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StephenR
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Kangaroo petrol

I'm new to seven ownership having got my 1.6 Ford Sigma engined car in April. 
 

Can anyone suggest a solution to this problem. I find my seven challenging to drive in town. I find that at low revs/small throttle angles the car jerks backwards and forwards and I have to dip the clutch to stop it. I have found that if I either take my foot off altogether and coast or put my foot down a little further I can more or less prevent it happening but this makes for uncomfortable progress in traffic. 
 

Is there something wrong with the car? I'm perfectly prepared to accept that the failing lies with the meaty part sitting in the drivers seat rather that the car itself, so if the answer is I'm doing something wrong happy to take that feedback too. 
 

Thanks

 

Stephen

GulfSeven
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The TPS could be out of calibration. That can cause those symptoms. You'd need a Caterham specialist with the right cable and software to set it up correctly.

Tim.

Gulf Racing 310R

Amos91
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TPS makes a big difference and set right improves the drivability at low speed.  Do you have a Sigma 150 with the throttle bodies?

Olly Amos - 2008 Caterham Superlight Sigma 150

StephenR
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I have a Sigma 150, but I've no idea about the throttle bodies. How would I know?

Thanks

Stephen

Jonathan Kay
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You're not alone: https://duckduckgo.com/?q=site:caterhamlotus7.club+kangaroo+sigma

You might get some improvement from pressing your knee against the sidewall and damping the control loop.

But as above there's a collection of technical problems that need to be excluded. 

Do you have the opportunity to compare it with other Sevens?

Jonathan

Jonathan Kay
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"I have a Sigma 150, but I've no idea about the throttle bodies. How would I know?"

Could you add some photos of the engine bay. Let us know if you need any help.

Jonathan

StephenR
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Thanks for the advice. I don't know anyone else with a seven right now, although hopefully I'll be able to go on a meet and meet some soon. 
 

I'm not home right now, but when I'm back at the weekend I'll take some engine bay photos and add them here. Thanks

 

Stephen

ScottR400D
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The TPS setting could be a reason as could a poor standard map. 

JK's idea of supporting you right leg is a good one too, and cheap to try of course!

My R400D has RBTBs and runs very smoothly from tickover but can still have the odd bout of kangarooing if not managed well. In my case it's just the sensitivity of the throttle; small movements cause accelerations and decelerations and if induced by a bumpy lane bouncing my foot, it soon gets out of hand! 

I stuck a small square of coarse emery cloth, using double sided tape, to the side panel just where my foot edge naturally touches the panel. Now, at slow speed on bumpy roads I push my foot onto this where it stays over the bumps and keeps the throttle steady. No more lurching! Simple but effective! 

L7C
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Arrow Up

Skateboard tape is probably easier and will be thinner, I use this on my brake and clutch pedals yo gain space between them by removing the rubber, you can get a fair sized pice for about a fiver Thumb Up

Tom_Arundel
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150s tend to go out of balance between the pairs of throttle bodies as well as the TPS tending to be unreliable (Ford part). Caterham also did a map upgrade years ago. They are a bit of a fiddle to get right but it can be done.

ChrisC
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Totally agree, my Sigma 150 when it first came back from a Caterham Specialist after upgrade was undriveable, but I knew the reputation and had read the monster thread on blatchat so I knew the answer.  The TPS and idle speed where set incorrectly.  Once correct it was a honey, even pulling cleanly from 5th at 1100 rpm.  The setup would wonder over time, I think due to the small springs holding the ITB screws.  I would be aware of it after 6 months, and I would reset it every service.

The only pain is if you have a version 1 Sigma 150, where the bleed screws are under the fuel rail, fingers crossed these don't need adjustment or it can take a fair bit of time.  Version 2 resolved that problem.  
 

Finally there is various spec of quadrant (the thing the throttle cable pulls) to help drivability, but I suspect if you have an early version it's going to be very difficult to track one down now.