SIGMA 150 start up problem

[timbo]

Engine starts. Not holding idle. Runs very heavily rich. All Injectors fueling. Appears to run off cylinder. Will rev but but as off cyilnder. When indvidual coil leads detached eng continues to run but evident off cylinder noise more apparent. Will start on high load throttle angles. Coils 1/4, 2/3 correctly batched and firing - strong spark even after a rich running short period. Cylinders 3/4 plug very sooted. Cyl 1/2 plugs wet but firing. New plugs tried. TBs correctly balanced across 2x banks. Exhaust headers hot across all 4. No ign light on tacho. No LCD display on tacho (modified tacho fitted for fuel guage reading problem).

 

 

We suspect TPS either wired incorrectly (reading inversely) or defective- Checked wiring to TPS/ECU - correct. (PS CC wiring diagrams are absolutely shoite all help). Still to try new TPS sensor (had no multimeter with us so unable to validate TPS voltage resistance range direction correct)

 

Still concerned maybe an ignition problem - tacho needle stutters - as in stepper motor action - simulating off cylinder symptom? We presume the tacho feed is from the MBE - again the wiring is no help. Have tried 2x coils.

 

Lambda sensor - may be suspect. To try replacement.

 

Anyone had the same problem or suggest help?

 

 

BUSA POWWWER

[mic]

YHM

[Eccles]

I hear that a number of people had problems with their TPS wired wrongly (can't comment on mine as CC had my car for the first start/set-up). Have a search through BC I'm sure the info's here somewhere.

 

Good luck

Ivan

 

 

[The Pikey]

My TPS was wired wrong on my 150 giving the same results as yours. I have sold mine now or I would tell you which way round the wires are but why not swop the top and bottom wires around (leaving the midle one where it is) and try that.

 

Once mine was put right I had to replace the plugs as even the best clean still left the car running on two. Also the Lamda sensor needed cleaning with a airline before it ran right.

 

Jason

 

Edit: don't bother looking for the TPS on the wiring diagram cos it aint there

 

Currently, I am qualified to plead ignorance.

 

 

Edited by - Jason Fletcher on 29 Mar 2008 20:49:08

[timbo]

Thanks Mick.

 

There is a vacuum take off on no.4 TB. This is not connected from memory on this guys car - if this is the same vacuum we are talking about.

 

BUSA POWWWER

[Johnty Lyons]

Weve already swapped the TPS wiring around as we ran into that problem last year on an MBE but a K. Swapping around made no difference so it might be the TPS itself Though the ;lack of Ign light which is very loosely connected with IGN is still unexplqained as is the temp gauge ramming to the end stop [hot] on sw on and staying there.

 

The new Chassis and Eng block diags are as Timo says Shoite

At least with a full diag and some specs you could check things

I presume Caterham just presume we are all muppets so theres no point.

 

jj

N.I. L7C AR 🙆🏻

Membership No.3927.

 

[mic]

Yes, the Sigma uses the vacuum for the bar sensor. With out it will not run properly.

 

Mick

[Johnty Lyons]

Thanks Mic that hose is missing.

 

jj

N.I. L7C AR 🙆🏻

Membership No.3927.

 

[timbo]

Mick... vacuum sorted 1x problem.. Owner confirmed TPS wired incorrectly upon consultation with CC... now if they made a proper wiring diagram (rant rant rant...)

 

BUSA POWWWER

[Johnty Lyons]

Timbo 🤔 Mich 🤔 Have we sorted the missing Ign light yet 🤔

 

jj

N.I. L7C AR 🙆🏻

Membership No.3927.