2G Slow free revs

[Spideydsm99]

Hello everyone I believe I know what's wrong with my 95 eagle talon tsi. But I'd like to get other people's opinion. So Ive had to put a new engine in it and I haven't put an alternator on yet because im still waiting on it to get back from the shop. But I tried starting it with a jump from my truck and it idles okay at around 8-900 but when you free rev it. It's very slow going up and around 2k it start missfiring/poping. The tach goes a little funky also. Now what im thinking is it's because the alternator isn't on yet. Oh and 1-4 plugs are dry but 2-3 are wet. But I was just wanting other people's opinion. Oh no cel on yet either.

 

[Spideydsm99]

And yes it passed a boost leak test.

 

[pauleyman]

2 and 3 aren't firing if they're wet. Start there.

 

[A Sharp]

This is a total shot in the dark, but are you using a late model 2g cam angle sensor with a 95 ecu? If you are, you need to rearrange the spark plug wires and, if applicable, set ecmlink to use a non-95 cas.

 

[Spideydsm99]

I've changed coil packs, ptu, and wires, plugs. It does have a 99 ecu put I've changed the wires around and it ran the same with the 95 ecu with the correct wireing too. Cam sensor and crank sensor is new also.

 

[Spideydsm99]

That's one reason I've thought it could be the fact I don't have a alternator right now and I've read a few threads saying that was there problems.

 

[pauleyman]

If batt is at full charge it should at least idle. Before you chase further why don't you put an alternator on it.

 

[Spideydsm99]

I am going to pick it up today. I just was wanting to see other people's opinion on it. I m also going to test the icm today with the 12v light test. Because I switch 1-4 coil pack to 2-3 with the same results. So I'll keep you updated! I'll know somthing by the end of today.

 

[Spideydsm99]

Okay so I didn't get much done today, but I did test the ptu it's good. I also installed the alternator fixed the tach issue so it's not bouncing all over the place. I swap the ignition coils around and it's not making a difference. So I believe the cam angle sensor wasn't good from the start even though it's brand new. Im gonna test it tomorrow, hopefully it's not raining all day. Haha

 

[Spideydsm99]

@pauleyman do you know how to test the cam angel sensor on a 95? I've looked and either im not looking hard enough or just can't find it.

 

[Spideydsm99]

So I went out just now to double check the crank and cam sensors to make sure they're not falling apart. And I noticed that the sensation plate for the crank is black, like it's been painted. I've never really paid much attention to it. Could that cause a problem for the crank sensor?

 

[A Sharp]

The fact that the trigger plate is painted doesn't matter. The crank sensor is a hall effect sensor, so as long as the plate is still metal, it's fine.

There isn't a good diy approach to test the cas directly. You would need an oscilloscope to verify that it's outputting voltage pulses correctly. A simpler approach would be to verify ignition timing with a timing light.

 

[Spideydsm99]

Would a log work? Because I have open port with evoscan.

 

[A Sharp]

To verify ignition timing? Not by itself. The logged ignition timing is what the ecu thinks it is. You'll want to use a timing light to verify that the ignition timing described by the ecu matches reality.

My honest opinion is that the problem is not being caused by the cas or crank sensor. Usually a bad cas or crank sensor leads to a that car won't start or a car that starts then immediately dies.

Paulyman's suggestion to investigate cylinders 2 and 3 is your best bet, imo. Sounds like those are getting air and fuel, but not enough spark.

 

[Spideydsm99]

Yeah that's why I going through everything that deals with the ignition. Because it's getting plenty of fuel but I've test the ptu, swapped 1-4 spark plugs to 2-3. And swapped the coil pack for 1-4 to 2-3 and of course by doing that moving the coil pack for 2-3 to 1-4. And it lead to the same result. Tested the plug wires also. So literally what else is next? Ha

 

[4g63popo]

My opinion would be turn the engine see if you are getting spark on 2 3 also compression test and make sure the gap is set on the plugs. That is where I would start.

 

[pauleyman]

Somebody posted something similar recently. Put an alternator on it.

 

[Spideydsm99]

I did yesterday @pauleyman

 

[tay97gst]

Have you checked that your TPS is adjusted properly?

 

[pauleyman]

It's old and cluttered but it's this one.
http://www.dsmtuners.com/threads/misfire-caused-by-alternator.375826/
And again....replace the alternator before doing any further diagnosis. I think you're chasing your tail until then. Alternately hook up some jumper cables to another car so you've got solid voltage. If it doesn't free rev then you've at least ruled out voltage UNLESS you didn't do at least basic maintenance. Like clean grounds?

 

[motomattx]

Are you sure that you dont have the cam or crank sensor plugged into the wrong connector? the AC connector will plug into one of those if I remember right.

 

[Spideydsm99]

@pauleyman that's what I saying I went and pick up the new one and installed it yesterday. But I'll check that thread out.

 

[pauleyman]

@pauleyman that's what I saying I went and pick up the new one and installed it yesterday. But I'll check that thread out.

I thought you meant that was your post. Lol. Well check voltage and then let us know progress. I'm leaning towards ignition still

 

[Spideydsm99]

@pauleyman yeah sorry im all over the place at the moment. Haha

So I did some more testing and looking around. I figured I'd look down by the ecu today, just to see if everything is in tack. Well I found pin #26 of the ecu cut and stripped. As if something was ran there like maybe a safe? But I will fix it when I get back home. I just wanted to share my findings.

 

[Spideydsm99]

I forgot to mention the crank and cam sensor is good.