535i Sport engine running problem?

[ADD]

Hi all,

My E34 535i Sport seems to be running rough almost like it missing. I would say it isn’t running 100% on idle but the problem is worst when the car is running at a constant rpm when you hold the accelerator. This doesn’t matter what gear you are in or if you hold the throttle in neural. The problem is worst at a lower rpm (like 1750rpm) but seems to be masked out the higher the rpm. The engine seems to perform fine on full acceleration.

So far we have,
• Carried out quick test using BMW GT1- Diagnosis – no faults found
• Checked and adjusted the tappet/valve clearance - ok
• Replaced the distributor rotor
• Check throttle switch – ok
• Checked for any vacuum leaks – none found
• Compression test for each cylinder – all between 12-13bar (recommend minimum of a least 10-11bar)
• Replaced fuel pressure regulator
• Carried out fuel pressure test – all ok (minimum of 2.9bar and then disconnected vacuum hose to check for maximum pressure – 3.5 bar)
• C02 emissions checked - ok
• Checked ignition coil – ok
• Tried a new air flow meter – no improvement
• Tried a new set of ignition leads – no improvement
• Listened to injectors using stethoscope – all sound the same
• No oxygen sensor fitted as no catalytic converter fitted at time of manufacture
• Disconnected idle control valve – no difference
• Disconnected air flow meter – no difference
• Replaced sparkplugs – no difference
• There is no loss of coolant

Any ideas what the problem could be?

Thanks to all those who reply.

Adam

[Kalevera]

Adam -- get the car back on diagnostics and clear any DME adaptations. Or do Shogun's reset procedure. See if that fixes anything. What year is the car and what country are you in that BMW got away with not installing a cat? No wonder we have bad air :D best, whit

[Lee in Ottawa]

same thing happenned to me replaced whole ignition system except for wires, guess what it was. Replace ur wires and see what happenns

[ADD]

Adam -- get the car back on diagnostics and clear any DME adaptations. Or do Shogun's reset procedure. See if that fixes anything. What year is the car and what country are you in that BMW got away with not installing a cat? No wonder we have bad air :D best, whit

What do you mean a shogun's reset procedure..?
I'm in the UK and its an 1989 model.

Cheers

Adam

[ADD]

same thing happenned to me replaced whole ignition system except for wires, guess what it was. Replace ur wires and see what happenns

Which wires?

cheers

Adam

[gtopaul]

Hi all,

My E34 535i Sport seems to be running rough almost like it missing. I would say it isn’t running 100% on idle but the problem is worst when the car is running at a constant rpm when you hold the accelerator. This doesn’t matter what gear you are in or if you hold the throttle in neural. The problem is worst at a lower rpm (like 1750rpm) but seems to be masked out the higher the rpm. The engine seems to perform fine on full acceleration.

So far we have,
• Carried out quick test using BMW GT1- Diagnosis – no faults found
• Checked and adjusted the tappet/valve clearance - ok
• Replaced the distributor rotor
• Check throttle switch – ok
• Checked for any vacuum leaks – none found
• Compression test for each cylinder – all between 12-13bar (recommend minimum of a least 10-11bar)
• Replaced fuel pressure regulator
• Carried out fuel pressure test – all ok (minimum of 2.9bar and then disconnected vacuum hose to check for maximum pressure – 3.5 bar)
• C02 emissions checked - ok
• Checked ignition coil – ok
• Tried a new air flow meter – no improvement
• Tried a new set of ignition leads – no improvement
• Listened to injectors using stethoscope – all sound the same
• No oxygen sensor fitted as no catalytic converter fitted at time of manufacture
• Disconnected idle control valve – no difference
• Disconnected air flow meter – no difference
• Replaced sparkplugs – no difference
• There is no loss of coolant

Any ideas what the problem could be?

Thanks to all those who reply.

Adam

Might want to check the engine to make sure it's grounded properly. A loose ground strap can make strange things happen. You really need to test the injectors off the engine with a pressure tester so you can see the spray pattern. Just listening to them click won't tell you a lot. If that's ok I would suggest maybe finding another DME (ECU) to swap in and test.


Paul

[ADD]

Might want to check the engine to make sure it's grounded properly. A loose ground strap can make strange things happen. You really need to test the injectors off the engine with a pressure tester so you can see the spray pattern. Just listening to them click won't tell you a lot. If that's ok I would suggest maybe finding another DME (ECU) to swap in and test.Paul
Where could I take the injectors to have the spray pattern tested?

Cheers

Adam

[gtopaul]

Where could I take the injectors to have the spray pattern tested?

Cheers

Adam

You'll have to ask around some repair shops to see who has an injector tester. You can really tell easily the difference because bad injectors send out a stream of fuel while a properly working injector will emit a fine spray.

Paul