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Hagerty
Hagerty Employee

Keeping your eyes open while troubleshooting

Groucho Marx famously used the line "Who are you going to believe-me or your own eyes?" Today, we're going to tell a troubleshooting story, one that shows how sometimes even your own eyes can fool you. I've made no secret of my love for the BMW 2002tii, the mechanically fuel-injected variant of the BMW 2002 that was sold in the United States from 1972-74.
https://www.hagerty.com/media/opinion/the-hack-mechanic/keeping-your-eyes-open-while-troubleshooting...
21 REPLIES 21
audiobycarmine
Technician

Rob — a superb "Mea Culpa" with a fantastically practical lesson attached.

Your: "Because we are more emotionally invested in our own past decisions than we’d like to admit." is wisdom for ALL events and occasions.
Thanks!
Rcwkr
Intermediate Driver

About 8 years ago, I bought a 1984 Porsche 928s on E-Bay from a salvage yard sight unseen. I'd had an older one a decade or so prior and have the shop manuals. I figured I could make it into a "driver" as I would be retiring soon, and this would keep me busy. (It's still mostly a non-runner" and I kinda gave up.) To the point of this article though, it would start quite easily but die after a few seconds. I went through the thorough troubleshooting routines in the manual but had no success. I posted the problem on a couple Porsche owner sites, looking to benefit from other's wisdom. I had many suggestions, bypassing a relay or two, swapping parts eventually. No change. Did I mention that it had a sticker on the driver's side window from a (now defunct) alarm company? No? This must be the part where you ignore what your eyes are telling you because it doesn't fit your narrative. I opened up the console and found some wire and a little box that didn't look OEM. quick bit of surgery and VIOLA!
TG
Technician

I have removed every aftermarket remote start and alarm system promptly from every car that I ever had that had one. Life is hard enough with normal car problems
ppointer
Detailer

Still the best stories around. Thank you for writing and posting.
thehackmechanic
Advanced Driver

Thanks!
Gary_Bechtold
Specialist

Very neat story. Old parts doing what old parts are prone to do.
jrmedsel
Pit Crew

... and old minds doing what old minds are prone to do.
NWJeff
New Driver

I loved my first car, a 1966 Triumph Spitfire. It too was plagued by an intermittent running problem that had me cleaning out gas tanks, rebuilding carbs and replacing other components. Getting stuck by the side of the road on a hot summer day while trying to make it over Steven's Pass led me to the solution! The SU carbs have a small plastic elbow at the base of each carb that pulls the needle out of the carb slightly to enrich the mixture for starting. When I was stuck, I discovered that the small, clear plastic tube feeding the fuel needle was collapsing from the heat, cutting off fuel to the affected carb. A replacement needle and tube fixed the problem for good.
NWJeff
New Driver

I remembered after I wrote the above comment that the little plastic elbow is really the seat for the needle and the needle rides up and down on the piston inside the carb. Same effect of creating a richer mixture for starting when the needle seat is extracted slightly.
DougL
Detailer

That is a funny story, only because I have done dumb stuff myself!
jrmedsel
Pit Crew

I've had to install a similar push button switch for the cold start valve on all of my Mercedes w108s (with Bosch injection). This takes me to the next level of diagnosing hard-start problems. Thank you!
TG
Technician

I don't have a good related troubleshooting story, but my Allante is afflicted with what the community refers to as sail-on, where the idle stepper motor (well the computer, not the motor itself) will go berserk and start increasing idle gradually until it fully strokes - which puts you close to 3000 rpm and can turn a peaceful afternoon drive into a hair-raising white-knuckle driving adventure very quickly. I currently have the stepper wired to a momentary spdt toggle that allows me to bump idle up and down as needed. It's interesting what you have to do to overcome tricky car problems sometimes
ctaarman
Detailer

I have a 69 Mustang with a 390 and petronix in the distributor that I had owned for less than a year. Car would run nicely, then inexplicably stall. After reading forums I discovered the pink resistor wire was dropping the voltage to the petronix, which needs 8 volts minimum. I bypassed the pink wire, but the problem continued. On a particularly bad running day I started the car and then ran a temporarywire directly from the battery to the distributor. The engine ran flawlessly without any hint of stalling. A friend lianed me his spare voltage regulator. No difference.

The schematic led me to the ignition switch as the last remaining element, but how could that be the problem source? With complete skeptcism, I pulled the ignition switch and then with a DVM I measured the resistance across the terminals in each key position. To my amazement the same position would give wildly different resistance readings each time I switched it, from 2 ohms to over 40 ohms. Obviously a bad switch but I had never seen one fail like that before. I replaced the switch and the problem disappeared.
thehackmechanic
Advanced Driver

Congrats. That's pretty subtle.
drm101
Detailer

I have a '63 Nova with 350 and never liked the HEI distributor. It's big and bulky and right up against the firewall. After installing a new 350, I decided it would be better to run a stock distributor with points. I bought a ballast resistor and installed the distributor. The car would crank fine, but not start. Then I noticed it seemed to have spark when I let off the key. After some research, I found out that these new fangled mini-starters don't have the 3rd wire with a diode like the old original style starters. I added an inline diode and wire and it started and ran fine. Sounds simple, but it took me about a week to figure it out.
TonyT
Technician

You might investigate using a small-cap electronic distributor like the Summit 850205. Easy to hook up, outstanding spark and doesn't take up a lot of room. It's our go-to for small block powered street rod engines because it fits an early (1927 to 1935) Ford firewall nicely. Should fit your Nova as well.
drm101
Detailer

I ended up using a Crane point conversion kit, mainly for the rev limiter function since I'm running a 4 speed. If the distributor ever gives me any hassle, I'll look for that 850205. Sounds ideal, and probably has a roller bearing vs. the stock distributors bushing. Summit is my go to source. They have always treated me well.
drm101
Detailer

I have another one.........As a kid our neighbor (a little older kid) had a VW bug. The bug had stalled and he monkeyed with it for a week or more and finally decided he was done, and it sat with a for sale sign on it in front of his house for a week or so. A few days later, I see the bug being towed down the road. They stopped in front of our house, the passenger got out and popped the hood to the engine, then closed the hood, started it up and drove away. I made a note to myself that day to never give up on a problem because you don't know what's going on. Figure it out first. You can give up after you fix it.
Billthecat707
Instructor

Hope you messaged the forum member back to thank him for his help. Just shows we need to stay humble.
SAG
Instructor

Haven't opened the hood on my 'Dutschn hot rod' in 20 yrs.
I my have to a nother peak.
Ha
C7W289
Intermediate Driver

I could list so many similar odd problems, I think that it should be a weekly column from readers. Some favorites:
My brother's fiesta would die at random times, seemed random. He said that it started up once when he squeezed a bundle of wires under the dash. After messing with those wires way too much, we found that it was the carb float needle sticking in the bore that would cause starvation.

Again my brother's 67 cougar would idle but stumble terribly much above that. A spare coil hastily connected fixed it. When I connected it all up properly, it had the problem again. Turns out it was a bad tachometer, that when I wired it up permanently I connected the tach which had some kind of short in it.
Last two were on my brother's 57 ford. Straight six, running a little poorly. I noticed that some of the rockers were only moving a little compared to the others. Turns out the lifters are mushroom shaped, and the top broke off a couple of them when they were stuck in the bore and the cam pushed on the edge. Without the top hat they were shorter and barely rubbed on the cam.
More some other time...