350i running far far too rich after clutch replacement
Discussion
Hi guys,
My 1989 350i has me and my mechanic stumped for ideas and hopefully someone can help please ?
It has just had a new clutch (so now new top engine and clutch) and is running far far too rich.
Black smoke coming out of the exhaust and only just idles.
We have tried a spare air flow meter but no change.
Have tried adjusting the mixture but no change either.
Have tried another auxiliary air valve but no change.
Have replaced the plugs/leads but no change and the plugs soon get covered in wet black deposits so it then starts to missfire.
Throttle pot all checked and readings correct.
For your info it has had a new fuel pump and new fuel filter and I'm wondering if the fuel regulator is at fault ???
Could this be the timing that is out or something else ???
Any advice greatly appreciated.
Kind Regards
Ian
My 1989 350i has me and my mechanic stumped for ideas and hopefully someone can help please ?
It has just had a new clutch (so now new top engine and clutch) and is running far far too rich.
Black smoke coming out of the exhaust and only just idles.
We have tried a spare air flow meter but no change.
Have tried adjusting the mixture but no change either.
Have tried another auxiliary air valve but no change.
Have replaced the plugs/leads but no change and the plugs soon get covered in wet black deposits so it then starts to missfire.
Throttle pot all checked and readings correct.
For your info it has had a new fuel pump and new fuel filter and I'm wondering if the fuel regulator is at fault ???
Could this be the timing that is out or something else ???
Any advice greatly appreciated.
Kind Regards
Ian
maston said:
It has just had a new clutch (so now new top engine and clutch) and is running far far too rich.
Black smoke coming out of the exhaust and only just idles.
I think some wiring has been disturbed - probably the earth connector at the the rear of the block, behind and below the LH rocker cover and the Coolant Temp Sensor is now showing permanent open circuit, so, as soon as the engine starts to warm up it overfuels.Black smoke coming out of the exhaust and only just idles.
If not the earth, then the symptoms still point to the sensor and/or its local wiring.
Read how to test - click here and select the Coolant Temp Sensor from the archive.
This sounds to me like the engine temp sensor (at the front of the passenger side head - on the diagramme below).
First check that the Thermo-time switch and temp sensor haven't been swapped - they are physically identical and close in position but have pligs colour matched to sockets.
If they are not swapped then get the car warm then short out the connectors on the temp selector with a paper clip or similar, if it runs OK then, you need to swap sensors. I believe they are available from landrover specialists.
Russ
First check that the Thermo-time switch and temp sensor haven't been swapped - they are physically identical and close in position but have pligs colour matched to sockets.
If they are not swapped then get the car warm then short out the connectors on the temp selector with a paper clip or similar, if it runs OK then, you need to swap sensors. I believe they are available from landrover specialists.
Russ
Lefthand bank of the 'V', just below the rocker cover bottom edge and above the bellhousing, on the rear engine face between the engine and the bulkhead, there are a number of black wires ending in loop connections that bolt directly in the block. Don't think I can photograph where it is as it is tight to get hand and spanner down there.
maston said:
Is the engine temp sensor the same as the Coolant Temp Sensor ?
Yes they are the same. Did the engine come out as part of the work? in which case check the plugs are back on the right sensors, the CTS is the one closer in to the centre/plenum. You can short it out as a quick check (though if the wires are broke somewhere that still won't work.)Make sure the earth strap from the rear of the block to the bonnet release catch is on and secure.
If you literally cannot see the two earth ring connectors (even from below the car looking upwards, which is dead easy) that are supposed to be on stud(s)fixed into the block behind and below the rear of the LEFT HAND rocker cover, then one must only assume that it has not been reconnected correctly after the clutch was repaired.
Are the studs there?
Perhaps on a TVR they connect elsewhere to the engine block, but I cannot work out why?
These two SD1 drawings depict the whole of the Efi loom which should be similar to yours, and the two ringed earth connectors are clearly shown.
The two BW wires go to the coolant temp sensor and to pin 35 of the ECU multiplug.
Are the studs there?
Perhaps on a TVR they connect elsewhere to the engine block, but I cannot work out why?
These two SD1 drawings depict the whole of the Efi loom which should be similar to yours, and the two ringed earth connectors are clearly shown.
The two BW wires go to the coolant temp sensor and to pin 35 of the ECU multiplug.
Edited by honestjohntoo on Tuesday 20th December 20:55
maston said:
honestjohntoo,
Excellent, thank you especially for the ecu multiplug diagram.
Where do I find what the voltages should be for each pin please
You worry me a bit. Excellent, thank you especially for the ecu multiplug diagram.
Where do I find what the voltages should be for each pin please
Please read the drawing notes!
Be aware that you cant get voltage measurements from the components specified unless the ECU is connected and the ignition is on - engine not running.
All the Efi test processes are specified in the archive or other places mentioned therein.
Edited by honestjohntoo on Wednesday 21st December 11:14
maston said:
Where do I find what the voltages should be for each pin please ?
You need one of these, you do:
Allows you to measure all the relevant voltages and currents while the engine's running and inject simulated values for the throttle pot and coolant temperature sensor. You can diagnose ECU defects, non-firing injectors, check the airflow meter flap spring is set correctly etc etc. - it even tells you if the fault is ignition rather than fuel-related.
Bearing in mind you have not reported any new symptoms other than running far too rich, I still think you have one simple fault caused when something related to the coolant temperature sensor became disconnected when the engine was moved during clutch replacement.
For example, despite a couple of prompts, I did not see if you confirmed whether the efi loom earthing tags are connected to the block as described, or somewhere else.
I also cant recall if you have confirmed whether the temp sensor is reading correctly at the sensor and/or at the ECU multi-plug.
You already have all the information needed regarding the multi-plug pin arrangement, the wiring colors and the expected temperature/resistance chart to see what's what.
Forget about pin-out boxes which are neither available to buy or loan as far as I know, just use a regular multi-meter to check resistance and wiring continuity.
If you don't have a meter or don't know how to use one this might be a good time to learn, CLICK HERE because as time moves forward your 350 flapper is gonna drive you to distraction with simple faults easily traced and fixed if you are willing to put in some study time.
Virtually everything recommended is written in terms that the average home enthusiast is able to follow.
For example, despite a couple of prompts, I did not see if you confirmed whether the efi loom earthing tags are connected to the block as described, or somewhere else.
I also cant recall if you have confirmed whether the temp sensor is reading correctly at the sensor and/or at the ECU multi-plug.
You already have all the information needed regarding the multi-plug pin arrangement, the wiring colors and the expected temperature/resistance chart to see what's what.
Forget about pin-out boxes which are neither available to buy or loan as far as I know, just use a regular multi-meter to check resistance and wiring continuity.
If you don't have a meter or don't know how to use one this might be a good time to learn, CLICK HERE because as time moves forward your 350 flapper is gonna drive you to distraction with simple faults easily traced and fixed if you are willing to put in some study time.
Virtually everything recommended is written in terms that the average home enthusiast is able to follow.
honestjohntoo said:
Forget about pin-out boxes which are neither available to buy or loan as far as I know, just use a regular multi-meter to check resistance and wiring continuity.
I didn't say I wouldn't sell (or even hire) one, just that I wouldn't lend one. You can dismiss it all you like but the diagnosis process takes minutes versus the potential hours involved in taking components off the car. My splitter-box plus a multimeter is capable of exactly what Lucas' own Epitest equipment could do, but without the hysterical prices they fetch on Ebay.Another benefit of the splitter is that you are not repeatedly disturbing those already-fragile connectors more than necessary, and as in my experience they are responsible for a fair few running issues of their own that has got to be a good thing.
Furthermore there are defects that will not show up merely by measuring resistance values with a meter; sometimes a test of the current flowing is also necessary and it's rather difficult to put an ammeter in series with any of the wiring unless you have, guess what, a splitter-box.
Granted the OP's problem is almost certainly down to a simple fault (as they usually are) and if I lived 200 miles closer I'd have fixed it for him by now, but that's the kind of guy I am. If you think that's just talk, ask Mark (Uglymug), whose 350i was essentially diagnosed in 10 minutes (although fixing the faults took rather longer) using the box in the picture above - and my trusty Tektronix.
[quote=honestjohntoo]Bearing in mind you have not reported any new symptoms other than running far too rich, I still think you have one simple fault caused when something related to the coolant temperature sensor became disconnected when the engine was moved during clutch replacement.
Thank you for your reply but perhaps I did not mention that is running VERY rough, clearly misfiring and not running on all 8 cylinders.
I have ascertained though that it is not a CTS fault and is now looking like an ECU fault.
Thank you anyway.
Regards
Ian
Thank you for your reply but perhaps I did not mention that is running VERY rough, clearly misfiring and not running on all 8 cylinders.
I have ascertained though that it is not a CTS fault and is now looking like an ECU fault.
Thank you anyway.
Regards
Ian
Whip the covers off the ECU (6 bolts, if the ant-tamper seals are still intact (doubtful) then just stick a screwdriver through the caps, they're only aluminium foil) and have a bloody good look at both circuit boards under a magnifying glass. If all the solder joints are good they'll all have the same appearance. If any are bad they'll look different, usually crystalline, sometimes (worst case) with a definite crack around a component lead.
Don't worry about anti-static precautions, it's almost impossible to blow these things up, same goes when swapping them from car to car (though it's a good idea to turn the ignition off while you do it).
Another test, if the car will start, is to have someone sit in the passenger seat and repeatedly hit the ECU with a shoe (or similar
) - if you have a poor solder joint the impact will often remake the connection, even if briefly, and you can often hear the engine note change as it does so. Happened to me, ironically, at one of the Wedgefests a few years back. I gave it a good shoeing until the connection remade and the car got me the 200 miles home without further incident. Now I take a soldering iron 
Worst case scenario, send the ECU up to me and I'll give it the once-over and sort as necessary - and I won't even charge you (apart from the return postage),
At the last count I had about a dozen spare ECUs (including 390, 3.9 Rangey and supercharged 350), I can match another to yours if necessary.
Don't worry about anti-static precautions, it's almost impossible to blow these things up, same goes when swapping them from car to car (though it's a good idea to turn the ignition off while you do it).
Another test, if the car will start, is to have someone sit in the passenger seat and repeatedly hit the ECU with a shoe (or similar
) - if you have a poor solder joint the impact will often remake the connection, even if briefly, and you can often hear the engine note change as it does so. Happened to me, ironically, at one of the Wedgefests a few years back. I gave it a good shoeing until the connection remade and the car got me the 200 miles home without further incident. Now I take a soldering iron Worst case scenario, send the ECU up to me and I'll give it the once-over and sort as necessary - and I won't even charge you (apart from the return postage),
At the last count I had about a dozen spare ECUs (including 390, 3.9 Rangey and supercharged 350), I can match another to yours if necessary.
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