Forums/Z31P/z31-repairs-forums engine-mechanical/No fire?? Wont start
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Khudohs: (2014-11-11 22:10:52)
My 1986 300zx has been having trouble and now it wont start at all. Before it would start up sometimes run a minute or two than die. Now it wont start at all. I have checked for fire and wasnt getting any so i started replacing parts. I bought a new Ignition Coil and than checked it for power and there was none. What would not be letting my Ignition Coil get power? Is this the Power Transistor and if so where is that ive heard of it and i cant seem to find it.
Augustus Maximus: (2014-11-13 13:23:53)
Power transistor is right beside the coil.
Khudohs: (2014-11-13 20:04:55)
Do you think this is the problem?
Butter: (2014-11-14 14:20:38)
So you have +12v at the coil with the key on or no?
Khudohs: (2014-11-14 14:33:12)
no
So you have +12v at the coil with the key on or no?
No my dad and I took a multimeter to it and it read nothing. I believe we had it right but we couldnt get it to read any power.
Butter: (2014-11-14 19:25:53)
Check fusable links by the battery. Use continuity test with meter because you can't tell by looking if they're blown. Sometimes they feel soft though.
Augustus Maximus: (2014-11-14 21:00:05)
Do you hear the fuel pump priming when you turn the key. That means power is going to the ECU and CAS. There is a 15A fuse that sends 12V directly to the coil, check it…good? Pull it and test for voltage on the supply pin (fuse take juice one pin to the other). After that it's the ignition switch then fusible link.
Khudohs: (2014-11-14 22:15:57)
Do you hear the fuel pump priming when you turn the key. That means power is going to the ECU and CAS. There is a 15A fuse that sends 12V directly to the coil, check it…good? Pull it and test for voltage on the supply pin (fuse take juice one pin to the other). After that it's the ignition switch then fusible link.
Okay cool, Yea i hear the fuel pump prime and the ECU make its noises. I have checked the fuses behind the kick panel under the dash and have replaced a few, im thinking i have replaced the 15A your talking about but havnt checked for voltage or anything. I also have not checked the fusible links by the battery for any voltages. .... I've replaced tons on the car and had it driving for awhile and this happened and its just not getting fire to start … ill be sure to check what you guys have said so far
slaponte: (2014-11-18 18:52:03)
I am diagnosing an identical issue on my 84 AE. I won't muddle the thread. Just a question on procedure : To test the links, you take it out, test for resistance/continuity between the two ends? I am not very good with my multimeter, mostly use it to test volts.
As I have seen this kind of thread in several places, maybe a checklist with order of propensity to fail (most likely to less likely) would help. Also, simple checks on top. So far I got
1. ECU Fuse and fuel pump fuse by driver kickpanel
2. Fusible link check by battery
3. 12v at coil (which terminal)?
I just sent for a coil (I think the one in there is the original), but the power transistor is $$$ so I would like to make sure before spending on that.
Parker: (2014-11-18 23:05:37)
A used power transistor isn't that expensive, and it's an opportunity for a cheap, easy engine management upgrade:
http://z31performance.com/showthread…ansistor-Unit)
You can get a used PRW-2 on eBay for like $10.
slaponte: (2014-11-18 23:26:59)
Thanks, outstanding link. I had not searched for that yet.
For quickness, I might go tomorrow AM pickup a couple used ones at my U-Pull-It. Then I can get a new one later.
Thanks again.
A used power transistor isn't that expensive, and it's an opportunity for a cheap, easy engine management upgrade:
http://z31performance.com/showthread…ansistor-Unit)
You can get a used PRW-2 on eBay for like $10.
Khudohs: (2014-11-19 21:22:32)
I seem to be getting voltage to all these places … I just dont understand, the car sounds healthy when your cranking … The weird thing is when i let my car sit for a few days and i hook up the battery and crank it the first time it begins to start and like you can hear the car coming alive and it struggles than dies like immediately not even a few seconds … Than you crank it again and its nothing just a healthy battery cranking the engine but it dosnt fire up … and another strange thing is if i crank the car for awhile idk if its suppose to do this but it makes a beeping noise and it sounds like when you turn the car off and the ecu and stuff shuts down, but i have a new ECU so im pretty positive it cant be that … im clueles, should i go ahead and buy a PTU and give it a shot or what?
Allout: (2014-11-19 23:37:00)
Have you tried shooting some starter fluid down it's throat when you crank it?
Khudohs: (2014-11-20 03:09:39)
No i havnt really tried that. Sounds like a good idea though … pretty much the whole story was i had the car driving fine pretty much and was cruising around and than my gas meter isnt exactly lined up i guess and ran out of gas … so i rolled into a gas station and it wouldnt start after that … but whats weird was i parked it and came back few hours later and got it running VERY ROUGH and it was coughing and stuff and died several times while driving and got it home cause i wasnt far but before you say any fuel related stuff i looked into everything about the fuel and i got fuel and have fine fuel pressure cause ive already checked it and bought new fuel lines and filters and all that jazz … but if this story has gave you guys anymore ideas what could be wrong … i feel like its gotta be spark issues specially cause my dad checked and its just not sparking …
Khudohs: (2014-11-20 03:11:24)
And by throat means the intake right??? Im sorta a noob, i love cars and am learning quickly but shes my first own car and i probably picked a bad car to learn on cause 300zx are insane
slaponte: (2014-11-20 22:44:48)
In my case, new coil, junkyard PRW2, and ITS ALIVE!!!!! :-) Sorry, just excited. [archived image: smile.png]
Khudohs: (2014-11-21 04:40:12)
i already have a new coil … so your saying i should most likely replace my power transistor?
slaponte: (2014-11-21 05:16:32)
I would. I went to the U-Pull-It, found two on the first row of cars. $9. Bought both just in case, installed the cleaner looking one. Took just a few minutes. There is a link to the instructions on this same thread.
Like you, I checked the other info provided : fuses, lights on ECU, fusable links, etc. I have a new rotor and spark plugs (it was due anyways). So it was down to coil and transistor, and they both looked original 1984 stuff, so it was a good thing to change them anyways. [archived image: smile.png]
C.Gesler: (2014-12-03 13:57:16)
Kudos you figure it out yet
Khudohs: (2014-12-08 03:36:13)
No, I installed the PRW-2 and still no change. Its just not getting power to spark : ( idk what else to check
visco1: (2014-12-08 14:43:17)
Did you swap the CAS yet?
slaponte: (2014-12-08 15:15:17)
@ same spot myself. Yes on CAS, but I need to pull it out and redo, I can hear some very light rubbing noise. I think when I put the distributor in it pushes up enough to make the wheel of the CAS touch. Still, no spark.
visco1: (2014-12-08 19:54:50)
@ same spot myself. Yes on CAS, but I need to pull it out and redo, I can hear some very light rubbing noise. I think when I put the distributor in it pushes up enough to make the wheel of the CAS touch. Still, no spark.
When I installed my new CAS from ASCO the trigger disc would not sit flat/square in the CAS body. I cracked the damn thing when trying to tighten it to lower the right front edge of the CAS. What I did see was a small tab/pin on the underside of the CAS that appears to be a locator pin or leg, I file that off and reinstalled and then the disc sat flat and even.. The disc would have been rubbing the fastening screw on the driver side front of the CAS. CAS wasn't sitting down low enough to clear the disc until I filed that nub off. I fixed my cracked CAS using JB weld, and 10 days later everything works fine.
Khudohs: (2014-12-11 14:39:40)
yea
Did you swap the CAS yet?
Yea, i bought a brand new distributor and installed it and still nothing.
C.Gesler: (2014-12-11 17:05:17)
Its probably a long shot but Have you checked volatility of fuel, maby you got bad gas After possibly running out of gas.
Pull hose to filter and drain some fuel into a can and se if it lights you dont need much and please be carfull as not to torch your self or your car
Prw-2… did you switch wires when installing, does it have power?
coil… have power?
Dizzy… have power?
Have you ohmed out the wiring harness (looking for shorts or open circuit's
I know we covered some of this befor just double checking
Khudohs: (2014-12-12 00:08:39)
Its probably a long shot but Have you checked volatility of fuel, maby you got bad gas After possibly running out of gas.
Pull hose to filter and drain some fuel into a can and se if it lights you dont need much and please be carfull as not to torch your self or your car
Prw-2… did you switch wires when installing, does it have power?
coil… have power?
Dizzy… have power?
Have you ohmed out the wiring harness (looking for shorts or open circuit's
I know we covered some of this befor just double checking
Yea thats one of the first things me and my dad checked. I bought new fuel lines and fuel filter and than checked for fuel pressure and it was there. Also can hear the fuel pump run and prime fine like it should.
I did switch the wires when putting the PRW-2 on … it was switch the 2 wires that wasnt blue right?
And for checking power to the Coil we did, i bought a new ignition coil and ran a multimeter and its not getting power …
visco1: (2014-12-12 15:23:39)
If your not getting power did you follow the FSM instructions (efec-60 in my 1987 manual) . If no power at main harness it points to the harness or a fuse. Did you look at the ECU and check pins for ignition signal. EFEC 94 - 98.? Swapping an ECU maybe the easiest try if you can find one
irace911: (2015-07-09 20:57:38)
Just buzzing in. I'd take the plug from the ignition coil to the distributor and measure for power there. If none, then the problem resides somewhere along the PRW2, Ignition Coil, and maybe but unlikely, the ECU.
If there is power coming out the wire that stems out of the ignition coil, then it might be the Distributor. I'd check the distributor cap, the CAS inside the distributor, or the spark plug wires.
If still no spark, I'd start thinking ECU. GoodLuck
pokeyquick: (2016-06-21 15:10:23)
Check the ignition relay on the driver side kick panel the third relay.