After 18 months, my Spec E30 build is almost done.
Background: 1987 325is with 1989 i engine. Engine harness is from original 1987 chassis.
I picked up a whole parts car and tore out the freshly rebuilt engine out of that car and transplanted it into my spec E30 build. After getting everything running, the engine is idling at about 2k RPMS. I do no believe that there are any vacuum leaks. I tore apart all the hoses and everything connected to the intake today and i COULD NOT find any vacuum leaks. No torn boots. I even sprayed some started fluid around in the engine bay and I didn't hear any increase in Rev's. Now, I did not have it smoke tested yet because the rest of the car is still being built.
The engine idles at about 1500-2000 RPM's now and if it hit the gas, it rev's right up strong, but then it holds that rev and then takes a little while to come back down. If I let the car run for a minute or two, the rev's come down a bit to like 1,100 rpms but doesnt run as smooth.
However, there are three things that I have changed/not completed yet. Would either of these three things cause the engine to idle like that?
1) Coolant system has not been hooked up yet. Sensors are all hooked up yet and installed but radiator, hoses and overflow tank are not installed yet.
2) Right now, the exhaust system is just open headers. There are no cats on the car and no mufflers, which means there are no o2 sensors hooked up yet either. Would this effect idle that significantly?
3) Also, I have not hooked up the charcoal canister yet. Right now, the vacuum line that runs to the charcoal canister is just plugged up. Can I even do this? Do I need to run a canister? What exactly do they do?
If neither of these things would effect idle, what else should I check for to cause this? swap MAF sensor?
The engine that I put in did have a adjustable fuel pressure regulator hooked up to it but I bypassed that I am using the stock FPR. Is there a chance that the FPR could be bad and too high/low of fuel pressure is causing this?
Thanks again guys for bearing with me through my first full E30 build. I've gotten so used to the M/S52 engines, working on the M20 is a bit different.
~Rich Montoni
Background: 1987 325is with 1989 i engine. Engine harness is from original 1987 chassis.
I picked up a whole parts car and tore out the freshly rebuilt engine out of that car and transplanted it into my spec E30 build. After getting everything running, the engine is idling at about 2k RPMS. I do no believe that there are any vacuum leaks. I tore apart all the hoses and everything connected to the intake today and i COULD NOT find any vacuum leaks. No torn boots. I even sprayed some started fluid around in the engine bay and I didn't hear any increase in Rev's. Now, I did not have it smoke tested yet because the rest of the car is still being built.
The engine idles at about 1500-2000 RPM's now and if it hit the gas, it rev's right up strong, but then it holds that rev and then takes a little while to come back down. If I let the car run for a minute or two, the rev's come down a bit to like 1,100 rpms but doesnt run as smooth.
However, there are three things that I have changed/not completed yet. Would either of these three things cause the engine to idle like that?
1) Coolant system has not been hooked up yet. Sensors are all hooked up yet and installed but radiator, hoses and overflow tank are not installed yet.
2) Right now, the exhaust system is just open headers. There are no cats on the car and no mufflers, which means there are no o2 sensors hooked up yet either. Would this effect idle that significantly?
3) Also, I have not hooked up the charcoal canister yet. Right now, the vacuum line that runs to the charcoal canister is just plugged up. Can I even do this? Do I need to run a canister? What exactly do they do?
If neither of these things would effect idle, what else should I check for to cause this? swap MAF sensor?
The engine that I put in did have a adjustable fuel pressure regulator hooked up to it but I bypassed that I am using the stock FPR. Is there a chance that the FPR could be bad and too high/low of fuel pressure is causing this?
Thanks again guys for bearing with me through my first full E30 build. I've gotten so used to the M/S52 engines, working on the M20 is a bit different.
~Rich Montoni
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