Rolls-Royce and Bentley Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
106 Posts
Discussion Starter #1
car running poorly again, this time feels electrical/ignition, fuel injection system pretty well fully sorted as far as I can tell. Just read the blink codes, as follows:

4431 - idle speed control -idle speed plug open or short circuit

2123 - Full Load Switch fault (closed) or yellow/purple wire earthed - ignition and fueling switched to part load map

2121 - Idle switch fault (closed) or blue/purple wire earthed - ignition and fueling switched to part load map

4312 - Spark timing sensor - engine reference sensor and/or its connection to the K Motronic ECU defective

I know what the idle speed control is as I just recently replaced it with new. Will review its electrical connection again.

I know what the Spark Timing sensor is as I removed and cleaned it recently, now I am guessing it needs replacing?

I have no idea what or where a Full Load Switch and an Idle switch are located. A search on Intro Car turned up the Spark Timing Sensor for 187.59GBP, but nothing described as Full Load switch or Idle switch.

any help appreciated
 

·
Registered
Joined
·
61 Posts
Widely, with K-Xtronic Bosch systems:
Full load switch is is IMHO just a kick-down switch under the acceleration pedal. It is switched when acceleration pedal is fully pressed down.
Idle switch is located somewhere under the hood, near throttling valve at the end of acceleration pedal linkage. It is switched when acceleration pedal is fully depressed.
Anyway, I think, that all errors pointed at electrical connections at the same area or even the same connector or the same module.
 

·
Registered
Joined
·
61 Posts
However in RR there is TPS (Throttle Position Sensor) (just checked).

28503


Looking at electric diagram I see, that TPS (30) is the two-state switch, so it acts as idle-switch, I believe. Maybe it works as full-throttle switch too? They drawn it in the middle position ;)
28504
 

·
Registered
Joined
·
106 Posts
Discussion Starter #5
thank you, checking that TSD and section now.
 

·
Registered
Joined
·
106 Posts
Discussion Starter #6
responded too quickly. Searched for TSD 5001, determined it is "Engine Management Systems 90 -93", but have not found it to download. I found reference to it from three different CD manual sellers, not keen to wait for ordering, delivery delays in the time of CoVid 19, clearing customs, etc.

Can anyone point me to a downloadable copy of TSD 5001????? Seems like exactly what I need, just have to find it.

Paul LeClair
 

·
Registered
Joined
·
42 Posts
Before going on a big tail-chasing safari, I would read up on how to erase the fault codes, verify that they are erased, then road test the car, and re-checking what if any codes come back.

The diagnostics on the early cars are crude at best and there is no way of knowing the age of the faults.

If memory serves me, 4312 - Spark timing sensor, will set when the key is on and the engine is not running.
 

·
Registered
Joined
·
3,538 Posts
Erase_Stored_Codes-Blink_Code_Era.jpg
 

·
Registered
Joined
·
106 Posts
Discussion Starter #10
As suggested, I will erase the fault codes and try to drive the car again. However, car is not really drivable, has again been stalling, not only at idle but while being driven. That is why I was trying to find out if the car has a MasterCheck port or not, why I was checking the blink codes, and why I am still trying to locate a copy of TSD 5001 re engine management. Anyone?

I had given up on self diagnosing and paid a local shop for several hours of diagnostic expertise which has not resolved the issues, so am back chasing the issue as the car is not useable again as it is. Now I am back to chasing whatever the issue is myself.
 

·
Registered
Joined
·
106 Posts
Discussion Starter #11
forgot to add, to erase fault codes the blink code instructions I have been following indicate to erase the stored codes is to remove the engine management fuse B9 on Fuseboard 1. I will try that first and see if the codes erase that way, seems simpler.
 

·
Registered
Joined
·
61 Posts
why I am still trying to locate a copy of TSD 5001 re engine management. Anyone?
I think, that 1990 cars don't have mastercheck port. I'm afraid that TSD5001 is available only as database, anyway I sent you in private conversation electronic diagram of engine management system.
 

·
Registered
Joined
·
3,538 Posts
It appears that several of us have shared with @Paul LeClair privately, and in extensive detail.

Please check your private messages AKA conversations. Your avatar icon, in this case large capital P with a green background, will have a small reddish colored dot at its upper right corner when you have alerts or conversations you have not viewed.

I can't possibly give more direct access to the requested documentation than I have already offered.
 
  • Like
Reactions: szdowk

·
Registered
Joined
·
3,538 Posts
1990 cars don't have mastercheck port
They do not, as first confirmed by myself, and supported by others, in topic, Bentley Mastercheck tool rental from Flying Spares, two days ago.

to erase the stored codes is to remove the engine management fuse B9 on Fuseboard 1. I will try that first and see if the codes erase that way, seems simpler.
If that does work, it is far simpler. But since the documentation reads, "permanent battery feed," I'm doubting it. I suspect that there's some "sneaky feed" that doesn't go through the fuse box. If it works, though, that's excellent information for all to have.
 

·
Registered
Joined
·
106 Posts
Discussion Starter #15
well, now I feel like a total idiot, going to the "Conversations" and finding messages going messages going back 1 months, as well as current very helpful and generous messages from guyslp and szdowk. I will read and digest that material, thanks so very much to both of you. Apologies to those who previously sent me a conversation, my lack of response comes from just finding them now.......
 

·
Registered
Joined
·
3,538 Posts
@Paul LeClair,

Your gracious, and appropriate, mea culpa is more than enough of an apology for me. I presumed you hadn't seen my reply, but couldn't for the life of me figure out why. Everyone's a "forums newbie" once, and we've all been in your shoes in the past.

Not calling me unreasonable or "mean" for expressing mild irritation gets you big points from me, too!! [Not that you need those, but, hey . . .]
 
1 - 16 of 16 Posts
Top