1995 Jaguar XJ6 : Air Idle Control and Headlight Trim

Backyard Mechanic


As of today, our 1995 Jaguar XJ6 (X300) has accumulated a total of 135,659 miles. I took the above picture today to figure out if the trip computer’s fuel economy of 11-12 mpg was correct. To do so, I filled up this morning at 135,592 and then filled up again this afternoon after work at 135,659. The 67 mile trip required 3.903 gallons of premium 93 octane gas. The end result was 17.166 mpg which is well within the advertised 15 city/22 highway. I guess the trip computer has developed a problem.

But my concerns were not limited to just the trip computer’s tabulations. My mechanic recently replaced the fuel rail, fuel injector o-rings, and checked the AIC (air idle control valve). The idle speed has been high (approx. 1100-1500 rpm) over the winter and the AIC would stick at times possibly due to moisture freezing inside. Unfortunately, the new AIC could not be installed without a Jaguar technician “re-learning” the unit. So, I have been communicating with a mechanic in Cleveland about doing the job. I have the new AIC in the box and am awaiting a time when the job can be completed.

3The other news is a recent “update” to the front end of the Jaguar. Trenton and I replaced the broken passenger side headlight bracket earlier this week. Then Jefferson and I installed the headlight trim pieces that were missing when we first bought the car. It wasn’t as easy as expected. After installing the headlight bracket, we found that the hood rubbed against the inner most headlight on the passenger side. To compensate, I used my “immense strength” (and a pair of vice grips) to bend the hood up and out of the way.

The end result won’t win us a spot in the Body Shop Hall of Fame but the hood no longer rubs the headlight and the trim pieces are installed. The biggest lesson I have learned is that accidents cause a lot of problems that aren’t easily addressed by this backyard mechanic. If I want things to be done right, I will have to purchase another fender and hood and have a real body man make things look right. Until then, we’ll be happy with our efforts and keep driving the car. After all, it is 20 years old.


P.S. The former owner used black electrical tape to hold the inside of the grill together. Nice. Seems like something I would do.

1984 Jeep DJ-5 : Rear LED Amber Flashers

A previous owner had oversprayed the rear lights (and anything else that got in his way) while painting the Jeep. So it was difficult to know how well other drivers could see my ambers flashing. That is important since I will be delivering the mail to mailboxes along the road. If people can’t see my flashing amber lights, there could be an accident — especially in winter conditions. Thanks to a pair of new LED amber turn signal assemblies, that will not be a problem anymore.

My mechanic, Chuck Widemire of Motorwerks Imports, installed the lights and then had me run the Jeep’s engine today while he tinkered with the carburetor. The Jeep repair manual mentioned a vacuum solenoid which could adjust the idle. After a while, he found that the carburetor was sending too much fuel into the intake which probably means the float needs to be adjusted. With the prospect of having to replace the cam shaft this sounds much more encouraging. Hopefully, this will make the Jeep fit to drive for delivery.

The Jeep’s engine is a 2.5L AMC unit with enough vacuum lines to tie up a prisoner. It reminds me of the time I took a college class on basic car care. The mechanic had two students bring their cars in. One was an AMC and the other a Volvo. The AMC had wires and vacuum lines everywhere in the engine bay while the Volvo’s was clean and empty. This Jeep isn’t a Volvo but with all those lines I’m sure there is a vacuum leak somewhere. A couple weeks ago, I replaced 6-8 of them but there are plenty more to check. The end result is that the Jeep should be drivable for work in the near future.

As a Christian, I pray about things like this. And I thank the Lord for the good results we are having thus far. But I also appreciate a good mechanic who has the knowledge to work on anything from a Jaguar to a Jeep. Thanks, Chuck!

QOTD #53: Why would a Jaguar XJ6 lean to one side?

During my last visit to the Jaguar Forums, I came across this helpful post. The owner of a 1997 Jaguar XJ6 L complained that the right side of his car rode lower than the left. After replacing the front shocks, nothing changed. The right side was still about 1/4″ lower than the left side.

Why would a Jaguar XJ6 lean a little lower on one side?

Several people came up with suggestions, but Don B. offered the most probable solution to the problem.

jaguar xj6 shock diagram“It is not unheard of for springs to sag with age, but the most common cause of sagging ride height is deterioration of the big foam rubber ‘donut’ spring isolator bushes, Part 5 in the diagram below. Since the bushes are more than an inch thick, there is a lot of ride height to be lost as they lose their resilience and compress with age.”

Hunting down a problem is the hardest part of working on cars — especially a Jaguar XJ6 (X300). If it had been my problem, I probably would have bought new springs, shock absorbers, tires, and then sold the car to relieve my frustration before realizing what the real problem was. That’s the beauty of visiting the forum when a problem arises.

QOTD #51: Should I replace a tire with a bulge in the sidewall?

Nobody told me about the bulge in the sidewall of one of the front tires. I was actually taking out the trash and just happened to stumble upon it as I walked past my wife’s minivan. “Wait a minute!” It didn’t look too bad. The rest of the tire had plenty of tread and the wheels drove straight. So, do I really need to replace the tire? Or would it be safe to drive it for the rest of the year?


From everything I have read, it would not be wise to continue driving on that tire.

  • “If you see a bulge or blister on the sidewall, replace the tire at once. These signal potential weak spots that could lead to tire failure.” —Consumer Reports
  • This is similar to an aneurysm in one of your blood vessels and you know that if your doctor tells you that you have an aneurysm, you’d better get to the hospital as quickly as you can before you blow out an artery. It’s the same with your tire. This weak spot can cause a sudden blow out, and if you don’t put the car in the hospital (or service center, as the case may be) before this happens, it may end up putting you in the hospital when the tire blows out on the freeway. —HowStuffWorks
  • “The bad news is that it is in the weakest part of the tire: the sidewall. This can not be repaired. The tire needs to be replaced. And yes, it can be dangerous. It can cause an explosive blowout which can be lethal at highway speeds.” —Yahoo.com
  • “The only reason that I can think of for this bulge is a weak spot in the tire. If that is the case you are about to have a blowout, which could cause you to lose control of your vehicle and wreck. Get thee to a tire store and get to one that is very close to where you are right now.” —Askville

The consensus online is that tire bulges and blisters are caused by either an impact (hitting a pothole or the curb) or a defect in the tire. Most drivers think it is the latter when it is usually the former. Whatever the case, get the tire replaced as quickly as possible. While you can visit a site like TireRack.com, you will have to find a place to install the tires once you purchase them. So, it might be best to consider a local shop. If you live near Cleveland, Ohio, consider using one of the Tire Centers at Leikin Motor Companies:

Volvo of Willoughby Tire Center

Mercedes-Benz of Willoughby Tire Center

2000 Mercedes-Benz S430 : OEM Wheels?

Backyard Mechanic

“A desire accomplished is sweet to the soul.” –Solomon

There has been a problem with our 2000 Mercedes-Benz S430 that has been bothering me for the past several months. Although I installed a new pair of tires, the back end of the car would jump to one side whenever I would hit a bump or pothole. Someone suggested that the rear air shocks might need to be replaced. But they weren’t sure. The other suggestion sounded a lot better to me: It could be the wheels themselves.

A mechanic at Mercedes-Benz of Willoughby noted that the 17″ wheels on the car were clever counterfeits — probably a Chinese imitation of the real deal. Stop for a minute and consider who I am. I have never tried to come across as some pompous buffoon who must have the original product or die trying. Not so. I don’t care where the wheels were manufactured or whether they are genuine OEM wheels. I just want them to work right! But what I found in this situation was that OEM was the better option.

The 2000 Mercedes-Benz S-Class was designed with hub centric wheels. That means exactly what it sounds like. The wheel is centered on the hub as opposed to the lug bolts. With that in mind, you can’t just slap any wheel on the rotor with five lug bolts and drive away. They have to be centered perfectly or you will quickly notice a vibrationspacers in the steering wheel at highway speeds. What happens is that the wheel is actually out of round because it is not centered with the hub. Does that make sense?

I was able to purchase a used set of 16″ Mercedes-Benz wheels with like new tires for a very reasonable price. However, they were from a pre-2000 S-Class meaning that they fit the front but rubbed on the caliper in the rear. You can imagine my disappointment. Thankfully, I was able to find a set of 15mm wheel spacers and longer lug bolts for the rear. That was my project tonight with my oldest son, Jefferson. With the help of a long guide bolt (borrowed from one of our mechanics) and a spacer on each wheel, there is now plenty of room for the brake components.

Last week pictured with 16″ front wheels and 17″ rear wheels

The “new” wheels are a bit worn and don’t look as snazzy as the 17″ aftermarket wheels but they work! The ride is much more comfortable. And the back end of the car no longer jumps to the side when going over bumps. I find it interesting that OEM parts often do make a difference. This job didn’t require brand new OEM wheels but using genuine Mercedes-Benz wheels did solve the problem. I had the car up for sale but now I may decide to keep it after all. We shall see.