Page: 1 2
RichTNorway
Date Registered: 04-2011
TOTAL POSTS: 17
|
|
|
|
Re: Engine Cutting out - idles fine
Hi,
Working a car such as the x trail is impossible without a really good diag tool, preferable nissan specific, and an oscilloscope. The scope really does make things a lot easier, since most engine sensors send a pulsed signal.
I thought about the air leaks as well, but the difference here is that if I used my hand to move the gas pedal the slightest movement its enough to stall it, i.e. as soon as the computer tries to move away from the throttle closed position.
But I may have had a minor break throu today, I decided to focus my attention on the throttle body, and the signals from that. I started with just putting the oscilloscope on the throttle motor wires, and I found something bad, but good if you know what I mean. In the esm it gives an example of what the output should be with the ignition on, and the gas pedal fully released, and vice versa ignition on, in gear and gas pedal fully pressed, I am not getting any output with these basic checks. This ties in with the symptoms as well, i.e. stalling on gas pedal input. But I know that the sensors send the correct voltage to the ecu. So my next plan is to fully check continuity from the throttle body and the ecu plug. To be honest I sort of ignored most parts of this, since the throttle being rather important is ring fenced so if any problem can occur a error code will be logged by the computer, and fail safe mode will kick in. But I notice that some lines, i.e. the second position sensor, and earths for example are not error detectable by the ecu.
I will keep you updated.
Rich
|
22/Apr/2011, 4:02 am
|
|
RichTNorway
Date Registered: 04-2011
TOTAL POSTS: 17
|
|
|
|
Re: Engine Cutting out - idles fine - Fixed
Hi,
I finally found the problem, a nearly broken power supply wire to the ECU. As I mentioned in a previous post the diag tool showed the ecu voltage to be 10 ish volts, which I considered to low.
So today I checked out the power supply to the ECU, the main power supply which goes from fuse 33 to ecu pin number 116, this pin showed only 10 ish volts as well so I worked back in to the wiring loom, and came to socket E60 - F36, this is found behind the air intake box, there are three connectors there, in this case its the middle one, and its pin 2 with in this connector, so I took this connector apart(which I have done before) and checked the voltage again 10ish volts, then I reconnected the plug to check the resistance from the fuse to the ecu(pin 116) and then it happened I checked the voltage again first, and it was 2V, then I moved the connector and it went up and down, then down. Then I checked the resistance which was very high very bad sign. So then I removed the air intake box and looked at the wiring loom and I found this: See attached pic(broken wire)
Then removing the tape show the full extent of the problem(broken wire exposed). This part of the loom had a bit of a floor, firstly it was not wrapped in the soft plastic that was a little further up, and this part had been pushed up against the side of the air filter box, and had been rubbing and wearing away for some time. Until it got to the critical stage, I guess there was just one strand left connected which explains the low voltage. So basically what was happening was that the voltage to the computer was low, and whilst it could idle since when idling the ecu does not use all sensor inputs or outputs, but as soon as the gas pedal was pressed the current requirement increased, and the voltage dropped, and this effectively cut power to the ecu, since it was not able to operate below a certain voltage, thus the engine cut out, as soon as the current requirement dropped the ecu came back on.
So now if I do the throttle closed position learning I can here the butterfly valve open and close, so less than 11v, and these test are not done, along with many other things I would think.
So if you have any strange stalling, and no fault codes. Check the voltage on pin 116 of the ecu plug, it should be battery voltage. Then check the connector and loom! It could save a lot of time and money!
So my xtrail is all up and running again! Thanks to everyone who replied, you got me looking at the area that exposed the problem.
Rich
Last edited by RichTNorway, 25/Apr/2011, 4:19 am
|
25/Apr/2011, 4:01 am
|
|
Shep65
Date Registered: 10-2016
TOTAL POSTS: 7
|
|
|
|
Re: Engine Cutting out - idles fine
ate:
My X-Trail T30 2007 would run fine but not tick over. It cut out below 1000rpm. Was showing “crankshaft” and “EGR errors” from time to time, but not always. So, injectors tested, timing chain set changed, brake servo (cam timing lugs sprocket) chain set changed, cam shaft and crank shaft sensors changed (twice). EGR sorted. Timing fully checked and OK. Diagnostics all check out fine, live data all fine. It will now tick-over when warm, but not when cold.
There is a connection plug with black and pink wires (white plug with black shroud / cover) which I found loose behind the engine. Can anybody advise what this connection may be please?
When warm, and releasing accelerator, it will tick over at about 900rpm for a short while, then drop to about 725rpm (checked on live data).
Temporarily I have “blocked up” the accelerator pedal with tape, though this makes the tick over 1500rpm or more when the engine is warm.
Can anybody advise why it won’t tick over when cold please?
|
18/Apr/2018, 7:09 pm
|
|
Page: 1 2
|