wont start when hot
90eighty8
10-02-2005, 07:18 PM
alright guys, im new to this forum and hope you guys can help me out. first the car is a 1990 eighty eight royle and it has some fe3 badge on the back that i dont know what it means. anyway, the problem is, the car will start fine, and run fine as long as i need it too, but as soon as the engine warms up and i turn the car off, it wont start untill the engine cools off. when i try to start it when it is warm, it cranks but wont turn over, and usually take around 2 hours before it will start again. i had a friend who used to be a mechanic run a spark test on it, and there is no spark coming off the coil packs. i heard it may be the coilpacks, so i just replaced that, and it still does the same thing. anyone know what the problem is and how much to fix or is there an easy way to fix this?
SpitAndDirt
10-02-2005, 08:22 PM
Very simple fix, sort of. This solution is dependant on the fact that you do have a 3.8L V6. You have what is called a waste spark type of ignition. GM calls it "C3i" if I remember correctly. It means that two plugs fire at one time. One of the plugs is igniting the compressed, combustable mixture of one cylinder; and the other is just sparking in spent exhaust gases, hence the name waste spark. As the engine turns, then the cylinders are switched in their function.
Anyway, to sync all this together you have THREE sensors that "look" at where the engine is at, at any given moment. TWO of these sensors are in the same physical component. So you have two physical components that you need to change out just to be sure, but most likely only one will fix the problem. It's just that when one goes the other is not far behind.
These magical eyes are : #1, the Crankshaft Position Sensor and #2 is the Camshaft Position Sensor.
The CRANKShaft position sensor is located just behind the harmonic balancer pulley on the passenger side of the car at the bottom of the motor. It contains two sensors in one. It should have 4 wires coming out of it.
It can only be replaced by jacking that corner of the car up, removing the wheel, removing a splash cover for access, and then by using a air impact gun, remove the harmonic balancer pulley bolt(32mm, I think). The balancer slides right off. And just to the right of the shaft is the Crank Sensor. I failed to mention that you will have to remove the drive belt in order to remove the balancer. The sensor is secured to the block by two bolts holding a bracket assembly. The new sensor will come with a new bracket most likely, but due to cost cutting, they may not anymore. So word to the wise, save old parts until problem is solved.
The Camshaft Position Sensor is located just above the water pump and to the left slightly. You will need a mirror to see it. It is secured by a 8 or 10mm bolt. Two wires go into it.
The whole reason for your being able to start the car cold and not hot is that the Crank sensor most likely has failed internally from constant heating and cooling. If one side of the sensor fails, it causes the car to start and run all day as you describe. If the other side of the sensor fails, the car will not start at all. The camshaft sensor will have a similar fate sooner or later.
You will notice on the back of the harmonic balancer that there are two metal rings with cutouts in them. These cutouts are what the sensor looks for. The sensor will need to be carefully aligned upon installation to be certain that as soon as you start the motor, the metal teeth do not rip the sensor right out of its bracket along with its wiring harness. Use the long visible bolt to clamp pressure on the sensor so that is does not move left or right.
The CAMSHAFT position sensor is replaced as a fail-safe. It also "looks" for something, and that is a magnet embedded into the Camshaft gear.
Just to get an understanding about how these sensors work, think of it like this: You are given a gun, a target, and a analog clock. Your command is that you are to shoot the target every 3 hours, on the hour. This means that you need two hands on the clock to figure that out. Without one hand or the other you would not be able to figure out what time it is. This is roughly how the sensors in the engine work.
When the teeth in the metal rings are in a certain position, the computer interprets the three sensors input into what degree of crankshaft rotation the engine is in at any given moment. This controls ignition spark advance, fuel injector firing, and even compensates for stretch in your timing chain, giving your motor 200k smooth miles.
Bottom line..........replace your Crankshaft Position Sensor and Camshaft Position Sensors. Your gas mileage may go up also. Be sure to change your fuel filter every 12k miles or every year, and make sure that your Oxygen Sensor gets changed every 30k miles for best performance and efficiency.
Here are part#s you can look up on www.partsamerica.com for pictures of the parts.
Fuel Filter - Purolator # F33144 $5.72
Oxygen Sensor- Bosch # 12014 $17.89
Camshaft Sensor -GP Sorensen # CSS5 $19.48
Crankshaft Sensor -GP Sorensen # CSS9 $27.48
Crank Sensor Bracket GP Sorensen # CSB1 $5.93
All these parts are stocked in every Advance Auto Parts. You can take these part #'s to them and they will have them. If you go through another parts store, just give them the technical names or just give them a copy of this post.
Good luck and I hope I helped solve your problem. -Chris
Anyway, to sync all this together you have THREE sensors that "look" at where the engine is at, at any given moment. TWO of these sensors are in the same physical component. So you have two physical components that you need to change out just to be sure, but most likely only one will fix the problem. It's just that when one goes the other is not far behind.
These magical eyes are : #1, the Crankshaft Position Sensor and #2 is the Camshaft Position Sensor.
The CRANKShaft position sensor is located just behind the harmonic balancer pulley on the passenger side of the car at the bottom of the motor. It contains two sensors in one. It should have 4 wires coming out of it.
It can only be replaced by jacking that corner of the car up, removing the wheel, removing a splash cover for access, and then by using a air impact gun, remove the harmonic balancer pulley bolt(32mm, I think). The balancer slides right off. And just to the right of the shaft is the Crank Sensor. I failed to mention that you will have to remove the drive belt in order to remove the balancer. The sensor is secured to the block by two bolts holding a bracket assembly. The new sensor will come with a new bracket most likely, but due to cost cutting, they may not anymore. So word to the wise, save old parts until problem is solved.
The Camshaft Position Sensor is located just above the water pump and to the left slightly. You will need a mirror to see it. It is secured by a 8 or 10mm bolt. Two wires go into it.
The whole reason for your being able to start the car cold and not hot is that the Crank sensor most likely has failed internally from constant heating and cooling. If one side of the sensor fails, it causes the car to start and run all day as you describe. If the other side of the sensor fails, the car will not start at all. The camshaft sensor will have a similar fate sooner or later.
You will notice on the back of the harmonic balancer that there are two metal rings with cutouts in them. These cutouts are what the sensor looks for. The sensor will need to be carefully aligned upon installation to be certain that as soon as you start the motor, the metal teeth do not rip the sensor right out of its bracket along with its wiring harness. Use the long visible bolt to clamp pressure on the sensor so that is does not move left or right.
The CAMSHAFT position sensor is replaced as a fail-safe. It also "looks" for something, and that is a magnet embedded into the Camshaft gear.
Just to get an understanding about how these sensors work, think of it like this: You are given a gun, a target, and a analog clock. Your command is that you are to shoot the target every 3 hours, on the hour. This means that you need two hands on the clock to figure that out. Without one hand or the other you would not be able to figure out what time it is. This is roughly how the sensors in the engine work.
When the teeth in the metal rings are in a certain position, the computer interprets the three sensors input into what degree of crankshaft rotation the engine is in at any given moment. This controls ignition spark advance, fuel injector firing, and even compensates for stretch in your timing chain, giving your motor 200k smooth miles.
Bottom line..........replace your Crankshaft Position Sensor and Camshaft Position Sensors. Your gas mileage may go up also. Be sure to change your fuel filter every 12k miles or every year, and make sure that your Oxygen Sensor gets changed every 30k miles for best performance and efficiency.
Here are part#s you can look up on www.partsamerica.com for pictures of the parts.
Fuel Filter - Purolator # F33144 $5.72
Oxygen Sensor- Bosch # 12014 $17.89
Camshaft Sensor -GP Sorensen # CSS5 $19.48
Crankshaft Sensor -GP Sorensen # CSS9 $27.48
Crank Sensor Bracket GP Sorensen # CSB1 $5.93
All these parts are stocked in every Advance Auto Parts. You can take these part #'s to them and they will have them. If you go through another parts store, just give them the technical names or just give them a copy of this post.
Good luck and I hope I helped solve your problem. -Chris
90eighty8
10-03-2005, 05:52 PM
thanks alot man, it sounds like you know what your talking about so i will definately give that a try.
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