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another no spark thread
car started fine last week. went out this morning to move it and nothing. engine is coming out for a rebuild tomorrow (bad coolant seal) so i will be able to diagnose easier.
i have fuel but no spark. fuses are good as are the relays. swapped out coils with known good ones. swapped out igniter, plug wires, and plugs. still nothing. any ideas? |
do you have power to the coils? what ecu are you running? is the black condensor wire attached by the igniter? hows the wiring by the crank angle sensors? do you have a tach signal?
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i have not checked for power to the coils yet. this car is bone stock, so stock ecu. condesor wire is connected. cas wires look good and intact.
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First I would disable the fuel pump. Then un-clip the ignition harness and use a test light to see if your getting power the 12v ignition wire. I forget the color but there 4 total and the 12v wire is a solid color so that can help you to not tap into one of the signal wires.
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the 12v wire i assume is supposed to have power when ignition is on? it does. but during cranking the signal wires have no change in voltage. i happend to have an extra coil harness that i did my testing with. one wire on all three plugs(plugs that connect to the coils) had 12v with ignition on. then the other wire had nothing during cranking which is what i would think is the signal wire. the weird part is i have fuel, but no spark. the crank angle sensors control both, correct? or am i testing wrong?
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real low compression im thinking
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Originally Posted by gripp2maxx
(Post 8741197)
real low compression im thinking
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Take out the fuel pump fuse and then take out each plug leaving it connected to the plug wire and have some one crank the car while you hold the plug close to a ground while you check the spark on each of the 4 plugs. That's what I did, worked to see if I was getting spark.
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you do know that the signal wire will not change in voltage, it is simply a switched ground.
coils get steady batt voltage on one lead, the ecu turns on the ground to power the coil, removes the ground to fire the coil. same way injectors work. a good way to test the systems is take a high impedence test light, clip the lead on batt neg, probe the + wire in the coil harness, have someone crank the car. the light should be bright and steady. unclip the test light from the neg terminal move it to the batt positive terminal, probe the coil driver side of the harness (not the one you probed before), have someone crank the car. the light should be a dimmer flicker. |
stick one finger in one of the coil sockets,then touch the negative battery terminal with your other hand-then have a friend try to start the car-thats the best way of knowing if you have power or not...
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Take out the fuel pump fuse and then take out each plug leaving it connected to the plug wire and have some one crank the car while you hold the plug close to a ground while you check the spark on each of the 4 plugs. That's what I did, worked to see if I was getting spark. stick one finger in one of the coil sockets,then touch the negative battery terminal with your other hand-then have a friend try to start the car-thats the best way of knowing if you have power or not... you do know that the signal wire will not change in voltage, it is simply a switched ground. coils get steady batt voltage on one lead, the ecu turns on the ground to power the coil, removes the ground to fire the coil. same way injectors work. a good way to test the systems is take a high impedence test light, clip the lead on batt neg, probe the + wire in the coil harness, have someone crank the car. the light should be bright and steady. unclip the test light from the neg terminal move it to the batt positive terminal, probe the coil driver side of the harness (not the one you probed before), have someone crank the car. the light should be a dimmer flicker. |
come on man I was kidding...
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the signal wires are dead during cranking per test above. so now i guess i have some wireing diagrams to read.
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when you turn the key to the on pos does the check engine light come on for a bulb check? there are no codes correct?
check the ignition sub-harness connector also |
did some more testing and it seems that the harness is the culprit. crank angle sensors test out good. but there is no continuity between the harness connector and the pin at the ecu for the sensor. also no resistance between the the pins on the harness at the ecu for the sensors. yay for a new harness.
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I will be at a wedding tonight, but call me tomorrow. I have had similar issues and their are a couple things I want you to check.
Also Landers has a harness with 18k miles on it for pretty damn cheap, I have seen it and it is pretty much perfect. |
Have you checked your EGI and Main Circuit relay? Those WILL make a problem like this...
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yes they are good, but how would they effect continuity?
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got the harness out today and found some interesting stuff. somewhere along the lines an owner of the car cut the CAS wires and respliced them. but when i say "respliced" i mean stripped the insulation off, twisted the bare wires together, and wrapped in electrical tape!!! i am flat amazed that the car ever ran. the crazy part is, when it was running, it ran fantastic! new harness going in tomorrow so we shall see.
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read the whole thread, congrats on finding the new harness, best of luck
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