89 240SX with no spark
89 240SX with no spark
Car cranks over but no spark at all. I have replace the cap, rotor, plugs and plug wires. My friend has a Nissan pick up with the same motor and we swapped the distributor and coil and nothing but they both worked in his truck just fine. I checked the computer for errors and got a code 41 but nothing else. Any info or advice would be great.
i seriously doubt its an engine harness. do you have a volt meter of some sort? you could try to test for a signal to the module from the ecm telling it to spark. Its kinda hard to catch it on a volt meter but you can see it once in awhile. Its easier to test with a DSO but that tool is extreamly expensive. How you car knows when to fire a spark is as follows. distributor ha a pickup wheel in it with 2 different reffrences one is cam position and the other is piston[crank ] position. It takes these 2 readings and sends them to the ecm the ecm determines what cyl is coming up by the last mark it saw and uses the cam position to determine how far before TDC the engine is so it knows when to spark. those 2 signals are calculated by the ecm. The ecm then sends the appropriate signal to the ignition module to fire the plug. The ignition module in turn sends a ground signal to the coil to actually fire the plug. so with all that in mind and a good wring diagram of your system you can check for these signals and determine which is not happening therefore isolating your problem to a specific component. all reffrences are 12v so a logicprobe would work to to see the signal. you wont know how clean the siganl is but you will know its there. Logic probes are much cheaper then a DSO but are still limited to mearly an on off signal from the component and wont really tel you the integrity of the signal. I suspect though you will find lack of any signal from the faulty component.
Curiosity though. Did you check for spark both from the coil and the plug wires, or just the plug wires? If you havent check for spark from the coil yet do so now before you get to involved.
I may have the wiring schematics here for your ignition system but it is based on production date of the vehicle. so let me know and I will thumb through them. Maybe I can tell you what wires to probe.
Curiosity though. Did you check for spark both from the coil and the plug wires, or just the plug wires? If you havent check for spark from the coil yet do so now before you get to involved.
I may have the wiring schematics here for your ignition system but it is based on production date of the vehicle. so let me know and I will thumb through them. Maybe I can tell you what wires to probe.
We only checked for spark at the plugs not the coil.
I will give that a shot and check the date when I get home from work.
The only reason I thought it could be the harness is I saw another topic where somebody tried everything and had no luck but got it to run fine after getting a new harness.
Speaking of harnesses. I got this car from a lady at work who's son gave up on trying to fix it. Apparently he seized the original motor and got another one to replace it. He says it fired up but fuel was leaking from the fuel line so he had to fix that. After fixing that he said it wouldn't fire back up like it does now.
My buddy looked under the car to see if there where any connections not made and said there was a harness coming out from near the transmission that had nothing plugged into it but he didn't figure that would prevent the car from getting spark so we didn't worry about it....yet.
There are also two other wires coming from the engine fuse box that aren't connected to anything either. One is yellow and silver and the other looks brown. On top of that there are two wires that appear to have some sort of odd connections at the end that aren't hooked up either. I'm no mechanic so I don't know the exact name for these two wires but they appear to be sensor wires of some sort. They have metal tips on them that look as if they'd plug into something (there not just plain wire).
He didn't think any of this would prevent spark but who knows. If you think these could be a culprit somehow let me know.
I will give that a shot and check the date when I get home from work.
The only reason I thought it could be the harness is I saw another topic where somebody tried everything and had no luck but got it to run fine after getting a new harness.
Speaking of harnesses. I got this car from a lady at work who's son gave up on trying to fix it. Apparently he seized the original motor and got another one to replace it. He says it fired up but fuel was leaking from the fuel line so he had to fix that. After fixing that he said it wouldn't fire back up like it does now.
My buddy looked under the car to see if there where any connections not made and said there was a harness coming out from near the transmission that had nothing plugged into it but he didn't figure that would prevent the car from getting spark so we didn't worry about it....yet.
There are also two other wires coming from the engine fuse box that aren't connected to anything either. One is yellow and silver and the other looks brown. On top of that there are two wires that appear to have some sort of odd connections at the end that aren't hooked up either. I'm no mechanic so I don't know the exact name for these two wires but they appear to be sensor wires of some sort. They have metal tips on them that look as if they'd plug into something (there not just plain wire).
He didn't think any of this would prevent spark but who knows. If you think these could be a culprit somehow let me know.
if you could snap a digital shot of them I could try to determine what they are. There are so many wires under that dash its really hard to say for sure without seeing them. Also aftermarket devices could have been added at one point then removed. The result is left behind wires. That info about it not running after a repair is very important as you should be focusing your search for the problem in the area of where the repair was made. It is very likely he left something loose. If you havent done this already check all your fuses make sure they are ALL good.
I do have a digital camera so when I get home I'll take pics.
I have checked every fuse in the car and they are all good. The fusible links all appear to be good. The car had no power going to it at all in the beginning. We found that the fusible link with the 75 on it was popped so I replaced that. We got brake lights, dome light, headlights etc after that. The auto seatbelt thing runs up and down the track now when the key is turned but the power windows and door locks don't work so I think there has to be something not connected somewhere.
The only thing we haven't checked are the relays because I we don't know if you can or how to check them.
I have checked every fuse in the car and they are all good. The fusible links all appear to be good. The car had no power going to it at all in the beginning. We found that the fusible link with the 75 on it was popped so I replaced that. We got brake lights, dome light, headlights etc after that. The auto seatbelt thing runs up and down the track now when the key is turned but the power windows and door locks don't work so I think there has to be something not connected somewhere.
The only thing we haven't checked are the relays because I we don't know if you can or how to check them.
I'll give that a shot too. This is so frustrating because it seems we are so close to getting this thing going. It sat for 4 years. I'm just glad we had a good vehicle to swap parts on the test instead of wasting hundreds of dollars.
I assume it's a wiring issue at this point since we've tried everything in the path that we can think of. The only thing we haven't replace is the key tumbler thing but we figure since it's cranking the car over that it's probably good.
I assume it's a wiring issue at this point since we've tried everything in the path that we can think of. The only thing we haven't replace is the key tumbler thing but we figure since it's cranking the car over that it's probably good.