The Machine

I'm going to try and be as detailed as I can, so forgive the long post. I have an 04 with the KW SC kit and AEM V2 engine management. My car is not my daily driver and is stored in my garage all winter, but I start it once a week to keep the juices flowing. All winter it started up just fine although it does take a few more cranks to start because of the AEM needing to sync. All of a sudden one week the car wouldn't start, even on cold starts. The only way to start it was to jump the car to get it to turn over. Did some testing and found that the battery was going bad so I replaced it and the car seemed to start up much better now on cold starts.

Fast forward a little bit because it is getting nicer out so I can drive the S. One day I took it on a small drive to get gas, maybe a five min drive down the road, but enough of a drive to get the car warmed up. I pull in, get gas, try and start the car and it doesn't start. It took me a few attempts, but it finally started. On a few other occasions the warm starting issue happened so I reached out to the shop that installed the kit as well as the tuner. I dropped the car off and the tuner adjusted the starting parameters some since the AEM can be very finicky on cold starts although my problem seems to be when the car is already warmed up. They eventually came across an issue with the crankshaft position sensor. They found that it was reading erratically when they tried restarting the car after a 10 minute drive. The sensor was replaced and they kept the car for a few extra days to do more warm start testing. They didn't encounter any more problems with it starting so I picked the car up. I haven't driven it a ton since I picked it up, but I have made a couple trips with no issues and have done a few random warm starts and everything seemed fine. That leads me to today....I took the S out and drove for about 10 minutes to go to Best Buy. I'm in the store for maybe 5 minutes and come out and try and start the car and it doesn't start. I even had my Weego lithium charger on the battery to assist with some extra juice to turn it over and also to make sure my battery wouldn't die when trying to get the car started, and nothing. I tried about 10 times to get it to start and nothing. So I sat there for about 10 minutes to let the car cool down more and then it finally started. The rest of the day I didn't have any issues getting it started since it had ample time to cool down between stops I made.

Also I should note, prior to storing the car for this past winter, I did have an issue once when driving because I had a LED digital readout terminal on the positive battery terminal. A screw from that terminal actually made contact with the hood and caused the car to ground out and shut off when driving. When the shop had my car, along with replacing the crankshaft position sensor the negative battery terminal and wire was also replaced since it was a little burnt up from getting extremely hot during that ground out.

Anyway, what else could be going on here? The crankshaft position sensor is brand new, the battery is brand new (1 month old), and the tune was adjusted to help with starting the car. Could something possibly be wrong with the AEM because of the ground out that happened prior to storing the car? I wouldn't think the AEM would be messed up since the car does run just fine once it is started, but who knows. The new sensor couldn't be going bad already, could it? I don't think any kind of timing would be off either because the car wouldn't even start at all if that were the case. I'd also like to believe that the shop/tuner would have found any issues with the that when they were working on the car. I'm just at a loss here and it's really annoying me. I just want to enjoy the damn car and don't want to feel like I'm going to be left stranded somewhere every time I take it for a drive.

Any help would be appreciated, thanks!

UH-60DRIVER

I don't want to scare you but mine was doing he exact same thing. After a bunch of back and forth testing and replacing a lot of unnecessary things it turned out that I had little to no compression in cylinders 1 and 4. Blown engine. My compression rings in both those cylinders disintegrated . My advise and I could totally be wrong would be to do a compression test.

The Machine

Thanks, for the response. Were you getting any kind of codes or anything? I'm not getting any type of misfire codes or even a bad crank position sensor code. Was your car running poorly once it was started? I don't seem to have any performance issues at all once the car is running. Also there are parameters setup within the AEM to cut boost among other things if the car is not running correctly to prevent damage.

The Machine

Well it did it again. Drove the car home from work, stopped to get gas, shut it off and it wouldn't start again. Cranks just fine and it didn't sound like the battery was getting weak from all the cranking. Since I was right down the road I had my wife come with jumper cables. Hooked my car up to her's and it fired right up. I'm wondering if there is some kind of voltage drop going on when hot and it's causing the AEM to not sync.

Of course I get the car home and shut it off and try starting it up after a few minutes and it started right back up. Ugh.

windhund116

Thrust bearing issues?

JUSTINTHECOASTIE

I had similar issues a while back. Replaced the battery several times, thought it was battery heat soak. Finally got around to changing the starter to a new starter, haven't had an issue since.

The Machine

After doing some looking around after your suggestion, I have a hard time thinking that it could be that. If the thrust bearing was bad or messed up, I would think it would give me a problem starting every time.


Honestly, when I first starting having this issue, and initially it was a cold start problem, I was leaning towards the starter. After going back and forth with the shop that installed my SC kit, he seems to believe that it isn't the starter because the car still starts up (most of the time). Personally, I feel like it wouldn't hurt to have the damn thing changed for peace of mind since it does have 129k on it, just sucks that it is such a pain in the ass to get to.

I've done testing before, but just at the battery. When I start my car, voltage drops to 10.55 volts. I had my friend in FL test his N/A S and his only drops to 11.20 volts. Now I don't know if this is because it takes a little more juice because of the SC, or because of the AEM, or if something else is causing it to drop that much?

iDomN8U

Shot at the dark, alternator?

Btw in the winter, let the car sit until your ready to take it out in spring. Charge the battery fully, pull the fuel pump fuse, crank it 10-15 times to get the oil flowing (it will crank slowly). Charge the battery again and turn on the car normally. This will circulate the oil so the first start of the year won't be too hard on the parts.

All that cold starting and not getting your car up to full operating temperate is bad for the car in many ways

The Machine

I don't believe it to be the alternator either since the battery seems to maintain charge on trips and at idle, I was checking it frequently with my volt meter when I was initially having issues getting the car started from a cold start. When I was having the issues in the beginning the battery was to blame and it wasn't holding a charge well. I think I toasted it when I had that grounding issue and the battery was scalding hot so it probably warped the plates inside somehow to where it was still reading good when tested, but not really holding a charge well. I keep my battery on a tender over the winter, but the one I was using was only keeping the battery around 12.2volts. It would charge it up some, then let it drop back down, so that was probably no good for battery life either. I bought a better battery tender this time around and it keeps the battery around 13 volts and doesn't let it drop from there.

I will try that procedure this coming winter when I store the car, but I guess I should note, when I did start the car over the winter once a week, I would let it run for around 10 min so the car did warm up fully before I shut it off. I never just started it and then shut it right back off, I always let it run a little while.

Soviet

Had the same issue and it ended up being the starter: https://www.s2ki.com/s2000/topic/113...m-bad-starter/