Hello, all. I'm starting to run out of ideas to fix what is a poor acceleration issue which started immediately after I performed a manual transmission swap in a totally stock 1985 325e m20b27. I'm pinning my hopes on r3vlimited after "shopping" forum sites and deciding make my post here. Seems like this is the E30 place to be.
Background
Car ran fine in November '14 when I became its owner. It's been in my family since 1990 and I've got records going back to new. It's got 69k miles, has a full service history, and is very clean. I always liked the car, but never appreciated the fact that it was an auto. Once mine, I drove it for a few weeks to see if I could force myself to enjoy the car even though it was an auto. I couldn't.
It took me a _long_ time to perform the swap to a Getrag 260. My goal was to make the car appear as though it came from the factory with the manual. No intention of heavy modification or the like (at least not at this point in my ownership). Working a few hours on weekends I finally finished the swap and put the car back on the ground in April of '15. I work slow but try to be methodical.
Problem Description
Starts fine warm or cold. Idles fine. If there's a miss, I can't tell. This is what the Bentley manual would call a "Normal Warm Running/Poor Acceleration" problem.
In neutral (whether in via the shift, the clutch, or both) while depressing the accelerator, the car is slow to climb the tach. Often it stops around 3200 rpms. Often it "flat spots" on its way up to ~4k rpm.
Underway it's much worse. It's as though the car has 10hp. It will eventually make it to 45mph if I have a landing strip's worth of straight in front of me. Intersection stop lights turn back to red before I can make it through the intersection. That kind of slow (yeah, I know its an eta so it's normally slow <insert slow joke here>).
What's Been Done
A lot but not enough evidiently.
My thoughts on upcoming checks
Pics as a reward to your consideration and reading this far:
Background
Car ran fine in November '14 when I became its owner. It's been in my family since 1990 and I've got records going back to new. It's got 69k miles, has a full service history, and is very clean. I always liked the car, but never appreciated the fact that it was an auto. Once mine, I drove it for a few weeks to see if I could force myself to enjoy the car even though it was an auto. I couldn't.
It took me a _long_ time to perform the swap to a Getrag 260. My goal was to make the car appear as though it came from the factory with the manual. No intention of heavy modification or the like (at least not at this point in my ownership). Working a few hours on weekends I finally finished the swap and put the car back on the ground in April of '15. I work slow but try to be methodical.
Problem Description
Starts fine warm or cold. Idles fine. If there's a miss, I can't tell. This is what the Bentley manual would call a "Normal Warm Running/Poor Acceleration" problem.
In neutral (whether in via the shift, the clutch, or both) while depressing the accelerator, the car is slow to climb the tach. Often it stops around 3200 rpms. Often it "flat spots" on its way up to ~4k rpm.
Underway it's much worse. It's as though the car has 10hp. It will eventually make it to 45mph if I have a landing strip's worth of straight in front of me. Intersection stop lights turn back to red before I can make it through the intersection. That kind of slow (yeah, I know its an eta so it's normally slow <insert slow joke here>).
What's Been Done
A lot but not enough evidiently.
- new crank reference sensor and speed sensors
checked the Air Flow Meter for smooth actuation and ohm reading during actuation
checked fuel delivery per Bentley manaul (30 secs of fuel pump running does indeed produce 30oz of fuel at the regulator)
replaced distributor cap, rotor, and ignition coil
dropped the catalytic converter downpipe and ran motor to ensure that it wasn't clogged
switched out DME (motronic v1.0) unit with another
replaced oxygen sensor
intake boot replaced after crack discovered (was hoping this was it, but no)
checked throttle position sensor per Bentley manual
checked coolant sensor (the one of four i see on the coolant outlet) seemed okay but might be some jitter here based on ohm readings coming and going (or coulda been operator error)
My thoughts on upcoming checks
- check for frayed wires underdash where I shoved in the manual pedal box
pinout motronic wires at the DME to see what's doing there
pinout idle speed sensor unit (it's separate from the DME in this car)
look for the magnetic pickup on the single-mass flywheel which should be the "early motronic single mass flywheel". Unfortunately, I only came to be aware that I needed this after installation, but the BMW salvage that put together everything I needed seems to have gotten in correct. I see the pickup in photos I took of the flywheel.
throw on a new coolant temp sensor just to be safe
adjust valves
Pics as a reward to your consideration and reading this far: