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I've been where you are at. You need to get the idea that everything is working correctly out of your head. There is a problem and you are failing to find it. The tests you are doing or the parts you are replacing are faulty. It's your fault and not the car.

Don't take this personal. I've been down this road more often than most. It was my job for 20+ years to fix Mercedes that the others [including their engineers] could not. If everything was good, there would not be a problem. Everything is not good and you are not testing it right. Once you wrap your head around this, then you can get back to testing. Every time I got painted in the corner, I had to look at myself and ask myself why I cannot fix it. Telling myself that everything is working right but the problem is still there is wasted time.

There was only 1 Mercedes I could not fix. The factory support was stumped too. After 20 hours of diagnosis, we had to shot gun parts and since it was customer pay, the client pulled the plug. They pulled the plug since I could not assure them if any part I replaced would fix it and the parts I wanted were coded for their car and they could not be put back on the shelf.

If I have a chance to play with my wife's car, I will. I will post my results and try to get some pictures.
 

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Discussion Starter · #24 ·
I've been where you are at. You need to get the idea that everything is working correctly out of your head. There is a problem and you are failing to find it. The tests you are doing or the parts you are replacing are faulty. It's your fault and not the car.

Don't take this personal. I've been down this road more often than most. It was my job for 20+ years to fix Mercedes that the others [including their engineers] could not. If everything was good, there would not be a problem. Everything is not good and you are not testing it right. Once you wrap your head around this, then you can get back to testing. Every time I got painted in the corner, I had to look at myself and ask myself why I cannot fix it. Telling myself that everything is working right but the problem is still there is wasted time.

There was only 1 Mercedes I could not fix. The factory support was stumped too. After 20 hours of diagnosis, we had to shot gun parts and since it was customer pay, the client pulled the plug. They pulled the plug since I could not assure them if any part I replaced would fix it and the parts I wanted were coded for their car and they could not be put back on the shelf.

If I have a chance to play with my wife's car, I will. I will post my results and try to get some pictures.

I understand and respect that. Basically thats where I am at now. It is clear what was happening but like I said according to factory service manual I have replaced the necessary part that would contribute the issue yet the issue is still but I can confirm that part works correctly as it was tested in a different car.
Either way I am currently waiting for a new coilpack connector so I can replace this botched conversion/splicing , as I have found out recently intermittently it was causing issues.

Also I dont believe that issue is lying with the factory car itself but a modification of it down its lifespan. Like I said it has many things retrofitted and even though I tried resetting everything back to its factory state who knows what has been touched that is not visible without pulling the car apart.

Either way once I get the connector and wire it up , I'll run some tests again and report back. Though the longass shipping on it is annoying me too..
 

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Discussion Starter · #25 · (Edited)
So update,

While waiting for connector went ahead and tested it(again) with bare wires which gives even less of a chance of a fault.

The bentley procedure to check which I posted above always fails. Testing the trigger signal vs ground there is always 0 volts on there , it does not ever show a positive pulse, even though bentley says it should and waveforms from multiple auto repair programs too.

BUT if I put the positive lead ( of multimeter, test light whatever) to positive power wire ( switched 15) and negative lead to trigger wire, it flashes , which means it sends a switched ground pulse instead of a positive pulse OR it does the same thing but the positive pulse peak is missing only the ground part is coming through, but this is not according to specifications/manual.
( Exactly the same outcome when you asked before ).

So how to proceed in your opinion.
 

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I'm trying to get a recently purchased Vanagon ready to go on a vacation for a client. They're leaving in a few days. So I have not had time to check my wife's car.

You are performing a test against the positive but that does not mean much since you do not have a reference to what it's suppose to be. So is it a good test or not. Right now, it's worthless information.

The test Bentley [again, I absolutely hate to be wrong and I rarely assume since it just leads down the wrong path] says is to use the ground pin. The test is measuring the power signal and you are not getting one. Sounds like that is the issue. Your test is showing it's getting a ground signal but the computer does not care, it needs a power signal. Does the connector need to be plugged in? Your car is old, but with the newest cars, most test must be hooked up or the computer may remove power/ground because it 'sees' it unplugged. If Bentley says to have it unplugged, maybe it's true but I would perform the test plugged and plugged in.

I'll do my best to make those tests today, but I do not want to look at this young family and say you're not going on vacation. I certainly do not want to get a call saying the Vanagon died too because of my hastiness.
 

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Discussion Starter · #27 ·
I'm trying to get a recently purchased Vanagon ready to go on a vacation for a client. They're leaving in a few days. So I have not had time to check my wife's car.

You are performing a test against the positive but that does not mean much since you do not have a reference to what it's suppose to be. So is it a good test or not. Right now, it's worthless information.

The test Bentley [again, I absolutely hate to be wrong and I rarely assume since it just leads down the wrong path] says is to use the ground pin. The test is measuring the power signal and you are not getting one. Sounds like that is the issue. Your test is showing it's getting a ground signal but the computer does not care, it needs a power signal. Does the connector need to be plugged in? Your car is old, but with the newest cars, most test must be hooked up or the computer may remove power/ground because it 'sees' it unplugged. If Bentley says to have it unplugged, maybe it's true but I would perform the test plugged and plugged in.

I'll do my best to make those tests today, but I do not want to look at this young family and say you're not going on vacation. I certainly do not want to get a call saying the Vanagon died too because of my hastiness.

Bentley says to perform test with connectot unplugged so its perfectly fine to have it floating and yes ofcourse you would think thats the issue. But then it says to replace ecu if wiring is good, which it is ,checked continuity etc all according to bentley procedures , and also replaced ecu (and the ecu was pulled from a working car, so i can deffo confirm that). And yes ofcourse real life tskes priority, i would not expect it otherwise.
 

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Discussion Starter · #28 ·
So update again..


I got the car to fire the plugs and start somehow using a newer style COP coilpack, I made a circuit that converts the ground pulse from the ecu trigger to a 12v positive as thats what this smart coil works with and yes it fires, I made a long threaded screw with SAE connector at the end so I can connect it to the distributor and car starts roughly, and when it does there are misfires and eventually dies, trying adjusting distributor etc but does not really help ( even though its bang on anyway), but I'll try sorting it out maybe change back to old plugs because they have less sparkgap and who knows how strong these coils are vs the stock coilpack.

If I wont get it running soon I might have to scrap the car, its been 2 months really, I cannot continue with my main build cause of this things and its very very annoying. :(


Anything new on your side Butcher?
 

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Discussion Starter · #30 · (Edited)
Aight cheers, but is that car a californian car? Else you will have the sepearate ignition module and stuff, only cali digifant is similar :/.


EDIT: Oh yeah, forgot to say , I knew some people reported their issues got fixed by replacing / resoldering their nr 30 relay ( power supply). Initially I didnt take the relay apart because like I said it passed all bentley tests including the connector too. Well 2 days ago I took it apart and sure enough there were 3 dry joints, which I resoldered( I resoldered all of them anyway) they are nice and shiny now, also purchased a new ignition switch - sometimes the starter would disengage while starting or engage while just switching ignition on ( but not starting) for half a second or so, hopefully this fixes that issue.. if not I really think something is shorted and somehow its turning the starter on for a sec without switch being turned to start lol. Havent had time to check yet.
 

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It's a Digifant I car, yes, California.

The coil has three wires. Power, ground, and signal. The power and ground is 12v. The signal wire is green/black and is located in the middle. It has a 1.6V reading when the engine is running [at idle] and a .02v when the engine is off [key on].


The distributor has 3 wires also. Power, ground, and signal. The signal wire is Green/White and is located in the middle. The power is also 12v. The signal wire is 7.3v while running [at idle] and 11v with the key on, engine off.


I did not move the distributor to see if the signal changed when the trigger lined up. I suspect it would since it's a hall effect sensor.

I suspect that the square wave that comes from the distributor goes to the EFI ecu. That information gets changed and modified. That signal is then sent to the ignition coil. That signal is normally grounded and the ground is removed when the spark needs to occur. The EFI controls the ignition timing as well as the fuel injection.

This what I was trying to say but I'm certainly not the best at explaining myself. I hope this additional information helps. Again, both the distributor and the coil have 12v. I did not bother hooking up my scope to insure the signal was indeed a square wave. In my book, it just makes sense that it is.

When I was in Reno with no spark, a quick test showed I had a signal out of the distributor and one going to the coil. The only thing left was the ignition amplifier that attaches to the coil. The ignition amp changes that EFI signal for something the coil can use. Now you can buy a coil with the amp built in. I was able to buy the amp and got home. I put a good coil/amp unit in because the new one I purchased would cause the tach to jump when the ignition key was turned on. It was a matter of time before that would fail.
 

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Discussion Starter · #32 ·
Yep.

My coil has 12 and ground, hall sensor has ground and 12v , and signal goes out to ECU(confirmed), it is like you say, gets modified based on coolant temp and dwell time and stuff and gets sent to the coil.
Now like I said and showed and your test now confirms , there should be a positive peak on the signal square wave, that is missing on mine, only the 0v ( ground) is present. So I am unsure why the ECU does not send the positive voltage down the wire, the only explanation I think of is that the wire is grounded somehow , but it shows no continuity to either positive or ground. the ECU is confirmed to be good, taken from a running car.

I will see if there a positive voltage on the signal again after I fixed up the ecu supply relay and cut off the broken connector( a while ago) tommorow, since I didnt get a chance today because I was charging the battery.
I assume you tested the signal positive vs the battery negative directly or did you test on engine(itself) earth ?
 

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So I am unsure why the ECU does not send the positive voltage down the wire, the only explanation I think of is that the wire is grounded somehow?
So what makes you think that the ECU puts power on the line? I would think that there is a slight bias voltage on that line and the ECU pulls it to ground. I'm certain you will agree, it's got to be one or the other but it's possible your thought is wrong. Yes, I know I could be wrong too. If there is a bias voltage, I would suspect the ICU in the coil.

On the bright side, I replaced my wife's valve guide seals [which I did 2 years ago] because of a misfire and blue smoke on cold start ups. It's fixed, she just drove out and no blue cloud.
 

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Discussion Starter · #34 ·
So what makes you think that the ECU puts power on the line? I would think that there is a slight bias voltage on that line and the ECU pulls it to ground. I'm certain you will agree, it's got to be one or the other but it's possible your thought is wrong. Yes, I know I could be wrong too. If there is a bias voltage, I would suspect the ICU in the coil.

On the bright side, I replaced my wife's valve guide seals [which I did 2 years ago] because of a misfire and blue smoke on cold start ups. It's fixed, she just drove out and no blue cloud.
The reason I think that is because Bentley says so and it very clearly fails that test( with the wires "floating" as in coil completely unplugged). The LED would only light up if its get positive from signal wire and the waveform info from Autodata and Vivid confirms it too.
Still didnt have the chance to test since the improvements I made and its half 9 PM again :p Gotta replace sparksplugs in main build, but hopefully I can do it or maybe tonight really fast, we'll see.
 

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Discussion Starter · #35 · (Edited)
Well just tested it again, there 0 volts on that line all the time( like before the wire if basically floating then ecu grounds it with no positive peak). Even if I can get it started with my contraption it will stop running after 2-3 seconds or so , and when it does I can hear the fuel pump prime noise( I can also hear it clearly during the motor is running the loud prime sound, which isnt the usual run sound of the fuel pump, I think) constantly going. Whatever I do I cannot it get to run reliably, and its very very very annoying , it has been 2 months now.. Without the MAF it starts a bit easier but it does the same thing.

I have confirmed that the ECU pulses the injectors , does not keep them flooded ( usual digifant issue).

Just for **** and giggles I am going to put my og coil back and see if I get a spark now ( very unlikely but I'll do it anyway thats how frustated I am).

Yup , no spark with either OG coil or new coil on factory like setup :D I love doing the same stuff expecting a different outcome
 

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I still have not swapped my downloaded Bentley file from my old laptop.

Just so I can understand what is going on, use my color codes on the pictures I posted.

When you install a diode to the Bk/Gn wire on the coil, it does not flicker? Do you have a wire going to the tachometer? If you do, can you disconnect that wire? I can see if the tach is shorted out, it could kill that circuit.

Try this link and see if it applies to you. If it does, I have something to visually relate to. It's Motronic, but I do believe it applies to your ignition system. It's a bit odd to navigate, but click on next to change pages.
https://vwts.ru/vw_doc/eva2/FU03/ch3.5.html
 

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Discussion Starter · #37 ·
I would not believe that Bentley is wrong provided I have the service info direct from Erwin.. This car has some other crazy issue... And lets not forget that the car has LPG system installed so who knows what wires are tapped into - I have the wiring diagram and it basically only shows the injectors and coil signal wire- but that does not explain why was the hall sensor output directly hooked to the trigger for the coil and it worked.. And when it died the first thing I replaced was the coil and that was without changing anything around just literally drop in but it didnt fix it. This was back in March 15...then after that came all the other stuff.

Unfortunately I cannot fire the COP coil directly as its resistance is too high vs the ecu input so all the current goes there, and if I increase the resistance toward the ecu it fires the coil fire but then the ecu does not fire the injectors and such because it senses no hall signal input( hall sensor output is 20ma nominal 40ma max not enough for both), so I'm gonna try coming up with a booster circuit so both can work.
 

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Discussion Starter · #38 ·
So update again...


So i managed to get the car to start reliably using my converted coilpack direct from the distributor... but now I am having another ghost issue.

Basically if I remove the battery negative, and put it back and I start the car it runs fine starts with half a key.. if I shut it down and try to start it again it cranks but as soon as it would start I hear a loud bang as you would jam the starter/flywheel with a big steel piece or something, and I stop cause I dont want to break something but it does it everytime. If i remove the voltage again and put it back it starts again fine... I dont understand this bloody car..

Any ideas?
 

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Does the engine lock up?

Not certain what you mean by half a key.

Does the engine lock up? If not, I would think there is an ignition timing issue. A spark at the wrong time will stop a cranking engine.
 

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Discussion Starter · #40 · (Edited)
Does the engine lock up?

Not certain what you mean by half a key.

Does the engine lock up? If not, I would think there is an ignition timing issue. A spark at the wrong time will stop a cranking engine.

Unfortunately i cannoy look at the engine too, but according to my dad it just stops, but if i keep the key in crank position and it will crank but it will do it every 1 second or so, sometimes i can start it up by keeping it going and maybe touching the throttle. Obviously the spark is not adjusted yet properly but for now I am taking off the starter for a grease job ( been 30 yrs) almost , then we will see.

Starting with "half a key" means that you start the engine effortlessy and nicely , a car does not need much cranking time.
Also i saw your last post today only sorry bout that. :D
 
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