Problem with 2000 HE Mondeo

XCeed · 12-03-2019, 09:39 PM

Hello fellow Ford enthusiasts,

The problem is my 2000 HE Mondeo misses under load. General driving around is fine. I've replaced the leads but still happens. The plugs are clean and gapped at 1mm as per the new specs (original plugs used to be 1.3mm). The coil resistance readings seem ok.

I put a timing light on each lead and 2 and 3 being connected at the coil are fine and the pulse is steady and consistent. 1 and 4 pulse at what seems to be double the rate and there is a definite miss, occasionally.

I'm thinking the coil is receiving an imperfect signal from the ECU. I've read on a UK site that this is a common fault. I'm thinking of trying a different ecu next.

Anybody familiar with this problem? I would appreciate some advice here as I've taken it to a Ford dealer and they were of no assistance. I don't have an ODBII reader but I think I'll go shopping online.

**russellw** · 13-03-2019, 08:08 AM

Certainly an OBD reader is a good start. I've not heard of the issue but there are a number of possible causes and some error codes will help with diagnosis.

Cheers
Russ

XCeed · 01-01-2021, 07:12 PM

Hello again,

The Mondeo is still going, still missing a bit under load. Just curious, what amps and voltage are coming out of the ecu ignition pulses? Thanks in advance for any info.

**russellw** · 02-01-2021, 09:47 AM

Did you ever gather any codes? Which engine?

XCeed · 02-01-2021, 10:45 AM

Hi Russell,

Not yet. I blew up my laptop trying to hook it up to the OBDII port with the wrong cable. I have since repaired my laptop and have an OBDII cable on order. It's a 'Modified ELM327' cable so fingers crossed.

I want to measure the voltage and current of the ignition pulses coming out of the ecu and might need my brother's oscilloscope I think. I'm hoping someone can tell me what to expect. I'm guessing 12V and maybe a couple of amps as I've read the igniters are built into the EEC V circuit.

The engine is a 2.0L Zetec 96kW, LAAN strategy EEC V. Thanks.

**russellw** · 02-01-2021, 12:42 PM

Let's get back to basics a bit.

The integrated electronic ignition system consists of a crankshaft position (CKP) sensor, coil (pack or coil on plug) and a PCM.

The CKP sensor indicates the crankshaft position and speed by sensing a missing tooth on a pulse wheel mounted to the crankshaft. The system uses the CMP sensor to identify the compression stroke of cylinder 1 and to synchronize the firing of the individual coils.

The PCM uses the CKP sensor signal to calculate a spark target and then fires the coil to that target.

The PCM controls the ignition coils after it calculates the spark target. The current flow, or dwell, through the primary ignition coil is controlled by the PCM by providing a
switched ground path through the ignition coil driver to ground. When the ignition coil driver is switched ON, current rapidly builds up to a maximum value, determined by the coil inductance and resistance. When the current is switched OFF, the magnetic field collapses which induces a secondary high voltage surge and the spark plug is fired. This high voltage surge creates a flyback voltage which the PCM uses
as a feedback during ignition diagnostics.

There is a misfire detection monitor that counts the number of misfires in an operational cycle but it's a value you need to read.

I can get reference values for most of these but it really will help to have a DTC to narrow down the several hundred pages of diagnostic data!

XCeed · 02-01-2021, 01:53 PM

Thanks Russell, I reckon I understand that comprehensive description.

I'm just having a look at FORScan and ForDiag software. As soon as I get this ELM327 device I'll have a look for error codes and hopefully find some sort of irregularity. Thanks for your help.

Cheers, Brenton.

cobrin · 03-01-2021, 01:28 AM

I reckon after 20yrs even though the resistance checks out it'll probably be a coil pack. But that's a stab in the dark from this side of the monitor I'm afraid.