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MG MGF Technical - Rough idle, stuttering and lack of power

I need your help to diagnose and fix the problem with my daughters F-1998-1.8i.

It started a few days ago while driving.
Tried to press the throttle pedal and it stuttered. Will accell on higher revs but a hit and miss.
Hard to start and when it does rough idle. When pressing the throttle pedal (when parked) the engine hesitates and "chokes" and coughs a nd splutters.

So far have,
Removed and cleaned spark plugs. They all looked OK. Removed and cleaned the HT leads. All look OK. Removed and cleaned the Distributer cap. Had some residue on contacts, but cleaned and now OK.
Unplgged most connectors to sensors and cleaned with cleaner. All "appear" to be OK.
Removed air cleaner and tried running without it. No change.

What next? Fuel Filter?

Help.

Cheers,
Branko



Branko

Sounds like an air leak to me. Could be a perished hose or an end has come off somewhere.

Chris
Chris

Hi Ozland Branco,
Sounds like it could be a faulty BROWN sender. Replace it ( about $20 Aus ) . Brown sender tells the K series MEMS to make leaner or richer the mixture and when they go faulty the MEMS keeps making the mixture richer and richer cos the sender is not doing it's job . Try it anyway . Bad idle and variable rev idle and roughness are the symptoms
Good luck
Swiss Tony
Tony Lawrence

>What next?

Remove and clean and put back the big connector to the ECU.
Check special the thin wires at this connectors, cause these are the wires coming from the sensors.

Then see for the brown coolant sensor as suggested by Tony.
The throttle position sensor (TPS) is linked to the same behavior as the coolant sensor is.
So that will be next to get changed if the CTS is OK.
Dieter

Thanks for your replys. Will try and attend to the suggestions soon. Just got back from 5 days sking, so I am a bit sore and worn out.

Cheers,
Branko
Branko

Here is the situation so far.
Any comments/sugggestions most welcome.

I removed and cleaned the IAC, Idle Air Control valve. It had some black soot deposits inside so I cleaned them with carbie cleaner and blew away any residue. I also cleaned the conical piston head inside so that it makes a perfect seal when closed.

The car was hard to start but once started it warmed up and seemd to idle OK.

The problem is when I flick the throttle. If I flick it (via pedal or dirctly via throttle cam) the engine hesitates and almost stalls. I then keep flicking it and it picks up speed OK. It also makes a "hissing" noise when I do that.

When I slowly increase throttle It can rev to high revs OK. While at high revs I can flick the throttle further and it gives engine power.

The engine was again hard to start after I turned it off but did start after about 6-8 secs crank time.

I also (one by one) unplugged each spark plug connector from the engine top and held it slightly away from the tip of the spark plug. Each time the engine ran rough. Then I placed it back and the spark ticked over and then the engine ran fairly smooth. This was the case for all 4 spark plugs.

I also removed cleaned and replaced the large ECU connector. No Apparent change.

I will check the fuel filter, but if the engine does run OK at high revs, then I doubt it could be the filter.


Is the "brown coolant sensor" the "Engine coolant temperature sensor" as in the Workshop manual page 201 item 6 ?

Cheers,
Branko

Branko

Yup, that's the brown sensor Branko :o)

BTW this does sound like a problem with the dizzy head - is there a crack that is not visible to the naked eye? Personally, if the dizzy head and rotor are more than 5 or 6 years old, I'd replace them anyway.

Failing that, this could be a problem with the crank position sensor (some mentions of this fault in the archives)

Good luck - and let us know how you get on!
Rob Bell

I think I have found the problem.

The Fuel Filter.!!

I go blue in the face when I try to blow through it.


Has anyone in Australia successfully found and bought an equivalnet after market one? or even a Bosch one?
I know Bosch Part Number is 0450 905 911 (F5911) but none of the shops (Repco/Bursons/Autobarn/Supercheap) list that number.

I may have to go to a dealer........ Ouch.

Cheers,
Branko

Branko

Branko
If you can wait a few days you could get the MG Rover fuel filter off ebay for about AU$20 plus $15 postage.
http://cgi.ebay.com.au/MGF-TF-FUEL-FILTER-ALSO-FIT-ROVER-200-25-45-400_W0QQitemZ290135369841QQihZ019QQcategoryZ10414QQtcZphotoQQcmdZViewItem
Mark Hughes

Still no joy.

Mark, Thanks for the link but, I just replaced the old fuel filter (which was definitly clogged) with a new crosland one from Link Automotive in Mitcham.

I also swapped out the throttle assembly including the TPS. Still kangaroo jumping on load/accel and erratic idle.

Compared the passive resistance readings from the TPS and they both read at about 4.05Kohm across 1&3. Across 1&2 from 0.52lKohm to 3.71Kohm and across 2&3, 3.7Kohm to 0.53Kohm.

Tested the engine bay air thermo and it reads 2.94Kohm.

Tested the water temp sensor and it reads 3.66Kohm.

When will unplugging and connecting of the IAC effect the engine? While it is cold or hot or both?


Cheers,
Branko



Branko

Hi! Branko,

Been reading all the comments. Back in the UK earlier
this year, two supermarket chains sold a lot of duff
petrol in London and the South East which caused a lot of problems, similar to what you describe. Apparantly the wrong sort or too much of a certain
additive was put into the petrol. It meant replacing the lambarda or oxygen sensor, cleaning out the fuel tank, resetting idle adaptions and fuelling adaptions.
Cost me about £225 which the supermarket concerned re-imbursed me for. Apparantly cost the supermarkets
millions to put right, apart from what they lost in petrol/forcourt revenues. Just a thought to add to the list of possible answers to your problem!

Bill
W.A. Pearson

Thanks Bill.

I thought about bad petrol but the car was filled several days before and was OK then.
Might pay to check out the oxygen sensor.

Cheers,
Branko
Branko

Branko, have you sorted out the problem with your daughters F yet? and if so what was it.
Andrew W Regens

Andrew,
the car has been with Links for over 2 weeks now and they have worked on it on and off (mostly off) They checked the sensors, fuel etc, but are all ok. I now find that Link don't have a testbook or similar tool that will talk to the 97' MGF's and had to get someone else in with a unit to check the ECU. The ecu has been taken out to get tested and they feel that the MAP within the ecu may be at fault? but no proof yet. This is taking far tooooo long to sort out.

Cheers,
Branko
Branko

Finally fixed!!
Picked up the car today. The ECU and emobiliser module had to be sent off to an electronics company and tested. They found the MAP clogged up in the ECU and apparently found a dry joint on the circuit board.
Once all fitted it was ok and the car was then hooked up to an engine analyser. They found that the dissy cap and rotor button needed replacing so as to increase the spark output. As I was driving it home I noticed a sound that was like the chillig knocking sound you get when a big end bearing is shot. Got it home, and I whipped out my mechanics stethascope and tracked from where the noise was actually coming from. It was coming from the top of the engine. After a little more investigation, I found that they had left a spark plug loose. Not impressed!
After I tightened it up, all was well.

Ooh, I so had wished that I could have fixed the original fault myself, but thats the way it goes sometimes.

Cheers,
Branko
Branko

Hi Branco, glad to hear you have fixed the fault. Might be worth finding someone with an analyser that plugs into a Rover MEMS unit any Landrover dealer or specialist in K series engine maitenance should be in a position to identify faults with the ECU in the car, Cheers, Alan
A.J. Mackew

Thanks AJ.
I wonder who are the K series specialists in Melbourne?
Cheers
Branko

Branko

Branko, I've been trying for five years and as yet none at labour rates I want to pay. You have Lance Dixons and Zagames with notebooks but knowone who sticks there hand up as a Freelander specialist.
I'm glad its back on the road again, see you at the hillclimb in November, same venue different event!.
Andrew W Regens

>> Picked up the car today. The ECU and emobiliser module had to be sent off to an electronics company and tested. They found the MAP clogged up in the ECU and apparently found a dry joint on the circuit board.
Once all fitted it was ok and the car was then hooked up to an engine analyser. They found that the dissy cap and rotor button needed replacing so as to increase the spark output. <<

Quite a list of problems - I am feeling pleased about spotting one of the three, but the other two I most certainly wouldn't! Glad its all sorted now - and great you found the loose spark plug in time!
Rob Bell

Hi Andrew,
we hope to get back into more MGF events soon, but at the moment we are somewhat in a sebatical with activities.
I am OK with working on most engines but due to my 8 to 5 job, unfortunatley I could not find the time I need to fix it. As it turns out the mechanics also had troubles fixing this fault, so I don't feel all that bad for not fixing it myself.

Rob,
It was a strssfull drive home with that noise. Thank fully a simple fix. The dissy and the rotor, I believe have improved the running but were not responsible for the problem. The tech did mention that the dry joint was to do with the crank sensor, so you actually had all three suggestions spot on!!

Now I need to find some time to check out the engine mounts problem on my Alfa Spider T-Spark.
More fun and games, I'm Sure.....

Cheers
Branko
Branko

Hi Branko,

tdk Engineering in West Heidelberg do a lot of work on performance improvements for Lotus Elises and Caterham 7's which, as you probably aware, use the K series engines. I recently visited their workshops and although very small workshop have a number of K engined cars being serviced/worked on. I am planning to get them to attend to the weeping head gasket on my Caterham 7 when the parts arrive from U.K.. I haven't had any work done by them yet so cannot coment any further on their competantcy. The Range Rover Freelander had a K Series engine fitted so I assume people like Lance Dixons would have the expertise to attend to any unique problems. Cheers, Alan
A.J. Mackew

Hi Alan,
Thanks for the info. I will certainly keep then in mind, but I only use mechanics as a last resort.

Caterham 7, you say?
I've always loved to get a ride in one of these cars. Hint, hint. :-)

Cheers,
Branko
Branko

This thread was discussed between 12/08/2007 and 29/09/2007

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