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Fixes - Engine rough - no start

Items to check for rough engine - no start


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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A more general list of things to check


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That is for all E32, so your car may of may not have an idle control valve:

) Spark plugs, plug wires, distributor(s), distributor rotors),ignition coils - Clean and inspect.
2) Check compression – poor cylinder head compression is common for an older car. Big job to fix this.
3) Use a good fuel-injector cleaning treatment into the tank – take it for a good run.
4) Change fuel filter.
5) Remove and clean injectors – might need to replace injectors.
6) Hose to fuel pressure regulator – might be cracked/worn (buy a new one)
7) Rubber hose between Airflow Meter and throttle – cracked?
8) Mass Airflow meter/sensor – if dirty clean it up. Bad Air Flow Meter will cause flat spots in acceleration or erratic spots in the throttle depending on the opening of the airflow meter not usually a complete lack of power.
9) Hose to air filter – cracked?
10) Air filter – replace if dirty, check seals.
11) Distributor cap – if eroded and worn - changed to new one
12) Check fuel pressure - Replace the Fuel Pressure Regulator. Might need to replace Fuel Pump.
13) Check and Adjust valves - throttle valves, PCV valve behind intake runner, Idle Control Valve (ICV).
• ICV Idle Control Valve. Remove and clean it with brake parts cleaner. This regulates the air coming in to your intake manifold when the throttle body is closed and it tends to get dirty, sticky and the motor inside could not turn the valve properly.
• Idle control valve sometime sticks open – causes issues when in Idle
14) Throttle Body - Clean it out and replace the gasket (can use gasket material cut to size).
15) Check all Vacuum lines.
16) Conduct a ‘leak down test’ on all exhaust valves.
17) Check for Oxygen (O2) sensor function tests.
18) Check the wide-open throttle switch under the gas pedal.
19) Check throttle position switch on the throttle body.
20) Make sure connections on battery (under back seat) are very clean. Use wire brush.
21) Check rubber boot between the Mass Air Flow and the DKM.
22) Check for intake manifold gasket leak
23) Have the transmission checked for correct functioning – (by mechanic).
24) Make sure there are no other sources of drag in the driveline.
25) Check coolant sensor.

Try the RESET Procedure before all of above.
Notes:
The reset procedure is billed as a ‘cheap fix’. It does often give good immediate results, however if there is something wrong with your car (any number of issues as listed above) then over a 2-8 week period the car will likely return to its original state.
The reset procedure removes all mean values stored by your onboard computer that control engine timing, fuel use etc. As you continue to drive the car, the stored values ‘average out’ to best suit the engine condition.
If your car has for example a leaking intake manifold gasket or broken O2 sensors, the readings are quickly going to become ‘corrupted’ with incorrect information. This can lead to the engine running too rich or too lean (check your sparks for evidence). Within a short period of time the car will return to rough idle as the underlying problem has not been fixed. That said – the reset procedure can reset values that are no longer applicable. You may have replaced something on the car (e.g. Catalytic Converters) thus causing a sudden change in normal engine running. The readings stored over 10-20 years will suddenly not suit your recently modified car. The car will however read new values in and average out over time. The Reset procedure simply speeds that process up.
The long and short of it is that this procedure can sometimes fix rough idle and transmission timing and seems to improve the cars performance. However with existing underlying issues as outlined above – it won’t be long before the problems return. Perhaps this procedure could be used if you’re trying to sell your E32 ;-)
Procedure:
1. Disconnect battery cables, first negative, then positive.
2. Cover and protect the battery posts! Leave no potential for a battery short circuit.
3. Turn ignition to position II.
4. Connect both battery cables ("SHORT") for at least 10 minutes. This step drains a capacitor in the ECU/TCU. (Covered the battery with a thick, dry shop towel to prevent actually shorting the battery! – careful of arc welding in your back seat! As the battery was in place, and the cables aren't that long, you could use a very long Craftsman screwdriver and two small vice-grips to actually clamp the negative and positive cables to the metal shank of the screwdriver.
5. Wait 10 minutes - then ignition off, key out.
6. Reconnect battery positive, then negative.
7. OBC says "PPPP", reset time. Start and idle the engine for 5 minutes, then off for five, then out for a drive.
8. Now, with the car in lowest gear (one or two depending on your make), accelerate until at least 5000 rpm is reached (only M70 engine). Allow the car to slow to idle, and then repeat two more times. Let the car idle for 5 minutes. All Done!
9. Idle should smooth out over 10-12 miles; shifts should be immediately smoother.

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