I've been having a lot of problems with my car over the past few weeks. The starter started not fully engaging and grinding against the flywheel.....and it would barely start, but then would finally turn over. Sometimes I would turn the key and absolutely nothing would happen and then I would wait, turn it again and it would grind and then eventually start. So I went down to buy a starter yesterday, and I'm on the way home and the car starts bucking really bad, it felt like it would downshift real hard when I let off the gas, and upshift again when I pressed the gas. So it ends up stalling out and I pull over and restart it and keep going. It starts to happen again up the road, but this time I notice that the volt gauge is jumping from 13...all the way down to 0 and jumping back and forth. Everytime it hit 0 it would start to bog out and almost stall and everytime it hit 13 again it would be fine. This happened about 8 times in a 10 mile trip. I really don't know what to do, or what it is. This car has been the biggest money pit I've ever had. BTW, it's a 86 Z28. Please help me...

 

The first problem, sounds like the starter (which you have already figured).
Now the 2nd problem sounds like a clogged cat, clogged fuel filter, bad fuel pump, or maybe even a short in the alternator. It really shouldn't be that tough to find the problem. Just use the process of elimination.

 

Thanks, how would I go about finding the short in the alternator? It's a TPI car, also.

 

Everyhting he said and I would do a full not screwing around tune up, it sounds like it needs it badly. How many miles are on it? Before you start calling it the biggest money pit you've ever had, just remember one thing, it is a Used car.

 

If you havn't already bought a new starter, just grab yourself a new bendix. They are super cheap, and almost always the cause of your starter problem. As for the voltage spikes, I have never heard of such problems on our cars. I definatly agree with the others that it could be a short in the alternator, most likely in the voltage regulator. Is it only the voltage gauge that jumps up and down? The reason I ask is to see if the system is losing power or getting "shorts" that are causing the computer to cut out. If your alternator is intermitanly making power off and on, it will not cause your car to lose power off and on due to the reserve power of the battery. What I would suggest is if the problem is happening as many as 8 times during a 10 mile drive, seeing as you have an 86 Z pull the alternator belt off and take a quick drive around your block. If the voltage spikes are gone, and the car runs good, replace the alternator. If the problem persists, you are going to have to start ohming out wires and checking grounds. WARNING: do not drive your car for more than a minute or so, and drive it while the coolant temp is cold, taking off your alternator belt also stops your water pump from working. Also make sure you have a fully charged battery. This is how I would check to see if the spikes are caused by the alternator, but I am in no way saying this is the right way, and seeing as I have never had this problem I invite the opinions of others to either back me up or discredit my suggestion. Good luck.

 

I would check the wires going to the starter, make sure they aren't loose or rubbed bare somewhere. There could be a relation between your two problems. If you got the starter put it on and go for another ride.
Good luck
Dan

 

Good call DanD 96 SS,
I would definately look into that.
You could start the car, disconnect the positive cable from the battery. Then check the voltage output from the alt. with a meter. See if it jumps around. check it at idle and at higher rpms.
I would also try what Blownyellow said. Especially if you don't have a volt meter.
And a tune up is definately a good idea. Along with a new fuel filter. Good luck.

 

Ok, I definitely know it's not the battery, cause it's reading 12.6 and turning the car over. I got the car started yesterday in my driveway, with some hesitation from the old starter....but it started up. After about 2 minutes it started bogging down and I watched the volt gauge in the dash start dropping, then it would bounce back up and the car would run fine, then drop again and almost cut out and bounce back up again. It did this for about 30 seconds until the car stalled out. Also, another thing that I noticed was that I left the keys in the ignition after it had stalled, and I came out about 15 minutes later, and since the keys were still in the ignition, the dash lights were on and the Cd player clock was on. Just the motion of me shutting the hood and opening the door was making the cut out and come back on, just like the car. So I'm thinking the pos or neg cables might be loose, or the neg has a bad ground....and it's cutting in and out when the car is running cause something is vibrating it back and forth. I'm gonna change the starter tomorrow, so I hope I find the problem under there.

 

3 things to check:

Starter cable.....could be loose at the starter end or corroded at the battery, check it out when you change the starter.

Battery ground cable.....loose at the block/corroded at the batt

Engine - body ground strap.....the source of all my electrical frustrations in my truck.....its a weak little copper strap that bolts to the back of the engine and the firewall.....it can snap under strain if your engine torques around in the frame (due to a broken motor mount or something) or could simply vibrate loose over time.....everything in the car other than the engine itself grounds through it. Yes this includes your FI computer and gauges both. This seems the most likely to me.

 

Just one more thing to add to "TheGreatJ"s post. On the positive battery cable, make sure it hasen't fallen away from the motor down near the bottom of the pan. My brothers 86 had a motor replaced from the people he bought it from and they didn"t attach it properly. It got pinched between the Tie rod end and the pan which cut the cable in two. It didn"t come completly apart and the car would cut in and out just like you are describing.

Good luck finding the problem.

 

I went out this morning.....expecting to be under the car for hours trying to figure out why it was cutting out. I followed the pos cable from the battery to the starter...and the bolt holding the cable on the starter was soo loose I spun it off with my hand. I took it off, wirebrushed everything, put it all back together, and tightened the hell out of it. The lights, fuel pump and CD player came right on, car started and the volts gauge is reading 13 volts again. Thanks for all your help guys.