Discussion
hello there,
my Chim started this funny high idle thing again, especially after flooring the pedal hard and reving to 6000 rpm. From my last post I have been advised to take it to a dealer who can read out the fault codes.
My question, can I take the ECU with me and go there with my Jag, or will this reset the ECU.
If so, where can I find the connector to plug in.
I have a Rover dealer who is very helpful, but 80 miles from where I live.
Sorry to ask such a stupid question.
my Chim started this funny high idle thing again, especially after flooring the pedal hard and reving to 6000 rpm. From my last post I have been advised to take it to a dealer who can read out the fault codes.
My question, can I take the ECU with me and go there with my Jag, or will this reset the ECU.
If so, where can I find the connector to plug in.
I have a Rover dealer who is very helpful, but 80 miles from where I live.
Sorry to ask such a stupid question.
Considering the distances you need to travel, Id buy a code reader. They are around £125 for a new copy of one in the UK, or they turn up on Ebay.com (as in the USA site- all US spec Range Rovers had them fitted as standard) on a faily regular basis, and sell for about $35. Socket is in the ECU loom in the passenger footwell. Part number for the Lucas unit is PRC7067, or seach for Range Rover OBD or the UK copy is here:
http://www.bespokeintelligentsystems.co.uk/Product...
They only pick up faults that make a sensor go out of range for a time period, so minor running problems or uneven tickover may not show a fault code at all.
Mark
http://www.bespokeintelligentsystems.co.uk/Product...
They only pick up faults that make a sensor go out of range for a time period, so minor running problems or uneven tickover may not show a fault code at all.
Mark
I sell original Lucas readers for £100 including postage worldwide.
I hire thaem for £10 per week including postage in the UK.
I'll hire abroad if the hirer pays the excess postage.
You'll be lucky to pick one up in the USA for $35 but you're welcome to try.
Note that I'm replying to a specific request for reader information in this post so I hope the mods are happy with this.
I hire thaem for £10 per week including postage in the UK.
I'll hire abroad if the hirer pays the excess postage.
You'll be lucky to pick one up in the USA for $35 but you're welcome to try.
Note that I'm replying to a specific request for reader information in this post so I hope the mods are happy with this.
Thanks for all your advises, I was talking to my local garage yesterday and much to my surprise I was told that his computer could read out all kind if different computers, if has has the right plug ( he has a box full of adapting cables and plugs), in fact it works on my Jag, on all german makes, japanese, italian and french cars and so on.
I will see him at the weekend. If it does not work I will buy one cause i intend to drive the car as long as I can still affford it.
At the moment even with quite sedate driving the consumption is about 17 mpg. I have never ever reached the 22+ mpg you sometimes read about in PH
:
I will see him at the weekend. If it does not work I will buy one cause i intend to drive the car as long as I can still affford it.
At the moment even with quite sedate driving the consumption is about 17 mpg. I have never ever reached the 22+ mpg you sometimes read about in PH
:You can do basic checks of the mixture control with just a test meter. Just measure across the black (output) and white (ground) wire from one of the lambda probes in the exhaust manifold. With the engine hot, the voltage will swing between about .2 and .7 volts DC (although it might glitch to 1.2v) at about 1/2 second intervals. This is somewhat irregular, as the fueling is constantly corrected. If it sticks for a time at over .7 volts, then its running rich, and a fault code reader will give a fault code. Likewise if it runs at .2 volts or less, its very lean, and a fault code will also show up. This switching signal remains up to 3400 rpm, or about 3/4 throttle. Above this it will stick at .7v or more. Note this is on Catalyst fitted cars only. I would think at 18 mpg, the readings should show rich !
Mark
Mark
Hello Mark,
after chipping the car, ifoolowed the instructions from RPI website concerning the throttle pot and AFM adjustment. the AFM showed 2.43 instead of 1.68, so since adjusting it, I somehow feel that the engine is running on the weak side, no more banging on the overrun. on the other hand, there was no increase of running temperature, so I am a bit puzzled.
Nevertheless thank you for your hint. I will have a go tomorrow and let you know what the lamba s***t says.
cheers
Bernd
after chipping the car, ifoolowed the instructions from RPI website concerning the throttle pot and AFM adjustment. the AFM showed 2.43 instead of 1.68, so since adjusting it, I somehow feel that the engine is running on the weak side, no more banging on the overrun. on the other hand, there was no increase of running temperature, so I am a bit puzzled.
Nevertheless thank you for your hint. I will have a go tomorrow and let you know what the lamba s***t says.
cheers
Bernd
From my experiments on the ECU, the RPI settings are a bit misleading. Firsly the throttle pot appears to be self calibrating (did yours have elongated fixing holes ...?). The earlier 3.5 engines can be adjusted,(probibly the 14CU, not 14CUX ecu) but on my 3.9 the adjustment has been removed, and a man who knows tells me the ECU can work out the maximum and minimum voltage swing for itself. Also the voltage trim output on the AFM appears to make no difference what so ever on the catalyst cars, and is purely a left over from the non catalyst cars. A bit on a forum by Mark Adams said this value did effect the basic mixture, before the ECU applies the correction with the lambda probes. To check this I ran the catalyst fuel map, but removed the lambda feedback, and altered the AFM trim, but the mixture did not change at all. Basically the ECU has 100% control of the mixture up to 3400 rpm, and you cant adjust it in any way. So if the mixture is wrong, there is a fault somewhere.
Mark
Mark
JKY said:
$60 including shipping though. I paid $80 for mine including shipping (so thats about what £50?) which I thought was a reasonable price. They often go cheaper than that but being impatient I couldnt wait for a cheaper one to come up ....hello Mark,
I just did the test you told me. I took the car for a small drive -12 miles- and returned to my garage. when I had to stop at the lights, the fans kicked in, also during the test, so the engine was thoroughly warmed.
the lh side lambda showed readings between o.6 and 0.75, the rh side lambda so showed between 1.3 and 1.66 I rechecked twice, so I am sure I made no mistake.
Regarding your post concerning the adjustment of the throttle pot. I openend up the holes by 1 mm so the adjustment is spot on, was only reading 0.1 low.
but will the adjustment of the AFM to the RPI figure make my engine run too weak above 3400 rpm? I found it lost slightly at the top since fettling the AFM.
I just did the test you told me. I took the car for a small drive -12 miles- and returned to my garage. when I had to stop at the lights, the fans kicked in, also during the test, so the engine was thoroughly warmed.
the lh side lambda showed readings between o.6 and 0.75, the rh side lambda so showed between 1.3 and 1.66 I rechecked twice, so I am sure I made no mistake.
Regarding your post concerning the adjustment of the throttle pot. I openend up the holes by 1 mm so the adjustment is spot on, was only reading 0.1 low.
but will the adjustment of the AFM to the RPI figure make my engine run too weak above 3400 rpm? I found it lost slightly at the top since fettling the AFM.
The ECU works in 2 modes. Firstly closed loop to keep the emissions low, and this uses lambda feedback to keep the mixture spot on. No amount of tweeking of any component will change this (within limits), as if you alter a setting, the lambda voltages will change, so the ECU re adjusts the mixture to bring it back in line. The ECU can tweek the mixture by a huge range, (and you would never know) to keep the lambda probes switching between .2 and .7 (aprox) volts. In your case, both probes are showing rich, so the ECU has lost control of the mixture, and the feedback is not working. You will get a fault code with a reader in this case, and the ECU may be running in a "get you home mode". It will do this when it gets a wrong or missing sensor input, so it ignors the failed input and relies an a fixed "fall back" fuel map. The voltages you are interested on the AFM are not the CO trim value as these are ignored, but the airflow output its self. You need to measure between earth, and AFM output. Voltages should be about .6 volts with no airflow, and about about 1.5- 1.7 volts at tickover. The reading will shoot up a volt or so if you blip the throttle. This is not a calibration, simply a basic test. Certainly contamination of the hot wire in the AFM can make the units go out of spec'. Its also worth noting that the AFM has its own earth wire back to the ECU (Its body is not grounded) so any poor connections can throw the relatively low voltages out, so the ECU gets the wrong reading.
Once the ECU goes open loop above 3400 rpm then there is no feedback to correct any fueling errors so if a sensor or fuel pressure is out, it has a much greater effect on the mixture. THe CO trim value on the AFM however only affects non catalyst cars up to 2500 rpm, so I doubt very much it would effect the value above 3400 rpm on your car.
Bit more here: http://www.g33.co.uk/fuel_injection.htm
Mark
Once the ECU goes open loop above 3400 rpm then there is no feedback to correct any fueling errors so if a sensor or fuel pressure is out, it has a much greater effect on the mixture. THe CO trim value on the AFM however only affects non catalyst cars up to 2500 rpm, so I doubt very much it would effect the value above 3400 rpm on your car.
Bit more here: http://www.g33.co.uk/fuel_injection.htm
Mark
Edited by blitzracing on Friday 10th October 12:49
hello Mark,
I checked the AFM with a warm engine. without airflow it measures a steady 0,39, with airflow 1,69, so everything seems ok, on the other hand it is the first time that I have 2 withish, greyish exhausts. I checked my fuelpressure witha gauge, it is between 39 and 40 psi. I am a bit puzzled. then I took the car for a short ride and the high idle disappeared, only after flooring hard, it comes back and takes about 7 to 9 seconds to come down to 900 rpm.
oh, to make it clearer, the high idle only disappears if the car is stationary, as long as the car is rolling - even at pedestrian pace- it stays at about 1500 rpm.
Maybe another myth of TVR
I checked the AFM with a warm engine. without airflow it measures a steady 0,39, with airflow 1,69, so everything seems ok, on the other hand it is the first time that I have 2 withish, greyish exhausts. I checked my fuelpressure witha gauge, it is between 39 and 40 psi. I am a bit puzzled. then I took the car for a short ride and the high idle disappeared, only after flooring hard, it comes back and takes about 7 to 9 seconds to come down to 900 rpm.
oh, to make it clearer, the high idle only disappears if the car is stationary, as long as the car is rolling - even at pedestrian pace- it stays at about 1500 rpm.
Maybe another myth of TVR
Edited by Krautchimaera on Friday 10th October 15:58
There’s no myths, if the tick over is too high or unstable, something is wrong. Firstly the fuel pressure, it should be about 37 psi, BUT only with the vacuum pipe disconnected from the plenum. With the pipe connected, the vacuum in the plenum at tick over will drop the fuel pressure by 4 or 5 psi, so a reading of 40 psi would be too high. You should be able to clearly see the pressure change as you disconnect the vacuum pipe if the pressure regulator is working OK. The ECU will battle to control the mixture, but as it exceeds its ability to correct the "error" condition, you will get the symptoms you describe. I did get exactly the same type of fault, but it was due to the screw on my variable fuel pressure regulator working loose, so I had 50 PSI on the rail! I think the ECU holds the rpm high in fall back mode to prevent the catalyst being damaged, so I really think you need that fault code reader.
Mark
Mark
Hi folks
I have encoutered the high-idling-problem on my own car and mostly it occurred after some spirited driving. I also do get another problem that occurres once in every 500-1000 km. When it happens the car drives like a complete dog, it shunts like hell and the idle drops to 500 revs and i have to drive with more than 2500 revs to keep the car going. Last time this happened i found how i can cure it! I just disconnect the battery for a minute and everything is fine again for the next 500-1000 km. On the search for the reason for this problem i drove about 600 km with a faultcodereader connected. This showed a code for AFM out of range or connectors defekt once. Prior to this i already had changed the AFM to a newer used item and fitted a new original steppermotor. I also had the car on a CO-tester and this showed no anomalies but the fault did not occur during this testing. My MpG is also in the usual range. My next idea is to try the car with a different ECU but i might have to drive another 1000 km to be more or less shure.
Any ideas to a cure most welcome.
@ krautchimaera: Wolfgang Burger from Freising lend me the faultcodereader and i still have it. If you want it i can ask him and post it to you.
Cheers Jens
I have encoutered the high-idling-problem on my own car and mostly it occurred after some spirited driving. I also do get another problem that occurres once in every 500-1000 km. When it happens the car drives like a complete dog, it shunts like hell and the idle drops to 500 revs and i have to drive with more than 2500 revs to keep the car going. Last time this happened i found how i can cure it! I just disconnect the battery for a minute and everything is fine again for the next 500-1000 km. On the search for the reason for this problem i drove about 600 km with a faultcodereader connected. This showed a code for AFM out of range or connectors defekt once. Prior to this i already had changed the AFM to a newer used item and fitted a new original steppermotor. I also had the car on a CO-tester and this showed no anomalies but the fault did not occur during this testing. My MpG is also in the usual range. My next idea is to try the car with a different ECU but i might have to drive another 1000 km to be more or less shure.
Any ideas to a cure most welcome.
@ krautchimaera: Wolfgang Burger from Freising lend me the faultcodereader and i still have it. If you want it i can ask him and post it to you.
Cheers Jens
Hi guys
I have to bump this since over here we have another victim of the erratic idle problem and mine just turned worse. My car now idles at 500 rpm when i coast to a halt. When i`m standing it takes several seconds till the idle starts to climb again to finally stabilize at around 900 rpm. Ironically my shunting has all but gone.
Any help appreciated
Cheers Jens
I have to bump this since over here we have another victim of the erratic idle problem and mine just turned worse. My car now idles at 500 rpm when i coast to a halt. When i`m standing it takes several seconds till the idle starts to climb again to finally stabilize at around 900 rpm. Ironically my shunting has all but gone.
Any help appreciated
Cheers Jens
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