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VATS problem ????
- Thread starter vetttta
- Start date
I have replaced the coil pack,ignition module,fuel pump relay,crank sensor,battery and checked cam sensor for anything loose under the cap. The engine cranks and the voltage drop is to 10.7v while cranking. Fuel pressure is 42lbs when the pump primes for two sec. When it runs fuel pressure is 36lbs at idle and when you increase the throttle is goes back up to 42 lbs.
I ran the car until hot and shut it off. No start. I unpluged the wire harness to the temp sensor for the ECM and pluged in a new sensor. The car started right up. I placed he sensor in a cup of 180 water while attached to the harness and the car would not start. So I thaught the ECM was bad. I replaced the ECM and got the same result, no start when hot.
Any help please.
Bruce Busse
I ran the car until hot and shut it off. No start. I unpluged the wire harness to the temp sensor for the ECM and pluged in a new sensor. The car started right up. I placed he sensor in a cup of 180 water while attached to the harness and the car would not start. So I thaught the ECM was bad. I replaced the ECM and got the same result, no start when hot.
Any help please.
Bruce Busse
V6UnderPressure
Active Member
If it was the Vats, the car would not crank at all. You would turn the key and get nothing at all. Did you check the coolant temp sensor?
As stated above I replaced the Temp sensor for the ECM which did not work. It is my undestanding that the other temp. sensor is only for your gauge on the dash and has no effect on any other electrical components.
The reason I asked about the VATS system is the manual for the 89 Pontiac states that the VATS controls both the starter and the signal to the fuel injectors. The way I understand it is the Vats sends a signal to the starter and then the starter ralay sends the signal to the injectors. It does not say if the VATS module has two circuits to do this or if it can crank the engine and not send the signal to the fuel injectors? Or is the starter relay is bad?
The reason I asked about the VATS system is the manual for the 89 Pontiac states that the VATS controls both the starter and the signal to the fuel injectors. The way I understand it is the Vats sends a signal to the starter and then the starter ralay sends the signal to the injectors. It does not say if the VATS module has two circuits to do this or if it can crank the engine and not send the signal to the fuel injectors? Or is the starter relay is bad?
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On the TTA the VATS do not control/block the injector signal only the starter ... so your problem is in the VATS curcuit not the ECM one ...
If the starter is turning over the engine at a high rate of speed but the car wont start, how can the problem be the starter. There is spark when cranking and fuel pressure is 42lbs. A noide light indicated a short burst but then nothing. Again this only happins when hot. When cold the car preforms perfectly. And I don't understand the temperature sensor not letting the car start when hot.
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jhill89tta
Active Member
The next thing I would suggest is using a scan tool to see what temp the PCM is reading. When the engine is cold the ECT and IAT should be about the same. You may have a wiring issue. If you don't have access to a scan tool, I would check for 5 volts at the black wire to the sensor with the key on and engine off, if that's ok, disconnect the battery, pull the connector at the sensor and the PCM connector then check for resistance or open in the yellow signal wire.
