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2000 2.8 V6 Won't start

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2000 start wont
6K views 37 replies 11 participants last post by  jopr175 
#1 ·
Went to turn her over this morning, and nothing. It would crank, but not catch.

Backstory: Changed the oil and filter about a week ago. Almost immediately after, coolant sensor says that fluid is low. Ok, so I topped the overflow bag up. Light goes away, and all is good. Well, except that now it sounds like there is fluid rushing just behind the dash. I assumed that I got some bubbles in the line when I topped up the bag, and I'd just need to outgas it when I had the chance. (wouldn't think this was relevant except for reason #3 I describe below)

Last night, we took the car for a short trip, and it seemed to hesitate a bit for the minute or so after she started, but that cleared up pretty quickly.

Jump ahead to this morning, and nothing.

Used an inline spark checker, and the spark seemed kind of slow, weak and yellow, though not having used this tester on the passat before, I dont have a good baseline.

I am getting fuel at least to the engine compartment as I pulled the line from the fuel rail and cranked it. Got a couple spoonfuls of of fuel in about 3 seconds.

I;ve been reading the forums all day, and it seems like folks have said either 1. coilpacks, 2. ICM or 3. coolant temp sensor.

I tried to pull OBD codes with my little actron, but it says no codes available, and I never threw a light either.

Anyone have any ideas?
 
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#2 ·
Give that fuel pump a look-see. If you're not getting codes, I'd consider something that doesn't code first. Fuel delivery until the injector does not code.

A few teaspoons of fuel seems inadequate. I would expect a torrent of fuel (which is why I wouldn't do this without a container to catch it in.).

Are you able to get sensor readings? If you read the signal for the coolant sensor, it should read ambient temperature if the engine is cold.
 
#3 ·
Thanks ctobio. I thought it weird that I wasn't getting any codes either. I think I may have misspoken about how much fuel came out. I taped the hose to a longer plastic hose that fed into a rubbermaid tub. I worked the ignition, and my Dad held the tub. He seemed to say it came out pretty good, I just didn't think it would have been more than a cup or so.

How would I go about reading the temp sensor?
 
#4 ·
You need a VAG-COM to read the engine coolant temperature sensor data. You can remove the sensor and measure resistance at various temperatures. I've posted the curve data recently. A bad coolant temperature sensor can make the car difficult to start but usually it will start after many cranks.

Coil packs fail very infrequently on a V6 and the V6 does not have a separate ICM. It's built into the coils.

The car will not start if the engine speed / crankshaft sensor is bad and that could be the reason for the hesitation you experienced.
 
#5 · (Edited)
are you sure they fail frequently? i rarely hear of this ever happening...
now, they fail all the time on the 1.8t's for sure.

now, the op said that he had an immediate issue after his oil change.

seeing as how the oil cooler device where the oil filter goes does have coolant lines, it is possible to believe that the unit could have sprung a leak from old age and being jostled just enough with a filter change.
hence the "low fluid" code.

afterall, with the v6 the coolant level sensor is in the bottom of the reservoir and works on continuity, and unlike the 1.8t, you do not need to move it for the oil change. thus i see a problem right there.

i would want to do an oil sample ASAP to make sure that nothing CATASTROPHIC is occuring!
 
#9 ·
Read carefully

Coil packs fail very infrequently on a V6
So most likely it is not coilpack that is causing the problem. Like suggested before, check the coolant temp sensor, better yet, just replace it and see what happens. It is a cheap part and with little effort can be replaced DIY.
 
#13 ·
Ok, the coolant temp sensor seems easy and cheap enough to replace. I think I can get that done.

But man, could a failed temp sensor really keep the car from starting?
Usually not. After you crank a while, do you smell gas? Generally, when the sensor fails, it opens up indicating to the ECM that the coolant is very cold and hence the ECM enriches the mixture way too much during startup which floods the engine.

You might want to check the engine speed sensor. Disconnect the gray plug (move coolant reservoir to get to it) and measure the resistance on the sensor across pins 1-2, 2-3, and 1-3.

1-2 = infinite
2-3 = 730-1000 ohms at 20*C
1-3 = infinite
 
#20 ·
And can I ask the follow on question... If the injectors are getting a signal and firing, where do I test next?

If in fact it were the coil pack, how would I test to confirm? Or can that even be done?

As I think I mentioned earlier, I used an inline spark checker I picked up from autozone, and tested several of the cylinders. They were getting spark, but it seemed slow, yellowish and weak. But I had nothing to compare it to before to see.

Is that at all indicative of a failing coil pack? (Or something else in the spark system generally?)
 
#21 ·
Ok, so I tried some things today, unfortunately to no success.

I picked up a set of noid lights. Only checked 1 injector, but it seemed to be functioning normally.

Replaced the coolant temp sensor. I lost the o-ring and broke the plastic horseshoe clip, but the new one is in. (I'll pick up the o-ring and hopefully a new u-clip tomorrow from the stealer)

I also, just on the off chance that I was stupid, tried jumping the car.

None of these worked. I still cant get it to catch.

Any ideas on where to go from here? If I cant get it going soon, a large bonfire with a blue passat at the middle is starting to sound like the most appealing option.
 
#23 ·
Went to turn her over this morning, and nothing. It would crank, but not catch.

Backstory: Changed the oil and filter about a week ago. Almost immediately after, coolant sensor says that fluid is low. Ok, so I topped the overflow bag up. Light goes away, and all is good. Well, except that now it sounds like there is fluid rushing just behind the dash. I assumed that I got some bubbles in the line when I topped up the bag,..<<<<<SNIPPED>>>>>>
What is this bag that you speak of?
 
#28 ·
Try taking a small propane bottle with a nozzle on it and add propane to the air box while you are trying to start it, if it starts you know that you have a fuel delivery issue. Your fuel pump should be putting out at a bare minimum 1 pint in 15 seconds. If your injectors are pulsing and the coils are firing and assuming that it hasn't jumped time or some other mechanial engine failure hasn't happened...like a blown head gasket(you did say that you had to put coolant in it, where did it go, did it overheat at all) then it has to be a fuel supply issue.
 
#29 ·
Ok, got the clip and o-ring so I can complete the temp sensor install tomorrow. I'll make sure its properly seated in the harness (hopefully anyway--I've got big hands, and man is it tight down there)

As a second question, I've been looking at the crankshaft sensor. Is this the same as the engine speed sensor? Haynes seems to say no, but on the boards, it looks like they are interchangeable. ie. I think kenblasko and sipes said it was http://www.autohausaz.com/search/product.aspx?sid=d4mo0u550jny30vee1yyeo55&makeid=800026@VW&modelid=1359547@PASSAT%20&year=2000&cid=sensor@sensor&gid=7196@Crankshaft%20Position%20Sensor

I think that would make the two the same, but I just wanted to be clear.
 
#30 ·
Yes, it's called either name but it's one in the same. You also see the sensor called an engine rpm sensor. It senses the position of the crankshaft and the speed (rpm) of the crankshaft as it is rotating.

I couldn't find anything on what the ECM does if it detects a bad signal from the sensor. I know on a b5, the car will still crank if the sensor is bad but the car will not start. So, the ECM has got to cut fuel or ignition or both. But, your fuel delivery appears okay, the noid light indicates the injectors are firing, and the plug tester indicates spark.

I'm still puzzled why you don't smell gas if you crank the car that many times and it doesn't start. It seems like the fuel pressure is too low, the injectors are not firing, or the pulse width is too short.

On your coolant temp sensor measure the resistance across the two sets of terminals on both sensors and compare the results when both are out.
 
#31 ·
Believe me, if you're puzzled, I dont stand a chance. I tried to measure resistance across the pins before, but had a hell of a time jamming the leads on my fluke in there enough to touch the pins. I'll try again tomorrow.

Also tomorrow I'll try to get the resistance on the crankshaft sensor measured and post it here.

I'll also finish the reinstall of the replacement coolant temp sensor.

Is there anything else I can do to try to give you guys some more info? Tests, pics or videos of anything?

I really appreciate all the advice I've gotten thusfar. You guys are a great resource, help and friend to the clueless (ie. me :) )
 
#32 ·
another thought...

my 01 v/6 wouldn't start last week, it cranked a long time and sputtered once in a while, I saw the fuel gauge low and got 5 gallons of fresh fuel and added a bottle of isopropyl drygas to the tank, I cranked for a bit but it started and ran ever since. I figured having to use premium fuel that with the price of gas the way it was people weren't buying it and it was sitting in the tanks in the ground collecting water:thumbdown, after it started I have had no issue except when the tank was low again it hesitated a bit until I filled it up and added more drygas, I'm pretty sure I picked up some water.
Try pumping some fuel into a glass jar and let it settle to see if you have water in your gas.
 
#33 ·
something else...

don't "jam the leads of your fluke" into the terminals of your sensor leads, you will create a new problem with expanded terminals, try going to a parts store and buying a few misc. terminal ends and if you have to modify them to adapt like the originals and use to hook up do that, or cut a paper clip in 2 and carefully insert them into whatever you are trying to probe, I worked at a GM shop as a foreman for 10 years and saw the results of spread terminals.
nagging over.
 
#35 ·
Additionally, I just tried to crank it again just now (why, I dont know, I just felt like it). Now I get the STOP STOP STOP oil pressure warning. High or low, I have no idea. All I do know is that I didn't get this before. Was it possible I was just trying to crank too long?
 
#36 ·
Damn Bro, You have really been spun in a circle on this one, I feel for ya. I know how frustrating it can be working on something, and ending up with nothing..again and again.

Hopefully something comes to light, and this will all make sense somehow. If not, send me your address and I'll mail ya a book of matches...
 
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