Berlingo Forum

Full Version: FLAT SPOT
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Hi all,

I have a few of problems with my 1.4 2001 Berlingo van.

It all started last December when the radiator decided to blow & overheat the engine. I had the block replaced because it had warped & I put in a new radiator.

The 1st problem is that it runs lumpy on start up with a rather erratic idle around 1500 revs then it drops to normal around 950 revs after 5 mins or so.

The 2nd problem is more worrying as it is dangerous when I come to a stop at traffic lights. When I go to accelerate away it starts fine then for some reason the idle drops to 0 & the vehicle nearly stalls if I'm not quick enough to press the clutch, the Citroen dealer called this problem a FLAT SPOT.

The 3rd problem is when I reverse the vehicle from cold start it jerks (Kangaroos) a few times then stalls.

Has anyone else come across any of these problems & if so what was the cause & remedy to rectify them.

Cheers PITPAN.
What does Lexia say? You may have an issue either with reference voltage fluctuation or erratic sensing (throttle pot or motorised throttle body).

Does it have a single plug ECU or the multiplug type?
Thanks for the reply Addo,

I'm not sure which type off ECU it has but I can find out by calling the dealer who services it or take a look at where is the ecu located if I knew where to look.

what is reference voltage fluctuation & erratic sensing and which sensor is at Fault
If you don't mind posting the last eight digits of the VIN I can look it up.

The sensors on the motor have a small voltage (5 volts DC) fed into them, the output of the sensor is a change to this voltage depending on what sort of sensor it is; a temp sensor will block more or less volts depending on the coolant temperature, a speed sensor will return pulses of voltage, a MAP sensor will also change the voltage it sends back based on the manifold pressure. So, if the starting point (your reference voltage) is inaccurate then the results come out messy.

Sometimes the battery voltage into your ECU (where the reference voltage is created) is affected by such things as a failing battery, a dying alternator, a cooling fan with sticky motor bearings, degraded battery terminals - and possibly other items.

If the battery terminals are the original crimped lead ones, you might do well to replace them first with all brass units that have multiple holes for the various cables. Look on Fleabay for a pair - it'll be under $40 posted.
Addo the last 8 digits of the vin are as follows 6555 2433

Now you mentioned it my battery did run flat but I jumped started it and it is now recharged, but I might go and replace it with a new one if all else fails plus the problems started before it went flat.
That's a S2000 series three plug Sagem ECU, I believe. I don't have the wiring diagram for it, Rustscrat might.

You've also got a mechanical throttle, which eliminates some fault areas found on later cars.
ok addo, so what am I supposed to do to address these problems.
As mentioned, first suspect from my experience is the battery. Get it load tested in case a cell is dying.

Next up, replace the battery cable terminals. I'd recommend aftermarket but you could buy new genuine if you're feeling wealthy. Check the motor/gearbox earthing wires are correctly fitted, too.

If you have access to a digital multimeter, you can probe the wires into the back of sensor terminals to see if the reference voltage is correct at 5V when running. It's pin 2 you check (the numbers are usually moulded on the plugs if you unclip and squint hard).

It won't hurt also, to check for continuity on the crank angle sensor. Getting the van plugged into a Lexia unit would be ideal but you need to find someone close by who's got one.
Thanks Addo,
Ive purchased a thermostat housing temp sensor on ebay.
Is the crank angle sensor also known as the crank shaft sensor or are there two sensors as i'm looking on ebay and trying to find the correct one. Also what is the sensor on top of the gear box, is that the reversing light sensor plus there is a black (plug?) on top of the gear box with no apparent wiring what is this for.