Very Bad Surge/ Hesitation/ Stumble @ 2,200 Rpm
Very Bad Surge/ Hesitation/ Stumble @ 2,200 Rpm
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Discussion

neutral 3

Original Poster:

8,561 posts

199 months

Monday 5th September 2011
quotequote all
Difficult to describe this fault exactly , but shes almost undriveable at the moment .
At approx 2,200 rpm, through to aprox 3,000 rpm, She appears to completely lose power, hold back, surge , lose power etc. As soon as 3,000 rpm is reached it's fine. It's as if the ignition key is being rapidly turned on and off again and again.

This problem seems to come and go, it started again recently after turning left at a set of lights. ime wondering if it's the Fuel Filter, thats clogged up , or the Pump, but why does it clear @ 3,000 ? when the engine needs more fuel . Hissys MX5 has a similar problem.

Got a strong petrol smell I'n the boot as well. Any ideas much appreciated!!

davetherave1970

2,144 posts

275 months

Monday 5th September 2011
quotequote all
First guess would be the air flow meter.
I think the ECU doesn't read it when above 3k or so revs.
I'm not that technical so don't take my word for it but do give me a price if i'm right smile

Barry Sheene

1,524 posts

312 months

Monday 5th September 2011
quotequote all
could be a faulty alternator....(but again this is a pure guess) had a similar problem with mine last week and the alternator was the culprit (only chucking out 11V or so)...

Simon says

19,440 posts

250 months

Monday 5th September 2011
quotequote all
With a fault like that I would get a ECU fault code reader on it,I had a similar problem years ago and turned out to be the throttle potentiometer (worn track) failed only at certain temps frown very hard to track down & I didn't use a fault code reader to find that one rolleyes

Barkychoc

7,848 posts

233 months

Monday 5th September 2011
quotequote all
Doesn't the ECU stop using lambda readings after 3k or so?

Simon says

19,440 posts

250 months

Monday 5th September 2011
quotequote all
Barkychoc said:
Doesn't the ECU stop using lambda readings after 3k or so?
yes about that wink

Loubaruch

1,444 posts

227 months

Monday 5th September 2011
quotequote all
Try unplugging the throttle pot and see if it clears. Most ECU's will revert to limp home mode with this disconnected but not sure if the Rover system follows suit, worth a try anyway. Fault certainly suggests it could possibly be the throttle pot.

neutral 3

Original Poster:

8,561 posts

199 months

Monday 5th September 2011
quotequote all
Thanks for replys and sugestions. Took her for a blast earlier, but almost undriveable. Will try have a look tomorrow if time.

John N

22 posts

181 months

Monday 5th September 2011
quotequote all
Hi All / OP - First post for a (very) long time under a long since lost different login.
I've experienced very similar symptoms myself this year. In my case, the cutting / violent surging happened repeatedly at 2600 rpm. Condition deteriorated rapidly from initially only happening after driving on full throttle to happening every time 2600 rpm was exceeded; made the car undrivable and unsafe. There have been some other posts around this topic recently which have suggested disconnecting AFM / ECU and resetting. For me, this had no effect and the problem remained, nor did the fitment of a new coil. Solution was a combination of problems that were the T'Pot and ECU - diagnosed and "cured" (items replaced) during a Mark Adams mapping session on my 500 at TVR Power.

As T'pot has already been mentioned as a candidate, you will find, like other electrical components they are available at a variety of price points; Mark Adams uses Land Rover ones...... good enough for me.

John

ESDavey

713 posts

248 months

Tuesday 6th September 2011
quotequote all
Sounds exactly the problem I had which turned out to be a knackered AFM. I'm told you can run without the AFM connected so pull the multi-plug & go for a test drive.

Good Luck

Also see thread :
http://www.pistonheads.co.uk/gassing/topic.asp?h=0...

Edited by ESDavey on Tuesday 6th September 08:01