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Car Forum / Mitsubishi Cars / March 200595 turbo wont start, has gas and spark
heres my problem, my baby, a 95 tsi wont start, fuel pump is running fine and there is plenty of preasure at the rail and there is spark. i pulled the ecu before i checked anything else so im not sure if i can pull codes or not. my first thought when there was fuel and spark was the timing belt but sure enough, its fine, cams turning just fine, my only other thought is a cam angle sensor but i dont know how to check it and due to its cost id like to try anything else first. any help will be greatly appreciated. thanks, john On that year you have both a crank and cam angle sensor to deal with.  SignatureTodd Honea > heres my problem, my baby, a 95 tsi wont start, fuel pump is running > fine and there is plenty of preasure at the rail and there is spark. [quoted text clipped - 4 lines] > check it and due to its cost id like to try anything else first. any > help will be greatly appreciated. thanks, john Most all sensors can be tested in the car, just depends on the type of sensor used. Most distributors use an opto interrupter, and a disk with holes punched in it at key points. This type of sensor outputs 5 volts, depending on whether the light is blocked or not by the disk. An analogue voltmeter may be able to detect these voltages as the engine turns. On the other hand, if you remove your spark plugs, turn the ignition key to "run" and rotate the engine by hand, while monitoring the output of these sensors, these pulses would appear very slowly, and the volt meter would be able to detect then easily Crank sensors (the kind that "crank walk" takes out) use a reluctance pickup. Basicly a "gear tooth disk" rotates very close to a coil (the sensor) and generates a low voltage in the coil as it passes by (typically less than 1 volt). An ohm meter would measure whether the sensor was open or not. These sensors are usually either good (have some resistance) or are open, and have no resistance. And just to be complete, temperature sensors are usually just resistors that change value depending on the temperature around them. Use an ohmmeter to measure them. Even if you've pulled your ECU, after attempting to start the car, it should have logged new errors. I would have though that if you had spark and you had fuel, unless the timing is out, you should have ignition. But I don't know much about the turbo, it may require some other input. I believe both of the sensors that "Nobody" mentioned, are located in the distributor, and are the opto interrupter type. > On that year you have both a crank and cam angle sensor to deal with. On the 1G they were Hall optical. On the 2g they are electrical pickups. Same effect, different method. The 95 and 96 are backwards on the cam sensor (driver's side) versus all other years (passenger). The crank sensor is at the crank. If he has spark, I believe those sensors are working. The ECU wont send spark without them. I would have said MAF, but that has a limp mode and should start the car. > I would have though that if you had spark and you had fuel, unless the > timing is out, you should have ignition. But I don't know much about [quoted text clipped - 3 lines] > > > On that year you have both a crank and cam angle sensor to deal with. Well, I wasn't sure about that engine / that year, anyway. I've worked on my sons 1.8L (1991), and that's what I based my response on (the factory service manual also covers the 2.0L engine). My other manual (Chiltons 1990-1993 eclipse) shows the same thing. The schematic definitely shows LED's and opto receptors, for the 1.8L, 2.0L non-turbo,and 2.0L turbo, and I can't find a "crank sensor"on the crank, for these engines. However, the manual I'm using is 4 years earlier than the poster's year, so I could definitely be wrong, about his engine. So if I understand your post "Nobody", this vehicle still has two sensors, a crank position sensor mounted on the block, at the crank (this would be a reluctance pickup (coil) then) and a TDC sensor off the cam shaft, which would also be a "reluctance pickup" (that was a question)? Not quiet sure what "hall optical" is though. I know what hall effect is and I know what optical is, but haven't heard that term before. I agree that the ECU will only fire the coil if the sensors report the correct position of the crank. But the ECU doesn't know if the coils do indeed fire when commanded to do so. If the timing is grossly wrong, the engine won't start. Are there two coils in this engine, and are they both firing. You can measure the resistance between the outputs of the coil to see if they have continuity. I believe cylinders 1 and 4 share the same coil, and 2 and 3 share the other coil. Resistance should be about 10 to 14 Kohms (well in 1991 anyway). I'm trying to keep my responses general, on this thread, as I am not totally familiar with this specific engines electronics. > On the 1G they were Hall optical. On the 2g they are electrical pickups. > Same effect, different method. The 95 and 96 are backwards on the cam sensor [quoted text clipped - 4 lines] > spark without them. I would have said MAF, but that has a limp mode and > should start the car. > So if I understand your post "Nobody", this vehicle still has two > sensors, a crank position sensor mounted on the block, at the crank > (this would be a reluctance pickup (coil) then) and a TDC sensor off the > cam shaft, which would also be a "reluctance pickup" (that was a question)? That is correct. The 95 DSM broke them into two sensors. Only on the 95-96 is it on the driver's side. All years (<95-, >97) it was on the passenger. The 1G (<95) had only the CAM sensor as does the 91-92 3000GT/VR4. The 93+ GT has two, also. The vehicles with two sensors will not allow timing to be adjusted. You are also correct about the coil pairing. One half of the coil effects two cylinders. Just because one is showing spark, doesn't mean the other is. SignatureTodd Honea > > So if I understand your post "Nobody", this vehicle still > has two [quoted text clipped - 20 lines] > two cylinders. Just because one is showing spark, doesn't mean > the other is. ok, went out and checked the other 3 cylanders for spark, yup, eack showed spark. interesting thing i found though, i took the cam sensor out via taking the cam gear out, found out its very different than the one my part place gave me so im sol there, but i just might not need it. heres the neet thing, for laughs i thought id check the crank sensor, following my books instructions i checked the harness to the sensor first, pole 3(the single bottom pole) was good, there was possitive voltage, next was check the voltage between pole 2(right of top two pins)and ground, is sopposed to be 4.8-5.2 volts, here i got nothing!!!!, pole 3 was good. the interesting thing is that when i tried to start the car for the past week i noticed that the fan was turning for a second when the starter was cycling, i thought well must have always done that..... but with ingition on i plugged the sensor back in and heard the tps move and a click down by the maf and then the fan clicked on for a few...... the wire is black with silver dots on it, anyone know where this wire goes or should i try to rip apart the harness and trace it? makes me feel good to think im getting somewhere on this, its driving me crazy and i miss drivin my baby thanks alot to all who are helping me with this "nirodac1" wrote: > Well, I wasn't sure about that engine / that year, anyway. > I've worked [quoted text clipped - 62 lines] > limp mode and > > should start the car. i only checked spark on one cylander, the closest to cam sprocket, i will chech the others in a few minutes, is there anything other than the ecu that makes the injectors work? i know i have pressure but i dont think the injectors are pulsing because i dont smell any fuel, i even took the return hose off the fuel pump and the fuel just cycles through, i dont have a noid checker.... (i think there called) but i will check to se if theres any voltage going to the injectors..... if there is no voltage what can cause this? thanks for all the help all, john > heres my problem, my baby, a 95 tsi wont start, fuel pump is running > fine and there is plenty of preasure at the rail and there is spark. If there's spark, the sensors are likely OK. If there's fuel pressure at the rail, your fuel pump is OK. Hence MPI relay is probably OK too. Its possible that the injectors are not getting power. On the 1G engines, there's a set of large ceramic resistors mounted in an aluminium cage on the firewall. 12V is supplied from the MPI relay, and then to the injectors. The ECU grounds the circuit when each injector fires. Check that you have 12v on the resistor block. If not, check the MPI relay behind the radio in the center console. Stewart DIBBS |
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