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Hmm...nothing there sounds like it should have caused this. I know this sounds like a dumb question, but how is your battery? The reason I ask is that I had a similar problem with my SC400 and it turned out that (well, at least the mech said) my battery was too small and not providing enough current to crank the car. It would spin over but not crank and smelled like it was flooded. I had it towed to the shop and the mech replaced the battery and it cured it.
I know it sounds dumb, but that's about the only other thing I can think of.
But my car WILL start, but then it dies within a second or two. How could that be battery related if the car successfully starts?
Do you mean that it actually runs before stalling? Or that is stumbles a bit (irregular firing) and never truly runs? If it is the latter, I'd also suggest that you load-test the battery, and make sure that the you didn't disturb any of the grounding. My SC430 is the first car I've owned where a battery strong enough to get the car to spin over (but not fast) and actually fire a cylinder or two wasn't strong enough to get it running fully.
Do you mean that it actually runs before stalling? Or that is stumbles a bit (irregular firing) and never truly runs? If it is the latter, I'd also suggest that you load-test the battery, and make sure that the you didn't disturb any of the grounding. My SC430 is the first car I've owned where a battery strong enough to get the car to spin over (but not fast) and actually fire a cylinder or two wasn't strong enough to get it running fully.
If it cranks slowly and a few cylinders fire before stumbling to a stop, then it could be the battery.
If it spins fast and the engine fires a few cylinder but won't stay running, then it isn't the battery.
Gosh I don't know. It just starts and then dies, and I don't feel gas on the throttle.
My plan today is to:
1. unplug the HID light to see if it starts
2. Remove negative battery terminal overnight to see if resets ECU
3. Try to find service valve to test fuel pressure
Disconnected headlight and car started! That's progress! But the idle extremely rough with multiple misfires!
So I can get the car to start, but idle is all over the place. I changed the maf to no avail. I checked every fuse in car too. Whats next? Anyone got any ideas? I'm starting to the the ecu is fried? Help!!
What is the voltage at the battery when it's running? It should exceed 13.5 vdc with engine running.
Don't know voltage running but I will check it out tomorrow and let you know. If it's less that 13.5 volts, what does that indicate? That all my problems are due to a low battery? Gosh, I hope that my problem is so simple!!
Yesterday I pulled the plugs on my new headlight to test whether the car would start. The car DID start but with an extremely rough idle and multiple misfires. At least I got to charge my battery and will be able to roll car off ramps so nobody complains.
I also noticed the following parameters that effected start up:
1. Changed MAF and starting car seemed to be a bit easier, but idle still extremely rough.
2. Plugging in HIDs no start at all.
3. When I switched Air Conditioning "on" car would die
4. My cone air filter fell off accidentally, and the increased air seemed to IMPROVE start up. Why the heck would removing the cone filter make it easier to start?
Conclusions/Theories:
1. I don't believe the headlights are necessarily causing the rough idle, I feel that the extra power draw is causing the no start and there is some other existing condition. Since the car stalls with AC on, and the car stalls with headlights connected, then these are likely drawing power and making the already rough idle worse.
2. Doesn't seem like this is MAF related, although the new MAF made it easier to start but still a rough idle exists.
3. Starting to feel one of the following is occurring: bad ECU, bad throttle position sensor, bad crankshaft position sensor, or a stray ground.
4. No specific codes, aside from the random misfires are being generated, so there is nothing the computer is telling me nothing is actually wrong. In fact, My diagnostic tool indicates that I am getting readings from all sensors.
5. Battery is a bit low, but last night it seemed to charge up and I believe is at normal threshold. Don't recall the actual voltage on the voltmeter while car was running. Will check today if it is less that 13.5, as another CL member indicated to check.
6. I feel this situation is related to the bad mechanic, engine install, and/or something to do with the accident.
7. Last night I was checking out the relays, and I noticed one was missing. The relay indicated in the pic, what would this cause?
Missing relay? Is this just for the rear defroster?
Next steps:
1. Taking my car off ramps so neighbors don't complain.
2. Investigating whether or not this is a computer related issue.
3. Will record battery voltage as well as all diagnostics while car is running.
The reason I asked about voltage at battery when engine is running is perhaps your charging system is not working properly. The first simple check would have been to measure battery resting voltage.
A good fully charged battery should read 12.5 volts resting voltage.
If you have a bad cell it will read 11.0 or lower
With engine running, the charging system should bring battery up to 13.5-14.2
If you have a bad cell or not charging properly any load while running could cause voltage to drop below theshhold where it would not enable a good spark.
Generally the first thing to check when you have starting problems is battery voltage.
The reason I asked about voltage at battery when engine is running is perhaps your charging system is not working properly. The first simple check would have been to measure battery resting voltage.
A good fully charged battery should read 12.5 volts resting voltage.
If you have a bad cell it will read 11.0 or lower
With engine running, the charging system should bring battery up to 13.5-14.2
If you have a bad cell or not charging properly any load while running could cause voltage to drop below theshhold where it would not enable a good spark.
Generally the first thing to check when you have starting problems is battery voltage.
From your description, it sounds like possibly a bad regulator. The car doesn't seem to be able to generate enough juice. After you start the car, the car will run off the alternator. Turning on the AC after it is running and it dies is a big indicator, IMO.
Either a regulator or an alternator going out. This also would prevent the battery from fully charging.
What type of headlights did you put in? The kind that needs the huge ballast resistors and slow start?
On my old car, I actually had the main battery cable fry (slowly over time) and it would act much like what you describe. Likely this was due to overstarts from my remote starter.
As for rough idling, check your PCV valve. You could have knocked something loose in the fuel system and got some carbon from your vapor canistor in the fuel line. This would prevent the PCV valve from closing fully and a drop in fuel pressure.
09-08-15, 05:31 AM
