Anybody who has taken money out of their pocket and bought steel on wheels, even in the form of a rusty/ragged old pickup, has, at the point of purchase, been fairly excited at the prospect of driving it for the first time as the owner. That feeling is multiplied when we’re driving a newer vehicle, and while all these rusty old hulks enjoyed that human attention at some point in their lives, we all know vehicles die – every one of them – sooner or later for one reason or another.
That being said, we all have known of (or owned) vehicles that seem to survive for many decades, having been mollycoddled and maintained by gentle, loving owners until they become something of an oddity, like an aged person who is still living and functioning well for years after all of his or her children have died of old age. This “cars that don’t die” syndrome is more prevalent in California, due to that state’s stringent emissions regulations. Now for a few short stories and then a long one.
When It Doesn’t Quite Die
Short story No. 1: We typically don’t do body work here except to adjust hoods, doors and tailgates, but this 2008 Mazda 6 had some cosmetic bumper damage. The short concrete post she had encountered managed to pop past that soft bumper shell so as to shatter the plastic radiator support and in the process make a nice French curve arc out of the bottom of both the radiator and the A/C condenser. Neither of those were leaking, which, in and of itself, was remarkable. The radiator support on this one was pricey but replaceable, and my student Bobby managed to get both of those heat exchangers and their housing replaced at a cost of about $750. That one didn’t die, but the Mazda had suffered a black eye of sorts that we managed to straighten out.
Short story No. 2: We tackled an EGR code on a 2009 TDI Jetta (P047A – EGR Sensor 2), which turned out to be an EGR sensor that had flatlined. Don’t get thrown by this, by the way, because there are two of those sensors. Sensor 1 is at the passenger side shock tower and No. 2 is hidden in a flexible heat shield near the oil filler cap. Measuring sensor output voltage at both sensors just to be sure, we replaced the one that wasn’t delivering.
Short story No. 3: A 2010 Altima came to us that had suddenly lost its air conditioning, and the owner said a tire store guy checked the fuses, shined a flashlight around under the hood and cartoonishly told her he didn’t know what was wrong with the car but that the repair would probably cost about $950. We found power going to the clutch coil, but no activation. Further investigation showed a burned out coil, so we replaced the compressor with a new OEM unit from Ranshu. A few days later another lady with the same vintage vehicle called me from a different town with exactly the same story. She added that the tire shop in that town wanted six hours labor to replace the compressor. ALLDATA’s labor guide shows less than an hour to swap that one, and it’s not that hard. Go figure.
When A Chevy CSFI Dies This is the saga of my dad’s 1996 Chevy pickup. In the spring, we replaced the intake manifold gasket for an oil leak concern – it was trickling down the back of the bell housing. In the process of that repair, we replaced the plastic distributor and its cam sensor with a nice robust aluminum unit we bought at Advance. We set the cam retard offset index to zero (that setting has been removed from the Genisys software for some reason, so we did it with the Autel MAXIDAS). There was another oil leak at the front of the oil pan that the previous owner had smeared with copious amounts of RTV that did nothing to mitigate the leak. That repair would have to wait until summer, because Dad was driving the truck in the meantime and said it had never run better. A few weeks later he mentioned some bucking and jerking that it would do from time to time, but it wasn’t regular enough to duplicate easily, so I didn’t take time to yank any codes.
When summer arrived, we found we had to replace not only the oil pan gasket but also the timing cover in order to stop the front leak. The exhaust had to be removed to get the flywheel cover and the oil pan off. The timing cover, which is supposed to be replaced if ever removed, was broken, but you couldn’t see that until the oil pan was removed. The cover wound up being the reason the oil was leaking in that area.
After dad took delivery of the truck that time, the bucking and jerking got a lot worse to the point that it was losing power in a big way. He attempted to bring it back the following week, and it died on the road about 15 miles out. We had a local wrecker pick it up and bring it in.
The first thing I usually do on those Central Sequential Fuel Injection (CSFI) Chevys is check the fuel pressure, because if it’s less than 60 psi, weird things happen. I had a fast student throw a $71 fuel pump in it, and the pressure rose to the comfort zone I like for these - about 65 psi. Because it’s my dad’s truck, I also had the same student replace the fuel injection spider with a newer one that has electronic injectors at its tips. It was pricey ($269), and I really didn’t expect it to fix this problem, but since this was Dad’s truck, replacing that spider was something I wanted done. But Melissa needed to be certain she was putting the injectors in the right ports, and she did.
I forgot to mention that I was getting crank and cam sensor codes on the scan tool. While the scope didn’t show any problem with the cam/crank pattern, the fact remains that there is a GM Technical Service Bulletin (TSB) on replacing the crank sensor and adding a shim (02-06-04-059 Engine Runs Rough, Service Engine Soon Light On, DTC P0300 OR P0335 SET), so that got done, too. We should have done that when we replaced the timing cover. The replacement sensor came with shims, by the way. Also interesting was that the Cam Retard Offset PID was showing -5 degrees before the crank sensor was replaced. Checking it afterwards showed a zero reading, which was what I wanted.
On the next Friday, while I was there by myself working on some other stuff, I started the Chevy and it sounded pretty good, so I figured I’d let it run a while. But then it began to deteriorate in a big way. I could see the cherry red glow of the catalyst on the pavement under the truck, so I switched it off. Were we over-fueling or firing out of time? Was the catalyst itself at fault? The brick wasn’t rattling, and I didn’t want to endanger a converter that might not be bad, so I had a student remove the Y pipe and converter on Monday.
The truck now would start and idle rough, sort of like it would if EGR was flowing at idle, but when you applied throttle, it would start backfiring out the exhaust at about 25 percent throttle and then totally shut down unless you let the throttle come below that spot where that was happening. The scan tool Parameter Identifiers (PIDs) didn’t shed any light on this anomaly either.
The truck had new spark plugs already, and fuel pressure was consistently at 65 psi, so I opted to snag a used VCM from the local salvage yard. With that VCM plugged in, you could accelerate the engine without the die-out and backfiring, but it wasn’t firing on cylinders 2 and 7, even though spark was present. A scope check revealed that those two injectors weren’t even getting signals. The same VCM fits V6 or V8 engines, the difference being the PROM chip, and so we jerked the PROM out of Dad’s VCM and plugged it into the salvage yard PCM only to find that the backfiring/shutdown problem followed that PROM. A call to GM revealed that the $70 PROM isn’t available from GM any more.
I found one aftermarket supplier who had new ones for $200, but that was a non-starter. I called Johnny at the salvage yard and told him what I was facing. He brought me four more VCMs. I plugged them in one at a time and found one that made the Chevy run showroom good. Virtually all the others were for V6s, so I marked them for him. He was appreciative, telling me that his salvage yard resources don’t give him a way to tell the difference between a V6 VCM and a V8, because the PROM chip is the only difference and those PROM numbers are kind of a wild card.
The Vintage Caddy Adventure
This past May, the president of our college showed me a photo on his smartphone of a 1971 Eldorado convertible that, from the picture, looked like something of a cream puff. Of course, everybody who has been sold on a burger because of a menu photo will know how deceptive those images can be. He told me the engine had been replaced with a rebuilt unit from a 1976 model, and he added that the transmission had been rebuilt as well. He asked me what he and his son needed to notice when they went to consider buying it, and I didn’t have much of an answer for him. I basically told him that on a 43-year-old car, all bets are off.
When the car was purchased in that faraway city, it ran like a dream for more than 200 miles, but then it lost power to the point that it couldn’t be driven. It was towed to a tire store, where the decision was made to replace the carburetor and the starter (which would make grinding noises). The bill was about $1,000, and the car was sitting there idling when the bill was paid (red flag!), but the car only ran another five miles before it quit again and wouldn’t start. A wrecker brought it the rest of the way home, and I came in one morning to find it sitting in one of my service bays, and that launched the beginning of a grand adventure.
To begin, we needed to replace the flywheel, which was missing seven teeth, no two of them adjacent. This starter isn’t one of the upward-bolted GM units – it bolts into the transmission housing like a Ford, and there is virtually no adjustment possible without modifying something. Peering with a mirror through the big bell housing starter drive inspection hole (that’s all it could be for), while the starter drive was kicked in without spinning the starter, we noticed that the one of the broken teeth was right there at the drive. Even if the tooth had been there, the starter’s teeth were barely making contact with the flywheel, so we yanked the transaxle, popped a $60 ATD flywheel in there, egged the bottom starter bolt hole and moved the starter into better mesh with the flywheel.
Then we tried to start that 500 CID powerplant and found that we had no spark, and with that brand-new distributor cap removed, we saw that the points had literally come apart. Because these were plain old GM points, it was a snap to get a new set (and an condenser) from Advance. Even with the points replaced, the engine was kicking back. The firing order was right, but the distributor was a tooth off so that attempting to adjust the timing to 8 degrees rammed the vacuum advance against the A/C compressor. Somebody had moved the wires one position to try and fix that without pulling the distributor. My student Bobby straightened that mess out and set the timing right and the car started and ran like a dream until about two days later, when the starter popped another single tooth off the new flywheel.
Interestingly, that single broken tooth was lined up exactly with the starter drive gear, as if the tooth had popped off before the engine had even started to turn. We did see the driver gear ram those square-cut teeth without meshing a few times when we were watching it. Could the starter shear a flywheel tooth that way? Searching online forums, I found that a few other people had the same trouble with Eldorados of this vintage. The transaxle and the flywheel came back out, and I put both flywheels on my tire balance machine so as to spin them and check for runout. The old flywheel had lateral runout and the new one had radial runout. Further, the gears on the low side of the radial runout were showing signs of shallow gear contact.
