Tddi ignition power cutting please help

[andyhot]

Hi everyone.

I have a 54 plate 1.8 tddi mk1 focus. I haven't had it long but when i first had it it was running fine but for the past couple of weeks its been playing me up. The car starts first crank and will idle fine but when im driving it can be running fine and then all of a sudden there is a sudden sharp power cut for just a second then it will pick up, sometimes it will do it repeatedly after a couple of seconds or sometimes it will be ok for a few minutes before doing it again. Sometime it happens when accelerating but usually its when trying to maintain a constant speed such as on a dual carriageway or motorway. When on the motorway in 5th if i try and sit at 70 it will constantly do it but if i put my foot down it will do it 2 or 3 times and then let me accelerate but as soon as it lift my foot slightly to maintain my speed it will do it again.

When i happens the Eml, glow plug, battery and immobiliser lights all come on and the speedo drops about 10mph for a second.

I have changed the accelerator pedal, crank sensor, cleaned maf sensor, cleaned and re secured all the earth points and battery terminals, swapped the engine and power relays with the headlight relays, removed and checked the instrument cluster pcb which looks in good condition, ive also visually checked all the wiring i can see in engine bay and under kick panels.

I have had a friend plug in his f super reader and its not showing any fault codes.

I am now considering getting a new ignition switch and maybe changing the vehicle speed sensor as thats all i can think it might be.

Im sorry for the long post but im at a loss and getting fed up with it now and it could be dangerous. If anyone could give me any advice or ideas of what else i could try or what it might be that would be great.

Thanks Andy

 

[Tdci-Peter]

4 hours ago, andyhot said:

When i happens the Eml, glow plug, battery and immobiliser lights all come on and the speedo drops about 10mph for a second.

I can't see how that can be any sensor, the battery & immobiliser lights should never come on due to a sensor failure. It really sounds like a complete power loss to a critical system like the ECU or the IC (Cluster). Ignition switch is possible, after that is is the major connectors, or the wiring itself, I think.

I do not have much info on the Mk1 Focus. On the Mk2, there are big loom connectors in the engine bay fusebox, and about 3 low down in front of the passenger door, under the plastic trim panel.

 

[Damien]

Hi peter

how are you mate? Hope all well, I keep getting notifications every time you comment on somebody's post.

dont take this the wrong way but it's getting very annoying lol

any idea how to stop it I haven't done anything different (I don't think)

not been on here for ages came on had like 168 notifications was like wow I been missed n all from you lol.

[andyhot]

Thank you peter.

I will replace the ignition switch and have a good look over all the loom connectors. It does seem like the ignition is turned off for a split second when it happens and the car instantly bump starts itself so you feel the sudden jerk but the engine doesnt stall due to the momentum.

Thanks again and if theres anymore suggestions please feel free.

Andy.

[andyhot]

Hi i have changed the ignition switch and its still the same. I will have a good look over the loom and connectors during the weekend. Is there any known points on focus where the loom is vunerable to damage or shorts?

Thanks Andy.

[andyhot]

Just to add ive also noticed last night when it was playing up bad that the temperature gauge dropped for a second each time it did it. (about 20 times in a 10 mile journey with forscan data logging.) It still isn't displaying any faults but i did notice a slight dip from about 14v to about 13v on the module voltage reading most of the times it did it and one time it dipped to about 5v for a few milliseconds. I believe this confirms an electrical short somewhere yet today i get up and go out in the car for a 4 mile trip and it hasn't done it once.

Any advice is much appreciated and needed.

Even though the instrument pcb looks in good condition and passes the onboard and forscan tests do you think it could be the problem? Or is it possible for me to try another pcm(ecu) on my car or would that require programming / coding?

I hate electrical problems, especially intermittent ones.

Thanks Andy

[Tdci-Peter]

4 hours ago, andyhot said:

one time it dipped to about 5v for a few milliseconds.

5v would upset a few things! One problem is, I am not sure where that reading is actually taken. It could be in the PCM, or the IC, or even the BCM (GEM).

Got a Forscan log? You can upload screenshots of the log playback, or the entire .FSL file. Not sure it will help, but there is a slight possibility it may give a clue.

On the Mk2, the PATS information is stored in the PCM, along with vehicle ID like VIN & model variants. Both the IC and the PCM need a fair bit of re-programming to swap them. I suspect the Mk1 is similar.

I too, hate intermittent problems. Usually all I can do is test them for an extended period, ideally with logging, until they fail in a way that gives enough info to narrow the search down.

The temperature gauge dip is consistent with voltage problems, the real temperature is not likely to do that.

I would be tempted to try a smallish (4 or 7 AH) SLA (sealed lead-acid) battery connected to the cigar lighter power point as a system voltage backup. On my Focus this is hard wired (via a fuse) to battery positive. It might temporarily solve the problem, and also narrow it down a bit. Mind you, starting the car with the SLA connected might blow the power point fuse. I have used one of those little batteries to aid starting with a seriously duff main battery on a couple of occasions, they can deliver quite a lot of current!

 

[andyhot]

Hi peter.

Thank you for all your help.

I did save the log but it is on my friends laptop as the forscan is his.

I will try and get him to email the log to me so i can upload it.

When i set up the log i was using the pcm options so i assumed the voltage was the pcm module voltage. 

I was considering running some new live wires via a fuse and switch from the battery positive directly to the pcm live inputs. 

I will try and get hold of a small 12v motorcyle battery to connect via the cigarette lighter socket. I dont mind just plugging it in once the car is started as the car starts first crank and idles fine.

Thanks for all your help.

Andy

[andyhot]

Hi everyone.

I think i might have a clue.

For the last 2 days it hasn't misbehaved once. The only difference is i haven't had the lights, radio or heater on. Also looking back it always seemed worse on a night. I cant be sure if its the lights, heater or radio but over the next couple of days i will introduce them one at a time to try and narrow it down. The only fly in the ointment is that i would of thought that the any of the above would blow the circuits fuse rather than cause the fault.

Any suggestions to my idea please let me know.

Thanks Andy.

[Tdci-Peter]

7 hours ago, andyhot said:

I cant be sure if its the lights, heater or radio but over the next couple of days i will introduce them one at a time to try and narrow it down.

I am wondering if it is the alternator. If a phase has gone, it can still charge, but there will be more voltage ripple than normal, made worse by electrical load.

I have heard a couple of reports of accelerator pedal problems that were due to a dodgy alternator. My neighbor (Renault van) had a poor alternator, and sometimes the engine would start, but pressing the accelerator produced no effect whatsoever. No lights, no change to engine. Just dead. Different vehicle, but shows that alternators can give peculiar symptoms.

[andyhot]

Hi peter.

I think you may have a good point about the alternator as on the log i did notice that the voltage wasnt a steady line but more of a wwwwwwwww type line between about 13.5v and 14.5v but i just assumed that was normal and that as it was over 13.5v it must be ok.

I might have access to another alternator so will try and get them swapped over and see if it cures it.

Thanks Andy.

[Guzzilazz]

3 hours ago, andyhot said:

Hi peter.

I think you may have a good point about the alternator as on the log i did notice that the voltage wasnt a steady line but more of a wwwwwwwww type line between about 13.5v and 14.5v but i just assumed that was normal and that as it was over 13.5v it must be ok.

I might have access to another alternator so will try and get them swapped over and see if it cures it.

Thanks Andy.

Over what sort of timescale was the WWWWWW? If it equates with roughly a third engine speed, that would point straight at one phase playing up...

[andyhot]

Hi guzzilazz.

Off the top of my head i cant be sure. I think it was milliseconds but will check tonight as im still waiting for my friend to send me the forscan log.

It wasnt a neat consistant wwwwww but seemed to fluctuate with higher and lower peaks but it was a jagged line.

Thanks Andy

[Guzzilazz]

Milliseconds is a bit rapid for a phase, 2000rpm is about 33 rev/sec, so i'd expect a phase to be 11 times a second, about a 100millisec period....

[andyhot]

Hi guzzilazz.

You're correct.

Sorry i should of been clearer, i didnt mean a spike each millisecond but im fairly sure it was multiple a second.

I will check when i get the log and update the post.

Thanks Andy

[Tdci-Peter]

3 hours ago, andyhot said:

It wasnt a neat consistant wwwwww but seemed to fluctuate with higher and lower peaks but it was a jagged line.

You will probably not get an accurate picture of the signal. Forscan can only sample readings when the car allows it, as the CAN bus can only do one message at a time. It is competing with all the normal stuff going on in the car. So the sample rate that you will get will be low and irregular. When the sample rate is comparable to the signal rate, or slower, you get what is called aliasing, where you get a sort of correct looking signal, but the timescale is shifted and distorted.

However, it is certainly interesting, and may be pointing to a fault. I look forward to seeing the log, or any results.

[andyhot]

Hi Everyone.

I cant upload the log file so have cut it into sections and uploaded it as pictures.

If you would like Close ups of any areas please let me know and I will upload them.

Thanks for all your help.

Thanks Andy

[andyhot]

Just to add

I got excited when I saw DTCCNT jump to 1 as I thought it had logged the fault but when we scanned it after the run it was still showing as none. Then I popped back to my friends for him to rescan it and there was a p1000 code.

Also on the log if you notice the clutch pedal being pressed 3 times quickly it is because I wanted some way of knowing where to look on the log. I didn't manage to do it every time it did it but when it was safe to do so I did. From memory it played up at least 10 times on that run.

Thanks Andy

focus log.txt

[Tdci-Peter]

4 hours ago, andyhot said:

I cant upload the log file so have cut it into sections and uploaded it as pictures.

If you re-named it with a .TXT or .PDF extension, I suspect it would upload, the system does not seem to check or interfere with these file types. Just say it has to be named back to .FSL to use. Though at about 2000 sec long, it must be pretty big!

I have had a quick look, and on a couple of times at least, events seem to co-incide with significant variations in the voltage.

It could be I am reading too much into quite small variations. I have never used to Forscan to monitor my system voltage, though I do have a continuous LED display of it available. It has always seemed dead steady when have looked at it on my car.

I guess CPP is the clutch pedal PID, and EVP is EGR position maybe?

The PID names & choices vary from car to car, so I can't check with my Mk2.

The P1000 DTC is not very helpful, it could be loads of things, but one of those things could be a voltage dip.

[andyhot]

Hi peter.

I have just tried to upload a renamed log and it still wont work. I think it is checking the file type and not just the name. The file is 4.5mb in size.

the Pids are

Vehichle speed 1

Vehichle speed 2

Engine RPM

accelerator pedal voltage 1

accelerator pedal voltage 2

accelerator pedal voltage 3

PCM module voltage

Clutch pedal position

Egr Voltage

DTC Current

 

Many thanks Andy

[Tdci-Peter]

2 hours ago, andyhot said:

I have just tried to upload a renamed log and it still wont work.

Maybe too big, or just some silly check. Pity, as in Forscan, I can use the cursor line to cross check events more accurately and zoom in if needed. But I doubt if it would really make much difference.

The link between your markers and those voltage dips looks to be 100%. Otherwise all I could see was a little spike in the speed signals at about 1700 sec.

If the battery is getting old or is defective, it can have a high internal impedance, one of its jobs is to smooth out spikes like that. It may still start the car adequately, but not react quickly enough to varying current demands.

Alternator faults are still on the list of suspects. Dodgy wiring in a rotor or stator coil, or a slipring on the way out.

Bad earths and wiring connectors can do that. You said you had checked for that, but did you remove the heavy earth connections on the bellhousing, body & battery to really look underneath, and also feel where the wire goes into the crimps. Wire conductors can fail inside the insulation, they will feel weak & floppy.

Every piece of evidence so far points to voltage variations, but is not so helpful in locating the cause. I think Forscan can monitor the AltMon & AltCom signals to / from the alternator. It just might help, but is unlikely to pin it down firmly. It is almost impossible to separate cause from effect in these sort of cases.

 

[andyhot]

Hi peter.

Yes i did remove all the earths and clean them with a wire wheel in a dremel back to shiny metal. I also did the battery terminals and lugs with wire wool, and all the connectors felt fine to me. I think i will get the alternator changed over just to rule it out and if that doesnt work ill change the battery.

I was wondering if it might be the alternator connectors or a slight belt slip but i can check those when i change it.

Thanks for all the help and advice and I'll keep the post updated.

Andy.