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hesitant engine for the first 2 miles from cold
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BigAl
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PostPosted: Wed Apr 01, 2009 3:03 pm    Post subject: hesitant engine for the first 2 miles from cold Reply with quote

hey guys, I have just fitted a new Lambda sensor and as the title says I'm getting a hesitant engine for the first 2 miles from cold.
You have to push the throttle pedal further as it holds back. It feels like my old knackered lambda sensor.
It was fitted on Sunday and all was ok but Yesterday Tuesday this started to happen.
Could the lambda be faulty??

I will be able to put the car on an emission tester on Thursday night and will do a test Thursday day to see if it is the lambda sensor by changing the relay type device that tells the ecu that there is no lambda sensor connected.

I know that when the engine is cold that the lambda sensor is not taken into account as the ecu runs in choke mode, so surely it isn't the lambda sensor, i am confused, could it be something else?

The engine has just had a new thermostat, flushed coolant and paraflu 11 put in, oil, valvoline racing F1 and filter was done the week before, ht leads are original alfa ones and has correct platinum plugs, rotor arm and dizzy cap were changes 2 weeks before.
Even before servicing the car ran fine, tick over was good throttle response was good, but i was running with no lambda sensor.

I did my best to calibrate the ecu, i did it from the tail pipe emissions and adjusted the idle mixture to about 2/3 from where the maximum co/co2 you are allowed is. I have not seen an emission tester that will fit into the 10mm hole plugged up with a bolt before the cat next to the lambda sensor on our cars.

Any ideas guys??
Thanks Alan.
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johnboy
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PostPosted: Wed Apr 01, 2009 7:13 pm    Post subject: Reply with quote

Push your right foot down abit more Laughing sorry
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BigAl
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PostPosted: Wed Apr 01, 2009 9:16 pm    Post subject: Reply with quote

johnboy, you joker Laughing
It didn't seem as bad today??
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john 33_16v
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PostPosted: Thu Apr 02, 2009 7:39 am    Post subject: Reply with quote

Hi,

It is a bosch lambda? If not that could be your problem.

JoHn
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BigAl
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PostPosted: Thu Apr 02, 2009 2:33 pm    Post subject: Reply with quote

hi John, its Bosch Bosch Bosch Bosch Bosch Bosch lol Laughing
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lee16v
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PostPosted: Thu Apr 02, 2009 2:36 pm    Post subject: Reply with quote

Mine's been like it since I had it Al. Somedays it runs fine others it has a misfire for the first few minutes. I've changed alot of components over the years and nothing has made any difference. Even my local garage couldn't come up with a solution. i'm just living with it now but would be interested if anyone comes up with some answers.
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BigAl
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PostPosted: Thu Apr 02, 2009 2:49 pm    Post subject: Reply with quote

Thanks for that john,
Its weird as its only just started doing it, i let it warm up a little bit longer last time, i should get it on the emission tester today but that doesn't tell me about cold starting.
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BigAl
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PostPosted: Fri Apr 03, 2009 1:14 am    Post subject: Reply with quote

ok i put the car on the emission tester and with out the fuel selector on adjusted the idle mixture to as low as it would go and it went down to 17% co
I cant remember what the hc were but they were in the green.
Turned off ignition and connected fuel selector for cat and 95ron timing.
Then got on idle and fast idle the following
co 0.45%
hc 20 ppm
FAIL!! on high co
Forget about the lambda reading as its false, i get a good reading when its not connected.

So we connected the scantool snap-on diagnostics tester and got
a lambda readout of .54 with no change and switching between rich and lean, as it should, is it knackered? as the car nearly passes with it not connected, as soon as you connect it the co is too high???

Im not sure what an o2 integrator is but it showed -3 -14 -18?? I think this indicates that the car is running rich and the injector duration is changed.

We did the actuator control tests and could hear the injectors and idle control valve, however it wouldn't accept the purge of the vapour recirculation thingy.

idle air controller 31.1
throttle valve position 30%
map mbar 227
map sensor .98
air intake temp sensor 2.96
" " " 24c
coolant temp sens .90
" " 95c

Can anyone make sence of those reading?
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johnboy
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PostPosted: Fri Apr 03, 2009 8:17 pm    Post subject: Reply with quote

Long and short answer no Laughing on the merlot Wink
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lee16v
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PostPosted: Tue Apr 07, 2009 2:43 pm    Post subject: Reply with quote

Al, been thinking about this and the only thing I've never replaced is the coolant temp sensors. Do you think these may be playing up causing the ECU to think the engine is warm when cold thus not giving the engine the 'choke' fuel mix?

I've got two spare sensors. I might pop them in when I do the water pump and see if they have any effect.
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BigAl
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PostPosted: Wed Apr 08, 2009 1:02 am    Post subject: Reply with quote

I have checked mine against a new one and mine, when i last checked, was ok. Compare yours to what is expected
http://www.alfa-pages.co.uk/viewtopic.php?t=5744&highlight=cts
They do fail after time, i have been told they are porous.
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BigAl
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PostPosted: Wed Apr 08, 2009 8:56 pm    Post subject: Reply with quote

He lee, i think you might be onto something, i went to double check my CTS and noticed that the engine note changed when i moved the cable, i think i might have a dodgy connection, i will only be able to tell when i get it on the emission tester.
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lee16v
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PostPosted: Tue Apr 28, 2009 12:16 pm    Post subject: Reply with quote

Al,
Did you get to the bottom of it?

Just to let you know, I changed my CTS with a spare when I did the water pump and all is well in the world again (but for how long Laughing ) Well, It was only 6 years in diagnosing Rolling Eyes
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BigAl
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PostPosted: Tue Apr 28, 2009 12:39 pm    Post subject: Reply with quote

Hey lee, well done mate.
No not yet, my mate hasn’t been working nights of late so no access to the emission tester. There is definite corrosion on the cable from the CTS to the loom, I should try some contact cleaner. When the car was on the scantools diagnostics, it was registering 90c so I guess it was working. The CTS is still reading correct, 300Ohms at running temp.

I have been letting the car warm up for 2 minutes of late, but will try setting off straight away today. I have noticed that since i have changed the ECU and lambda sensor that the car now gets to idle speed in 5 seconds, whereas before it used to take up to 3 mins.
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BigAl
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PostPosted: Wed Apr 29, 2009 1:20 am    Post subject: Reply with quote

no hesitation from standstill, wahoo, changes are, different ecu and running with lambda correction and new lambda sensor.
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lee16v
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PostPosted: Wed Apr 29, 2009 12:18 pm    Post subject: Reply with quote

Cool Always nice to have a good running motor Al.
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JeremyC
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PostPosted: Wed Apr 29, 2009 2:31 pm    Post subject: Reply with quote

Lee, that's the CTS in one of the throttle bodies yes?
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lee16v
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PostPosted: Wed Apr 29, 2009 10:25 pm    Post subject: Reply with quote

Yes Jeremy, the one in the passenger side throttle body.
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JeremyC
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PostPosted: Thu Apr 30, 2009 8:51 am    Post subject: Reply with quote

Thanks.

Hmmm, think that might be my next target though the car is definitely running better with the new 'stat.

Are they generally available from motor factors? How much was it?

Cheers
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lee16v
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PostPosted: Thu Apr 30, 2009 10:31 am    Post subject: Reply with quote

I dont know how much Jeremy as mine was a spare. I'd of thought it was a main stealer part but a quick call to your local factors can't hurt. There was one on ebay last week (i've checked and it has gone....doh!) and that was up for 25 quid so that might be a reference.

Cheers.
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JeremyC
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PostPosted: Thu Apr 30, 2009 10:34 am    Post subject: Reply with quote

Do you still have the packaging, any sort of part number? Bosch or QH.

Sorry to be a pain (may even pick one up at Brooklands!).

Thanks again.
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lee16v
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PostPosted: Thu Apr 30, 2009 10:46 am    Post subject: Reply with quote

I think we've got our wires crossed.......when I say spare I meant a replacement that was sitting in another throttle body I had not a brand new spare! Sorry for confusion.

Anyhow, I've been out and had a look at the one I took off and it is a Bosch with the number 0 280 130 026 stamped on it.

Hope that's of some use.
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JeremyC
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PostPosted: Thu Apr 30, 2009 2:40 pm    Post subject: Reply with quote

Cheers.

Stock item at my local factors, about £11 plus Darling's cut.

Is it a plenum off job or is it on the outside?
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BigAl
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PostPosted: Thu Apr 30, 2009 2:44 pm    Post subject: Reply with quote

hey JeremyC
have you checked the reading from yours? I wish i did before I spent £20 on a new unwanted unused one.
http://www.alfa-pages.co.uk/viewtopic.php?t=5744&highlight=cts

Multimeter set to 20 kOhm, should get

-10C = 9 kOhm
0C = 6 kOhm
+10C = 3.8 kOhm
+15C = 3 kOhm
+20C = 2.5 kOhm
+25C = 2.1 kOhm
+30C = 1.7 kOhm
+40C = 1.2 KOhm
+60C = 600 Ohm
+80C = 330 Ohm
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JeremyC
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PostPosted: Thu Apr 30, 2009 2:49 pm    Post subject: Reply with quote

At the risk of appearing to have too much cash, at less than £15 quid I'd rather just whack a known good one (as 'known' as any new part can be anyway) and have done with it.

Measuring static with the engine off is one thing, a hot engine bay with coolant rushing past it and the vibration of driving is something else althogether.
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