July 2023 – Love the F355

I’ve been battling a ‘chugging’ issue at warm start up now for almost 12 months, without a great deal of success. The last episode was:

It’s still an issue

After all the engine checks, by two mechanics, i still get the issue. Not all the time, but often enough to be really annoying. Problem is, I can’t replicate it on demand. That makes it extremely tough to troubleshoot.

After the engine check failed to resolve the issue completely, the focus turned to perhaps the problems being related to the third party alarm I have. As I understand things, the 2.7 355’s didn’t come with a factory alarm, while the 5.2’s did.

So I got a clever auto electrician/alarm guy to have a look and he is very confident that it is not the alarm. However, he said that it sounds like the evap system to him!

The evap system is designed to capture fuel vapour and store it in a charcoal canister to be burnt off later. As you can see from the above diagram, the system has 2 x solenoids, 2 x valves, hoses and the charcoal canister.

Looking at my car I see:

The vapour separator,

and the bottom of the charcoal canister, which all look good visually. The charcoal canister is housed inside a fibreglass housing.

The suggestion is that if the ‘chugs’ re-appear I should stop the car, take the fuel cap off to let the pressure equalise, restart the car and see if the ‘chugs’ are still evident. If so, that kind of confirms that I have an evap issue.

Typically, the ‘chugs’ only happen after I have been for a long drive, fill the car with fuel and then try and restart it. I’ve had the ‘chugs’ return after paying for fuel and also when I put the car away. The only real commonality is the car needs to be warm for the ‘chugs’ to appear.

Armed with this new method of dealing with the ‘chugs’, of course, nothing happened on my drive and refuel today. However, at least I’m now armed with a simple action that may over come the issue. If that in fact does, then looks like I need to focus my attention on the evap system to find the source of the issue.

Until that happens and I can confirm that it is indeed the evap system causing my issue, I’ll continue to reach troubleshooting techniques. Interestingly, I can’t find a lot about this issue on the Internet. It does seem to be something rare, but then my mother always told me I was special!

Many moons ago a cog in the AC timing actuator failed as I detailed here:

Gear of misfortune

I thought it would be easy enough to get a 3D printed version as a replacement. Oh, how wrong I was. I tried some trusted contacts who were in the 3D printing industry. They referred me onto a number of businesses who unable to print a cog for me.

After more than 2 years trying to get a commercial 3D printing business to print a replacement cog for me, I decided that the only way it was going to happen was if I did it myself. Thus, began another long quest to learn about 3D printing.

A few weeks back my 3D printer selection arrived. After assembling it and doing some test prints, I turned my attention to the real reason for my purchase, to print a simple cog!

Attempt 1

As you can see from the above, this attempt didn’t go well. The issue was the fact that due to the small size of the cog the print lifts from the bed.

Attempt 2

Things are looking better now after some adjustments to the printing process. I can at least see that it is starting to look like a cog, but again the print is detaching from the bed. More adjustments.

Attempt 3

YEAH BABY! We have a winner. As you can see the print completed successfully. I needed to some minor clean up on the finished product but I tested it in the Timing Actuator and it seems to work fine.

Oh man, has this been a long (and expensive journey) all to get a replacement for this tiny cog! However, there are a few minor tweaks I need to make to the model so it needs less clean up after printing but I don’t expect that to be too hard. It’ll also be a good way to learn more about the 3D modelling process.

I can now finally say that I have the ability to produce a solution for the 63307100 Timing Actuator gear failing from about two years ago! Even though I do have a number of cogs made by others that work the one I just printed myself now holds pride of place.

During this process, a few readers of this blog contacted me about obtaining a replacement for themselves if I managed to produce them. Well I have and you are welcome to reply to this post, or contact me directly via email and I’ll send you what I have made. Note, that I am still tweaking as we speak and I have not yet actually put the cog into the car so I can’t guarantee that it works on the road, but I’m pretty confident it will. But, if you want to try it and let me know if it indeed does work, contact me a I’ll send you a print.

Hopefully, after a few adjustments I can offer these to people who experience the same issues.

Month: July 2023

Solving the ‘chugs’

Project COG is back in business