Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Diagnosis please?

Crumbs what an effort to get that off. Only achieved by lying across both seats and using two screwdrivers. Hope I don’t need to do that when I’m 80. It looks pretty clean to me but I have squirted it with contact cleaner, now just waiting for the roads to dry off (or it’ll be back to Craig’s)

So, finally managed to get the throttle connector off and sprayed it with contact cleaner, then off for a blast and, the fault is still there. Bit windy though, isn’t it?

One tip, Colin, Spanner Juggler, was recommending as well, which I did also, unplug the main plug of the ECU carefully. It is saved with an allen screw which has to be turned out. My plug was not 100% aligned. It may help, but we are in the level of trial end error. Do not use contact spray regarding this mail plug. It can be cleaned mechanically just by pulling it out and then carefulle putting it back again.

The ECU is below the smaller box (anti theft) in the tinny compartment in front of the windscreen at your driving side, where the fuses are as well.

Because I still think, the brake pedal circuit could be the culprit, could you check if the wire from this switch to the ECU pin is not broken? usinf a ohm meter. TBH I do not know which contact tap it is, but I think it was mentioned here in this thread somewhere. I may be too stubborn and too insistent, sorry, but I just want to help. Sometimes the devil is in the details. If I were you, I'd bypass the new switch for a while to be sure it's not the fault.

SFG, if I were in your area, you can be sure that I would help you there as much as I can. I had this drama for over a year and I know how frustrating it is.

Don't forget the MAF sensor (the plug I mean).

And because I want to test under all operating conditions that this error has disappeared permanently, I installed the open air filter again today. That's when it all started. I will report.

BTW(sorry if off topic) this is my new K&N type open filter which also has the connection for the breather. Almost the same one as coming with the Ford Fiesta Sigma VCT 57i kit. Connecting the breather is important in my view, a) because there is still energy in these gases that is used a second time and b) because it helps the engine to get rid of the blow by gases by negative pressure. So she has more power.

Me again:) SFG, I took another test a year ago. Drive a lap without the plug of the MAF sensor connected. In this case the car drives in emergency program. When the error in this status is gone, you can limit the search to the parts that are not involved in the emergency program. Your car will drive terribly, without power, without VCT, without input from the Lambda sensors. And much too fat in the mix (so nothing will break this emergency mode is set so fat).

But for me the error was still there! And that is logical, if it was because of the brake pedal switch. Because this is a switch to another mapping, which also remains in the emergency program.

You would be one step further where to look and where not.
You will get the engine light in this mode, you should delete the errors with your OBD2 after you have reconnected the MAF sensor finally.

Heinz I really appreciate your help, especially as this is not your first language and you make an excellent job of explaining.
Perhaps the correct pin on the ecu is noted on the wiring diagram, so I'll set out to track that down and try to work out if the circuit rings out. I agree it seems likely there is something causing it to behave as if the brake is being pressed.
However, if it is a damaged wire, there is still contact some of the time , and always when the car is stationary, so I might not be able to trace it by ringing out.
The switch is normally open, meaning that braking opens the circuit and cuts the signal, and thus the fuel. If there's a broken wire, there would be an intermittent open circuit to the ecu, so it could momentarily cut the fuel. That checks out.

But I'm not sure what you mean by the "MAF removed" test you have suggested.
Are you saying that, if the car drives in emergency mode, the fault cannot be in any of the circuits which support emergency mode, and must be elsewhere?

By the way, I've forgotten-are you still getting this problem?

Does anyone know what is done at the service that might have triggered this fault?

SFG, in my case the problem is 100% cured...until now. At least since some weeks and several longer drive after I first bridged the switch and secondly after I replaced the switch it is still fine. This is the reason I go back to the open filter just to see if it is really solved. Because when I drove with an open filter it occured the first time.

When I had removed the MAF plug the car turns into emergency mode. That means that essential features which provide the good performance are out of the way. E.g. MAF sensor itself, Oxygen sensors, VCT (the control of the variable camschafts), and I think (I do not know exactly, but it should be logical) the petrol/oxygen mix is statically fixed because there are no more parameters that optimize it for all different situations.
This means that all these sensors, which are no longer in play, cannot be the source of error if the error still occurs when driving in this mode. Maybe another experienced TM can confirm what I say so that you feel more secure. But I think it's true.
At the moment it's all about isolating the error, like a differential diagnosis by a doctor.
If the error is still there when driving in emergency mode (some say limp home mode) you can concentrate on the parts which are still with a function despite this mode.

I also thought, if you have a dealer close to you perhaps you could change the ECU for a drive to see if that makes a difference.
BTW do you have a battery switch? Or can you disconnect the battery easily? Sometimes it makes a difference if the ECU is interrupted from voltage for a time, even if this will not delete faults which can be seen in a OBD2 reader.
An example, after I installed the K&N filter today I got 7 times after a few minutes the error that the Oxygen sensor 1 shows wrong values in pushing mode. I deleted it again and again in OBD2. But it came again and again this message.
Then I disconnected the battery and connected it again after one minute. Since then the error did not appear after 100 km and the car drives very well.

Do you have an OBD2 reader?

Just a thought: if we’ve both had the same fault, and yours is cured? Less likely to be a broken wire? Might be a good plan to disconnect the battery, that works with our laptop!
I bought an OBD2 reader
Ok I will try the “MAF test “ and let you know

Stuart, yes, a broken wire could be a cause, This is why I suggested to check the wire from the pedal to the ECU plug with an OHM meter.
It must be a fault where the contact is sometimes given and sometimes not. If the wire is „really“ totally broken without a frequent contact you would probably drive in the wrong mode but you would not experience the interruptions. Then you would have a constant drive, even if is too fat in the fuel mix and not intended with the exception of braking times.

Yes, let me know the „MAF test“ result. Have a good night.

Ok MAF report:
First I disconnected and reconnected the battery and did 20 miles. The fault began to occur after about 15 miles.
I disconnected the MAF connector and did another 20 miles. I think there was one hesitation early on but then nothing, it drove happily.
Also the car did NOT go into limp mode and showed no engine warning lamp. The mixture is running richer.
I have two fault codes :
- intake air temperature Sensor circuit 1 High
- mass or volume air flow A circuit low
(Not cancelled yet)
Haven’t done the “bypass BPS test” or the “check wiring” tests yet.

So something to think about while I conduct the “GTASSABPC test”


(Gin tonic, and Sea Salt and Black Peppercorn Crisps). I’ll report later on that one.

Stuart, thanks for the update. First of all, I might have confused it with another car and the engine light doesn't come on when the MAF sensor is disconnected but that shouldn't bother us.

Nevertheless, it is obvious that without the MAF sensor connected, the ECU must fall back to fixed stored values. These values are richer in the mix for safety against engine damage.
The messages in the OBD2 you mentioned are totally normal when you disconnect the MAF sensor.

Did you drive again with connected MAF sensor at the end?

I would proceed as follows. My thought is that you drive another one or two times a distance of several miles - with MAF sensor connected, and without MAF sensor connected.
The error of jerky driving with the MAF sensor connected should be repeatable. Driving without MAF sensor should be repeated without this fault. Thus I would like to exclude the possibility that it was only a random result today.

If everything turns out as intended and as expected, the error could be further circled.

As I wrote, with my car the error was always there... with and without connected MAF sensor. This suggests that the fault in your car has a different origin than mine.

If the error repeatedly disappears when the MAF sensor is not connected, I would actually focus the further analysis on the MAF sensor.

Three things can perhaps play a role here.
1) the MAF sensor itself is defective and must be replaced
2) The plug is defective. I spoke to the master mechanic of my Morgan workshop about our problem when I changed the BPS switch. He told me that they couldn't find a similar defect at first, when they tested the same Sigma 4/4 as ours. The MAF sensor was replaced twice (for testing purposes only, not at the customer's expense). But nothing got better.

In the end they discovered that one of these five wires had a cold solder joint on the plug. They re-soldered the connection and the fault was gone.

I would remove this red plastic oval of the MAF sensor plug with a very fine pair of pliers and check if everything is ok behind it. It looks exactly like in your photo of the gas pedal plug. There could be a grease film behind it, which causes a light current conduction between the pins. At least rainwater and washing water goes there. Spray with contact spray and let it dry very carefully. Afterwards very carefully push the red oval plastic part back onto the free standing and vulnerable pins.

3) This is just my guess: The way to the MAF sensor is much shorter in the original Ford Fiesta or Focus. It could be, so my guess, that under the wrapping these wires are extended at MMC, soldering or cold pressed. Because with the Morgan the way to the MAF sensor is much longer. This can also be a source of error.

So first drive again to create the symptoms repeatable and to stop them repeatable.
Then test these three possibilities described above. This is only my suggestion, maybe our TM friends have other ideas.

I have the good feeling that you have come a step further. At first enjoy your GTASSABPC test, it sounds good:)