Engine problems such as rough idle/no power:
- 1. -
The easiest way is to have a possibility for fault analysis at the
dealer with a DIS, or a PEAKE fault code tool, or the stomp test.
The delaer testing computer is of course the best and most
comprehensive one and gives online results while the engine is running,
while for example the PEAKE just can show stored results in the system.
As for Peake tools, see www.peakeresearch.com
Fault code test/stomp test
see
procedure on my website (fault codes also listed)
-2.-
Important is that the EML light in the dash goes on for about 2 seconds
when the ignition is set to position 2, after that it should disappear.
Actually there are 2 bulbs for the EML, and one of it functions as a
resistor for the other one.
detailed introduction to EML, how it works
and what items it controls.
Cockpit/cluster repair:
If the EML light does not come on when ignition is in position 2, the
engine will always run in limpmode. So this has to be repaired. Not
many professional shops know that, they just replace the complete
cluster or ECU modules because of lack of knowledge.
Remove the cluster from cockpit, see Johan and Sean's page.
Pay special attention when you have an airbag, all mentioned on Johan's
page. Link on my website if you do not know it.
Repair method:
The EML light should come on when engine is started in ignition
position 2 for about 2-3 seconds and then go off. This is a kind of
test for the 2 bulbs inside the motherboard of the cluster. One bulb
acts as a kind of resistor for the other, to speak in my no-electric
expert words.
People have paid hundreds or thousands of $ to repair shops because
they replaced unneccessarily MOTRONICS, EML and other parts of the car,
as the car was in limp mode and they could not solve the problem.
Limp mode, also known as failsafe mode, limits throttle openings etc
and runs off a preprogrammed setting, limits rpm and speed as well...
Vmax after 2 minutes approx.50 kmh in 3rd gear, at max. 1500 RPM, no
ability to climp uphill and so on.
A member of 7er.com has just made a write-up with pics. Of course it is
in German, but the pics are most important to understand.
Main points I just translate in brief into English, I will omit the
general info on how to remove the cluster from the dash, and other
points known to all of you which are regular visitors on this board.
Pin 16-17, the only connected soldering points of the "white" plug are
to be connected to the "upper contacts" of the 2 EML lights.
Option: Pin 12 of the "brown" plug to be connected (soldered) with the
"lower contacts" of the EML lights.
As connector he used hot glue.
Leave cable long enough to assemble the cluster again.
Notes:
No guarantee for correct translation. It is your car when you repair it.
Description is based on a cluster from a 750iL from 05/1989.
If you are not able to see the pics in the link to the German board,
you might have to register first. Easily done, no cost involved, and
they have a very good repair page, done and maintained mainly by Erich
= shogun ;-)
http://www.7-forum.com/forum/showthread.html?t=41084
http://www.7-forum.com/forum/attachment.html?attachmentid=5109
http://www.7-forum.com/forum/attachment.html?attachmentid=5110
http://www.7-forum.com/forum/attachment.html?attachmentid=5111
Pins location:
1 26
2 25
3 24
4 23
5 22
6 21
7 20
8 19
9 18
10 17
11 16
12 15
13 14
- 3. -
In case the EML works fine, check the gear and trans mode in the
cluster. If they are not shown, engine runs in limpmode.
repair procedures
- 4. -
Visual check of the intake system.
Use brake cleaner and spray it when engine is running in all areas
around the intake system, but NOT into the air intake duct directly. If
the RPM changes, you have an air leak somewhere. Check all the rubber
connections in the intake system
- 5. -
Should all this not help, check by cylinder bank to identify which side
of the engine is the problem. Remove one connector after the other
from the throttling valves -- check if the engine stops when
one is not connected. Can be done while engine is running, connecting
and disconnecting.
In case one cylinder bank stops the engine, concentrate on that side.
But remember, the intake system you see in the car on the passenger
side actually goes into the cylinder bank of the driver side and vice
versa.
Start changing parts from one side to the other, throttling valve, MAF.
If the fault moves to the other side, you have the culprit.
- 6. -
I so far nothing could be found, check the area of the oxy sensors.
Remove one plug of the 2 after the other, if a big change in engine
running, it could be the sensors or one of them.
-7.-
All this provided that you already have made the basic checks such as
distributor caps and rotors (often the original ones are still inside),
crankshaft sensors, cylinder identification sensors, spark plugs etc.
A good help is the ECU pinout, where you have the data you should be
able to measure
details here
A Bentley Repair Manual is a must for you, as there are many data,
although sometimes we find mistakes.
Wiring data and other hints you
find here under electronics
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