Rough Ilde, Wont stay running.

[99 svt]

I love how my car always breaks down hundreds of miles away from my house. I'm training in NC and parked my car by the store on base. It was running as usual, but I smelt burning plastic. I saw no smoke, so I though it was something else.


I come back, and the car won't start. It would finally catch, idle very roughly, and cut off after 30 seconds. If the gas pedal was touched, it died right away. I checked for codes, and had nothing.


I look under the hood, and found the power wire going from the starter to the alternator was fried, and that melted a vaccum line. Great! Easy fix. So I fixed the issues, and it still does the same thing, just this time no wire melting.


I need to go over it again with a fine toothed comb, but nothing obvious jumps out. Anyone have this issue before?

 

[PaulMN]

Yep. Turned out to be water in the gas. Like 5 gallons of water in 14 gals total. Heavy rain the night before had gotten into the gas station tank, wife topped off car with 5 gals (all water, it turns out), drove 2 miles home, next day, car won't start, exactly like you describe.

The other problem you found may not necessarily be the direct cause, or even related.

Can you hear your fuel pump run for a few seconds when you turn the key on, before starting? Bad fuel pump or no power to the pump (fuse?) could do this too.

Easiest way to diagnose water in gas tank is to disconnect the fuel filter, dump the contents into a clear container, see what settles out. If it's a water in gas problem, I'd expect to see mostly water, maybe a little gas floating on top. It's worth checking out this possibility.

I drained the tank dry by pulling the fuel pump relay and jumpering the two contact terminals (not the coil terminals). Disconnect the fuel line at the filter, hook a hose on and run it into cans. You'll also have to purge the tank and fuel lines with fresh gas. Don't try to separate the gas and re-use it, the water combines with ethanol and strips it and blended additives out. You could get by just dumping out the fuel filter contents and re-installing it in a pinch, but a new one would be better.

Let us know what you find.
Good luck.

 

[99 svt]

Thanks. I will check it out. The pump runs, and the car even runs for a short time. Tomorrow I will be starting at the basics with the fuse box and go over everything with a fine-toothed comb. I will be sure to check the fuel to see if thats the issue. Thanks.

 

[99 svt]

Well the feul has no water in it, the vaccum lines were double-checked, and all the fuses checked out fine. Its obviously getting some spark since it runs for a little bit, but it seems to only be firing on a few cylinders. Will a bad coil pack throw a code? Or possibly the TP sensor?

 

[99 svt]

Well I replaced the ignition coil and that wasn't it. I'm going to pull the plugs tomorrow. They are only a year and a half old, but I'm running out of ideas.

 

[naujcdl]

Ok, i see you replaced your coilpack with a non-cracked one/new, correct? Let us know on that one. People don't realize that cracked coilpacks, even new, create headaches, MK3 VW's did this and it was a PITA to figure it out.
Next, you do the wires and spark plugs, probably due to be done anyways. Check
Now, here is the fun part, if you hear that fuel pump prior to starting the car, that's a good sign and that will feed the lines and engine and even if it does die, it will cause the engine to run and it would need gas to do so, make sure this is true. If this checks out, check this:
Under the PDU next to the battery there is power wiring and fuse wiring that is known to burn out and cause all sorts of headaches ( i was a victim myself) and may cause some issues for some components to run like crap and half or some power issue that causes some weird stuff to happen (trust me, i have some experience with this), this may not be a definite solution but is a good thing to check especially with that battery cable toasting on you, check ALL grounds and so forth.

Check those wires in there and then make sure you have no vaccum problems, eh, how is the IAC, new used, original???

 

[99 svt]

Brand new coil pack that looked good. Tonight, once my buddy gets back with his truck for me to borrow, I'm going to buy new plugs, wires, and fuel filter and install them. I unhooked the fuel line and ran the pump in order to check the gas for water, and the car runs a little, so its at least getting some fuel and some spark.

I will check out those power lines. I have checked the vaccum lines a million times, and I'm going to tighten my intake just in case.

The IAC is original as far as I know, but that wouldn't cuase it to die when the throttle it opened, just when it closes, right?

 

[99 svt]

So, new fuel filter, plugs, and wires. It runs better, but still not good. It won't rev above 3200rpms I did finally get a code, a p1409. Tomorrow I am going to trouble shoot the EGR solenoid and probably just replace it. At least its one step closer to getting the car fixed. Hopefully the last.

 

[naujcdl]

That sounds like a bad EGR, let us know how that goes.

 

[greasemonkey1489]

It does sound like a massive vacuum leak. Id whack the EGR valve a bit as it might have stuck open. And you should be able to safely disconnect it from the vac line to allow the diaphragm inside to return to closed.

If not the EGR, double and triple check all the vacuum hoses back near the firewall. If you can remove the two big vac lines in the top of the plenum and plug them (WITH SOMETHING THAT WON'T GET SUCKED IN!), then start the engine to see if it will run well, then you can isolate the problem to be vac related.

 

[99 svt]

Thanks. With the power line that grounded onto the EGR pipe, that may have caused the valve to get stuck open. I will check it along with re-checking the vaccum lines.

The P1409 code was just the connector not being plugged into the solenoid.

 

[99 svt]

I put a sheet of aluminum between the EGR valve and intake, and it ran no better. I unhooked the two main vaccum lines and plugged the holes in the intake, and still ran the same.

I drove it back to the barracks. It had no power or usual throttle response. Right before I parked it, it threw up P1131 and 1151 codes, usually indicating a vaccum leak, but they were there before the car died since I haven't finished tuning it.

With it being sluggish, and knowing the ignition n fuel are good, I'm assuming air. The intake is good, so tomorrow I'm going to check the exhaust. The headder to Y pipe joints and the CAT to see if its clogged. Thats all I can think of for now.

 

[99 svt]

So the CAT looked fine from the exit side, and there was a good smell of fuel behind it. I'm assuming its not clogged.

I re-checked vaccum lines and grounds. I'm running out of ideas.

Fuel, yes. Spark, yes. Air, yes. Trouble codes, just the P1131 and P1151 which it produced before it stopped running right.

Should I re-flash the PCM? What else am I missing? I'm about to take it to a shop to see if they have better luck.

 

[99 svt]

So I cleaned the MAF and IAT sensors, and re-flashed the computer with the base tune that was in it. It runs, revs and idles much better now. The valves and injectors seem loud and the exhaust sounds raspy, almost like a chainsaw. At idle it sounds like there is still a miss somewhere. At least now I can drive it to a shop without to much hassle.