between the turbo solenoid causing it to overboost then cut the power or poss DMF issues.

[Birk]

90s have boost solenoid on front of engine as well.

Just unplug it and remove it, job jobbed.

[rd070707]

Iirc 90s arent ecu controlled boost? I had boost issues caused by wiring to the boost solenoid

[Toms306]

RD, power loss doesn't always mean limp mode. And things like MAF reading incorrectly, EGR stuck open, vac leaks etc don't always cause an EML....

[Birk]

I had several 90bhp 307's with boost solenoids on the front of the engine.

[Tom]

Not limp mode it will rev right round just take an absolute age to do so. Almost like a blocked cat but it only does it here and there. Sometimes its completely fine so it cant be something mechanical like thag as such. Good shout on the boost solenoid i will have to take a few pics and see whats going on.