Huge flat spot circa 3500rpm

[Emsman]

Blimey,

2 weeks in. Speedo due to be fixed.

Booked in for straight through exhaust at same time as sender being replaced (seems worthwhile)

Now, can anyone assist with the flat spot i get in any gear at around 3500rpm?

Pulls beautifully below that, and clears its throat again at 4200rpm, but really struggles between the 2.

Any suggestions???

Feel better for a couple of sunny days, and a good clean and polish, just looking forward to being able to see how fast i am going, and of course, having a clean run somewhere.

[Corky]

I am no expert, I had this and it was the cam, this ocurred at 45K? Hopefully someone else can disprove this.

[Emsman]

Great.

Car has done 44k

That doesnt bode well at all, does it?

Any idea of cost for said items???

[absolutely]

Too much oil? An employee of ours filled my racing car up with oil after draining it, he put in about a quarter of a pint too much, so when I went from 3rd to 4th it had no power and struggling to get up the hill.

[Corky]

Look on the bright side, it may not be the cam, but mine cost me £1200, mine had been running very badly and sadly I just didn't notice it, the one bonus is that it is now like driving a new car, absolutely amazing. I hope someone else who has mechanical knowledge can offer some alternatives up.

[Emsman]

Hopefully a lot cheaper too.

I have had the car 2 weeks and covered less than 160 miles.

Not a good start to ownership i would suggest???

[chrispitman]

Not shure why it recovers again but at about 3500RPM thats when the ecu stops reading the lambda sensors, for fuel adjustment so could be a fuel/air ratio problem.

[StreetDragster]

If the lambdas are suspect, for testing purposes only you could install the 'green' tune resistor, which allows the ecu to run without lambda sensors without throwing a fault code.

Thanks

Matt

[Emsman]

Streetdragster,

If i had any idea of what that meant, I would do it without hesitation.

Unfortunatly, I dont, but will ask the appropriate mechanic as soon as i can.

Thanks very much for all of the advice though, its all much appreciated, even from a mechanical dunce like myself.

[StreetDragster]

Ah, sorry, shoudl have elaborated.

In the passenger footwell there is a panel that is pulled out, and behind that you'll find the loom, ecu, and battery.

If you pull out the ecu/loom and look on the loom within about 12" of the ecu there is a blue plug, with two wires out of it with a resistor in clear shrink wrap.

This is your tune resistor, and the value of that resistor tells the ecu which one of its stored maps to use.
The colour of the wires dictates usually which resistor you have, white for a cat map, green for a decat map

if your in the North West, i have a green resistor you can try?

THanks

Matt

[crispian22]

could be ignition timing slightly out,or the vacuum advance unit on the side of your dizzy being a bit worn.both relativley cheap fixes.worth a try before lashing out on a cam job.

[Emsman]

Folks, thanks for all of the advise.

Went for a quick drive last night and the probem is getting worse.

Now running foul between 2500 and 4000. Really isnt happy, then the oil light came on.

All on a car that has 'just been serviced'. Gutted.

Will change oil tonight, and have a look at the proposed ideas posted here.

Many thanks indeed so far..................

[Corky]

Sorry to hear about your dramas, good luck with the fix, once its fixed you will never regret having got ot, honest.

[Emsman]

Corky,

I dont regret it now!!!!

Just wish that the first 2 weeks had been slightly more enjoyable!!!!

Was planning on a straight through exhaust, but finances may be better spent elsewhere for now i think!!!!!!

Fingers crossed its something straightforward (ie cheap) to sort out.

Its seems a shame to have polished it to within an inch of its life, only to be unable to use it to the full potential

[blitzracing]

Its worth considering borrowing a fault code reader to plug into the ECU loom, as a fault this bad should generate a fault code. A local Range Rover dealer should be able to do it, or there are people on this forum who hire them out for around £10 a week.

Mark

[Emsman]

Didnt realise that such a thing would show up on those, im a bit new to all this TVR type stuff im afraid.

Im sure i can obtain one from a friend though, he deals with such things on older Range Rovers, so, if he is back from his holiday, i shall have a word.

Pics of my old girl under the 'my new chimaera pictures finally thread'

[Corky]

Emsman said:

Corky,

I dont regret it now!!!!

Just wish that the first 2 weeks had been slightly more enjoyable!!!!

Was planning on a straight through exhaust, but finances may be better spent elsewhere for now i think!!!!!!

Fingers crossed its something straightforward (ie cheap) to sort out.

Its seems a shame to have polished it to within an inch of its life, only to be unable to use it to the full potential

Fingers crossed

[coetzeeh]

I gather you have done the obvious stuff first?

Check all plug leads + connectors are properly seated - especially after a service. Stranger things have happened.

[Emsman]

Yeah,

I checked all of the obvious, but to no avail.

Not even an HT lead loose

I shall have a better look tonight and see if i can get to the bottom of the problem, its heartbreaking, it even sounded poorly last night!!

[Emsman]

Just found this on another forum, and think this may be worth a try.

Now, if i only knew where the injectors where, i would be in business!!!!!







I have just diagnosed a misfire on my chimaera after about five weeks of head scratching and thought I would post it up here as I have found this forum very useful in trying to diagnoses it.
The syptoms were a slight loss of power, misfireing between 4000 and 5000 and sort of clearing after that also it hadn't been idleing quite as well as normal.
The first starting point was the ignition although the cap, arm, leads, shrouds and plugs were all new two months ago. I'm in the fortunate position of having a landrover with the same engine to swop parts between the two. After trying a couple of things I swoped everything off the land rover from the distributer to the plugs and still no improvement. So then I tested all the injection components with a mutimeter and still nothing showed up. The next step was too conect up a fuel pressure gauge and I changed the filter as a matter of course (the old one being very old) and whilst the misfire was happening on a road run I still had 42psi of fuel pressure so that eliminated the pump, filter and fuel lines. Feeling a bit depressed I booked it in our local land rover specialist to have to codes read only to find the computer wouldn't register with the igintion on as someone had cut the third wire to the plug off and I ended up with just about every code in the book with the ignition switched off. Then on the way home the fuel pump stopped and I had to push the car the last half mile home! Although that was soon rectified as I had disturbed the spade conector on the pump changing the filter.
Having left it for a week I decided to have another go this weekend in my mind it had to be a weak fuel mixture and all the plugs were the same brown colour with no variation and no glazing which made me think it was the ecu weakening the mixture at higher revs I had already tested the injectors with a mutimeter and they were fine.
Then with the bonnet up in the workshop I reved the engine up to 4000 and the miss was more like a popping back fire sound so I went along the injectors pulling off one connector at a time and reving it up until you could hear it popping and then to my Joy I pulled off no.7 and the popping cylinder changed to a missing cylinder and the culprit was found! It had obviously been delivering a weak mixture after 4000 due to blockage or somthing a quick spin up the road with the plug off confirmed the problem and I now have them all out for repair and a service.
Looking back at it now its probaly quite a simple cause but apparently quite rare as well, so if your trying to diagnose a misfire and it has a popping sound to it, try pulling the injector plugs off one at a time it doesn't take long and doesn't cost anything so its worth a try.