bgbfflochp

Ok, I have about a 10 minute drive from work to home. There's a gas station near my house, so I'll stop by the gas station on my way home from work, and when I get back in the car, it won't start. If I let the car sit for about 5-10 minutes, it'll start up again. I went to get the battery checked today, and when they came out to look at it, the car wouldn't start (drove about 8 miles). It sounds like it's turning over but just not getting any spark. We checked the plugs and they're fine (about 1000 miles on them). This problem has happened with my last 2 sets of plugs also, although now it's a lot more frequently. Sears and Advanced Auto both say the battery is fine. Does anyone have any ideas on what could be causing this? I have to let my car sit for awhile, sometimes even 15-20 minutes and then jump it.

I used my cigarette lighter to power a tire pump for about 5 minutes, and afterwards it wouldn't start. I had to jump the car. If the battery is fine, why would it be dying so quickly? I don't have any amps or speakers or anything like that. I have a wideband, V-AFC hooked up although I'm using the AEM EMS (just haven't gottten around to taking the V-AFC out), and a Valentine 1 hooked up through the cigarette lighter. I don't see these draining that much power at all. When my car won't start, I get about 4-5 tries at it before the battery dies. Does this not sound like a battery problem to you guys? Both places I took it to swear it's fine. They also said the alternator is fine. If my car won't start, and sounds like it's turning over, my limited knowledge tells me battery/plugs/alternator malfunction.

From work, I get in the car, let the wideband warmup (1 minute) start the car, wait about another minute, and then start driving home. When I stop at the gas station, I let the car sit for a minute, then turn it off.

When the car runs, it feels perfectly normal. A/F around 14 when cruising, and 11-12 when I'm full throttle. I don't get on it very often at all though.
What else is there? I haven't done any mods directly prior to when this started occuring (almost a month ago). All of my mods are listed below.


My mods are:
Comptech SC (2 years) w/ 3.5" pulley (6 months)
front mount intercooler (at least 1 year)
AEM EMS (6 months)
550cc injectors (6 months)
V-AFC (although it's just there, completely initialized) (2 years, initialized for 6 months)
Comptech Headers/Straightpipe/Catback (2 years)
AEM Fuel Pressure Regulator (6 months)

Any ideas or questions, please let me know. I am mechanically challenged so to speak, so please let me know if there's something I can do to help narrow it down.
Thanks guys!
Dave

YOD88

hmm....
maybe you just have a bad connection or 2?
have you checked to make sure all your electrical is connected properly, and everything gets power?
if the motor runs perfect when it does... im assuming your starter is good too? maybe your starter is just running out of life...
or maybe... your alternator has a problem...
just to throw out some ideas... im not sure what is causing the problem, but it sucks!

-Yod88

xviper

I'm assuming that you have a stock sized battery.
Try this:
Check the "resting" voltage on the battery (ie, after sitting for a few hours). It should be around 12.5 to 13.0 V. Next, start the car (jump it if you have to) and take the voltage again (with jumper cables removed if you used them). It should now read around 14.0 to 14.5 V.
1. If you don't get the running voltage as indicated, something is wrong with your charging system (alternator, voltage reg, etc.).
2. If the charging system is up to snuff, then the battery may not be holding a charge. This would be indicated with a low resting voltage.

bgbfflochp

once again, XViper nailed it. Thanks guys! My dad got his mechanic to look at it, and after the speech he gave me, turns out a long the lines of the battery not holding the charge.

Thanks a ton for responding guys! I was wondering if I could just be flooding it but turns out it'll just be an easy fix. When you get your battery checked, what exactly do they check? Two different places told me it was working perfectly, that the battery would probably last longer than the car. How did they not catch this?

Dave

xviper

My method is the "Backyard mechanic's" way. Pros should have done a proper "load" test on the battery and a proper charging system test. I guess they were late for their coffee break?