Hello everyone, I've been lurking about for the last few weeks reading and soaking in the knowledge that's here. You guys are incredible!
I bought a '93 400e a couple months ago, knowing it had a few issues (197k miles). I had done quite a bit of research beforehand and being a long time wrench-turner, and a fan of German engineering, I couldn't pass it up for $800!
I knew the wiring harnesses were original, and surprisingly, the car ran quite well. It had a bit of a stumble once it warmed up, but I was convinced that the harness replacement would fix it. I opted to rewire the upper harness myself...that wasn't as bad as I thought it was going to be. It was kind of relaxing to have a project to work on in the garage, with a fridge full of beer close by! There is a bit of delay going into reverse...I've already started saving for that...
Anyway, upper harness done, now the problem is that the car wants to hunt for idle when cold. Sometimes it hunts itself to death (literally). From all the "Rough idle" threads I have read here and on other forums, it seems my problem is a bit different than most others. Seems the majority of trouble with idle is after warming up in those threads. My car actually runs much better after warming up...the Italian tune up I did was quite...ahem...exciting.
But, the cold idle is a problem so I start troubleshooting:
Plug wires look fine, no light show in the dark.
Checked resistor ends of the plug wires (mine are all Bosch), and they are all 1800-2000 ohms.
Installed F8DC4 plugs...PO had 5Kohm NGK's in it.
Pulled caps and rotors and they were a little crusty, but no carbon tracking evidence anywhere, so I cleaned them up and reinstalled.
I noticed that if I gently push on the MAF body, the car would immediately sputter (this happens regardless of operating temp). More on this later...
I built a blinker box and pulled/cleared all codes. Drove it for a couple days, and read codes again. Surprisingly, I only had 3 codes, and thanks to the pdf found here, this is what I see for those codes (the car does have ASR):
Code 13 on pin 4: IAT sensor open/short - (I had unplugged it and forgot to plug it back in...
).
Code 2 on pin 7: EA/CC/ISC control module - this one is a bit of a mystery, as there are several possibilities here, but I did check the ETA wires, and they're in great shape. Maybe this had been replaced by PO?
Code 30 on pin 6: CAN data bus to EA/CC/ISC control module interrupted.
So, it seems that the two remaining codes after plugging in the IAT sensor both deal with the ETA. I leaned over the engine while it was idling to see the sticker on the ETA, and that's when I discovered the MAF sensor sensitivity to touch. If I barely push it in any direction the car will sputter and most of the time stall out...weird.
I unplugged the MAF, and viola! Car has no troubles at all, even when cold. I can now almost rip the MAF sensor off the boot, and there's no change to the idle.
I guess the TL,DR version is this: I unplugged the MAF sensor, theoretically speaking, how long can I run it this way? What are the risks here? Chance of clogging the cats? I'm expecting a bit of a mileage hit...but how bad will it be?
Or, in other words, how long can I cruise eBay/Craigslist/junkyards looking for a deal on a used one?
I bought a '93 400e a couple months ago, knowing it had a few issues (197k miles). I had done quite a bit of research beforehand and being a long time wrench-turner, and a fan of German engineering, I couldn't pass it up for $800!
I knew the wiring harnesses were original, and surprisingly, the car ran quite well. It had a bit of a stumble once it warmed up, but I was convinced that the harness replacement would fix it. I opted to rewire the upper harness myself...that wasn't as bad as I thought it was going to be. It was kind of relaxing to have a project to work on in the garage, with a fridge full of beer close by! There is a bit of delay going into reverse...I've already started saving for that...
Anyway, upper harness done, now the problem is that the car wants to hunt for idle when cold. Sometimes it hunts itself to death (literally). From all the "Rough idle" threads I have read here and on other forums, it seems my problem is a bit different than most others. Seems the majority of trouble with idle is after warming up in those threads. My car actually runs much better after warming up...the Italian tune up I did was quite...ahem...exciting.
But, the cold idle is a problem so I start troubleshooting:
Plug wires look fine, no light show in the dark.
Checked resistor ends of the plug wires (mine are all Bosch), and they are all 1800-2000 ohms.
Installed F8DC4 plugs...PO had 5Kohm NGK's in it.
Pulled caps and rotors and they were a little crusty, but no carbon tracking evidence anywhere, so I cleaned them up and reinstalled.
I noticed that if I gently push on the MAF body, the car would immediately sputter (this happens regardless of operating temp). More on this later...
I built a blinker box and pulled/cleared all codes. Drove it for a couple days, and read codes again. Surprisingly, I only had 3 codes, and thanks to the pdf found here, this is what I see for those codes (the car does have ASR):
Code 13 on pin 4: IAT sensor open/short - (I had unplugged it and forgot to plug it back in...
).Code 2 on pin 7: EA/CC/ISC control module - this one is a bit of a mystery, as there are several possibilities here, but I did check the ETA wires, and they're in great shape. Maybe this had been replaced by PO?
Code 30 on pin 6: CAN data bus to EA/CC/ISC control module interrupted.
So, it seems that the two remaining codes after plugging in the IAT sensor both deal with the ETA. I leaned over the engine while it was idling to see the sticker on the ETA, and that's when I discovered the MAF sensor sensitivity to touch. If I barely push it in any direction the car will sputter and most of the time stall out...weird.
I unplugged the MAF, and viola! Car has no troubles at all, even when cold. I can now almost rip the MAF sensor off the boot, and there's no change to the idle.
I guess the TL,DR version is this: I unplugged the MAF sensor, theoretically speaking, how long can I run it this way? What are the risks here? Chance of clogging the cats? I'm expecting a bit of a mileage hit...but how bad will it be?
Or, in other words, how long can I cruise eBay/Craigslist/junkyards looking for a deal on a used one?
