TheRealLefty

Here are the aftermarket chips that were replaced with OE by the previous owner, who was suffering from very rich mixture and unburned fuel...which, in retrospect was likely being caused by the removal of the boost controller by a prior owner.

TheRealLefty

I think my first needed action has come clear. I should not be running a two stage waste gate without boost control. If this is my situation, the simplest, conservative fix is at hand.

I need to confirm that the current waste gate is a two stage with top port connected to the IC tube by the left hose coming off the banjo bolt T-fitting...and that the side port of the WG opens to the atmosphere via the uncapped blue tube that can be seen under the fuel rail...THEN, the most prudent, conservative, cost effective action will be to purchase the Lindsey Boost Controller, set it to something conservative (less than 15 PSI?) and put it in line between the blue hose and the now-plugged side of the IC tube banjo bolt. This should restore the correct function of the aftermarket WG, right?

This would bring intended mechanical boost control to the current WG with the protection of the stock chips still in reserve for overboost cut off protection. I would be spending $70 on a part at Paragon and adding one pressure line connector to get all this done.

I think this is minimal effort/cost path to correct the current risk of overboost and stabilize things. This is probably what Previous Owner 2 or 3 thought he was doing by rigging up the current situation. But this "atmospheric" fix apparently does not respond quickly enough to overboosting spikes linked to vacuum....needing the assistance of the pressurized side port to get the WG open to respond to high boost. Right?

If this removes the major risk of overboost then I have some time to consider whether I should enhance the boost control system or use the OE waste gate and j-tube in my spares box to go back to factory and put the cycling valve back in play.

tconn

Yes that will get the wastegate working correctly.
With the stock chips you must run stock boost. Otherwise the car will be lean
under boost, risking blowing something up.

TheRealLefty

Stock boost will be fine for now And that number is.......?????

tconn

1.8 bar on the stock boost gauge.

Porsche-O-Phile

Translates to about 10-11 psi.

TheRealLefty

Got it. Going to order controller today and install sometime after the current perma-monsoon subsides, perhaps in July

Dal Heger

Ok, I'm confused. How is the car limiting boost when you have taken the CV out of the equation? With a manual/stand alone electronic boost controller the DME/KLR has NO direct control over boost. The only level of protection you now have on your car is timing retardation and fuel cut off. This is one reason that I don't like taking the CV out, it acts as the MAJOR protection and troubleshooting mechanism in the car. It seems like you have some other basic problems with your car that need to be addressed before you start on your quest for more horsepower.

To me it sounds like you have a major problem with detonation, which is most likely how you blew your headgasket. Keep running as you were and your new headgasket will go in the same manner relatively quickly.

Dal.

Evan70

The KLR overboost protection mode is the fuel cut off. It's not limited soley for use with overboost situations (can also kick in due to knock/detonation and various other reasons), but sustained boost over the max spec is one of the reasons it can be invoked.

At this point I'm swapping out to some different chips since I don't like the A/F on the top end of the rpm range (13-13.5:1) and putting in some used Vitesse chips. Hopefully those will work a little better, and combined with all the other work that's been done I hope it solves this issue. If not, I'll get the fault codes and see what they say.

Dal Heger

Right, so my question was, how/why is your boost fluctuating when there is nothing that is controlling your boost via the chips? My guess is that the computer(s) have pulled the ignition timing down to the max allowed and you're not getting the same heat/flow through to the turbo - just a guess. The MAJOR safety valve in these engines is the ability of the DME/KLR to reduce the boost via the CV to control knock. Obviously your car is knocking (otherwise you wouldn't hit the "overboost" protection at 11 psi or 9 psi or whatever you stated). Even the stock chips will handle 11 psi (that's stock boost) without knock - and without invoking the overboost protection circuits.
All I'm saying is that something else is wrong. If you set your manual (electronic - whatever) boost controller at 11-12 psi and still trigger the fuel cut then there is something else wrong. Solve that problem first, then play with chips.

edit: another thing just occurred to me, how is your AFM? If the AFM values are off then you could be confusing the hell out of your DME.

I'd look at the fuel system - pressure and fuel injectors (pull them and get them checked cleaned at Thompson turbo ($25 each - same day turnaround)).

Dal.

Dal Heger

That's simple. It counts. It has a TDC reference on these engines to start a sequence (cyl 1 or 4 are at TDC, it doesn't matter which, the DME doesn't control the routing of the spark, just the timing - the distributor controls the routing). From that it just counts. It fires two times for each full rotation of the crank (every 180 degrees), every 4th time (720 degrees) from where it "hears" the knock it will pull the timing back on that one spark.. So, it really doesn't "know" which cylinder is knocking, it just knows that last time in that firing sequence that one cylinder had a detonation event. Simple sequence of operations.

Dal.

Evan70

My boost isn't fluctuating, it's behaving perfectly normal. The problem is that if I go full throttle from 3000rpm in 4th (or 5th) the KLR kills the fuel pump at 3500rpm. Boost is building normally and the car runs just fine other than that one spot. I guess I should mention, that if the problem is still persisting once I get it back, that I'm already planning on replacing the knock sensor and probably just upgrading to 55lb injectors. From everything I've seen, I'm already getting very close to the limit of the stock injectors, so I'll just put the $100 I'd spend on cleaning the stock ones into some bigger ones.

Also, I did hook the stock CV back up when I first started troubleshooting the problem and it didn't make any difference. That's one reason I'm kind of leaning towards the KLR being bad, but it doesn't make any sense to me why it would only do it at that one point in the rpm range. Of course, another possibility is that maybe there's something rubbing/vibrating somewhere at that rpm that is making the knock sensor think there's detonation.

Dal Heger

I could be wrong, but I'm not leaning to the KLR being bad. There is a blink code for that, easy to test. There is also a blink code for the knock sensor (before you buy a new one). When you hooked the stock CV back up, did it drop to 1.2 bar and then run fine, or still hit the cutoff at 1.2 bar?

Sucks. I hate chasing electrical issues.

Good luck.

Dal.

Oddjob

The overboost fuel cutoff is from the DME measured by excessive airflow through the airflow meter, not a measured intake manifold pressure by the KLR. The KLR has a separate protection which causes the car to run at low boost and retarded timing (a number of things can cause this - bad TPS, knock sensor, KLR unit, etc).

The DME fuel cutoff is an almost violent stumble during a full throttle condition. In the KLR safe mode, the car will only make a little over atmospheric pressure (manual says 1.3 bar abs), but runs normally, just with no/low power. Does your car have both these symptoms or just one or the other?

Evan70

The initial symptom is a complete loss of power, after that the car will run fine but will start stumbling really bad as soon as it gets sligthly over atmospheric pressure (around 1.1-1.3bar on stock gauge). If I then shut the car off and restart it runs just fine until I duplicate the condition that triggers it again.