Another weird SR20DET starting issue!

[Moogle]

A little background info first, the car is a 1993 240sx with an S14 SR20DET installed. The motor has been fully rebuilt twice (had to rebuild twice because first builder messed up). So I finally got my car back after the engine was rebuilt again, and of course there are more issues. So the issue that I'm having trouble figuring out is the starting problem. The shop owner that re-installed the motor told me in advance that the battery was weak from sitting for so long, and would need to be replaced. So when I picked it up, it took quite a while for the car to start. I didn't even make it home before the car died at a stop light and wouldn't crank again. Then some nice gentleman come and jump start the car and I manage to make it home. So I replace the battery today with a brand new Optima Yellow Top, and again it has the same issue. Two times it doesn't start, then on the third try it finally comes alive but very slowly again. The weird thing is that when I try to start the car, the speedometer and tach will jump around like crazy while the car is cranking. I've never seen it do that before, even before after the first rebuild. I have a new Mishimoto starter, so I know that's not it, and I'm stumped and can't find any answers from searching. Does anyone have any idea's on what the problem might be? Thanks!

[EvoVIII808]

Sounds like ALT not providing power back into the car to keep everything running.. The jumping spedo/tach is from low battery.

[Moogle]

Sounds like ALT not providing power back into the car to keep everything running.. The jumping spedo/tach is from low battery.
Thanks for the advice! I'll definitely check the alternator while combing over everything. The only thing I don't get is the jumping speedometer, especially since I just put a new Optima Yellow Top battery in. Oh well, I'll check the alternator and post up the results!

[jedi03]

check all ur grounds too

[Moogle]

So I went through last night and found some interesting things in the engine bay. One, the oil filter was leaking because it wasn't even hand tightened all the way. Two, the ground from the interior harness that runs through the driver's side wheel well through the firewall at the BMC wasn't even connected to anything. I fixed those two things, and it still is starting slow, so I'm guessing there is another messed up ground somewhere. I tested the alternator and it's working perfectly, and I know the battery and starter are good because they are brand new. The hard part is that the guy who re-installed the motor didn't use all the factory grounding points, so now I have to go through the wiring he did and re-check all the grounds. I'm not too happy with the work so far from this shop. I'll keep you all posted, but if anyone has any more advice in the mean time please feel free to post it!