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MG MGF Technical - Poor throttle response??

A few months ago I started to notice that I had a noticable throttle response problem, in initially I consider that this might be a result of the MEMS having difficulty with the 162bhp (it's an mpi remember, so it's on the perifery of working perameters). Anyway, when I was last in Wolverhampton I stuck the car on the MGF Centre testbook (thanks Victoria) and it turned out that there was a marked step in the throttle response. In real terms this meant that blipping the throttle on changing down would often provoke no response at all and so requiring a rather heavier foot.

Last week I finally go around to cleaning all the electrical terminal in the engine bay (and radiator fan) including the accelerator potentiometer, lo and behold the throttle response in alive and kicking again.

So, to sum up, electrical connector can be the route cause of a number of problems, it doesn't take more than 20 minutes to do with a can of contact cleaner (thanks Rob), so come a decent weekend you could do far worse than doing the same.

Tim
tim woolcott

Well done, Tim.
I think all the sensors are from good reliability, but the connectors almost do the probs. Had similar with my MGF. (High idle, do you remember?)

Cheers
Dieter
Dieter K.

Dieter,

So which connector was it that caused your high idle problem?

Per
Per

Tim, how is your 1.8i set up? 162bhp is a good figure. Whats your touque like?
Steve Ratledge

Poor throttle response?
good time to upgrade to DTH throttle bodies! ;)
Kingsley


Also noted by an absence of engine braking. All down to a faulty TPS and/or wiring.

P.
Paul Nothard

Bugger. That means Tim is suddenly going to be going a whole load quicker on track days now! :o))
Rob Bell

Steve,

The spec is:

Includes a fully ported big valve cylinder head with larger REC inlet and exhaust valves and bronze inlet guides, the head is fitted with Piper fast road cams and Piper springs to allow later fitment of more aggressive cams if desired. The head is provided on an exchange basis and as supplied  flowsenough air for 200BHP so is ideal when later upgrades are planned. Gives large gains in torque and much better drivability. Works with the standard ECU.

Work to the cylinder head includes extensive porting to both inlet and exhaust ports, heavy modification to the combustion chamber , radiused valve seats and tapered guides. The valves are stainless steel and tufftrided and fully lapped to the seats. Inlet valve size is 29.5mm and exhaust size is 26mm. The valve springs will accomodate all cams up to 11.5mm lift.

Comprises

Pair Piper fast-road cams
Extensive porting work to your cylinder head including REC valves / guides and Piper springs
Modification work to your plenum and exhaust manifold
Vernier Pulleys

Next on the list is the Emerald....at some point in the future. This will give a little more power, a little top end torque and a load more low down torque and the best bit user adjustable.

Tim
Tim

Tim

The head sounds like a nice piece of work. I am busy thinking about my next upgrade already and doing my home work. Were your Piper fast-road cams the BP270H ? The valves sound like Paul Ivey's (Race Engine Components).

Cheers
Steve

Tim..... dont forget the Nürburgring Porsche Team work done on the exhaust manifold !!

Ted
Ted Newman

Steve, I think that Tim's got Piper 633s...

Ted - I can remember Tim's grin when he got back! LOL
Rob Bell

Tim,

How about maintainance, weara and drivability? Any changes there ?

Dennis
D Fleurbaaij

Dennis,

This is where you need to know what you're really after. If the ultimate route is to be Emerald and MTB's then the Kit I have is a sensible option, however if you do not intend anything quite so radical then a lesser port would be a better bet.

With this particular conversion although both the max torque and power are considerably up on standard, the lower end torque does not show such a marked increase. This is where the Emerald comes in, its 3D mapping can be tailored to the engine specification which the standard ECU is stuggling with a little.

The car still drives beautifully with no lumpiness at all. The only real critisism is that with the standard ECU you can't really enjoy the full potential of the conversion. The engine comes alive at 4500 and pulls right to the redline but the limiter comes in and spoils all the fun... The Emerald can change the redline :0)

So if considering the an engine conversion think very carefully how you intend to drive the car. If it's around town then this is not the best conversion, but if it's for the track or some fun back road stuff then it's spot on, instead a lesser port would be suitable.

The problem with swapping cams without the head work is that you'll simply be sacrificing torque for top end power, so there is there is the risk that unless you're in the narrow power band the car may feel slower :o( Also, swapping cams without fitting verniers is a bit of a waste, the car may become VERY lumpy and almost undriveable around town... so be warned....!

If you need any more infor drop me an email woolcottt@aol.com


Dave Andrews Web site www.dvapower.com

Steve, yes piper 633's as Rob says and Paul Ivey innards....
tim woolcott

>So which connector was it that caused your high idle problem?

Per,

Not the 100% proved cause/solution, but it's gone.
Was the mpi ECU connector, but not due to corrosion. The whole harness was loose and was pulled downwards cause of a loose cable tie at the ECU bracket.

Theory: Thin wire inlets to the ECU multi plug where _pulled_ straight instead of smooth curved and I think this resulted in force and bent spade connector females. The Tyco female contacts are two blade springs and the male contact can move irregular out of direction or give contact to one blade spring only.

However, if you like to verify, then I think it's enough on first hand to unplug the ECU multiplug once and reconnect.
Clean all like Tim said, if you feel any difference and then see for smooth curved wire inlets to the multi plug and harness fixture to the ECU bracked (bottom bracket part)

Cheers
Dieter
Dieter K.

Dieter,

Thanks for your help!

Cheers,

Per
Per

This thread was discussed between 22/01/2004 and 26/01/2004

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