Dead cylinder @ 2700 RPM+

[i_nick_2005_i]

Well, I have a 97' Tsi AWD, I can drive it all day around town, but as soon as I hit a speed around 55 mph for a few minutes or so, it will drop to 3 cylinders and stay that way, unless I shut off the car and then restart it, but then in a few more seconds it will go dead again.....I pulled over and let it idle while it was still missing and narrowed it down to cylinder #4. As I pulled the plug wire it had insane (healthy) spark from wire/coil, but made no change in motor, so it's the culprit for sure......So I changed the plug, to no avail......And the wires are new...Once I get in town going around 45 mph or below it's fine, all day.......What could be that sensitive to the greater amount of heat produced by the higher RPM to kill a cylinder? Unlikely an injector, so I'm thinking ECU related...or the harness maybe? I just don't even know where to start......It has EPROM ECU, with a DSMLink that's been reset to defaults.......Any other details are in my profile, Thanx for any help...

Also, I can fully boost and "get on it" fine without a mis-fire, it's only when I drive at a constant higher RPM, such as highway; it'll run fine on short full rpm pulls all day....And when I pulled the plug from that cylinder, t was not fouled, which leads me to believe it's not a spark issue....but a fuel cut on the one cylinder.....

Edit: My cam angle sensor is not reversed and it is a 6-bolt swap, could this be the problem?

Nick

 

[chaggard27]

This won't solve the problem but it can narrow it down a bit. I would switch the num 1 and num 4 plug wires on coil and see if the num 1 cyl starts to die at highways speeds. If so then it could be wiring to coil or plug wire itself. If it is still cyl 4 that dies then I would look more along the fuel side. Check injector. I hear they can be temp sensitive. Hope this helps you.

 

[rush2252]

If you were seeing healthy spark did you consider the injector on the mating cylinder?

 

[i_nick_2005_i]

Well, I did the swap with 1 and 4 (which was pretty genius, nice trick) and it is definately a fuel issue, what would be the best course of action....check the voltage on the injector harness, would it just drop to 0 volts if the computer was at fault or wiring was bad? Thanx for the help.

 

[phillabaum03]

I've seen this similar problem when doing a 6bolt swap into a 2g. You need to go into your dsmlink and in setting i believe switch it to inverted cam sensor..

 

[chaggard27]

Ok well now u know that it is a fuel issue. Now follow that same kind of thinking as with the plug wires. Switch two of the injectors and see if it affect the same cylinder or if it follows the injector. Chances are it is the injector that is the culprit. I had two of mine go out at the same time one day. The car ran great until it warmed up or i got it up into higher speeds...then it was no faster than a moped Anyways good luck and try switching the injectors

 

[ilco187]

i would say one of the injectors could be sticking closed at sometimes, one of my 550's did that and died out after 1500 rpm but i tapped it with a ratchet and problem solved.

 

[da1sexmonk83]

Mine will do this cruising down the road sometimes. 55 or 65. It will have a dead cylinder I will take it out of gear, put it in 4th then shift back into 5th and its perfect again for 20 - 30 minutes.

 

[twicks69]

Check your cam angle sensor for oil or contamination in the inspection plate (take off the three 10mm bolts from the cover and check the 14mm bolt holding the "wheel" to the camshaft for tightness and proper alignment -- it is keyed, and should be checked with the engine turned to the #1 at Top Dead Center). As well, this is common and has been discussed before in the problem diagnosing forum in the Newbie section at the top of the page. It can also be a result of a dying Crank Angle Sensor OR a toasted crank harmonic damper pulley. Check the crank pulley for a missing counterweight, counterweight seperation, or delamination of the crank pulley outer section resulting in the outer section rotating on the delaminated section of the inner pulley.

Get a timing light and check the timing to make sure it is properly lining up.

These are the main things to look at for this problem.

 

[da1sexmonk83]

You have a link for this other page? I couldn't find it

 

[twicks69]

http://www.dsmtuners.com/forums/problem-diagnosis/242628-problem-while-freeway-crusing.html