CamH

Hey guys I just put a new alternator in the Z today and now I am idling at 13.7V, and the car is running much better.

Yes, it does, and it is a direct swap in to a 280ZX Turbo distributor. It's necessary for using a 300ZX Turbo ECU on an L28ET.

Yeah, alright, basically what you'd have to do is stick those in and start it up, and lower the fuel pressure until it idles alright. Then, you'd need to hope that it's driveable at that setting.

You could probably pull that off with some very low fuel pressure but it will be very difficult to get it running right, I'm sure.

I think what he is saying is that he bought a Scarab or Scarab replica, and he also may have found a Bob Sharp Racing 240Z that is right hand drive.

Well, gents, I think this was a combination of a few issues, and I think it is mostly sorted out now. 1. I am fairly certain that the alternator is weak. If I leave my electric fan off, with no headlights on, I am sitting at about 13V at idle. After turning on my electric fan and headlights, I am idling at about 12.5V. Not really very good. I will probably take this unit out and get it replaced tomorrow. Good eye on you guys for noticing this first. 2. The solder joint for the MegaSquirt power was not in very good condition. I fixed this and it helped out a little. 3. Also, I think my injector settings were a little bit off. I changed my injector open time to 1.3 and my PWM time threshold to 1.5 and it seemed to like these settings quite a bit more. The combination of these things and the car is running much more smoothly. Hopefully a new alternator will clear up the rest of the issues I am having. Thanks guys for all your help! I'll report back if I have anything else to add, and I'll let you guys know what happens after I swap alternators.

Okay, false alarm. I'm now thinking this has something to do with MegaSquirt getting power though.

Alright, you guys are not going to believe this. I just double checked my fuses, and the fuse for the MegaSquirt itself looked a little funky (but was still working). I went ahead and replaced it and loaded up a tune from Christmas eve, and, uhhh, it is back to running normally. Has anyone else had that problem before? It just seems so improbable that a fuse would not blow out completely. Anyways, I'll report back if I have any more issues.

I may consider ordering the stim this afternoon. I think I am also going to try replacing the alternator, and a user on another forum suggested that I measure the resistance through the injector wires from the DB37 connector to the actual injector connectors. Seems like a solid enough idea. Also, the car was running great across the entire powerband. The issue from the other thread was actually due to a stuck injector and I corrected that issue by swapping out to a set of RC Engineering 550CC injectors. Now, though, I am having issues throughout the entire powerband.

Probably, but you may have brake clearance issues - especially if you want to go to better brakes.

I'm not an expert on the subject by any means, but it seems like, if you were to use them, they would eat through lash pads quickly, depositing metal shavings in to the oil. You may be able to have them welded up and reground, though. However, I think at that point, it would be cheaper to just buy new cams.

Hmm, I wonder if that means my alternator is on the way out again. These remanufactured alternators are garbage. I did put the battery on a charger before that run so it seems like that should have at least temporarily solved the issue. I doubt that the voltage is only dropping for the MegaSquirt because it gets its power right from the + battery cable where it connects to the starter...

Okay, so, I left the battery on the charger until it the charger said it was done. Hoping this would work, I took it out on a drive, and to get gas. So, anyways, it ran like crap the whole way there. While I was waiting for the gas to pump, I richened up the VE table. By 40. Across the board except for the bottom left part of the table (idle was doing fine) Anyways, that made it run pretty much fine, but it doesn't really solve my issue. There's no way my VE tables should be this high with a 6.4 req fuel and 550CC injectors! Anyways, here's another datalog and MSQ if anyone cares to look at it. datalog200912272146.zip

Voltage looks low, huh? Do you think just the voltage being low could affect everything else to that extent? I'm gonna go toss a charger on the battery right now and let it sit for a while and give it a shot. edit: not ignoring the rest of your post. It sounds like you're noticing some nose in the TPS signal - I've had this the entire time. I think it has to do with its proximity to the coil. It hasn't caused any issues for me in the past though...

Any good way to test for this, or should I just consider ordering another MegaSquirt unit?

OK, I just compared the log files from today, with a log file from the 24th (the day before it started running poorly) Apparently, now it idles at 36KPA, and on the 24th, it idled at about 30KPA - however, I'm not sure that this indicates anything out of the ordinary because I now have it idling slightly higher and I had to go up in my VE tables to get it idling at a decent AFR. What do you think?

OK, I just disassembled my fuel filter to check things out. It looked perfect so I don't think I'm having issues with that.

Well, I just redid the vacuum lines and it didn't help at all. Great advice though! Keep it coming!

Cool. Thanks for the advice. I will look in to that ASAP. Also, I just reflashed the firmware on the MegaSquirt. No difference.

Okay, guys, here is another datalog of the car with an MSQ file. I richened it up a little and it hasn't seemed to have done anything. The thing that really sucks is that this car is my DD junk.zip

I don't think it's CLT (you meant CLT and not CTS right?) because I am basically ignoring CLT in my tune. (All values about 80F are 100% warmup enrichment.) However, what's the best way to test the MAP sensor? Should I consider buying another MegaSquirt unit? My tune is actually based on yours! But yeah, I thought about dirty injectors as well. After posting this thread, I went and ran a bottle of injector cleaner through the main fuel pump (which feeds the fuel rail directly), I swapped out for brand new spark plugs (NGK BPR6ES), and I changed the oil (Royal Purple 5-30W and K&N filter). None of these things made any noticeable difference.

Hey guys, I'm having more MegaSquirt troubles. On Christmas, I was driving along - car was running really great, and all of the sudden, the wideband started reporting very lean while driving (like 16-17), and the car developed a misfire. I've checked all electrical connections, and they look alright, all of the fuses look good. I checked the spark plugs and they were white so I am thinking the wideband is probably accurate. Fuel pressure at idle is just above 30PSI and it goes up with manifold pressure (1:1) just like it should. Another thing I've noticed: the AFRs will vary from when the engine is started (they seem normal) until the engine is revved (they go higher) - so if I change my VE table to get a decent idle prior to revving, it will be too lean after revving, and vice versa. This makes absolutely no sense to me! Anyways, I don't think I should need to change anything in the tune because the car was running so good prior to this. But now I am bashing my head up against a wall. I'll try pretty much anything. Umm, here are two datalogs and the MSQ I am running off of. I'm not sure how helpful they will be though wtf.zip

Another Z?

Hmm, that sounds fun. It would be cool to park a few Z's next to eachother. Any one want to set up a good time?

http://cgi.ebay.com/t3-t3-t4-t04e-turbo-dual-port-wastegate-actuator-8psi_W0QQitemZ160388814928QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item2557eb1850 This should work just fine.