Engine won't start/run? Beginners, read this.
Posted 29 May 2007 - 08:29 PM
From the beginning:
If you car doesn't do anything when you try to start it:
You might have a bad solenoid, starter, or ignition switch. A Voltmeter should be used at the starter solenoid to make sure you have 12V going to the main power prong and the switched 12V (small wire) when your ignition is in the "start" poistion. If not I don't envy you and you will need a wiring diagram, voltmeter and a few hours to trace which wire does what. Start at the ignition switch and move forward.
If your car clicks while you're trying to start it:
You probably have a dead battery which could be caused by a bad battery, a bad alternator or faulty wiring. Jump the car off and if the car will stay running your alternator is working and your battery is probably bad. If your car dies soon after disconnecting it from the other car your alternator isn't working properly AND your battery is dead (but the battery is only dead because the alternator isn't charging it). If you can make it to a place that tests batteries and alternators you should. Taking just the battery to get tested is not a bad idea. In the process of testing the battery some places will charge it for you also.
If your car loses all power as soon as you try to start it (lights go off and won't come back on, radio stays off etc.):
You probably have a bad connection at the battery or solenoid. Clean the terminals and tighten.
So the car will crank but not start, now what:
Engines must have fuel, spark and air to run:
One of the easiest ways to figure out if you're NOT getting fuel is to spray gas, starting fluid or carburetor cleaner into the carb/throttle body. If you are able to get the car to fire or even run for a short period of time then you're not getting enough fuel to the engine. Many things could cause this with the most prominent probably being the fuel pump. You can of course hear an electric fuel pump running and it will probably be near the gas tank if not in it. If you have a mechanical fuel pump you probably can not hear it and will need to use a fuel pressure gauge or prime the engine as said earlier. If you have a carburetor with sight plugs you could pull them to see if there is fuel in the floats. With fuel injection, if you are getting fuel pressure you should move on to things like checking to see if your injectors are getting 12V from the computer while cranking (use a voltmeter). A clogged fuel filter will almost NEVER cause an engine to not start. This could be possible in a car that has sat for a long time and then run close to empty or if you were experiencing an EXTREME lack of power before.
(If the above didn't work) The easiest way to insure that your are getting spark is to take a spark plug out and ground it to the engine or body (not a painted or plastic/aluminum part). You can also do this with a timing light. If you do not get any spark you should check to make sure that your coil (this could be part of the distributor such as an HEI) is getting power (with a voltmeter) and that your ignition module is hooked up properly. If you still do not get any spark you should think about replacing your coil.
So you've got spark and fuel but your car still won't start. It is very likely that your timing (either ignition or valve) is wrong. Backfiring and popping through the intake is a good sign you have your ignition timing wrong. You should triple check your firing order. If you have moved the distributor or are working on a car that you do not know what the PO has done, you should set the car to top dead center. You can usually do this by setting the slit on the harmonic balancer to the "0" on the timing indicator. You must make sure you are on the compression stroke when you do this which can be done easily by holding your finger over the #1 spark plug hole while cranking or turning the engine (taking all of the spark plugs out will help because you won't be fighting the compression of the engine). When the pressure pushes your finger off of the hole and you are nearing "0" on the indicator you are on the compression stroke. Now you need to get it right on "0" (and you might have to try it a few times), remove the distributor cap and make sure the rotor is pointing to the #1 spark plug post. If it is on the complete other side ("180 degrees out"), you should unbolt the distributor and move the rotor to the #1 position. With an L28 this should be easy because it should only go in two ways and if you haven't messed with the oil pump rod rotating it 180 degrees around should be perfect. On a Chevy engine you might have to move the oil pump slot/rod with a long flat-head screwdriver and do your best to put the rotor around the #1 position.
So you're getting fuel, spark, you're at top dead center and your rotor is pointing at the #1 post and still the thing won't start. It is very possible that your ignition module is bad especially with a Z. You can take these off the distributor and have a parts store test them. Take what the machine tells you with a tiny grain of salt because I've had good modules test bad (one time it was new off of their shelf and another time it was off of a car that I had been running for about a year) and I've also had bad modules test good. Sometimes modules will work some times and not other times. If your Z will start only sometimes and even die on the road sometimes and start right back up you probably have a bad ignition module. You should check to make sure your spark plugs aren't fouled. You could be flooded at this point also in which case you should try to crank the engine with the throttle wide open (gas floored) and if that doesn't work you might think about calling it a day and trying tomorrow. I'm not going to cover valve timing because if you think you can play with a cam you should be able to install it correctly .
It would be pretty rare for a car not to start because it either can't get air or can't let the air it gets out of the exhaust. If the car has sat outside for a long time you could have a rat or bird nest in the exhaust or intake. If you have some punk friends they may have tried to plug your exhaust with a potato or sock. If your car has been sitting long enough for it to be clogged you should go through every aspect of the car (including the brakes) before you decide to start/run/drive it. Weed eaters/whacker/trimmers, mowers and small engines are pretty notorious for having their little muffler or a screen that goes over it to be clogged to the point where they won't start. Maybe someone will get their weed eater running from me writing all of this
Anyone have anything to add?
- I am in no way responsible for the use or mis-use of these "opinions".
Posted 30 May 2007 - 08:05 AM
Dome lights may do for a solo tester, but don't provide much battery load.
Vehicles with a dropping resistor in the ignition circuit usually bypass it when starting. If this resistor goes bad (open) the engine will start, but die as soon as the starter is disengaged.
Looks like a good start on a 'sticky'.
I'd Add a caveat about the dangers of playing with gasoline, starter fluid etc. because someone, somewhere could do something stupid and find a lawyer.
(My paranoia/ faith in lawyers is showing).
In the canyons of the night,
What mere mortal hand and eye
Hath formed thy fearful symmetry?
Posted 07 December 2007 - 08:21 AM
Posted 11 December 2007 - 10:16 AM
IN my case the voltage does not drop, instead it peaks out. I changed my MAF sensor for a twin turbo MAF ( I have and 1986 Turbo Z) and I don't know if that is one of the problems and I wish somebody could answer mew this. Another thing a friend of mine told me is one of the "Fusible links" gone bad...can this be it? Another thing is that I changed my stock regulator for one that looks from a Porsche and I don't seem to find where's the fuel entry, the fuel exit and the air vaccum. This fuel regulator is completely different because unlike the stock one it only has one fuel entrance ( the stock one has two). I'm breaking my head here because of thinking too much, can someone somewhere help me?!?!?!?!
If the engine isn't running, I don't see how the voltage can be going up... starter and other electrical loads will be draining the battery, eventually causing the voltage to go down.
You can check your fusible links with a voltmeter: If you find battery voltage across one, it is blown. I'd change any link with a significant (volt or so??) reading.
Sorry, I can't help with EFI stuff.
Sounds like you may have picked up a 'deadhead' fuel pressure regulator to replace a bypass type. Not a good idea. http://forums.hybrid...ad.php?t=105947
I'd guess that you also need that vacuum/pressure connection on your regulator for boost enrichment, but that is strictly speculation.
Life is simpler if a person makes only one change at a time.
In the canyons of the night,
What mere mortal hand and eye
Hath formed thy fearful symmetry?
Posted 16 December 2007 - 05:42 PM
Posted 18 December 2007 - 12:09 PM
Posted 03 January 2008 - 04:32 PM
I sent the car to a Nissan Service Center and they cant figure it out. It is still there at the moment.
Now here is the weird part. I found a technique that if I hold the key half way from ON position and Start position it will stay as long as im holding it there. As soon as i let go the car will either shut off at the moment or stay on for a bit and shut off again.
What nissan has done is got another ignition switch because they swore 99.9% that the the problem but nothing. Then they said it may be the ballast resistor. Still nothing. And they havent called me back with any update yet. Nissan states it is something to do with my ignition/electrical system.
Any input would be great
Posted 04 January 2008 - 02:57 PM
Posted 13 January 2008 - 04:31 PM
Posted 26 January 2008 - 02:07 AM
ur problem is in ur ignition barrel itself, behind it r 5 wires! there is obviesly 1 loose or very weak, try checkn that mate get back to me,
people i alo got a problem myself,,,, my L20et is gettn fuel,, its getting spark, valve and ignition timing is fine, yetwont start, it wont even try start, it jus turns over by the power of te starter motor n thats it,,,,, nufn else, wont even try to ignight itself,,, yet its gettn all it needs, any ideas??????
Posted 17 February 2008 - 09:57 AM
Nathan11 - did you fox your issue yet?
Anyone else on this thread have an idea what happened to my Z? Sounds like possible bad grounds on my engine/dash connections (and/or alternator and battery issues).
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1 Car garage
Posted 17 June 2009 - 04:40 PM
Posted 13 June 2010 - 09:04 AM
Posted 06 March 2013 - 03:00 PM
Ok guys i have a problem as well my car starts runs for a few seconds then dies i can re start it and it will do the same thing i can repeat this about 5 times then it wont start at all. the guy i bought it off of said it sat for 6 years and then he started it and let it run for a while (before i came to buy it) and it died and did the same thing its doing now. any ideas ?
Posted 06 March 2013 - 05:45 PM
By the way, the FAQ sections are usually meant to be read and not posted in, unless useful information is being added.
Edited by NewZed, 06 March 2013 - 05:46 PM.
Posted 06 March 2013 - 05:46 PM
Always include the make and model of the car you are discussing. Also, include type of fuel and ignition system.
The car sat for six years. What is the most likely cause of the symptoms you are seeing? Go back to the very first post in this thread. The answer is there. You just have to think about it logically.
Edited by Miles, 06 March 2013 - 06:45 PM.
“Life is like arriving late for a movie, having to figure out what was going on without bothering everybody with a lot of questions, and then being unexpectedly called away before you find out how it ends.” -Joseph Campbell
Posted 02 October 2015 - 09:22 AM
where is tdc for my heads?
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