# Ran out of gas, car bogs down now.



## willister (Aug 14, 2010)

First time poster (kinda), long time reader. Before I get the lecture about driving until I'm out of gas, my needle was barely under 1/4 and I was on my way to the gas station  Also, this is on a 1990 Golf GL, everything stock as far as I can see. 

Now then, on thursday I was driving and ran out of gas. Once the car started chugging, I shut it off and had my sister bring a gas can from home (which I later found out had old gas in it from around January.) I hardly put any of it in, just enough to get me down the next hill and two blocks to the gas station where I then went ahead and put in about 8 gallons of 87 octane. 

After that my idle was hanging up around 1.5-2k. Aside from that, the car ran pretty normal for about the next 8-9 miles which is when I got to school. The idle even dropped back to normal after a mile or two. After class I got in the car, fired it up and made it roughly 30 parking spaces when it started chugging along. I got off the gas for a second and the revs dropped back down. But then when I would try to get on the gas, rpms would drop from around 700 to around 500, then try to climb back up. From time to time things would smooth out and the rpms would jump, but it wouldn't last long and they'd drop back down and the car would be incredibly hard to drive. Needless to say I didn't make it out of the parking structure. 

I pulled the spark plugs and they were pretty foul. I'd just swapped in some new ones a couple weeks ago and the tips are now black (varnish?) and one of em even had part of the threading blackened. I swapped my old spark plugs in and they helped (but now they've got the same blackened tips as the old one, though not quite as bad). I was able to drive the 10 miles home by keeping the car under 2.5k rpm and just going slow in general, but obviously I need to fix this. 

My question is how should I go about rectifying the problem. I'm assuming there was probably junk in the fuel tank that was sucked up when I ran out of gas. Over time, the car has gotten ever so slightly better, but I still think I should do something else, I'm just not sure what. Would there be a way to flush my fuel line in case there's crap in there? Should I be looking elsewhere? 

tl;dr Car ran out of gas, car runs funky now. Where should I start my fix and what should I be thinking of replacing/fixing. 

Edit: I replaced the fuel filter and used a fuel cleaner. Car still runs like crap and now I'm seeing blue smoke out of the tailpipe. When I get a chance I'll check my gaskets (and probably end up changing em) and report back.


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## wantacad (Apr 4, 2003)

Have you changed your fuel filter yet?


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## willister (Aug 14, 2010)

Not yet. I wanted to get some feedback before I started doing anything. I'd like to do this right the first time and not have to replace new parts that I put in.


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## epjetta (Sep 19, 2006)

the fuel filter is a good place to start as the pump can pick up debris and move it into the filter when it starts sucking from the bottom of the tank.


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## willister (Aug 14, 2010)

I replaced the fuel filter and ran a fuel cleaner today and it didn't help at all. The car is starting up fine every time now, but after a few seconds it starts to have a really rough idle. I did find a slight pattern in the bogging down though. If I hold the throttle at around 1750rpm (while it's rough) about every six seconds it will spike up around 2500rpm and be smooth for about a second, then drop back to being rough around 1750. 

Edit: lol... getting blue smoke. Wonderful...


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## brimoner (Aug 8, 2010)

It sounds like your air intake boot is torn. Check it for cracks and tears. 

Sean


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## willister (Aug 14, 2010)

Is the boot the casing around the filter (sorry never heard of it referred to as a boot before)? If so, that has had a slight chip in the back right corner near the hose/arm. Hasn't seemed like a problem in the past though.


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## brimoner (Aug 8, 2010)

The big black tube connected from the throttle body to the air filter box. 

Sean


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## MK2SnowPilot (Sep 8, 2005)

Not good to run these cars out of gas. Fuel pumps tend to fail shortly afterwards since the fuel is also the lubricant and coolant for the pump. 

These cars actually have two - one is a transfer pump that sits inside the tank while the fuel pump sits in the plastic housing just in front of the rear beam. Considering the car is running at all I would suspect that the transfer pump is failing....


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## willister (Aug 14, 2010)

brimoner said:


> The big black tube connected from the throttle body to the air filter box.
> 
> Sean


It's not cracked or anything, but it does have oil in it near the throttle body (tb also has some oil in it.)



MK2SnowPilot said:


> Not good to run these cars out of gas. Fuel pumps tend to fail shortly afterwards since the fuel is also the lubricant and coolant for the pump.
> 
> These cars actually have two - one is a transfer pump that sits inside the tank while the fuel pump sits in the plastic housing just in front of the rear beam. Considering the car is running at all I would suspect that the transfer pump is failing....


I ran a pressure test a little while ago and was sitting at 40psi when both the system first pressurized and while idling. Residual pressure sat at 36 psi. My chilton manual just says fuel pressure should be 36psi. Is 40 running too high? Should I be looking into my injectors now? Problems elsewhere?

Edit: I went back outside after a few minutes and the gauge had gone up to 46psi. It shouldn't be going up like that while the car is off right?


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## MK2SnowPilot (Sep 8, 2005)

It's possible your fuel pressure regulator valve is acting up. That would definitely cause drivablilty issues. Could also be the fuel return line too. Blow some compressed air into the line and see if that changes anything.


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## willister (Aug 14, 2010)

MK2SnowPilot said:


> It's possible your fuel pressure regulator valve is acting up. That would definitely cause drivablilty issues. Could also be the fuel return line too. Blow some compressed air into the line and see if that changes anything.


Alright, not to sound like an idiot or anything but where the hell is the pressure regulator? If I'm looking under the chassis I've got the fuel tank and next to it I've got the fuel filter and what I believe is the fuel distributor. Aside from that, I can't find a regulator unless it's hidden behind the fuel tank or elsewhere.

Edit: I'm dumb, disregard that question...


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## willister (Aug 14, 2010)

I replaced the fuel pressure regulator earlier today and ran some compressed air through the return line. Didn't help at all. My fuel pressure sits around 40psi at proper idle (700-800ish) but at around 2k (where it's actually idling when I first start it up) it sits at the correct 36psi. When I pull the vacuum line while idling at around 750rpm I jump up to around 48 psi, and after leaving it off for about 10-15 minutes residual pressure can be anywhere from 38-48 psi. Should I start looking at a sensor or something? I disconnected my battery before and let the power completely drain so the ecu could reset (in case it was still thinking I was running with almost no gas) but it didn't change anything. Maybe the O2 sensor went bad?


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## willister (Aug 14, 2010)

Update.. 

Replaced the spark plug wires, spark plugs, dist. cap, and rotor. Put some new gas in and played with the idle screw a little bit. Also cleaned the valve cover and installed a new gasket. The car ran fantastic for two days (did this sunday afternoon, was running fine until tuesday night.) 

Wednesday morning, I drive for about a mile and it runs like crap again. Managed to drive to school and back (~20 miles). Driving wasn't completely bad, just sounded/felt like it was missing from time to time. 

Fast forward to tonight. I was driving home from the train station (maybe 3 miles?). Car ran fine as I went down three floors, but as I was sitting in the driveway waiting to exit the garage, the car stalled out. It was hard to get it back on. Starter motor was going, but it was having trouble turning over. Held the key down for about 6 seconds before I heard it successfully turn, then it fired up. Driving it was terrible. Missing a lot, hard to accelerate due to that, every once and a while it would all of a sudden start working right, but shortly after (


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## admassa1 (Oct 11, 2010)

This may sound strange but have you pulled the fuel pump in the tank out to check for debris in the pick-up? I realize that you have fuel pressure however pressure and volume are two different things all together especially under load. Pull that back seat, remove the access panel and pull the fuel sender / pump assembly. I'll bet you find some funk in the pick-up or right under it in the tank.  

P.S. make sure all your windows are open and don't use a drop light to look in the tank. I'd hate to have you blow up


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## willister (Aug 14, 2010)

There was a little bit of debris on the pick-up filter. Maybe 0.2 sq.in. if even that much. I got the car running again, but what I did was weird. After reinstalling the pump, I fired it up to see if it had done anything. Still ran like junk with blue and black smoke. I pulled the fuel injector harness off by the fuel rail and tried starting it. Obviously it didn't start, but I let it try turning over a few times. Went back and plugged the harness in and restarted. Car fired up no problem. Drove it around for a few miles taking it throughout all the gears and rpm's and I had no issues. Blue smoke stopped as well though I'm still getting black smoke when I snap the throttle.


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## admassa1 (Oct 11, 2010)

Hmmm, that is weird. You may have more than one issue and it reared its ugly head when you ran it out of fuel. What you did would only have made a difference if you have a poor connection some where. Have you cleaned/replaced your grounds yet? If you have access to a DVOM check them before and after you clean them. While your at it get some good contact cleaner and clean all the engine management connections. It's worth a try. :thumbup:


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## willister (Aug 14, 2010)

Yeah I remade a few of the grounds and checked a bunch of connections and they're all good. I've tested a bunch of the connections with a dvom as well and things seem to be working properly. The fix didn't last. After running the car I had my sister take me to the vw dealership so I could let the car cool before I put new coolant in, but when I got home it ran like junk again. I'm having constant loss of power (it's stalling more often now when I come out of gear) and when I accelerate in any gear it will run okay for a second or two then it starts missing. If I double clutch in the same gear, it'll usually run smooth again for a second or two. I'm probably going to end up selling it sometime soon and let someone else fix it. I wish I had more money/time to fix it, but unfortunately I don't. I did hear about a MkII GTI that may be for sale from a friend, so I may just pick that up


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