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slimecity
P Plater
20 Posts
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 Posted - 21 Oct 2010 : 2:26:58 PM
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Hi there - i need some help with this. Once engine is at operating temp the CEL comes on - the code is 44 (running lean). I've had an error code for a while but only recently confirmed its a 44. Thsi code can be caused by the O2 sensor - however these werent fitted on the NZ VN's (i have a series 1).
My question is - from where is the computer receiving this code that is telling it the fuel mix is lean - if there is no O2 sensor? The computer has recently been changed - how does the car normally determine the fuel mix, for a system designed to have an O2 sensor as part of the circuit? By changing the CPU, is there a danger this system has somehow been mucked up? (ie: is there a different CPU with different fuel mix systems in NZ than for the VN's used in Oz?)
This may sound like a mental question but I'm quite confused about the code. I know I need to check vacuum and exhaust systems (etc) next, but would like to clarify this point first! cheers, simon
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Simon |
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Mechknight73
National Driver
1001 Posts
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Posted - 21 Oct 2010 : 4:27:56 PM
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| The ECM usually figures out fuel mix from the air flow meter. To the best of my knowledge, the O2 sensor, that's uspposed to be on the exhaust near the manifold, is only meant as a "trim;" it can fine tune, by telling the ECM how well the fuel mix is burning. If possible, could you shine a light up from underneath both exhaust manifolds and take a photo. Especially where the pipe goes, because this is where you would find the O2 sensor on a VN, I just can't remember whether it was left or right manifold. |
Edited by - Mechknight73 on 21 Oct 2010 4:28:48 PM |
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SKDWGN
P Plater
80 Posts
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Posted - 21 Oct 2010 : 8:36:08 PM
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| its on the left hand side mate |
wheres theres smoke theres rubber |
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slimecity
P Plater
20 Posts
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Posted - 22 Oct 2010 : 08:20:23 AM
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Hmmmm, I think a MAF was only on the VS upwards? So if no MAF, is it the MAP in my VN that helps determine fuel mix? Maybe replace this? There is defo no sensor on the intake box inline with the air filter.
Also looking down on LH side of engine to exhaust manifold, i can see a nut screwed into where (ia ssume) is the most logical place for an O2 sensor to normally sit, hence, no O2 sensor from wot i can tell. cheers! |
Simon |
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Mechknight73
National Driver
1001 Posts
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Posted - 22 Oct 2010 : 1:13:07 PM
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| There's definitely no single pin connector just hanging there? The sensors are usually acting funny for several reasons: defective component, fouling, dodgy connection, and sometimes vacuum leaks. If you had a serious vacuum leak, it would run rough as guts. If you had a minor one, it may be messing with the sensors. Check both, and if all is clear, replace them one at a time. Stress one at a time, otherwise you might never know which one was the culprit. Not just those connected to the throttle body, but check all of the sensors anyway. I'll admit I'm vague on the electronics if the air flow sensors, I just know the ones that take the place of a carburettor throttle body all seem to live around that butterfly on the intake plenum |
Edited by - Mechknight73 on 22 Oct 2010 1:17:13 PM |
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slimecity
P Plater
20 Posts
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Posted - 26 Oct 2010 : 06:36:27 AM
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| Thanks for your help - so far have checked off the TPS as being OK, and have taken the MAT sensor - its coated in layers of oil thats obviously occured over some time - should it be like that? I'm hoping to be able to test its function with a multimeter. Pretty sure the vacuum system is holding vacuum OK, have re-checked the thrtt body connections, will also check the CTS. My feeling is that I need to change the MAP sensor - if i can buy a new one here in NZ without getting too much of the RIPCO treatment.... |
Simon |
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Mechknight73
National Driver
1001 Posts
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Posted - 26 Oct 2010 : 5:04:51 PM
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| Any kind of electrical/electronic connector or sensor should be free of grease because 1. it makes it easier to spot faults 2. all dirt has traces of iron in it and 3. some sensors need to be clean to function properly e.g airflow sensors, which will carbon up over time. Just be careful how you clean them; if it looks like water can get into a connector, don't hose it. Use some WD-40 and a toothbrush, as that stuff will repel water |
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slimecity
P Plater
20 Posts
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Posted - 29 Oct 2010 : 10:31:41 AM
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OK how about this theory - the temp guage never goes above the first line - my thinking is that the thermostat coud be stuck open, meaning the engine never really warms up and the CTS keeps reading the engine as "cold", so the computer delivers a rich fuel mix.
Where is the thermostat located in the series 1 VN? I have a metal can-type assembly connected to the water hoses down by the battery - but i've read the therm is under some kind of housing at the back of the engine in the series 1? Do I have the right thing? cheers!!!! |
Simon |
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Mechknight73
National Driver
1001 Posts
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Posted - 29 Oct 2010 : 8:21:03 PM
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| Yes, you're right. The thermostat housing on an S1 is at the back of the manifold, at the end of a long stainless steel pipe. In theory, the thermostat stuck open means it will take longer to get to operating temperature, but it should get there after a while. I have to ask, are you in a cold part of NZ? That would have a bearing with a stuck thermostat. By all means, take it out, stick it in a pot of water, bring to just under the boil and see if it moves at all. |
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