Beejay993 Posted June 20, 2014 Share Posted June 20, 2014 Good evening, I'm wondering if anyone can offer me some advise...my Sigma 150 has developed a rough idle, whereby it sometimes gets close to cutting out, before eventually settling out again about 850rpm again. I would say it's idling lower than normal however... The other strange thing, sometimes when starting the car it struggles to fire up, and when it does, it runs with a severe flat spot, before clearing itself, alternatively, if I shut it off and start it again, it's normally fine ? When I started it tonight, it was idling ok, then out of the blue it started stuttering and spitting then cut out altogether. Any ideas as to where to start ? It's worth pointing out it does have the usual 150 flat spot, and the nice pops and bangs that go with it, but at present it's worse than normal... Link to comment Share on other sites More sharing options...
AdrianC Posted June 20, 2014 Share Posted June 20, 2014 I have Sigma 150 and regularly find the butterflys go out of sync. Check 1&2 are opening and closing exactly the same as 3&4 . Adjusment screw is nearest the air filter. I also have found setting the idle to 1000rpm also helps, adjustment screw nearest the block. Adrian Link to comment Share on other sites More sharing options...
slap_ed Posted June 20, 2014 Share Posted June 20, 2014 Hi I have the same sigma 150. I too tend to set the idle speed to around 1000 rpm and balance the air intake for each of the four trumpets. The little grub screw and lock nuts allow all four to be individually balanced. After that the TPS needs to be set to the correct voltage which I think is 1.03 volts (memory). Adjusting any one of these areas has a knock on effect with the others so you might need to go back and re-tweak the others. Then disconnect the battery for a few minutes and then re-connect. If you get it right then it should tick over smoothly and run sweet as a nut. Touch wood... Mines never been a problem and runs beautifully. Best of luck Link to comment Share on other sites More sharing options...
diggerman Posted June 21, 2014 Share Posted June 21, 2014 I also have a 150,andt touch wood it runs perfectly. 16500 miles. Two things ooccur to me. Have you had the latest map applied? Caterham Midlands remapped mine about 3 years ago with what I think was the 4th version. There are less pops and bangs, but it still sounds great with no flat spots and great peformance. The second thought is that your lamda sensor might be failing. They do that! Its an easy, relatively simple fix. If the running/idling gets worth suggest you fit a new one. Peter Link to comment Share on other sites More sharing options...
Beejay993 Posted June 22, 2014 Author Share Posted June 22, 2014 Thanks for the feedback guys...send the ECU back to caterham and they have remapped, which made little difference so disconnected the lambda probe sensor and it runs much better - now I have the task,of removing and replacing it! Any tips for removal? Will it need a heat as it's solid ! I must say the car does run better, but it seems slightly slower...maybe it's just me over analysing things ! Link to comment Share on other sites More sharing options...
ChrisC Posted June 22, 2014 Share Posted June 22, 2014 My 150 will run like a bag of spanners if its not setup exactly as per the recommendations, which is all throttles drawing 4-5Kg/h at 950rpm (+or- 50rpm) with the ECU reporting 1.04v from the TPS. You really need the easymap software and lead to get it spot on, but when you do the 150 is a little honey. Pulling clean in 5th from 1200rpm without hesitation and perfectly steady idle. Link to comment Share on other sites More sharing options...
ChrisC Posted June 22, 2014 Share Posted June 22, 2014 PS you don't have a location, willing to help if your local. Link to comment Share on other sites More sharing options...
Beejay993 Posted July 3, 2014 Author Share Posted July 3, 2014 Thanks guys, any advice on removal and replacement of the lambda probe...it's solid and cannot get it off...does anyone know the part number for a replacement ? Thanks in advance Link to comment Share on other sites More sharing options...
ChrisC Posted July 3, 2014 Share Posted July 3, 2014 My original Ford part was manufactured by Bosch, and had the Bosch part number 0258006599 stamped on it. I recently purchased one from eBay using that part number for my cat bypass pipe, which was a perfect fit, had the correct connector and functioned perfectly. You can get cheaper alternatives, or more expensive ford branded. Edited by - ChrisC on 3 Jul 2014 22:13:16 Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted July 4, 2014 Share Posted July 4, 2014 You need a long spanner ... leverage is your friend. You could warm (quickly) around the pipe to make that expand and release corrosion on the thread. eBay is also your friend. Look at the number on the removed sensor and search. Link to comment Share on other sites More sharing options...
Beejay993 Posted July 20, 2014 Author Share Posted July 20, 2014 Now I'm stumped...I sent the ECU back to caterham and got the most recent map installed, replaced the lambda and the TPS with new items. I also carried out the recommended mod of taking the vacuum pipe off the MAP sensor and leaving it open to atmosphere and blocked the pipe at the manifold end, throttle bodies balanced and TPS set to 1.03v. Initially the car idled ok, but when I took it out and it comes to a stop (at a set of lights got example) it cuts out every time; clearly does not want to idle. If I disconnect the lambda it stops cutting out ? Any thoughts at what could be causing this issue ? Could it be a faulty lambda? Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted July 20, 2014 Share Posted July 20, 2014 Got it in one. As per my suggestion in several other threads recently. Remove it and read the number. Find and buy on eBay. Link to comment Share on other sites More sharing options...
ChrisC Posted July 20, 2014 Share Posted July 20, 2014 I think your going to have to see what the ECU is thinking, seeing to get to the route of the problem. Your going to need to get the MBE lead (or purchase one from SBD). You will be able to connect a laptop and take it for a drive. You will be looking for sensors that are repotted as missing or the values that look strange. Sorry Link to comment Share on other sites More sharing options...
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