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Disconnect coolant temp. switch-car runs 100% better.

  • Thread starter Thread starter f6cobra
  • Start date Start date Mar 29, 2004
F

f6cobra

Member
Feb 24, 2004
38
0
6
Mar 29, 2004
#1
  • Mar 29, 2004
  • #1
So I did the maf conversion a little while back. When i first did it the car ran sort of crapy. Stalling surging and a real bad hesitation. Had a buddy adjust the tps and idle/set screw. It was better, but not great. The stalling is gone but the surging is not. Since i had it "in" for the winter i did not drive it that much. Now i want to and the surging is driving me nuts. I read a lot of the other forums and so I spent all day cleaning the TB and Idle Air Control Valve and also the egr vavle. It did not seem to make that much of a difference. I then remembered that with the directions for the MAF conversion it said to disconnect one of the hoses from that vaccum block or whatever on the drivers side of the car. It was the second hose from the left. I had done this earlier and it did not seem to make a difference. I then tried blocking it and the surging seemed to go away. But during driving it seemed like it was starving for fuel or air. I left the port open and it ran like it did before, with a hesitation. I then remember someone telling me that if you disconnect the Coolant temp switch (the one for the computer) it will make the computer think the car is cold all the time, therefore giving it more fuel. Anyway I disconected it and the car feels like it gained about 25hp. Thats not real acurate but it ran a heck of a lot better and was much snapier and faster. Oh yeah I also have new spark plug wires (taylor) custom fit- and tonight I was getting ready to close the hood and I saw the boots of the wires lighting up with the spark. Very faint though. I moved the wires around and it seemed to go away. Did seem to change anything though???? Should i keep it disconected? Why is it running like this? Why do I keep typing? Can anyone help?
 

cjones

Founding Member
Jul 20, 2002
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37
Avondale, AZ
Mar 30, 2004
#2
  • Mar 30, 2004
  • #2
the vacuum hose that you leave off is the hose going to the MAP(Manifold Pressure) sensor. a Mass Air car uses a BARO sensor(a MAP sensor without the vacuum hose)
 

jrichker

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Mar 10, 2000
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Dublin GA
Mar 30, 2004
#3
  • Mar 30, 2004
  • #3
Check the ECT and replace it if needed. here's a table that can help...

Pin 25 ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

The ACT & ECT have the same thermistor, so the table values are the same.

Pin 7 ECT signal in. at 176 degrees F it should be .80 volts

Here's the table : The values are +/- 15%, so don't get worried if your readings vary a little bit.
Voltages are measured across the two connector pins with the sensor connected.

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
 
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