Kroon Harness for 944 Turbo

[NCGermerican]

Thanks for the feedback. I've seen 968 owners use them on RL and always wondered if they did any damage. Do you recall which model QuickJack you have? And do you need to use any support blocks in the front or rear to get everything level?

I’ll do a specific video on my YouTube channel for this to show it.

Did you ever get a chance to capture a video of your QuickJack set-up?

Not yet, but once I get the car back together (should be this weekend) I'm going to do a separate video on using quickjacks on a 944. It will hopefully explain it a lot better than just pictures.

[Gaspowered]

Regarding your AFM pvc sleeve dilemma...

I sometimes go to BAT and look at engine bay pics of very low mileage cars to get an idea of how some of the original wiring and vacuum line routes may have been done.

This is from a 3,100mile '89 Turbo.

A8704C9C-CEE4-4691-99F9-79B0EB648926-scaled.jpeg (389.4 KiB) Viewed 947 times

Cheers

[NCGermerican]

Regarding your AFM pvc sleeve dilemma...

I sometimes go to BAT and look at engine bay pics of very low mileage cars to get an idea of how some of the original wiring and vacuum line routes may have been originally done.

This is from a 3,100mile '89 Turbo.

A8704C9C-CEE4-4691-99F9-79B0EB648926-scaled.jpeg

Cheers

Well my goodness. I can't believe I didn't think of that! For some reason, I just didn't think there was enough room between the top of the AFM and the airbox snorkel. I wonder if the factory put a plastic grommet somewhere on the AFM to hold the harness in place. I GREATLY appreciate you posting this!!!

[Gaspowered]

I reference the low mileage car pictures for quite a few things i.e., to see if I might have undercarriage clips missing, bolts, interior screw caps, etc.
Glad it helped.

Cheers

[NCGermerican]

Well, I was able to get everything installed and got the car fired. All went great until it went lean at idle. I'm back at square 1 before I started all this work. As a reference, I replaced the short block in August. Everything ran great for about 2 months. Then, I started noticing a faint miss while just cruising at 45mph. Started happening more. Then at one point the car just wouldn't go unless I floored it. Saw that it was lean, but could smell a "sooty" smell from the tailpipe. I'm at a loss. I'm sure we've all experienced these issues with old cars.....

I made sure to call out Carpokes!

[Tom]

Nicely done video! Love the Carpokes shout-outs! Thank you! And those gauges!

Sure seems like you have a vacuum leak. Did this start after doing any particular work, or just out of the blue one day?

A smoke test may be your next best move. That said, I see in one of the clips that you had the top of the AOS removed. How did you reseal it? Is it possible the j-boot is sucking unmetered air in through a leaking AOS top? It's a little shade-tree for such a nice engine bay, but spraying starter fluid around suspected leak points and listening for rpm changes is a time-honored technique, and one you can do in your pajamas at midnight without all the set-up of a smoke test.

Your balance shaft belt is a tad on the tight side.

If I saw it right, that flat black connector under the dash holds the signals for the tach, boost gauge, and oil level sender. Earlier cars with no oil level sender had a red 4-wire square connector.

Unrelated, but are your chips mapped for the 3 Bar FPR?

[NCGermerican]

Nicely done video! Love the Carpokes shout-outs! Thank you! And those gauges!

Sure seems like you have a vacuum leak. Did this start after doing any particular work, or just out of the blue one day?

The low vacuum has been there for years. I just thought it was normal, but in one of my interactions with John Vitesse, he noticed that it was low but didn't really dwell on it. I thought maybe the gauge just wasn't accurate, but I just did an external vacuum test on it (using the FPR vacuum line) and it verified that my Autometer guage is reading correctly.

It is important to note that I replaced the short block on this car in August, and the reading is the same, so if there is some sort of vacuum leak, it's hidden somewhere and I just CANNOT seem to find it. That being said, what a vacuum leak wouldn't explain is why my idle is rock solid at 880-900. Typically, a vacuum leak would result in a much higher idle, wouldn't it?

A smoke test may be your next best move. That said, I see in one of the clips that you had the top of the AOS removed. How did you reseal it? Is it possible the j-boot is sucking unmetered air in through a leaking AOS top? It's a little shade-tree for such a nice engine bay, but spraying starter fluid around suspected leak points and listening for rpm changes is a time-honored technique, and one you can do in your pajamas at midnight without all the set-up of a smoke test.

I just finished filming my next video when I did a smoke test. I also did one before I started this latest project. I'm getting NOTHING. I just don't understand it.... From my research, and from what ChatGPT is saying, for the vacuum to be that low the vacuum leak would have to be pretty massive and therefore, should smoke like a chimney. But, I get no smoke coming out. I may need to try and put smoke somewhere other than the j-boot (I used the evap line).

For the AOS - I tried to reseal it, but it broke, so I shelled out almost $700 for a brand new one. I had noticed, even after the new motor, that there was oil residue on the top of the AOS. The whole start to my "mini-restoration" job was to originally try to remove that cap with the AOS still in the car. That's when I noticed that with an aftermarket downpipe (mine is fabspeed) you can remove the AOS heatshield and the AOS itself WITHOUT removing the turbo! So i removed the original AOS and tried to remove the cap after applying a little heat and it pretty much immediately broke. I figured, well, since I'm spending a boatload on a new AOS, I might as well spend more and get a new wiring harness! Can't take it with you, right?

Your balance shaft belt is a tad on the tight side.

I have tried loosening that belt so many times with no luck, that I even replaced the belt (which was still like new) with the other brand that is supposed to be quieter (I forget the brand). Still whines like a Banshee.

If I saw it right, that flat black connector under the dash holds the signals for the tach, boost gauge, and oil level sender. Earlier cars with no oil level sender had a red 4-wire square connector.

That's probably correct. When I helped a friend install his Kroon harness last year (his turbo was an 86), we had to swap over the red, 4-wire connector

Unrelated, but are your chips mapped for the 3 Bar FPR?

Yes - it's the Lindsey Racing "Maxx" chip, from when I bought their "300hp kit" a few years ago.

Is it possible that something INTERNAL to the system would be causing this much of a leak? Perhaps a bad brake booster (170K mile original) or diverter valve (aftermarket piston-style)?

I took some temperature readings on my header runners. Only cylinders 2 and 3 were over 400 degrees. Cylinder 4 would fluctuate between 300-400, cylinder 1 was consistently 280. So, that makes me think there's an ignition issue at least on cylinder 1. But - then it's a chicken or the egg conversation. Could it be low vacuum and lean condition causing misfires or misfires causing low vacuum and a lean condition?

I need to step away from this car for a bit. My son's A5 needs a rear main seal so I have to focus on that for awhile.

[Tom]

Nicely done video! Love the Carpokes shout-outs! Thank you! And those gauges!

Sure seems like you have a vacuum leak. Did this start after doing any particular work, or just out of the blue one day?

The low vacuum has been there for years. I just thought it was normal, but in one of my interactions with John Vitesse, he noticed that it was low but didn't really dwell on it. I thought maybe the gauge just wasn't accurate, but I just did an external vacuum test on it (using the FPR vacuum line) and it verified that my Autometer guage is reading correctly.

It is important to note that I replaced the short block on this car in August, and the reading is the same, so if there is some sort of vacuum leak, it's hidden somewhere and I just CANNOT seem to find it. That being said, what a vacuum leak wouldn't explain is why my idle is rock solid at 880-900. Typically, a vacuum leak would result in a much higher idle, wouldn't it?

A smoke test may be your next best move. That said, I see in one of the clips that you had the top of the AOS removed. How did you reseal it? Is it possible the j-boot is sucking unmetered air in through a leaking AOS top? It's a little shade-tree for such a nice engine bay, but spraying starter fluid around suspected leak points and listening for rpm changes is a time-honored technique, and one you can do in your pajamas at midnight without all the set-up of a smoke test.

I just finished filming my next video when I did a smoke test. I also did one before I started this latest project. I'm getting NOTHING. I just don't understand it.... From my research, and from what ChatGPT is saying, for the vacuum to be that low the vacuum leak would have to be pretty massive and therefore, should smoke like a chimney. But, I get no smoke coming out. I may need to try and put smoke somewhere other than the j-boot (I used the evap line).

For the AOS - I tried to reseal it, but it broke, so I shelled out almost $700 for a brand new one. I had noticed, even after the new motor, that there was oil residue on the top of the AOS. The whole start to my "mini-restoration" job was to originally try to remove that cap with the AOS still in the car. That's when I noticed that with an aftermarket downpipe (mine is fabspeed) you can remove the AOS heatshield and the AOS itself WITHOUT removing the turbo! So i removed the original AOS and tried to remove the cap after applying a little heat and it pretty much immediately broke. I figured, well, since I'm spending a boatload on a new AOS, I might as well spend more and get a new wiring harness! Can't take it with you, right?

Your balance shaft belt is a tad on the tight side.

I have tried loosening that belt so many times with no luck, that I even replaced the belt (which was still like new) with the other brand that is supposed to be quieter (I forget the brand). Still whines like a Banshee.

If I saw it right, that flat black connector under the dash holds the signals for the tach, boost gauge, and oil level sender. Earlier cars with no oil level sender had a red 4-wire square connector.

That's probably correct. When I helped a friend install his Kroon harness last year (his turbo was an 86), we had to swap over the red, 4-wire connector

Unrelated, but are your chips mapped for the 3 Bar FPR?

Yes - it's the Lindsey Racing "Maxx" chip, from when I bought their "300hp kit" a few years ago.

Is it possible that something INTERNAL to the system would be causing this much of a leak? Perhaps a bad brake booster (170K mile original) or diverter valve (aftermarket piston-style)?

I took some temperature readings on my header runners. Only cylinders 2 and 3 were over 400 degrees. Cylinder 4 would fluctuate between 300-400, cylinder 1 was consistently 280. So, that makes me think there's an ignition issue at least on cylinder 1. But - then it's a chicken or the egg conversation. Could it be low vacuum and lean condition causing misfires or misfires causing low vacuum and a lean condition?

I need to step away from this car for a bit. My son's A5 needs a rear main seal so I have to focus on that for awhile.

ChatGPT is amazing but it's not always right on technical things like this. I do suspect you have a vacuum leak based on all the clues, but it doesn't need to be 'that' big to get what you are seeing. The fact that the idle isn't too high means the leak is controllable with the ISV, which means it's not huge huge (or not a vacuum leak issue). Have you checked your timing marks? What is the injector duty cycle at idle? Having been an arm-chair internet mechanic for decades, this feels like one of those situations where you eventually have a D'oh moment and discover something basic... The more I convince myself I have a one-in-a-million problem, the more likely it turns out to be some overlooked basic thing...

You can rule out the bypass valve, booster, ISV, AOS, etc. by capping them off... I'd probably try that. You wouldn't be the first to be fooled by a smokeless smoke test.

[NCGermerican]

ChatGPT is amazing but it's not always right on technical things like this.

I'm definitely seeing this. It's also plagued with some confirmation bias to make you feel better about things.

I do suspect you have a vacuum leak based on all the clues, but it doesn't need to be 'that' big to get what you are seeing. The fact that the idle isn't too high means the leak is controllable with the ISV, which means it's not huge huge (or not a vacuum leak issue).

I agree and I think the low vacuum is the tell tale sign. I've been doing more research on how "old school" mechanics could diagnose issues purely with a vacuum gauge. With a reading of only 10 in HG, it points to vacuum leak OR timing being off.

Have you checked your timing marks?

I re-checked my timing (video releasing today at noon EST) and it's spot on. That being said, IS IT POSSIBLE that the TDC mark on the cam sprocket, or I guess even the flywheel is off? You'll see in the video that it looks close to dead on, but could it be that it's still a tooth off?

What is the injector duty cycle at idle?

I honestly don't know how I would even check that. Would be awesome if the ODB software on the F9 would show that. I used my stethoscope and confirmed all 4 injectors are firing.

Having been an arm-chair internet mechanic for decades, this feels like one of those situations where you eventually have a D'oh moment and discover something basic... The more I convince myself I have a one-in-a-million problem, the more likely it turns out to be some overlooked basic thing...

I truly hope so. At this point, just about the only major component in the engine bay that is still original is the brake booster, EVAP Control Valve

....and I guess the Cruise Control solenoid......

You can rule out the bypass valve, booster, ISV, AOS, etc. by capping them off... I'd probably try that. You wouldn't be the first to be fooled by a smokeless smoke test.

That's my next course of action when I get the car back into the garage (after the A5 RMS replacement).

Here's the kicker - this car has had low vacuum for years, but it only seems to be causing an issue recently. Even after replacing the short block, the issue persists. When replacing the engine, vacuum lines, etc are repeatedly disconnected/connected, etc. This leads me to believe it would have to be something that is NOT touched during an engine replacement. The ONLY components I can think of, that would possibly have an effect on the vacuum system is the Brake Booster and the EVAP Control Valve. I know the climate control system works off of vacuum, but that should be gaurded by the check valve (black/blue valve), and as long as that's working, the CC system shouldn't affect engine vacuum at all, right?

If my line of thinking is somewhat correct, the issue would have to be one or some of the following:

1) Vacuum system component that has remained untouched before or after the engine replacement
2) I forgot to tighten a clamp somewhere, each and every time I have worked on the car
3) Timing actually being off, despite what the timing marks being correct
4) Something in the valvetrain being off or not working?
-Head was rebuilt about 2 years ago, but I'm still using original lifters (170K miles and 40 years old)
5) I'm not destined to have this car running correctly

[chrischrischris]

I enjoyed watching your youtube video. Sorry you are struggling with this lean mixture issue after going through so much work to refurbish the engine. I saw your teaser about the Storch MAF - very interested in seeing your comments on that once it is installed.