Hi, I definately have a significant difference in low end performance when my car (89 760T, 104K miles) is cold than when it is at normal running temp. The performance actually seems to improve as I watch the temp gauge needle rise. Should I suspect the heater on the O2 sensor? It's been like this for along time. It's also been getting poor gas mileage for awhile (maybe related?) I've recently checked the O2 sensor and re-set the mixture. The O2 sensor voltage is fluctuating properly but I noticed when I attempted to check it under a rich mixture (run at 2500 RPM and pinch vacuum line at FPR) the voltage reading was .87-.88 V and did not vary when disabling the FPR. I'm also having an intermittent stalling problem at idle (most times sitting at a light or braking). I have recently serviced my idle control valve and replaced my Hall effect sensor.

Again, current symptoms:

1) Poor low end performance when cold.

2) Poor gas mileage.

3) Intermittent stalling at idle.

Here's hoping any or all of these could be caused by the same thing ;^)

Thanks for taking the time

Steve

My 1988 760T has poor low end power at all times. For reference, should I be able to 'burn rubber' with this car?

1. clean throttle body.

2. check for vacuum leaks, especially at the amm to turbo intake hose. Not unusual ot have a leak or bad hose from the intercooler to the metal tube to the throttle body or at the tube to throttle body hose. Even the hose at the turbo to intercooler could be rotted by now...mine were bulged and I replaced them and added a third clamp in the middle to keep it from flexing under 15-18psi boost....

You might also check the coolant temperature sensor. To do this, remove the wiring harness from the fuel injection control unit. Take the wire harness connector out of it's housing by removing the screw at the bottom and pushing on the wires. Find terminal 2 (which is connected to the coolant temperature sensor), and connect an ohm meter betwen it and ground. The resistance of the coolant temperature varies according to temperature according to a logarithmic chart, but you should have from 2,280 to 2,720 ohms at 68 degrees F., about 3,800 ohms at 50 degrees F., and about 330 ohms at 176 degrees F. The coolant temperature sensor is installed in the head and it is just under cylinder 3 intake port. To replace it, it is best to remove the intake manifold. I just replaced one in one of our three 740 turbo cars, and it made a big difference in the running and economy. It was about 9.5 meg ohms to ground at 50 degrees F. The car started okay, but it was a dog off the line, no torque at low rpm.

Hi John, thanks for the response. I've checked my temp. sensor recently and did not get values inconsistant with the normal curve. Certainly not an order of magnitude off. Believe me, I was hoping. I did do this at the sensor which did not check the wiring and the ECU connection as your suggestion would. I think I'll still give it a try.