Electric Air Pump Woes

King Snake · 11-01-2000, 01:24 PM

I installed my new MAC cold air kit last night. Anyone who says installing this kit on '96-'98 Cobras is easy has never installed one. But here's the question: I disconnected the battery while I was installing the kit. I did this because I heard any time you make a mod you should reset the computer. I expected it to run a little ruff until the computer relearned
everything, which is does, but what I don't understand is why the electric air pump, which had to be repositioned to make room for the air filter, has started coming on after the car is started and also occasionally during operation. This pump should come on only if the car is running rich, which it may be since I reset the computer. Why has it never come on before? Is this a normal thing when resetting the computer, or is my cold air kit the cause of this? Also, would it hurt anything to disconnect this pump if it continues to come on? Any thoughts on this would be appreciated...

------------------
'97 Cobra, K&N, 3.73s, Rio Red

97snakedriver · 11-05-2000, 09:53 PM

You can unplug it, but that doesn't really solve anything. If the car is running rich, which loses hp, it will continue to do so rather or not the air pump is running.

How long ago did you reset the computer? How does it idle?

Also, I'm not familiar with the MAC intake. are there any bends in the intake close to the MAF?

King Snake · 11-06-2000, 08:55 AM

It has been 4 days/150 miles since I reset the computer. The idle was a little rough right after I reset it but it is perfect now. There are 2 90* bends in the pipe. It is definately running rich, I can smell it. But do you think this is something the EEC will compensate for after a while? The EEC does not use the O2 sensors for the first couple of minutes after startup but instead the tables. But I assume these tables are the same ones that are being updated during normal operation, right?

------------------
'97 Cobra, MAC Cold Air Kit, 3.73s, Rio Red

97snakedriver · 11-06-2000, 03:58 PM

When the car first starts up the computer goes into open loop mode, where it just uses a table and the MAF, RPM, and TPS.

After the O2 heat up and start working it goes into closed loop where it uses the input from the O2 sensors. How it learns is actually by adjusting a multiplication factor. So it shifts the entire table (be it timing or fuel) up or down by a certain factor. I think the closed loop tables are different then the open loop ones.

Anyway, my thought is that if there is a bend near the MAF then it may be causing some turbulance and false readings. Or it could just be with the MAF positioned differently, the readings are a bit off and its just taking the EEC longer to adapt.

So I would drive on it for a bit longer and see if it doesn't get better. If it doesn't, reset the computer again. But after you do so, start it up and let it idle for 15-20 minutes, then drive it around.

11-08-2000, 04:30 PM

whatever you do don't damage the airpump! mine went and it caused the check engine light to come on. I think mine only comes on when it's cold or on startup. I agree with snakedriver on this. give the computer some learning time..

------------------
(96Cobra/softtop-3.73,almdrvsht,fancontrl,steeda sbfrmes+shifter,eibachspgs,pulleys,Bassani X pipe,C&L 80mm
Cobra DYNO 301rwhp horsepower w/out steeda timing adjuster
93 Ford Probe Gt(slower but turns)

King Snake · 11-13-2000, 09:25 PM

96cobra89Lx306, is your air pump loud from inside the car? Has yours always come on, or have you made a change that causes you car to run a little richer that factory? How many miles should it take for the computer to tweak things to its liking? Mine continues to come on each time I crank the car, even after it has warmed up. I can also tell by the smell of the exhaust that it is running too rich.

------------------
'97 Cobra, MAC Cold Air Kit, 3.73s, Rio Red

97snakedriver · 11-14-2000, 03:59 PM

If it hasn't gotten better by now, then it probably won't. I would try reseting the computer again. If that doesn't fix it, then it gets more difficult.

Call MAC and see what they say.

11-18-2000, 09:51 AM

I'm pretty sure mine comes one only at start-up when it's cold but it has come on at idle too. I believe it is mostly when the exhaust temp is below a certain level. Now that I have the MIL eliminators, it will be interesting to see when it cycles.

It is loud when it comes on though. Not too bad but noticeable. I run my cooling fan just about all time too so it drowns it out.

11-01-2000, 01:24 PM	#1
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	Electric Air Pump Woes I installed my new MAC cold air kit last night. Anyone who says installing this kit on '96-'98 Cobras is easy has never installed one. But here's the question: I disconnected the battery while I was installing the kit. I did this because I heard any time you make a mod you should reset the computer. I expected it to run a little ruff until the computer relearned everything, which is does, but what I don't understand is why the electric air pump, which had to be repositioned to make room for the air filter, has started coming on after the car is started and also occasionally during operation. This pump should come on only if the car is running rich, which it may be since I reset the computer. Why has it never come on before? Is this a normal thing when resetting the computer, or is my cold air kit the cause of this? Also, would it hurt anything to disconnect this pump if it continues to come on? Any thoughts on this would be appreciated... ------------------ '97 Cobra, K&N, 3.73s, Rio Red

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11-05-2000, 09:53 PM	#2
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	You can unplug it, but that doesn't really solve anything. If the car is running rich, which loses hp, it will continue to do so rather or not the air pump is running. How long ago did you reset the computer? How does it idle? Also, I'm not familiar with the MAC intake. are there any bends in the intake close to the MAF?

11-06-2000, 08:55 AM	#3
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	It has been 4 days/150 miles since I reset the computer. The idle was a little rough right after I reset it but it is perfect now. There are 2 90* bends in the pipe. It is definately running rich, I can smell it. But do you think this is something the EEC will compensate for after a while? The EEC does not use the O2 sensors for the first couple of minutes after startup but instead the tables. But I assume these tables are the same ones that are being updated during normal operation, right? ------------------ '97 Cobra, MAC Cold Air Kit, 3.73s, Rio Red

11-06-2000, 03:58 PM	#4
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	When the car first starts up the computer goes into open loop mode, where it just uses a table and the MAF, RPM, and TPS. After the O2 heat up and start working it goes into closed loop where it uses the input from the O2 sensors. How it learns is actually by adjusting a multiplication factor. So it shifts the entire table (be it timing or fuel) up or down by a certain factor. I think the closed loop tables are different then the open loop ones. Anyway, my thought is that if there is a bend near the MAF then it may be causing some turbulance and false readings. Or it could just be with the MAF positioned differently, the readings are a bit off and its just taking the EEC longer to adapt. So I would drive on it for a bit longer and see if it doesn't get better. If it doesn't, reset the computer again. But after you do so, start it up and let it idle for 15-20 minutes, then drive it around.

11-08-2000, 04:30 PM	#5
96cobra89Lx306 Guest Posts: n/a	whatever you do don't damage the airpump! mine went and it caused the check engine light to come on. I think mine only comes on when it's cold or on startup. I agree with snakedriver on this. give the computer some learning time.. ------------------ (96Cobra/softtop-3.73,almdrvsht,fancontrl,steeda sbfrmes+shifter,eibachspgs,pulleys,Bassani X pipe,C&L 80mm Cobra DYNO 301rwhp horsepower w/out steeda timing adjuster 93 Ford Probe Gt(slower but turns)

11-13-2000, 09:25 PM	#6
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	96cobra89Lx306, is your air pump loud from inside the car? Has yours always come on, or have you made a change that causes you car to run a little richer that factory? How many miles should it take for the computer to tweak things to its liking? Mine continues to come on each time I crank the car, even after it has warmed up. I can also tell by the smell of the exhaust that it is running too rich. ------------------ '97 Cobra, MAC Cold Air Kit, 3.73s, Rio Red

11-14-2000, 03:59 PM	#7
97snakedriver Registered Member Join Date: May 1999 Location: Blacksburg, VA Posts: 1,526	If it hasn't gotten better by now, then it probably won't. I would try reseting the computer again. If that doesn't fix it, then it gets more difficult. Call MAC and see what they say.

11-18-2000, 09:51 AM	#8
96cobra89Lx306 Guest Posts: n/a	I'm pretty sure mine comes one only at start-up when it's cold but it has come on at idle too. I believe it is mostly when the exhaust temp is below a certain level. Now that I have the MIL eliminators, it will be interesting to see when it cycles. It is loud when it comes on though. Not too bad but noticeable. I run my cooling fan just about all time too so it drowns it out.