Hello from a new guy with car trouble.
I have a 92 Nissan Stanza that went from what seemed to be running fine to dead as fast as you can switch a light off. It won’t start.
I’m not sure how to check if gas is getting to cylinder with fuel injection. I do hear the fuel pump come on when I turn ignition switch to the on position. Also there was enough pressure in the line at the fuel filter to squirt gas when I loosened the fuel line clamps and started to slide the fuel line off the filter output. I was going slowly because I knew the fuel line might be pressurized.
I pulled a spark plug and clamped the body of the plug with a jumper cable and grounded the other end of the cable. When I cranked the engine the spark looked weak. I’m thinking of taking an old plug and gapping it wide (.20) and seeing if there is enough voltage to jump this gap. Not sure how else to check for proper spark.
I pulled the diagnostic codes and got a 13 (engine coolant temp sensor). Don’t understand why I got that. Also got a 21 (No ignition reference). I have 12V at primary side of ignition coil with ignition switch on. The primary resistance is about 0.7 ohm. The secondary to either terminal of the primary measures 9.4Kohm. I think the secondary should be 8Kohms. There are 35ohms to ground through the primary wire harness. From the fail code of 21, I’m guessing there is a bad ground wire somewhere.
I would really like to rule out either a problem of no gas or weak spark and proceed from there. Any input will be appreciated.
I also should say that the problem isn't with the distributor cap or rotor.
1. Obviously the primary voltage and resistance are good. You're correct
that the secondary resistance should be 8k but more often they're at 9.5 to
10.5k and still work great.
2. I'm not sure about the 35 ohms to ground. At which component connector are you testing? Are you checking a wire that is a direct ground or one that is switched by the PCM? Normally Nissans don't have a ground problem unless someone has damaged the wiring or simply not reconnected it after doing repairs.
3. Are you sure you didn't accidentally create to DTC 21 by cranking the engine without the distributor plugged in? You wouldn't be the first person this has happened to and then end up taking the wrong path of diagnosis.
4. Have you checked the compression just to be safe? I've seen a crapped out timing chain or tensioner send many a tech on a wild goose chase on these engines. They generally have about a 120k mile lifespan.
5. If you don't have the proper equipment its hard to test the injectors to see if they're moving fuel. The easiest way to do it is give it a good long crank and pull the plugs out to check for wetness. It's the caveman way but it works.
6. Lastly if you have a donor car, grab the distributor and throw it in. Another common problem (actually the crank sensor inside the distributor) on this engine, usually good for about 150k miles.
Sorry if this is a bit of a ramble. I spent 14 hours today never getting more then 12" away from my scan tool. Good luck.
Thanks for all the info!
I guess red font doesn't show up very well on the grey background.
There are two wires going to your coil. One as you have discovered is a
switched 12 volt power source. The other is a ground switched by the PCM.
The switching ground is what causes the coil to fire. If you have a closed
ground circuit at all times, even with 35 ohms resistance the coil won't do
diddly. If you're measuring it at the switch point and it has 35 ohms you
have a bad ground.
Based on all the info I've read so far my educated guess is still the Crank Position Sensor being the culprit. And you're right about the red.
The switching ground is what causes the coil to fire. If you have a closed ground circuit at all times, even with 35 ohms resistance the coil won't do diddly.
That makes sense. If you don't collapse the primary field there will be no high voltage on the secondary. I will look into this. How do you tell if the spark at the plugs is sufficient for firing?
Once again the quickie caveman way is to ground a plug to the block when cranking and look for a nice fat spark. More caveman advice... Shoot some ether in the throttle body while cranking and see if it tries to start. Not to much though, unless you want to push out the head gasket.
Once again the quickie caveman way is to ground a plug to the block when cranking and look for a nice fat spark. quote]
I have done this. The trouble is I am inside the car looking under the hood at the sparkplug. From that distance the spark looks kinda small and weak. I guess I will have to get someone to crank the engine so I can get a closer look.
Again, thanks for the advice. I like the idea of using a little ether too. It would be nice to just hear the darn thing fire once.
Make yourself a test lead a couple of feet long with alligator clips on both ends. Clip one end to the starter solenoid switched post then touch the other end to the battery positive post, presto your engine cranks. Make sure you have the ignition on or you'll have no spark.
Just out of curiosity, if I had 2 good ignition coils could I take the high voltage from one and feed it into the secondary of the other and step it back down to 12V.
Well I sure don't know the answer, but I think not. What I'm wondering is why you'd want to do that.
Make yourself a test lead a couple of feet long with alligator clips on both ends. Clip one end to the starter solenoid switched post then touch the other end to the battery positive post, presto your engine cranks. Make sure you have the ignition on or you'll have no spark.[/quote]
I would also have to bypass the clutch pedal switch, or put a stick between the clutch pedal and the seat.
Nope, you're already bypassing everything by going straight to the starter. Caveman shit but it works great. ;)
I was just thinking it would be a way to tell if I was getting high voltage out of the first coil. I guess the spark plug method is the tried and true way.
After days of being wiped out by a nasty cold or flu, I finally got back
into trouble shooting the car problem.
I got some info from a Mitchel's service manual. It said to remove the harness from the crank angle sensor, turn key to on position, and measure the voltage on terminal "a" of the connector. It is supposed to be same as battery. My battery measured 12V, terminal "a" measured 11V. Does this seem close enough to 12V to rule out?
Also I would think if the cylinders are getting gas, should I smell the unburned gas at the tail pipe since the engine isn't firing?
1. Yes it would be but... That only tells you that you have the input
voltage not what you're output is.
2. That's a definite maybe. The easiest way to find out is to pull a plug and check it. Have you tried it with ether yet?
My car is running again, but I'm not sure why. :screwy:
I was checking out the coolant temp sensor last weekend and everything checked out ok. 5V on one terminal and the other had continuity to ground. The temp sensor is new. I sprayed the contacts with electrical contact cleaner and reconnected the wires to the temp sensor.
Today I was rechecking spark, and making sure the fuel pump was running when I turned the key to the on position. I pulled some of the under hood relays and ohmed out the coil side to see if it ohmed out like a coil of wire should. They all checked out ok so I replugged them in.
I gave the starter a crank and the engine fired right up.I let it run for about 20 seconds and shut it off. I tried again and it started up again so I drove it around the neighborhood and it seemed fine. After driving it I ran a diagnostics and a code 13 (coolant temp sensor) was again being reported. This was one of the fail codes I got when I initially had car trouble. During trouble shooting last December I somehow cleared all the faults and the last time I had checked the codes it was sending a 55 which is the all ok code. I did disconnect the battery for a few days last week to charge it, could this have reset something that does not get reported in diagnostics?
Is it possible the temp sensor problem was shutting down the pulse width modulator to the fuel injectors? I'm thinking I will have a repeat of the problem as long as there is a code 13.
Anyway, thanks for all the input vwhobo!