I have a 1991 325i automatic with 185k.
I just recently got the car and like any older car I buy I go through and replace most of the sensors, maintenance items, and do a little "tune-up".
The car has a flat spot/hesitation as you initially get on the throttle ( light load, heavy load, its all the same) that lasts for for a half second or so.
Within the few weeks of ownership, I have done the following:
-replaced the air filter
-cleaned out the AFM housing
-adjusted the valves (new VC gasket to avoid vac leaks)
-replaced the timing belt (the valve timing is spot-on)
-replaced the distributor cap and rotor
-replaced the spark plugs and properly gapped them (Bosch Super copper electrode)
-cleaned the battery terminals
-checked for any obvious vac. leaks
From this little maintenance the car runs more smoothly and a slight bit of power has been restored but the flat spot/hesitation remains.
Being a poor student I haven't had the cash to replace the plug wires and O2 sensor just yet but the spark plug wires look like they could be the originals since they they have the BERU markings and look like they have dried egg over them ( cracked yellowish film on the wires).
I am not very familiar with the Motronic system but I am guessing that , like most EFI systems, the O2 sensor is ignored until the car warms up and begins to run closed loop. The hesitation happens regardless of temperature.
I am thinking the plug wires are the cause of the hesitation but will not know until I can spare ~160 for some new ones.
1)Should I get the original spec or the "high performance" spark plug wires for 10$ more from Turner motorsports.
2)Does the coolant temp. sensor have an impact on drivability when the engine is cold? what are the symptoms of a bad CTS/where is the CTS located that the ECU takes orders from?
3)Suggestions on any other items to check / not so obvious vac. leak sources.
CLIFFS NOTES: engine hesitates upon initial throttle application at any engine temp. Most of the obvious items have been checked and replaced except spark plug wires, what esle should I look at?
I apologize for the lengthy post, the ADD crowd wont get all the way through , but I appreciate the input!
I just recently got the car and like any older car I buy I go through and replace most of the sensors, maintenance items, and do a little "tune-up".
The car has a flat spot/hesitation as you initially get on the throttle ( light load, heavy load, its all the same) that lasts for for a half second or so.
Within the few weeks of ownership, I have done the following:
-replaced the air filter
-cleaned out the AFM housing
-adjusted the valves (new VC gasket to avoid vac leaks)
-replaced the timing belt (the valve timing is spot-on)
-replaced the distributor cap and rotor
-replaced the spark plugs and properly gapped them (Bosch Super copper electrode)
-cleaned the battery terminals
-checked for any obvious vac. leaks
From this little maintenance the car runs more smoothly and a slight bit of power has been restored but the flat spot/hesitation remains.
Being a poor student I haven't had the cash to replace the plug wires and O2 sensor just yet but the spark plug wires look like they could be the originals since they they have the BERU markings and look like they have dried egg over them ( cracked yellowish film on the wires).
I am not very familiar with the Motronic system but I am guessing that , like most EFI systems, the O2 sensor is ignored until the car warms up and begins to run closed loop. The hesitation happens regardless of temperature.
I am thinking the plug wires are the cause of the hesitation but will not know until I can spare ~160 for some new ones.
1)Should I get the original spec or the "high performance" spark plug wires for 10$ more from Turner motorsports.
2)Does the coolant temp. sensor have an impact on drivability when the engine is cold? what are the symptoms of a bad CTS/where is the CTS located that the ECU takes orders from?
3)Suggestions on any other items to check / not so obvious vac. leak sources.
CLIFFS NOTES: engine hesitates upon initial throttle application at any engine temp. Most of the obvious items have been checked and replaced except spark plug wires, what esle should I look at?
I apologize for the lengthy post, the ADD crowd wont get all the way through , but I appreciate the input!
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