Throttle pickup

[Wheelnut]

Hi, I am new to my Caterham Roadsport 1600 sigma 150 HP. It seems to stutter slightly as you blip the throttle from idle, especially if the engine is slowing to idle (revs dropping). This is a pain when changing down as I tend to double de-clutch to rev match in the down changes. This means I have to give a huge bootful of throttle when on the brakes and there is a delay before the revs rise ready for the lower gear. Caterham says "they all do that" but I don't know - it seems odd to me.

 

Anyone with a Sigma 150 know anything about this or have any suggestions?

[Stationary M25 Traveller]

There were apparently a lot of 150 cars that were really difficult to live with. One solution has been to get it converted to the Supersport 140 spec.

 

How old is your car ?

 

Believe the 150 is no longer offered from CC.

[Wheelnut]

Thanks. It's a 2010 reg, factory built in 2009. I would quite like to get it running properly before I go down the road of converting it though.

[Domus]

Mine is of similar vintage. Built from a kit in the summer of 2010. Hesitant to pick up, pinking in third, a few pops and bangs. It has just destroyed it's Lambda sensor and 4 plugs whilst using two and a half tanks of fuel in 180 miles. Booked in with the two Steves' at the end of the month. Will report on here. Stand by.

[RedCat7]

They don't all do that Wheelnut. On mine, any poor running is usually sorted by balancing the Throttle Bodies.

[Domus]

Whilst on this subject, has anyone on here fitted a lightened flywheel to a 150? If so, how is it?

 

Thinking ahead to next winter's project.

[steve m]

Mine has been like that on some occasions, I adjusted the idle back up to 900rpm and it doesn't seem to do it any more.

[Michael G]

Wheelnut,

Of the several woes I acquired with my new 150 three years ago, this was the the one which most spoiled my driving fun and for exactly the reason you describe.

YHBM

Michael

[slap_ed]

As RedCat7 says. It's probably down to the throttle bodies. I have the same spec 150 2009 and it runs as sweet as a nut with no hesitation. (Love it)

I think if you balance each throttle port air intake (not just each pair) and set the TPS to the correct voltage, I'm sure it will go a long way to fixing that problem.

Also, how many miles have your plugs done? It might be worth checking the gaps, although they don't tend to need any adjustment.

 

Graham

 

[Wheelnut]

Thanks Guys - some really good ideas. It nice to know it's not just me! I knew it would be a bit touchy to drive and I have got used to it and love it now in every way. If I can find a way to get the throttle to pick up a little better for the down changes I would prefer not to go down the 140 route. Anyone know where I can find the details on how to setup the throttle bodies? I have done all this before but with the old SU carbs etc, never with this more modern arrangement ( showing my age now!).

 

As a new member ( albeit not entirely new to a Caterham) it's grate to know you guys are there to offer help - thank you. By the way who and where are the two Steves?

 

[Stationary M25 Traveller]

Track & Road, Rainham in Essex. Near Circus Tavern

[ChrisC]

Quoting slap_ed: 

As RedCat7 says. It's probably down to the throttle bodies. I have the same spec 150 2009 and it runs as sweet as a nut with no hesitation. (Love it)

I think if you balance each throttle port air intake (not just each pair) and set the TPS to the correct voltage, I'm sure it will go a long way to fixing that problem.

Also, how many miles have your plugs done? It might be worth checking the gaps, although they don't tend to need any adjustment.

 

Graham

 

Your looking for a steady 950 rpm, all throttle bodies balanced and a TPS voltage of 1.05v. The best way to get the TPS voltage is connecting a laptop to the ECU, and let the ECU tell you the voltage its seeing. It takes a bit of fiddling because each adjustment effects the others.

 

My 150 (newly converted from 125 this year) is a dream to drive once these settings where correctly adjusted. It will pull in 5th from 1500rpm, could not ask for more really.

 

 

 

Edited by - ChrisC on 4 May 2014 13:44:29

[ChrisC]

To keep your 150 singing your going to need the laptop to ECU lead (or find someone that has it) any a synchrometer to get the throttle bodies balanced.

 

The lead (and software) you can get from SBD at here

 

Once you have the lead you won't be able to make changes to the map, but you can see the live display of information from the ECU. This will also help with diagnosis of other sensor / wiring problems.

 

Willing to help you, but you may find someone local that has the equipment.

 

Hope this helps

 

[Wheelnut]

Thanks again guys. Looks like I have a little work to do! I will try the suggestions made here and see how I get on? If I fix it I will let you know.

[ChrisC]

Sent to me via email from Malcolm Temporal

 

I also have 150bhp

7 which was a 140 and upgraded by a friend that works for caterham. now there is a new

software for the 150 which I have, which is much better. also they found it better with

the air for the fuel injection, piped from the 140 filter. I am watering for caterham to make a mod .

 

I think his referring to the "h" version of the 150 map, you can tell is this is fitted because the map sensor won't be connected to the inlet manifold.

 

Hope this helps

[John Hughes]

Hi ChrisC

 

Do you have or could Malcolm send more info / pics on how the air from the 140 filter is piped to the 150 throttle bodies.

 

I have done some comparison run with my 140 against Domus's 150 and found the air intake temp on mine to be a steady 15C but on the 150 it was 35-40C.

 

Edited by -

 

Edited by - John Hughes on 5 May 2014 17:47:39

 

Edited by - John Hughes on 5 May 2014 17:48:20

[Domus]

Been called many things in my life ..........but never Sinus

 

Edited by - Domus on 5 May 2014 14:41:29

[ChrisC]

Sorry this was a copy and paste from a former member (that is obviously lurking on here) but is off to Cyprus soon so is not renewing his membership. So I am not 100% sure how this was done.

 

Yes a 140 will have the advantage of colder air intake, but (and the reason I went 150, over 140 at considerable additional effort) the 150 has throttle bodies, and they look nice 😬.

 

PS Yes I am that shallow

[Domus]

Well, what can I say that has not been said before. The Two Steves' are fantastic. The attention to detail is first class as is their knowledge and expertise. My car has been transformed, it picks up instantly and pulls all the way across the rev range. I was thinking of a lightened flywheel for my next upgrade but their work has negated that idea, it really does fly. Very impressed, the workshop may not look like the McLaren centre but the end product is top quality. 😬 Next project is trying to get cold air into the throttle bodies. Top tip, take a chair it could be a long night.