me612
20+ Year Contributor
- 1,423
- 5
- Aug 8, 2002
-
Minneapolis,
Minnesota
First off I will give a little info about the car. 1991 Tsi Awd. Mods are 50-trim and typical supporting mods such as fmic, 255hp walbro, IE fpr, 2g MAS, etc. Emissions, ISC, FIAV are all removed and blocked off, and my FP solonoid is not hooked up.
This problem started out of the blue last fall, and has gradually gotten worse. I don't drive this car in the winter, so once the problem got to the point where I couldn't rely on the car starting, i parked it. It seemed to help if I kept the gas peddle to the floor while starting, and sometimes it would start after trying for awhile, and once it started, it would seem to idle fine and seem to drive fine. I don't really floor it because I have a knock issue that I haven't solved yet either, but it seemed to drive around town just fine. This kind of confused me a little bit.
OK, but the problem was still that basically the car would have a very difficult time starting. It would crank and crank, and even sort of hicup a few times like it wanted to start, or it would start but it would be so lumpy and crappy that it would quickly die. I checked compression, 150-150-150-145. I made sure all connections were connected. Timing is good as well. My injectors are pretty new still so I don't think they are leaking. When I did get it started, I used my logger to turn off each injector individually and they do shut off just fine. Also I checked my coolant temp sensor because I heard that it can cause this problem. It is reading fine. And I do have a spark. I was leaning towards the ECU being the problem, but I've been doing a lot of reading lately and started to question my fuel pressure. Now this problem started when I still had a stock fpr, and did have the FP Solonoid hooked up. This past weekend I installed the FPR kit from IE, so now I have a gauge I can watch the pressure with, and also unhooked my FP solonoid. I started doing some testing today, here's what I have found and hopefully someone on here can give me a little insight based on what I found.
First thing, is the fuel pump supposed to start building pressure when I turn the key to the "on" possition? I really don't know, but mine sure doesn't.
Once I crank over, the pressure quickly jumps up in the 30's or so. I can't tell perfectly because I am in the car cranking, and the gauge is in the engine bay. The car is still doing the same thing with this FPR as it did with the stocker. But I did eventually get it started, and set it to 37 with the vacuum hose unhooked. Now once I shut the car off, by the time I get under the hood to see what my pressure is at, it's already around like 25, and slowly bleeds off to 0 after a minute or 2. Is this normal, is it supposed to bleed like this?
Next what I did was hook up my logger, and turn on the fuel pump with it. When I turn it on, i immediately hear the pump turn on, and the pressure jumps to 37. It stays at 37 the whole time that it's running the test, but soon as the logger stops the test, the pressure begins bleeding off to 0, again in about 1-2 minutes. Again is it supposed to be bleeding off like this?
Now I am thinking to myself that this doesn't seem right to me that it's bleeding like this. I go back and removed the trunk cover that is over the fuel tank. I notice there is some fuel around that PITA connection where the hard line coming off the top of the fuel pump cover connects to the rubber hose. I undid the connection, cleaned it off, put some teflon tape on it, and reconnected it nice and tight. I then turned the pump on a few more times after this and I don't see or feel any fuel leaking now. I thought this may have been my pressure leak, but the car is still doing the same thing
Now I decided to try something else, a quick test. What I did next was turn on the pump with my logger. Again the pressure is up at 37 until it shuts off and bleeds off. Well I turned on the pump, watched it go to 37, then once the test stopped, I immediately attempted to start the car. It started right up without any hesitation. Now that right there makes me think that this really is fuel pressure related. Am I right in thinking this?
Next I know that many people have problems with their O-Rings when they install aftermarket pumps. I removed my pump, looked at the O-Ring, and it looks to be in very good shape still. I will be buying a new on tomorrow anyway because it's so cheap anyway, but I honestly don't think anything was leaking past that because I saw no rips or anything in it.
Lastly, I also added some teflon tape to the FPR adjustment screw because I heard of people having slight leaks right there. So I just added a small amount of teflon tape to that screw to hopefully help in case of that.
Any insight is greatly appreciated. I think I am on the right track, but not really sure where to go from here. Thanks!
This problem started out of the blue last fall, and has gradually gotten worse. I don't drive this car in the winter, so once the problem got to the point where I couldn't rely on the car starting, i parked it. It seemed to help if I kept the gas peddle to the floor while starting, and sometimes it would start after trying for awhile, and once it started, it would seem to idle fine and seem to drive fine. I don't really floor it because I have a knock issue that I haven't solved yet either, but it seemed to drive around town just fine. This kind of confused me a little bit.
OK, but the problem was still that basically the car would have a very difficult time starting. It would crank and crank, and even sort of hicup a few times like it wanted to start, or it would start but it would be so lumpy and crappy that it would quickly die. I checked compression, 150-150-150-145. I made sure all connections were connected. Timing is good as well. My injectors are pretty new still so I don't think they are leaking. When I did get it started, I used my logger to turn off each injector individually and they do shut off just fine. Also I checked my coolant temp sensor because I heard that it can cause this problem. It is reading fine. And I do have a spark. I was leaning towards the ECU being the problem, but I've been doing a lot of reading lately and started to question my fuel pressure. Now this problem started when I still had a stock fpr, and did have the FP Solonoid hooked up. This past weekend I installed the FPR kit from IE, so now I have a gauge I can watch the pressure with, and also unhooked my FP solonoid. I started doing some testing today, here's what I have found and hopefully someone on here can give me a little insight based on what I found.
First thing, is the fuel pump supposed to start building pressure when I turn the key to the "on" possition? I really don't know, but mine sure doesn't.
Once I crank over, the pressure quickly jumps up in the 30's or so. I can't tell perfectly because I am in the car cranking, and the gauge is in the engine bay. The car is still doing the same thing with this FPR as it did with the stocker. But I did eventually get it started, and set it to 37 with the vacuum hose unhooked. Now once I shut the car off, by the time I get under the hood to see what my pressure is at, it's already around like 25, and slowly bleeds off to 0 after a minute or 2. Is this normal, is it supposed to bleed like this?
Next what I did was hook up my logger, and turn on the fuel pump with it. When I turn it on, i immediately hear the pump turn on, and the pressure jumps to 37. It stays at 37 the whole time that it's running the test, but soon as the logger stops the test, the pressure begins bleeding off to 0, again in about 1-2 minutes. Again is it supposed to be bleeding off like this?
Now I am thinking to myself that this doesn't seem right to me that it's bleeding like this. I go back and removed the trunk cover that is over the fuel tank. I notice there is some fuel around that PITA connection where the hard line coming off the top of the fuel pump cover connects to the rubber hose. I undid the connection, cleaned it off, put some teflon tape on it, and reconnected it nice and tight. I then turned the pump on a few more times after this and I don't see or feel any fuel leaking now. I thought this may have been my pressure leak, but the car is still doing the same thing
Now I decided to try something else, a quick test. What I did next was turn on the pump with my logger. Again the pressure is up at 37 until it shuts off and bleeds off. Well I turned on the pump, watched it go to 37, then once the test stopped, I immediately attempted to start the car. It started right up without any hesitation. Now that right there makes me think that this really is fuel pressure related. Am I right in thinking this?
Next I know that many people have problems with their O-Rings when they install aftermarket pumps. I removed my pump, looked at the O-Ring, and it looks to be in very good shape still. I will be buying a new on tomorrow anyway because it's so cheap anyway, but I honestly don't think anything was leaking past that because I saw no rips or anything in it.
Lastly, I also added some teflon tape to the FPR adjustment screw because I heard of people having slight leaks right there. So I just added a small amount of teflon tape to that screw to hopefully help in case of that.
Any insight is greatly appreciated. I think I am on the right track, but not really sure where to go from here. Thanks!
) and rigged up a "spacer" of sorts to make sure the o-ring stayed put...I cut a 1/4 inch (? you'll have to measure this ?) piece of fuel line and inserted it directly below the o-ring on the fuel pump, so it pushed the o-ring up into its housing, and didn't allow it to slip. This has worked fine for me, and hasn't given me any more problems. Also gives me peace of mind knowing that i won't have to rip out the fuel pump any time soon. 
Thanks for the coffee all over my keyboard and monitor.
). My logic in trying this was that the fuel line I used had the same diameter as the o-ring, thus adding it underneath the o-ring would in essence make one "big" o-ring. My stock fuel pump had a crappy little POS plastic "spacer" on it that I assumed was there to keep the o-ring seated....Not the case on the Walbro, though, so I decided to rig this up. 
)
