Extra wire to the +ve battery terminal?

[sirwiggum]

Hi all,

Newbie here just registered.

My 406 is a 2002 HDi 90, Rapier spec.

I am going to start by asking for a bit of info, google hasn't got the answer, and I tried searching the forum but can't see any info.

Earlier on I was helping jumpstart a neighbours car.

When we got it running, I took off the jump cables (in order) and the +ve terminal came off as I had accidentally undone the big clip.

However, what I noticed when putting it back, was that there was a connector end that looked like a little loop
To do my best in ASCII:

=o

It was just this end, and it didn't have a wire coming off it.

The +ve cable housing looked like it had a groove for a wire to run along it, presumably to this ending.

My question is - am I missing a wire here? If so, what is it for? Is it important?
The car seems to start, run and charge ok.

I'm just baffled as to what this wire could be. Is it some earth that a previous owner has disconnected?

Any insights would be appreciated. Apologies for diving in to a question on my first post.
Cheers!

[teamster1975]

Welcome wiggum!
To be honest if you can't see any loose wires around the vicinity and everything is working I wouldn't worry. One of the Hdi owners will be along with more advice!

[BruceT]

On the misses hdi90 when we changed her battery, there was an aditional wire to the + side of the battery (Closest to engine, or is that negative?).

I think it was a wire running to the MAF/Throttle Pot as hers as had some funky wiring done...

[sirwiggum]

Yes that's the one, closest to the engine bay.

I hadn't really been poking round the battery until today.

Hopefully the previous owner hasn't snipped the MAF due to issues. I'll take a look tonight.

[BruceT]

I believe (Without checking whether this wire is attached to the negative or positive side) that her car has had the 'Earthing Mod' done on it which basically means, the on-board computer was flagging a Throttle Posistion Sensor/MAF issues intermittantly, which where due to a bad a earth. What they did was snip the wires off the maf and tps and ground them on the block or in some cases the negative terminal of the battery.

Her car still occasionally idles at 1200rpm, then corrects itself and then does the same and sometimes gets a flat spot where it appears to be not registering the throttle input.

Now, this has been tested and shown as a TPS sensor, so ive bought a used one of a 2002 HDi and will fit tomorrow afternoon and reset the codes and see if it appears, if it does,ill buy a cheapo maf of ebay as this is what the more expensive peugeot planet was showing TPS and MAF sensor but my cheap ELM323 code scanner was only picking TPS fault.

[sirwiggum]

Last night I couldn't see any stray wires coming from the MAF / throttle pot. Tried to take pictures on the phone but they didn't come out well as it was dark. Will hopefully get some sunlight this weekend.

The idle seems fine. I remember the 1.8 petrol Xantia I had once had idle issues. Sorted with a quick spray of Air Intake cleaner on the idle control valve and was grand for the next 20k miles I had her for. Don't think an HDi would like that though.

The only thing I can fault on the 406 is that sometimes it feels like there is a flat spot - almost like a misfire on a petrol would feel.
Occurs sometimes around 1000-2000 rpm. Occurred yesterday evening when I was enthusiastically taking a large roundabout in 3rd gear

I have a fuel filter housing as a job to do this weekend, will see if there is any blockage there, and will look in the old housing for the dreaded metal shards of fuel pump death.
Air filter changed (easiest job even on dark / rainy night) as the old one was pigging.
Oil and oil filter change to come too hopefully this weekend or weekend after.

One of my colleagues has speculated (tongue in cheek perhaps) that it was maybe a taxi in a previous life. However it definitely looks like the cladding of the +ve cable has a groove for a smaller cable to come off it. Curiouser and curiouser...

[BruceT]

I was fiting a new throttle position sensor today, the side near the wing is the negatie side, this is where our extra wire goes as a ground for something.

We dont have anything that was additional on the postive side.

Could of been power for an aftermarket amplifier, hands free kit etc?

[sirwiggum]

Thanks for your suggestions BruceT.

Had a closer look today in a lull in the never-ending rain!

There seems to be a similar loop connector end on the negative terminal on the bolt between the 2 sides of the terminal connector.

I reckon you are right, the previous owner maybe had some wacky accessory being powered directly here. Nothing seems affected so I'm no longer worried. Was more curious than anything. The positive lead that I thought was a groove for a lead I now think it's just the shape of the lead to allow it to bend round the top of the battery.

While I was there, changed the fuel filter housing. Made a huge difference! Drives like a new car and the lumpiness at low revs is gone.
Absolutely chuffed.
Will leave the paint touchup and foglight to a less rain-threatening day. And the com2000 will need a whole day I reckon.

Thanks again!

[lakemaligne]

Hello Bruce T and SirWiggum, I cannot shed any light with the original query I am afraid. Please forgive me if this seems a bit cheeky butting into this thread,but could'nt help noticing that you mentioned another car with tickover issues and flat spots, which my 406 is also experiencing, which you attrubute to the TP and MAF. I have had the TP replaced on my car but have not heard of a MAF,and was wondering if you could explain what its for.Below is a section from one of my previous threads currently lurking on this forum.Sorry if its a bit lengthy ,but i have had this fault for over 2 years now and its driving me round the bend.

I have owned a MK1 1996 2Ltr 16v LX petrol Peugeot 406 from new,which has covered 154,000 miles. For no apparent reason the engine tick over will suddenly remain at 1200rpm if I shift in to neutral while the car is still moving, and only drops to the normal 950 rpm once the car comes to a complete halt. This happens moving forward or backwards! If I let the car start to roll forward the revs start to rise steadily as the cars momentum increases.. The revs drop down again the moment the car comes to a halt. During this period the car will also jerk, as the power comes off when i completely lift of the accelerator. When I depress the accelerator again, there is another jerk when the power comes back on. This condition will persist for a few days , then clear itself for a few days, then come back again. On some occasions when I start the car from cold, the tickover is very erratic ,one second revving at 1200 rpm and then back down to 900 rpm. On some occasions the engine tries to stall when I engage neutral. Occassionally the car hesitates ,like a flat spot as i go to pull off. My dealer has replaced the MAP,Oxygen,Throttle pot,Stepper Motor and throttle cable,and has reset the adaptives. After the Oxygen sensor was renewed the fault light to started appearing, which until this point had never appeared in the cars life. All faults/symptoms remained.

The fault is not linked to changes in driving conditions ,ie heavy rain or dry spells, or bumps in the road. The vehicle tech who worked on the fault said that the ECU had recorded an "intermittent fuel regulation fault"(MP511), but was getting a reading of Lamda1, and said that his laptop was showing emissions levels of that of a new car, and everything was spot on, but agreed that the symptoms I described existed.

Bruce ,could this MAF sensor be responsibe for the above symtoms.

[sirwiggum]

Mine still isn't right at about 1500rpm.

I'm treating it as a "quirk" until I can afford to get diagnosed / buy more bits, after I (hopefully) can get it through an MOT in a months time.