30 Nov 2023 (con't)
Engine bay was cleaned up (really wasn't bad - only went 600 miles since last cleaning!


And reinstall the engine:



Suffice it to say that it is all back together and running. So what happened? Well, that is often a process of elimination. The tune was the same as what had been running, so probably not that. Next will be a look at fuel delivery. Fuel pressure is monitored, and it was ok, so on to the fuel injectors. The logical thing to do here is to have the fuel injectors flow tested, and cleaned, if necessary. These are very low mileage (<10k miles) Bosch 630cc/min injectors. However, failures happen, dirt happens. A few phone calls around revealed that testing and cleaning could be done for $38 PER INJECTOR! $38 x 8 injectors = $304! Time to consult the AliExpress app! For a grand total of $354, I had an Autel fuel injector test and cleaning machine and 1 gallon of cleaning fluid at my door step! Left over from a previous injector flow project were a few gallons of n-Heptane, which is the fluid that the OEMs use to flow test injectors. All set then, so flow test the injectors.

Perfect machine? Well, no. Adequate? More than enough. The injectors were all very even, and if they were not, there is an ultrasonic bath on the backside of the machine to help clean them out. For roughly $50 more than a one time flow test and cleaning (which wasn't even needed in this case), the machine now lives in our shop. Every time injectors come off of something, they will run through this machine, now!

So, it wasn't the injectors, what could it have been. The answer is that it was not a single thing. The first known issue was the intercooler circuit. Remember back in an earlier post it was mentioned that there were issues with the Killer Chiller (KC) ? The issue was that the KCwas over-taxing the entire A/C system. In the summer heat, neither the intercooler water, nor the HVAC were getting cold, and a ton of heat was being dumped into the radiator (via the condenser). The root cause was the TX Valve (TXV). This had to be replaced once, but Kincaid Performance (makers of the KC) made an odd choice. Normally in a refrigeration circuit, the TXV sensing portion is tied to the suction side of the A/C core. This is the large hose that gets frosty cold in an HVAC system. The idea is that this get cold, and the TXV starts closing a bit to moderate the refrigerant flow. Kincaid elected to wrap the sensing bulb around the water outlet. In essence, they were looking for ice cold water to exit the core, and until that happened, the TXV would be wide open. This resulted in a huge pressure drop, and no hope for the regular HVAC to get enough flow to work, which is exactly what happened. Unfortunately, the KC core was tucked away on this car, and difficult to access, so in the short run, I cheated. The fuse for the water pumps was pulled to stop the water flow, and allow the HVAC a chance to work. This results in no flow through the intercooler, and instantly hot IATs. Yes, the SC will eventually disengage, and the knock sensor will reduce timing if it knocks. However, this is not a "feed forward" system, and it only reacts to problems. In other words, the ME2.8(.1) only reacts AFTER the engine knocks, not before. This is why I refuse to put low octane fuel, even in the N/A CFs. In this case the engine was likely knocking, and then the knock sensor would reduce timing. As I left the car in this state for a long time, plenty of knocks occurred. 100% self-induced problem that should have been addressed. During the rebuild, the TXV was moved to the suction hose of the KC core. Now there is cold water and the HVAC works. Amazing! Don't be like me, and leave a problem like this. Also, NEVER BUY A KILLER CHILLER! Go to Forced Induction or ChemCool.

Remember when I said it was not a single thing? When the tools came out to check the cam timing on the 'new' engine, it seemed like a good idea to just check the old engine. First, set the crank to 40° ATDC:


Put the cam tool into bank 1 (passenger side). Not too bad, maybe some chain stretch?


Now to Bank 2 (driver side):

Uh, Houston, we have a problem. Your eyes do not deceive you. The tool most definitely is not sitting flat. That cam is advanced 1 tooth! Yes, this is the bank that contains the failed piston.

So there you have it. Cam timing off, high IATs, boom! So now what? Well, we do have good cam timing and good IATs. Testing of the electronics has just resumed on the 7G, with a couple more good usability breakthroughs. Weather has been less than ideal for this area, so only a little driving has occurred so far, but things are moving forward in a very measured way. The new engine is a LOT more rev happy than the old one ever was (go figure!), but no power pulls have been made. Right now, driveability is the main focus, getting the 7G MCT to behave on this engine with this computer system is not a plug and play deal. It is taking a lot of programming work. The good news is that regular 7G is far less complicated, and also that when the code is cracked on this setup, it will be easily reproducible in other cars, and it will also open the door to other exciting things. Right now, we are back on track from where we were in September, but just in a much more healthy way.

My parting thoughts are these: The cam timing was an issue, no doubt. Odds are that this issue existed from before I put the engine in this car the first time. I never touched the timing, and I had no issues with it (other than a tuner telling me something was off, which he was right). However, I 100% KNEW that the coolant was NOT flowing through that intercooler. I 100% KNEW it was a problem waiting to happen. I was 100% bitten by my OWN negligence. The worst part? It took 30 minutes to correct that problem with the KC. Swapping the engine took well in excess of 80 hours (admittedly being OCD on details).

In the end, it turned out OK, but only because I had a spare M113K that I intended to tear down to build up. That was *the* happy accident in this whole thing. Now the 'old' engine will serve in the rebuild capacity, and effectively I am just out the time and a set of engine swap materials (fluids, seals, gaskets, etc). Had I not been prepared with a spare engine, this could have been much, much worse. Don't let things that you should take care of pile up and then become an expensive bill, not to mention major headaches!

Onwards, charge!