BlaneR

Been having an issue with my 2002 - November last year I replaced the fuel pump 'cause it died on the side of the road, no code, nothing. Just wouldn't start. Got it towed to the shop, where it started right up. Anyway, since then, it'll occasionally stumble (doesn't matter if it's idling or under load). It also still will die out on me from time to time. Wait a minute or two, and it starts back up.

Now, I did just replace the plugs and wires (that was a chore) a month or so back, but I'm not so sure it's related. What might be related to that is that sometimes it'll run rough like it's missing on one plug, but I still get no codes; and the next time I start it, it runs fine.

Thoughts? I'm thinking that with it having 140k miles, it could be a couple of things going on at the same time, but it's frustrating and my wife's nerves get shot 'cause she's afraid to drive it.

Peace!

The Doctor

Any codes?

Cancel that. I just read that again and I see there are no codes.

Bad ground or ground missing.
Bad voltage. (alternator)
Something computer related.

BlaneR

OK, so yesterday after lunch, it wouldn't start. Been sitting about 1.5 hrs. Took six or seven tries - turns over fine, even kicked off a time or two, but would immediately die. After about five minutes, it finally started and ran fine the rest of the day and did fine today going to the gym and back.

I'm at a loss. There's so many things it could be - crank sensor, fuel pump, even the MAF (but that usually goes along with a few other symptoms). Few weeks back it threw an O2 sensor code, but that was right after I put some pulstar plugs in, so I figured that was 'cause it was trying to learn the new plugs...

BlaneR

How do I test for that?

The Doctor

Your first step is to narrow it down a little. Is it losing fuel, or spark?

Did this begin just after you did some work on it?

BlaneR

Well, depends on which symptom we're talking about.

The "feeling like it's missing on one cylinder" started after I put in new plugs and wires about six weeks ago. However, it doesn't do it all the time, and it's not as rough feeling as it is when there's actually a misfire or loss of power on one cylinder (or doesn't seem so to me, anyway).

The "dying on the side of the road" has happened a few times. First time, like I said before, we took it to the shop and it started right up. I went ahead and replaced the fuel pump anyway (this past November). Had to drop the tank again shortly after that because the o-ring was too big and slipped out of place so it wouldn't pressurize. I siliconed it in place. One after-effect of replacing the pump was that I noticed that a "slightly rough idle in gear" that we'd experienced the entire time we'd had it stopped completely for a short while and stayed gone for the most part. It died on the side of the road again about three months ago, and I put a new fuel filter in it then. The 'no start after sitting for a short while' has happened a couple of times, but never any way to tell what caused that. One other time that happened, though, it was because the rear crank position sensor wire was breaking. It would give us a fit to start, then start but run real rough - did that for a few days, then the wire finally broke through and it wouldn't start at all. That was back in '06.

The 'loss of power' and/or dying with immediate restart is a new thing. Sometimes, on the loss of power, all the electrical stuff will slow down like it's running on battery, then spin right back up as the engine picks back up to speed. Almost like when the alternator is starting to go out so it's not putting out full power, I guess (only way I can think of to describe it).

Not sure what else to say.

No matter what, I TOTALLY appreciate your time and effort in helping me think this out - I know that I'm all over the map with this one...

Peace,
Blane

kevinkpk

Well the quick thing is to check the alternator. If the voltage is up, and way down, then backup causes all kinds of wierd things with electronics, that's the first thing I'd suggest, check the alternator.

The Doctor

I say that because a voltage or ground problem can play havoc with the computer. I'm sure we've all had our home computer freeze when an electrical storm causes the lights to flicker. So you need to verify with a multimeter that the alternator is putting out the proper voltage. Is it possible the belt is slipping?

Also, check the connection from the positive battery terminal to the underhood fuse block. Better yet, take it apart and clean the terminal and the lug.

Beyond that, the computer circuit board can be visually inspected for obvious problems such as corrosion or burns or other damage. But I would leave that for last. Exhaust the simple stuff first.

I just re-read your last post and you say that the electrical seems to die when the motor slows down. This would suggest that it's running mainly on the alternator. Have the battery tested too.

BlaneR

I'll check the battery stuff and the computer. Not too sure it's the battery - I forgot to mention I put a new one in ~ two months ago. Could be bad, but not likely.

Thanks!

BlaneR

Didn't get a chance to do the battery/cable stuff this weekend - too tied up on other stuff. However, was able to note that the cut-out while running happened three times. Twice, it cut out completely for about .5 seconds, then picked right back up. That might be what I was sensing earlier when I said that it appeared to have 'a loss of power'. I had the radio and a/c off, with the cruise set, so I hear/felt it clearly. Third time it just died completely, and I was able to immediately restart it on the 2nd try.

Don't know if that gives you any more info or not...

Peace,
Blane