Eggplant Jeff

Well, it's that time of year.

After sitting a week in near freezing / below freezing temps, my car wouldn't start. I cranked so long my battery ran out and I had to jump it.

This morning was an extreme example, but the behavior is similar to this any time it's sat overnight in very cold weather.

When I first crank, it seems like the engine isn't firing. The starter is turning it over and over and over but nothing's happening.

As I continue to crank, the engine starts firing intermittently. After a while, it starts firing more frequently. Keeping the throttle partly open seems to help at this stage.

Eventually it will start, but it will run incredibly rough, I have to keep the throttle open in order to keep it going. After a few seconds, it will start smoothing out, I can take my foot off the gas, it still runs rough, and finally smooths out over the next minute or so.

It's a basically stock 305 L03.

The battery is only a year old, it was obviously good since I cranked for probably 2 minutes before it had a hard time turning the engine over and I had to jump it. Of course, I probably didn't do it any favors draining it like that.

The starter is new-ish, it came from a 350 that spun a bearing after 3500 miles (NOTE: When trying to save money on a rebuild, bearings are NOT the place to do it). So the starter has 3500 miles on it originally plus maybe 5 - 10000 since I put it on my car. I've got a 305, the 350 starter was significantly beefier looking (probably 1/2 inch larger in diameter than my stock starter). It has no problem turning the engine over.

I've had the car two years and have replaced all the sensors in that time (except VSS, which still needs fixing) - IAT (also known as MAT), MAP, knock sensor, CTS, IAC, oil pressure, TPS, whatever else there is, I can't think of them all at the moment.

There is no vacuum leak that I can detect. Fuel pressure was consistent when I tested it, although I didn't check it while cranking this morning. I did try pouring fuel into the intake this morning, which made no difference at all (should have helped it start if there were a fuel delivery problem).

Spark plug wires are MSD superconductors, coil is MSD stock replacement, cap and rotor are new (MSD) within the last year. Plugs are AC Delco's gapped to 045 and also new within the last year.

Oil pressure was fine, in fact it went up to 45 (according to my gauge) while cranking.

I did a compression test a while ago, compression was good on all cylinders, highest and lowest were about 5% from average. Not super, but not bad.

An engine needs fuel, compression, and spark, right? So if it has fuel and compression, I must have a spark problem. Could this problem be related to timing? My timing is 0 degrees, just like stock spec (for the L03). It's possible my balancer slipped I suppose... I do also get slight knock in high-load low-rpm situations (accelerating up an offramp in 4th gear). Unless someone here has any other good ideas, I'm going to try retarding the timing 4 degrees and see what difference it makes (whenever I can get my hands on a timing light).

I have not replaced the alternator, however, at idle the voltage drop between the battery and back of the alternator is only 0.25 volts, and unless I have everything on at once (radio, headlights, fan, etc) it keeps the voltage at 14 or so even at idle.

If anyone has any suggestions I'd be delighted to hear them!

Eggplant Jeff

Further updates...

I talked to a friend who said it's probably not timing too advanced, that would make the starter really sound like it was straining a lot mine sounds normal.

So I checked the spark, I put the #1 plug wire on a spare plug and grounded the plug, then cranked the engine over. The spark was yellow/orange... I think it's supposed to be blue/white isn't it? I believe this means I have weak spark.

So my MSD coil may be a POS. I'm going to try to get a spare coil somewhere and see if it makes any difference.