View Full Version : Weak spark. Car barely runs. Which part to replace?

12-08-2017, 10:55 AM
Car was running fine. Then started to sputter and hesitate. RACV guy connected something to the plug lead. Car starts eventually but won't rev then stalls. He said it's in the distributor and arranges a tow truck. What bit would it be? Thanks.

12-08-2017, 11:52 AM
New rotor and cap are cheap as chips from Nissan (Should be less than or around $100 from memory at max) - Leads - perhaps, but my money would be on rotor and cap. - This is just based on what what you are saying old mate told told you - could be something else not even mentioned!

12-08-2017, 12:37 PM
Thanks. Only just got home 5 minutes ago and I think this is going to be annoying. When it started going wrong, I could barely get it off the road. Eventually it wouldn't fire up. When the racv dude got there, it would take about 8 seconds of cranking then idle but touch the throttle and it stalls. He had a lead plugged in to a to and said he could see spark when running but was very weak. Hitting the throttle kills the engine. He said it's something in the distributor, then arranges the tow truck.

When I got home, started fine and drive in to driveway. Playing around with it whilst originally waiting, between racv and tow truck, when truck got there it started and reversed out of where I'd parked, then died. When I got home, it started and drove it in to driveway but that's all I've done.
Kind of like if it's hot it won't run.

Many years ago my older 89 pulsar died in the same way, but wouldn't fire at all. But I can't remember the part it needed. (The name) It was like a little square metal block with a wire or two.
I hate electrical problems.
So, about to go pull it apart and see what the cap and rotor are like.
Thing is, it was and has been perfect until it suddenly developed this fault. Bad cap or rotor should have shown symptoms before hand?
And thanks for your reply too.

Sent from my Nexus 5 using Tapatalk

12-08-2017, 04:30 PM
So frack. Got a 2nd hand dizzy and now it won't fire at all. No spark. Then it started raining, so it'll have to wait until tomorrow and I'll put the original one back in, and see if I get spark from that. :(

13-08-2017, 09:25 AM
Voltages are all OK ?

13-08-2017, 09:34 AM
Cozzm0, I'm going nuts trying to research about this thing. The Haynes manual I have says stuff all about fault finding/checking.
I just came back from Repco as I was going to replace the cap and rotor button as suggested above. But $215 for both parts!!
Forget that. I would if I knew it was the problem, but it's an expensive way of fault finding.
Plus, entire dizzy can be had on ebay for less than that.

I have a multi meter but I have no idea what/where to check.
If you're unable to help point me in the right direction then I'll have to take out a bank mortgage and get a mobile mechanic.
On another note, sorry for the double spacing in my reply. Tapatalk does it.

13-08-2017, 09:37 AM
I should also point out, when I connect a new spark plug to a lead and earth it, then crank it, I can see spark but it seems weak and doesn't seem to be every time the piston would fire. Gonna go check it again now someone is home to help me out.

13-08-2017, 10:59 AM
So now I'm really confused. Grab Son to help push car out of driveway. Put it in reverse to help by cranking it over in reverse to help start moving the car, and it starts and runs perfectly. Sitting in it now idling away waiting for it to get warm and see if that changes anything.
I tried cranking it over earlier and it wouldn't start at all. Now it's perfect. What the hell????
From reading, a crank angle sensor stuff things up if it's warm. Could that be it? But why no start earlier on. Dammit.

Edit. Adding info. So sat here until up to temp. Turn off. Restart and it takes about 10 seconds of cranking to kick over, then idles fine.

13-08-2017, 11:26 AM
This is turning in to a novel. :-)
So after warming it up to temp, drove up our street. All good. Back down again. (Only about 100 meters each way) Back up street, car starts to hesitate. Manage to turn around and then car dies. Cranking won't kick it over. Wait a few minutes, crank for about 10 seconds, slowly fires up and move to where I need to park it. Switch off. Try and restart and just cranks. That's all the info I can give to help diagnose it. So it won't even drive long enough to get to a mechanics.

13-08-2017, 12:47 PM
Fuel pump maybe ?

13-08-2017, 12:48 PM
If it just cranks and cranks and cranks then you need to pull the plugs and see if they're wet. If they're wet, they're getting fuel but no spark. if they're dry there is no fuel, but there is probably spark.

13-08-2017, 03:06 PM
Sorry. I'm at work now and can't use phone when I want. It's an iffy one. I understand what you mean about the wet or dry plugs, but it only cranks and cranks after the engine is warm and turned off. It now starts like normal when cold, but up/down the street twice when warm and then it dies. Then it is a crankfest.

13-08-2017, 03:45 PM
Do the radiator fans come on randomly or anything like that ? Its possible if the coolant temp sensor is bad it could be making the mixtures wrong/bad especially when warm.

13-08-2017, 03:47 PM
I would think the rotor button or the distributor would have to be seriously damaged to stop the car from starting. I've had them in the car for 80,000km and they were burned up and cracked but the car still ran, but was smoother with a new one in the car, no misfires or anything.

If its a fuel pump problem sometimes banging on the bottom of the tank (similar to banging a starter motor) could help locate it to be the issue or not.

14-08-2017, 06:42 PM
Well, due to the stupid hours I work and no garage to keep me dry, I just can't find a way to diagnose this problem. So I've found a mechanics near here and hope they can figure it out. Getting it towed there tomorrow. Will update with what the problem was. Thanks for your help.

16-08-2017, 04:27 PM
Update. Car went to a mechanic. They said 100% distributor. Replaced it with an aftermarket one and car seems fine now.
So glad to have my own car back.

16-08-2017, 06:06 PM
Glad they were able to sort it out for you and that you were on the money from the beginning.