Going for first fire

I guess I'll leave it for a while. I need to procure a new connector anyway. I'm thinking of starting over completely. The car runs just as well with the FI disconnected (ECU connector off) as it does after all the fiddling I've done. That's just crazy. Maybe I should back way way up and start from square one.
 
Here's a thought...

jvandyke said:
I guess I'll leave it for a while. I need to procure a new connector anyway. I'm thinking of starting over completely. The car runs just as well with the FI disconnected (ECU connector off) as it does after all the fiddling I've done. That's just crazy. Maybe I should back way way up and start from square one.
Click to expand...

Dunno if it's a good one or not. The ECU does not control spark, it just fires the injectors. If you have leaky injectors that are pooling fuel into the manifold, that would account for the temp startup. Basically the same as dumping gas down the throat of a dry carb.

Obviously you also have other things going on that are causing the injectors to not fire, but at least this theory might account for the temporary running with no ECU connected.

Pete
 
Stupid question

Have you checked that the injector harnesses are working with a noid light? Have you verified the wire from the coil to the ECU (yellow wire with piggy-back connector on the coil end) is installed and on the correct coil terminal?

These are fairly simple things to check...
 
There are no stupid questions. Assume I am completely inept (that's how I feel right now).
I got weak intermittent voltage at one of the injector connectors during cranking, which I believe is correct.
There's the piggy back connector on the coil as I've seen pictured. Removed cleaned replaced. No idea if it's the "right" wire or not. Will check that out. It is probably something stupid simple like this.
 
I'm pullin' for ya here.

Every time I click on the thread I'm hoping that you'll be yelling that you miraculously got it to work. After having fought with my engine all last summer and finally just giving up and having the whole thing rebuilt, I feel your frustration and pent up rage. Keep at it, it will eventually pay off. Again, we're all pulling for you!
 
I'm wondering where I turn next. Keep hammering on the weird CTS readings or move to something else....I'm still thinking of pulling an injector and checking for spray, sounds like some work but I'm now used to 2 hours a day 7 days a week.
 
It would not surprise me if you can find the CTS connector locally. VW and Audi dealers will probably have the connector, but possibly not with the pigtail.

I don't have my wiring diagrams handy, but your comments about connecting or not connecting the ECU not making a difference is intriguing. I seem to remember the dual relay being grounded through the ECU, so the fuel pump should not run at all with the ECU disconnected. Is this the case? I.e. with the ECU disconnected and ignition on, does the fuel pump turn on when you open the AFM flap?

You had been following the "engine starts, then stops" section in the trouble shooting guide, but the starting part you see might be a fluke (seeing as the ECU does not make a difference), so perhaps start at the "engine does not start" section instead?

Pulling a fuel injector is a lot of work, the hose going to each injector is short and stiff, so I don't know how feasible it is to pull just one to check. Other in the forum might have experience with this, I don't.

As for the grounding of pin 5 at the ECU connector, I dont know that there is much mystery left here. Perhaps I have misread your posts, but this is my understanding:

  1. You consistently see continuity between pin 13 of the ECU connector and one side of the CTS connector.
  2. You don't see continuity to ground at either pin of the CTS connector
  3. When the ring terminal at the valve cover is screwed down, you see continuity between pin 5 at the ECU and ground.
  4. When the ground terminal at the valve cover is floating in the air, you do not see continuity between ground and pin 5 at the ECU.
Have I understood this correctly? If so, it would seem that the wire from the ring terminal to the CTS has at least one more break in it (in addition the the one you found at the CTS connector), and that the wire from pin 5 at the ECU connector to the ring terminal is just fine. The ring terminal is used to pick up ground for the CTS and part of the ECU, it is not used to ground the valve cover.

To test the signal to the injector, you might try to hook up an LED with a 470 Ohm series resistor. Connect the resistor to the anode side (longer of the two pins and the one on the side without a flat spot on the lens) of the LED.

One pin of the injector connector has constant battery voltage on it as long as the ignition is on (The ECU must be connected also, again due to the dual relay begin grounded through the ECU). Connect the other end of the resistor to this pin. Connect the cathode end of the LED (the shorter of the two pins, there is a flat spot on the lens by this pin) to the remaining pin of the fuel injector connector.

An LED is much faster to turn on and off than an incandescent bulb, so the LED will allow you to see the pulses better. Does the LED flash when you are cranking the engine? Does it keep flashing after you release the key?
 
Amen to that Jeff.. I am following the saga as well

Jeff N said:
Every time I click on the thread I'm hoping that you'll be yelling that you miraculously got it to work. After having fought with my engine all last summer and finally just giving up and having the whole thing rebuilt, I feel your frustration and pent up rage. Keep at it, it will eventually pay off. Again, we're all pulling for you!
Click to expand...

We are all wishing you well jvandyke. :grouphug: I just don't having anything to offer technically... so I stay quiet and send out good thoughts I hope it gets sorted soon.
 
ng_randolph said:
I seem to remember the dual relay being grounded through the ECU, so the fuel pump should not run at all with the ECU disconnected. Is this the case? I.e. with the ECU disconnected and ignition on, does the fuel pump turn on when you open the AFM flap?
Click to expand...
No
Just now I disconnected the ECU turned on the key, opened the flap, no fuel pump (as expected) Hit the starter and it ran and stumbled for a few seconds (same as always) This is long after all pressure has dropped off.
Second and third attempts no fire at all (whatever fuel was there is gone). It seems like a case of gas fumes burning for a few seconds, clogged injectors doing a very poor job but a little gets in to fire a few cylinders off for a few seconds before.....the ECU shuts it down (why?) or the fumes are gone and that's all she has until the next round...just a complete neophyte's theory.

ng_randolph said:
You had been following the "engine starts, then stops" section in the trouble shooting guide, but the starting part you see might be a fluke (seeing as the ECU does not make a difference), so perhaps start at the "engine does not start" section instead?
Click to expand...
I've long since gone back to that section yes. I want to move on to check other things, even though the CTS issue isn't resolved. Throttle position sensor, air temperature....injectors....
I should probably start tearing the harness apart but I'm a bit squeamish on doing that, even though it can be rewrapped and all.

ng_randolph said:
Pulling a fuel injector is a lot of work, the hose going to each injector is short and stiff, so I don't know how feasible it is to pull just one to check. Other in the forum might have experience with this, I don't.
Click to expand...

Yep, but it would tell us a lot, no?

ng_randolph said:
As for the grounding of pin 5 at the ECU connector, I dont know that there is much mystery left here. Perhaps I have misread your posts, but this is my understanding:

  1. You consistently see continuity between pin 13 of the ECU connector and one side of the CTS connector.
  2. You don't see continuity to ground at either pin of the CTS connector
  3. When the ring terminal at the valve cover is screwed down, you see continuity between pin 5 at the ECU and ground.
  4. When the ground terminal at the valve cover is floating in the air, you do not see continuity between ground and pin 5 at the ECU.
Have I understood this correctly? If so, it would seem that the wire from the ring terminal to the CTS has at least one more break in it (in addition the the one you found at the CTS connector), and that the wire from pin 5 at the ECU connector to the ring terminal is just fine. The ring terminal is used to pick up ground for the CTS and part of the ECU, it is not used to ground the valve cover.
Click to expand...
Yes, that all sounds right.
But since I cobbled the CTS wiring, I can jump that pin straight to ground, bypassing the infamous wire #49 and it makes no difference as to how the car runs or how the ECU "sees" the CTS (ie, ECU pin 13 to ground is still infinite ....I did get 1750 once which is really weird)

As to the LED injector tester....sounds interesting and I'll probably do it (are these the same resistors I bought to use on the CTS earlier?) but it might be better to spend that time taking the fuel rail apart?
Heck, I'll probably do both.
It's not so bad because I don't need to drive this car and I like working on stuff, but not making any headway is getting a bit old. I spent most of my time today working on the Midget and fixed everything I went after and drove it all over.....got my fix in that way! Still looking forward to getting this X going though....very anxious. I think, if I survive the "rejuvenation" of this car, that I will LOVE it.
 
Debating whether to tear into the wiring searching for the problem with wire #49 or look for a problem elsewhere and just jump wire #49 to ground and leave the harness alone.
I guess I'll tear into it. I really should find the issue and fix it, even if it isn't "the issue".
I'm guessing by the overly simplified wiring diagram that #49 runs from the CTS up to ground (even though it "looks" like it heads toward the firewall first) at the cam cover ring terminal. I will start dissecting from the ring terminal back toward the CTS. Why I don't know as a jumper here should solve it, but....whatever.
 
Got harness off all engine connections: injectors (PITA) and such, unthreaded from engine, started slowly dissecting, slow going, layer upon layer of coverings, old hardened and not willing to come apart.
I will continue until I find the secret of wire #49. :jedi:
 
harness dissected
wire #49, as suspected, heads toward firewall for a bit, does a u-turn and heads straight for the ring terminal at the cam cover. Even with the wire pulled out it has no continuity from one end to the other. I don't think I did much damage to the old harness casing either, I can fold it back together and wrap it, I think. I found a dremel cut off wheel and a very light touch to split the harness casing nicely. EXTREME care was taken.
This was probably a waste of time, but at least I can replace this wire easy enough and set THAT to rights. Makes me wonder what other wire may have gone bad in the middle making the car not go vroom vroom.

49uturn.jpg


FIharness.jpg
 
At least you found it...

And knowing what the problem is is always better than "just" fixing it.

Many times the crimped connections on the wires themselves fail somehow even when they look fine.
 
So, for fun. And it is fun, isn't it? I put my ohm meter on the homemade leads from the CTS and got infinity. ?? Pulled the sensor back out (because I know the guy who soldered those leads on the pin and he's not much of a mechanic, let alone much of an electrician....me).
So I could put the tester probes right on the pins.....infinity. Now I was getting 1750 which is something closer to correct but not spot on (book says between 2000 and 3000 at room temp I believe).
So perhaps despite earlier tests saying it was "good', the CTS is crapped out.
Any one got a used one they are willing to part with? I'd rather not buy a $65 part that I'm not sure I need, rather buy a $20 or whatever.
Whatdya all think? Would a freaked out CTS cause all this? Again, even if it isn't THE problem, it too is begg'n for something.
I'm now after a CTS.

Vicks has for $22, that's not bad at all.
http://www.vickauto.com/cgi-bin/store/33-2601.html?id=xShZBNSq
 
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Sticking pins in wire 49 and and checking continuity, moving back until I found this, right in the middle and not at the u-turn I don't think.
It seems junk all the way to the CTS end. But I didn't keep tearing at the insulation.
wire49.jpg
 
I retested the sensor. As soon as it touched warm water it jumped down from infinity to 1800 or so and rapidly began falling as the temp of the water increased. As it should. I question the infinity reading while cold though. Could be my cheapo meter. Could be bad sensor. Book says it should be 2000-3000 at 68ish degree, in cold weather it would go even higher. I will get a new sensor. Even though, once again, I doubt this is my main problem. Once I get all this stuff cleaned up and put back together I'm going to ensure I'm getting spark after the crank cycle. I guess I do that with a timing light, what's the proper way? I want to be sure the ignition side is making spark in RUN, not just START.
 
Once I get all this stuff cleaned up and put back together I'm going to ensure I'm getting spark after the crank cycle. I guess I do that with a timing light, what's the proper way? I want to be sure the ignition side is making spark in RUN, not just START.
Click to expand...
What I do is I clip the inductive pickup for the timing light onto the high voltage wire that goes from the center of the coil over to the distributor. That gives you two flashes pr. engine revolution (rather than one flash for every two revolutions if you clip it to a plug wire). This makes it a bit easier to tell if you have spark in that brief period after you release the key and before the engine stops. Then I bring the timing light with me into the car and squeeze the trigger as I start the car. Pay attention to what happens after you release the key. Does the timing light keep flashing for a bit?
 
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