Hard to crank when hot

[snrusnak]

Ok I understand about the meter and measuring voltage cold and hot while cranking. I'll have to reread your last paragraph later to try to understand it better. I'm flying out of town for a week tomorrow so won't be able to mess with it for a while...

Thanks for all the help.

[blindsquirrel]

Imagine a section of plumbing, and think of voltage as pressure and flow volume as current. Say you have a valve in a section of plumbing and you want to know if it is restricting flow. If you had a pressure gauge tapped in before the valve, and another gauge tapped in after the valve, you could compare the two pressures and find out how much of a restriction the valve was creating. I think it's obvious that this would only work while there was flow in the system. And, the higher the flow rate, the greater the difference in pressure between before and after the restriction. With the system static, pressure would equalize on either side of the restriction as long as it wasn't totally blocked solid.

You could do the same thing by measuring the entire plumbing circuit all at once, comparing pressure at the pump outlet to pressure at the end of the run. That would tell you if there was an acceptable pressure drop or if there was a problem somewhere, but not where the problem was. By moving the gauges around to different locations you could pinpoint the area with the restriction.

That's all a voltage drop test is, checking the differential pressures in different locations to find a problem.

[snrusnak]

I understand, thank you.

I just noticed you're in Meridian. I'm in Gulfport, not too far away.

[snrusnak]

I need to reread some of these past few posts to do some troubleshooting, but I've been out of town and am going out of town again tomorrow, and just thought I'd do a quick voltage test today when I started the car. I was just firing it up to let it run a while since it's been sitting a couple weeks, so had the wife watch the multimeter probed to the battery leads. At cold start, the voltaged dropped to 10.2 while cranking. I let it fully warm up then shut it off (ECT at 204 deg F) and immediately restarted it and the voltage dropped to 10.5 during cranking. It actually wasn't really that hard of a start either, much more in line with a cold start. So I'm now thinking about about heat soak type issues (keep in mind my hood was up all this time today).

Anyway, I'll do some of the checks you mentioned when I get back next weekend hopefully.

[snrusnak]

So it's been a while but I wanted to report back. I decided to get out of the MAF only world and try my hand at tuning VVE tables (first time doing any of this!!!). I fortunately did good initially and on my first attempt the car fired right up and ran decent. It was a little rich (good....like I intended), and I quickly got the normal driving areas dialed closer in. As I kept doing iterations of driving and making adjustments, I found myself starting to sway back and forth from rich to lean and starting to get humps and peaks in the table. I can't figure out what I'm doing wrong (I've mainly followed goat roap garage videos).

Anyway....keeping this relevant, I noticed the hard start when hot issue seems to be less of a problem when on the SD only tune. I currently am back on the MAF only tune and honestly the car feels significantly weaker, and the hot start issue is there. I won't say on the SD tune the issue is completely gone, but it is much less noticeable. Could it be related only to the MAF tuning? What tables are used during startup?

I do also still think this is very much a heat soak issue. Whether it be the starter or whatever, but I left the hood open in the driveway one day and let the car get to full operating temperature, shut it off, then restarted it 5 minutes later and it wasn't nearly as bad. I think with the hood open it allowed the heat to escape. Maybe just ceramic coating my headers will help take some of that strain off the starter???