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Discussion Starter #1
Hello! I have a 1989 4 door Jetta, base model, 1.8L 5 speed manual. When I first bought her, she would start right up, but idle kinda rough. I bought it anyway ($500), took it home, and gave it a tune up (new cap, rotor, plugs, plug wires, air filter, fuel filter and an oil change), rough idle did not change much. Drove it that way for a tank of gas, and noticed my mileage was very sub-par (about 11 or so miles to the gallon). I pulled my dipstick and smelled gas. Researched that online and came up with a burnt out Digifant. Replaced that ($100 later), and still had that issue. Ended up being a stuck open thermostat, which I replaced, as well as changing the oil again. She was running good, and my mileage increased by about double. The other day, I went out to fire her up, and she started, then died, and would not start again. I thought maybe the timing belt had gone, but I pulled the top cover, and everything seemed fine, and the belt seemed to be in decent condition. I finally got her to fire after about 30 seconds or so of cranking, but if I did not hold the throttle at about half, it would die. She also sounded as though she was running under water, which previous experience has been the catalytic converter. So, I removed that from the equation, but with the same results. The Bently will be here today, so I'm kind of just fishing for opinions at this point. It sounds starved for fuel, so I will go that route, although I can hear the pump prime when I turn on the key. Also, I have read that the coils on these are prone to failure, although I verified spark by having my wife watch a spark plug ground to the valve cover. Thanks for any and all help/suggestions, and I apologize for the book size post.
 

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Okay... I'm fairly stumped over this! I replaced the timing belt this last weekend, and triple checked the timing marks. Cranked her over, and still nothing... so, I went after her again last night. Pulled plug #1, cleaned it (fluffy carbon, but not in excess), hooked up my compression tester, cranked her over and got a reading of 140lbs. Replaced plug and wire, pulled number two, cleaned it, then thought I'd try to jostle the car around a bit and see if I could hear gasoline sloshing in the tank, since my gauge says I have 1/2 tank. Removed the cap and bounced the car up and down, but couldn't really hear anything, so I connected my compression tester and cranked her over... and she started right up. Even with cylinder #2 dead! Ran pretty good, at first, but drove her to work today and she was missing, running rough, and wanting to stall at idle... I really don't get what's going on here. I will consult the Bentley some more... Any suggestions on where to look are appreciated. I'm thinking maybe the pickup screen is plugged?
 

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Discussion Starter #3
I'm also not sure if this may be a contributing factor or not, but the car fluctuates RPM's, although not drastically. Sometimes when I shift, it will stay at whatever RPM I was at when I engaged the clutch, and then slowly drop, almost stall, then bounce back up to around 800, or so... I have done a quick visual inspection of vacuum lines, but can't see anything that jumps out as an obvious issue.
 

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Okay, so, I fixed a loose wire on the MAF and disconnected the Idle Air Stabilizer valve, and she purrs like a kitten at idle... are there any negatives to just leaving that sucker unplugged? I've read on other forums about how some guys will just pull the valve and plug the hoses... Also, she still has a rough acceleration, so I guess a throttle body cleaning is now in order... I think I'm getting somewhere now, though!
 

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I cleaned up the throats and butterflies on the throttle body and changed the oil today... turns out I'm still not getting anywhere with this cars issues. She'll idle smooth for about 30-40 seconds, then try to stall out. I'll give her some gas, and it'll jump around all rough, then it sounds like she clears her throat, and will idle all smooth again- for about 30-40 seconds, then the process starts all over again. What am I missing here? I've either tested or replaced almost everything on this car. I'm back to thinking it's fuel related again. I'm going to go pull the fuel pump in a minute. I also just filled up (first time with premium), and did the math, and I'm still only getting about 13 - 14 MPG. What could be causing it to run so rich? Had to change the oil again, because she gets to a certain point that the oil loses enough viscosity due to the mixing in of gasoline, that my warning light and buzzer go off... Oh, I also ohmed out the fuel injectors, and the Bentley says, if there's nothing wrong, it should be between 3.5 and 5 ohms... I got a reading of about 4.3, so I don't think I have an injector issue, unless the o-rings are bad... anyone have any thoughts? Anyone?
 

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Discussion Starter #6
I took a video for reference....

https://www.youtube.com/embed/Wlw3RQzBv0Q

Now that I've watched it again, it almost sounds like something builds up pressure and it starts to bog down. Then, after I rev the rpms for a few, you can hear a "whooosh", like a pressure release, and then it idles good again, until it builds up pressure again...
 

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Today, I cleaned the MAF sensor, ohmed it out, and it's within specs. Started her up and did a vacuum leak test and came up with nothing. Yesterday, I finished my compression testing and came up with 140lbs #1, 120lbs#2, 110lbs#3, 120lbs#4, cold. I have a blue temp. sensor on order, and it will be here Tuesday. I'll update then.
 

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Discussion Starter #8
She seems to run really good now that I replaced the temp sensor, but does not want to idle whatsoever. As soon as I take my foot off of the gas, the RPMs nosedive and she stalls right out. I'm going to plug the IAC valve back in and try that again. I'm thinking I may need to pull that and give 'er a thorough cleaning... I'm also thinking I need to test my oxygen sensor... more later...
 

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Hi, nervensage! I will keep posting as I eliminate possible problems. I kind of view this as an online "blog" of sorts as to my dilemma. Hopefully, when/if I get this fixed, it will help others who may have the same issues. I have cleaned the IAC valve and put it back together, with no positive results. I also have a new coil on order, that should be here tomorrow. I have spark, but it is yellowish-orange... I will update when I install!
 

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Discussion Starter #11
After much screwing around, I finally got a new coil and replaced the old one (there is some merit to the words "buy your parts from a reputable source"...). She still doesn't want to idle much, especially when cold, but all in all, she is running better. I'm thinking of replacing the oxygen sensor, the knock sensor (on the knock sensor, the jacketing has crumbled off of the wire, due to age, and I'm left with a bare wire), the fuel filter once more (just for grins), and my drivers side CV axle, and then drive her as much as possible...
 

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Discussion Starter #12
So, question for you guys... how do I know which CV axle to buy? I see on the ECS Tuning web site that there are two different sizes for my year of car. Do I need to remove the axle to verify size before I can order? Thanks for any replies...
 

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Discussion Starter #16
Hi, Randy! Thanks for the reply. I was thinking of replacing the in tank pump/filter. I have suspected the regulator could be a culprit... I will consult my Bently when I get home. I tried to bring it with me to work, but couldn't get it to fit in the bike saddle bags!
 

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This is a great thread, Hey Randy or megeneration you talked about 2 fuel pumps. Where are they located and how can you test them?
 

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one pump under car in front of the passengers rear tire and one in tank you can get to from a panel in trunk. way to test is to disconnect the exhaust end of pump and watch it spray. what problems are having?

Sent from my SM-G925V using Tapatalk
 

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one pump under car in front of the passengers rear tire and one in tank you can get to from a panel in trunk. way to test is to disconnect the exhaust end of pump and watch it spray. what problems are having?
I am not getting any fuel to the injector pump. I took off the intake line to the injector pump from the fuel filter and than took out the line from the tank to test flow and nothing. My jetta is a 92 diesel I replace the fuel sending unit in the tank, though it was just a something to read the fuel level though, not a pump. I will check out the one under the drivers side, Thanks for the help
 
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