Interesting. I did a leakdown tests with mixed results last time I had my engine out. Will this help determine if there is a compression issue as well since not all the exhaust is flowing through that exhaust port or would that be too nominal?

Leakdown test are better than compression tests, way more information.

Update: Replaced my torsion bars and rear shocks years ago, but didnt' get around to the front ones, finally threw in some Koni sports the other dayyy:

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Super easy/quick to change, pleasant surprise! Hope this vid helps someone, honestly you could probably get this done over a lunch break.

Tom, I promise I could get a minimum 10% if not 20% more power out of your engine .

I think it would be to your benefit to make step by step documentation for all of the engine systems . Based on your video , the sound and acceleration, the power is way off.

Ian

Tom, good video. Thumbs up on the Koni sport shocks. I think those are the best option for the fronts and rears of the cars up through 1989, short of spending the big bucks for a two-stage valved setup like the KW's. You should start out with the Konis at the softest setting for street use.

Also mention the option of using a big pipe wrench to remove and install the gland nut. I think it works better than the hammer method. I've seen shocks damaged by the chisel or drift slipping and nicking the chromed shaft. Or maybe wrap some tape around the shaft to prevent that damage. :)

Yeah, I would have used a pipe wrench but I didn't have one with jaws big enough, it was just a hair too small. Oh well. I'll bring my IR gun next time I drive it.

I bought one large enough at HF for less than $20--the iron one, as the aluminum ones weight less but cost more. It's also good for crushing rocks.

I watched the video above. The good news is that as good as you think it is, there is so much more power to be gained.

It sounds like it’s missing on at least one and possibly more cylinders. It could be fuel or spark, or both.

You shouldn’t have to rev the engine and spin the clutch to get it going, that might be an indicator that you’re down on power. The sound of your motor during acceleration is another indication.

I have the light clutch and can let it out at a 900 rpm cold idle without stalling.

Check your plugs and exhaust manifold temperatures.

@Tom - I checked the temps today. Starting new thread below for my car, so I don't hijack ADDvanced's thread.

http://forums.pelicanparts.com/porsche-911-technical-forum/1141052-83-sc-check-operating-temps-each-cylinder.html#post12014742

Welp, I did the same thing with an IR gun, and I'm on 5 cylinders, you guys were right. The rear most passenger cylinder exhaust primary isn't getting hot like the others. God dammit. So where do I start on this? Car drives pretty great, I had no idea, lol.

@ADDvanced - well, at least you were able to verify. That's a start!

What were the temperatures for the firing/hot cylinders, and the non-firing? Where did you point the red dot to take measurements? What is the "exhaust primary" that you mention? Same location as the foto I posted?

I was able to measure 4/5/6 at the intakes of the heat exchangers (passenger side); for the driver side 1/2/3 I could not reach so instead measured the bottom of the HE's. For both sides, the cylinder closest to firewall (1 & 6) were much hotter the rest.


http://forums.pelicanparts.com/uploa...1685859809.jpg

@ ADDvanced - I'd start with leak down. Could be something as simple as a tight valve. Spark can be easily checked. Also, I think I read where you had replaced all of the injectors. You could still have one that is misbehaving. Pull them, point them into a can, jumper the fuel pump, and raise the CIS metering plate while checking out the injector flow. Vacuum leak would usually affect all cylinders with CIS, since its a common plenum design. However, a more localized leak, like intake runner to intake port gasket or injector seating/o-ring, would likely affect the associated cylinder only.

tom, I did a leakdown when the engine was out of the car, here:

https://youtu.be/PUn1QOK5vDg?t=255

cold engine leakdown was 15-20% across all cylinders. Injectors are brand new, like you said. I'll pull it and put it in a jar and see if it squirts tho. Maybe double check the spark plug wire is seated.... I'll report back when I get some time to mess with it.

Is that typical for an older engine? Regardless, hoping for the best for your car dude. Really enjoy your videos. They've assisted me a couple of times.

Yeah, consistency is the biggest thing. If it was brand new, factory fresh, you want 5-10%. 10-20 isn't great but it's not bad. 30% is when you really need to start redoing everything. Some may disagree but they have larger pocketbooks than me. Thanks for the comments on the vids, the 911 vids don't really do well so it's not worth my time from a financial standpoint, but I enjoy sharing what I learn.

Speaking of which; I learned a lot today. Video incoming tomorrow morning. lol.

You can try testing whether there is an air leak at the intake of the cold cylinder. Check if the nuts on that manifold are tight.

Incredibly easy to test whether your dead hole is getting fuel. Pull the injector (with fuel line attached) from the bad cylinder, put it in a jar, put key in on position, lift up on sensor plate. You should hear all the injectors sing, and you should see the one in the jar spraying.

Back when I had a CIS 911, I had a dead cylinder and it was the fuel distributor. I would check fuel and ignition before doing a leakdown. Almost certainly a fuel/spark problem, or a vacuum leak (check runner boots, runner/cylinder mating area, etc by spraying carb clean and listening for it to pick up a cyl). Leakdown doesn't test for any of this.

And please, stop driving the car. If you have no spark, that cylinder is getting washed down with fuel. Keep it up and you will be doing another engine rebuild.

Well, I don't know what to say, other than thank you to iCarp, Tom and others who suggested I wasn't firing on all cylinders, you were totally right, and I made a video about it. Idk how but my spark plug wire was pushed all teh way in but not contacting the plug of Cyl #4, and BAM. Problem solved. I am blown away by how smooth the car is now, and how much faster it is. Thank you guys so much!!!!!

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That sound @ 0:10 mark !!!!!!!
 

Well done ADDvanced!!! Congrats on the diagnosis and fix. That engine is sounding really smooth!

That's awesome news!!! And the giggles! Hahahaha.... I can relate!

@ADDvanced/Rob - just a quick follow up. In your video you mention measuring the temp @ "primaries", is that same as the locations I illustrated back on post #310, the red dots?

Thanks!