Originally Posted by Warren348tb
Here's the original description of what happens when I try and start the car (hot or cold makes no difference):
"At the moment when I start the car it idles rough, and in the background of the engine noise you can hear a bom....bom...bom, almost like a miss-fire sound. Black smoke can also be seen coming from the exhaust if you look closely. After about 2 or 3 minutes the idle settles down and the smoke disappears. ...
Please, please, if anyone has any suggestions, no matter how crazy or far fetched, let me have them. As I said my mechanic is fast approaching the time when he'd be willing to try just about anything.
Right at startup you've got additional things going on (e.g. cold start equipment, ECU computer-learning/re-learning curve, etc.).
But I would *bet* money that one mass air flow sensor is set too rich compared to its identical twin on the other side of the engine.
To measure the mass air flow setting, remove the rubber-covered data cable to both maf sensors and put an Ohm-meter to pins #1 and #6 (the outermost pins on both sides of the data line). The stock setting is 383 Ohms.
Both mafs should have the same value.
To adjust the Ohm value, pop off the blue cap and use a regular screwdriver to turn clockwise or counter-clockwise. Then measure the resistance value again with your Ohm-meter.
My guess is that setting both to the same value, preferably 383 Ohms, will eliminate your startup problem...though you may have to make your mixture leaner to get rid of the black smoke that you were seeing on startup.
Cheap and quick fix, though. just need an Ohm-meter and a screwdriver.