Ok so I'm gonna start this off by admitting I'm an idiot. I was replacing my valve cover gaskets on my 87 Z31 Turbo and 8n doing so I removed the distributor to get the driver side valve cover off. This car is a project for me, in order to learn and have fun with. It is also the first car that I have owned that has a distributor. After replacing the gaskets and reinstalling everything, I attempted to start the car. It would turn over but wouldnt start. It was a very rough turn over too. I just replaced the spark plugs and wires and the distributor looks healthy. I attempted to re time the ignition by turning the crank pulley to 20 degrees BTDC and made sure the distributor rotor was pointing toward spark plug wire #1 but still had the same issue with starting. What am I missing??? I'm at a loss...

I feel it is important to mention that in doing the valve cover job I also removed the throttle body, some intercooler piping, and the intake plenum along with the distributor. I was careful to label parts and any wires or tubing. I can't find anything obvious that I missed, it seems like a timing thing to me, but I am very far from an expert. Any insight would be greatly appreciated.

The crank hits TDC twice for every revolution of the distributor. You probably lined it up at TDC on #4 instead of #1. Try flipping the rotor exactly 180 from wherever it's pointing now.

VStar650CL wrote: ↑

Thu Jan 06, 2022 7:10 pm

The crank hits TDC twice for every revolution of the distributor. You probably lined it up at TDC on #4 instead of #1. Try flipping the rotor exactly 180 from wherever it's pointing now.

I'm going to try that. That would make sense considering the car won't start at all. Would that definitely be the case though even if I made sure piston #1 was for sure at TDC? I removed spark plug 1 and used a plastic straw to be sure the piston was up when I was turning the crank and also that the rotor was pointing at wire #1.

No, if you made sure #1 was at the top and the rotor was pointed at #1 wire, then your problem is something else.

I'm actually starting to think this may be a starter issue. The way the car is trying to start is strange. It is sluggish in trying to turn over and is accompanied by a grinding/whirring sound. I just recently replaced the starter, but the previous owner did some diy electrical things to the car. I'm wondering if it's possibly a short that damaged the starter or maybe a fuse. Whatever the case might be I can't see how this could be a timing issue anymore. I thought it might have been considering the car started fine before I did this job, albeit has a number of issues. I'm going to look more into the possible starter issue. Any thoughts on this?

It does need to spin fast enough to start. Put a tach on the engine, healthy Nissan starters typically spin it at 180~250 RPM. If it's a whole lot slower than that, it could be causing your no-start. If the speed is normal, then it may be noisy but it isn't your issue.

Ok so I believe I've made some progress. I discovered a couple of my spark plug wires were not seated properly. I managed to push them and seat them nicely on the plugs. I retimed the ignition. The car now sounds much more normal when turning over (the engine doesn't shake and it sounds like the starter is much faster) however, still no start. I have retraced my steps multiple times to see if I didn't connect something properly but can't find anything that I missed. The only thing that I can think of now would be a fuel issue. When I turn the ignition on I can hear the fuel pump (which sounds healthy) the fuel filter does look older and I am at about a quarter tank of gas. This would be total coincidence but it's my prime suspect at this point. When I first got the car I filled the tank and also added a bottle of Techtron fuel system cleaner. Could it be more likely that this additive could have loosened some gunk in the fuel tank and clogged the filter??? The only thing that confuses me is that I can smell gas in the engine bay after trying to start. Now, I've tried to start the car several times but never too much at a single time. Once (maybe twice) per day, only on days I've worked on the car. Could it be flooded? I wouldn't think so but again I'm a total rookie. Today I at least feel like I've made some progress, but I really want to get this old girl purring again. Any thoughts?

One thing I forgot to mention. I also replaced the distributor cap since it looked pretty old. The new one is identical except for one thing the "C" plug is on the front of the cap (between 1 & 3) instead of on the back (between 2 &6) This wouldn't make a difference would it? The cap I bought claimed to be a "guaranteed fit" for my car.

It shouldn't make any difference as long as it's making good contact with the center terminal and you lined it up on #1 TDC as discussed above. Check spark, if it's there at the plugs then nothing about the rotor is causing your issue.

VStar650CL wrote: ↑

Sun Jan 09, 2022 5:37 pm

It shouldn't make any difference as long as it's making good contact with the center terminal and you lined it up on #1 TDC as discussed above. Check spark, if it's there at the plugs then nothing about the rotor is causing your issue.

Thanks for your replies. I am going to replace the fuel filter (since it's old) and the ignition coil. If that doesn't do the trick then im going to replace the rotor as well. I'll let you know what happens

So here is an update.

To recap, I replaced my valve cover gaskets. In getting to them I removed the intake plenum, throttle body and distributor. After finishing job, I replaced all parts and then car would not start. The crank was sluggish and the engine would move more than usual with a crank. I then realized that I may have not put the distributor back properly and suspected an ignition timing issue. I think this thread has evolved outside of the initial topic but I want to see it through.

I retimed the ignition (15 deg BTDC) I also replaced the rotor, cap wires and plugs. Still no start. I discovered that a couple spark plug wires were not seated fully and fixed that. I also upgraded a part on the ignition to PRW2. After doing this the car had a much healthier sounding crank but still no start. Next, I replaced the ignition coil. After doing this I noticed when the car would crank I could here the exhaust sputter a little, but yet again, no start.
Now tonight I checked the fuse to the ECU which was fine. I also replaced the fuel filter. I have not tried starting yet because I was giving overnight for any leaked fuel to evaporate out of the engine bay. I will say though that the old filter had a ton of sediment in it (but maybe this isn't unusual, again I'm a rookie). I will try tomorrow but honestly my hopes aren't too high, mostly because I feel like the issue should be something related to the job I did originally. I'm wondering if it is possible that the intake plenum isn't seated correctly. I might check that tomorrow. I didn't remove it all the way just enough that I could move it to get the valve cover off. Maybe I messed something up. We will see, fingers crossed. I will update again tomorrow.

Another update

So like I mentioned before, I replaced the fuel filter. And again still no start. It sounds like it cranks just like it should but just won't catch. My last ditch effort to a simple solution was to replace the Crank Angle Sensor (CAS) on the distributor. This task was easy enough and when I put the distributor back together I timed the ignition again just to be sure it was correct. I tried another start, and again, nada!
I removed spark plug #1 to inspect it and there is oil on the tip (which I will admit, there was oil on the old spark plugs too) but the car started before. I also noticed that the side electrode was bent, to the point that I could not even fit my gap tool into the plug. Now I was getting nervous! I checked the other plugs and they were all healthy with the exception of a small amount of oil, but to physical damage. I'm hoping this was merely damaged in shipping. I ordered them from Amazon and they sent them in an envelope and the boxes were very beat up. I will admit that I did not check the gap on these because NGK pregaps them, but I should have checked.
Just to rule out my worst nightmare, I checked the timing belt and fortunately it looks healthy. The pte ious owner had it replaced less than 10k miles ago.
I'm wondering if the turbo is shot... not only is there oil on the tips of the plugs but there is oil in my intercooler piping. It is the original T3 Garrett and it has over 100k miles on it. The previous owner drove this thing pretty hard too. Hopefully I can get to the bottom of this. Not sure why it's not starting. Could a failed turbo cause the car to not start at all??? It still just seems weird to me that it started fine before I changed those valve cover gaskets and now, this

At some point in your life you may have to pay an expert . Seems like it might just be something stupid or could be a shot turbo or starter. If you have no record of the starter being replaced than that is probably not optimial no matter what. My 84' is on only its 2nd starter but that was replaced probably 19990-2000 time frame. But at some point if you have a mechanic that works on these older cars they will probably figure it out in 1 hour of labor.

So it's been a couple months since I updated about this. I ended up dropping my fuel tank to replace the fuel filter. I discovered that the stem for the EVAP line was rusted and broke off of the fuel tank. By the grace of the Lord our Father there was a refurbished fuel tank available on ebay. I installed the new fuel pump along with the new tank, but guess what?... the car still wouldn't start! I finally realized that there just had to be something simple that I over looked. Everything on the ignition system had been replaced as well as everything on the fuel system minus the injectors. I verified TDC and the position of the rotor, so I knew my timing was right and the timing belt looked good. So what on earth was going on???

Well, I finally figured it out! I Uninstalled the distributor and rotated the gear. I thought something felt strange as if it there was so.ething rubbing in the distributor. I disassembled it and inspected the small disc on the inside. It seemed like it was slightly bent and was rubbing. Luckily I had kept the old disc from before, so I reinstalled the old one. I placed the distributor back in the car, verified my timing again AND... VOILA!!! That old girl fired up like she had been waiting for 4 months!

So bottom line was my timing was originally the main issue. I think I had ot 180 out in the beginning and went on to trying to fix other things too quickly. Luckily everything that I replaced really needed to be replaced for the most part. I wouldn't have discovered the issue with the fuel tank and most of the other parts were pretty worn and old. I learned a lot from this experience, but I'm very glad to get to finally move on to other projects with this car! Next up, full brake job and shocks/struts. Plus I'm shopping new turbos!

BadQ45t wrote: ↑

Sun Feb 13, 2022 2:03 pm

At some point in your life you may have to pay an expert . Seems like it might just be something stupid or could be a shot turbo or starter. If you have no record of the starter being replaced than that is probably not optimial no matter what. My 84' is on only its 2nd starter but that was replaced probably 19990-2000 time frame. But at some point if you have a mechanic that works on these older cars they will probably figure it out in 1 hour of labor.

Sorry i never replied back. You are right and I was on the verge of taking this thing in to a pro. I finally managed to figure this out. But yeah, if I get stumped this hard again I will probably have an expert take a look. I know I will have to for the front shocks/struts because there is welding involved and I definitely don't do that! Thanks for the help!

Glad you figured it out!! I had my car go completely dead at one point a year or so ago and my friend thought he could figure it out and we spent 3 hours trying to figure out. I finally had it towed to my usual mechanic, not my Z speciality mechanic because he's in LA and I live in the Bay Area (400 miles away) and he diagnosed in 30 minutes and took 30 minutes to fix!