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Tech Editor's DeskProjects, papers, writings, thoughts, musings of our technical editor Joe Padavano. To begin with, he will be making threads and can approve posts to it if he wishes. This can be changed in the future if it does not work out well.
People often ask how I've learned so much about Oldsmobiles. As I've often responded, it comes from over four decades of screwing up and breaking stuff. Add another lesson to that list...
Frequent readers may recall that I recently picked up a second 1985 Delta 88 for my wife. This is the black one that came from Las Vegas. As I was checking it out prior to getting the VA safety inspection, I found the wipers did not work. Frequent readers will also note that I regularly admonish people to troubleshoot before spending money...
The wiper motor looked shakey, I had a lot of business travel coming up and not much spare time, so I just bought a new wiper motor. Installed it, working fine, passed inspection.
I went to drive the car one morning recently and turned on the wipers to clear the dew off the windshield. Wipers did not work. @%!@##
I followed the troubleshooting flowcharts in the CSM, but couldn't get the wipers to work unless I jumpered the pulse relay under the wiper cover. Once jumpered, the wipers worked fine until shut off. This was NOT one of the failure modes in the CSM troubleshooting chart, so I figured it had to be the switch. Ordered a new switch from RockAuto.
Switch arrived, and before tearing the column apart to swap it, I plugged the new one in to the connector at the base of the column. Wipers still didn't work. @%!@##
I took the wiper motor off the car and hot wired it on the bench. New wiper motor worked exactly as it was supposed to. I used the VOM to check the function of the switch at the connectors to the motor - also fine.
At this point, it suddenly dawned on me that the ground path for the wiper motor is through a ground strap to one of the mounting bolts that pass through the rubber bushings to the bracket on the firewall.
No, it wasn't the ground strap that was the problem, it was the BOLT! The mounting bolt was just a little oxidized, to where apparently it wouldn't pass enough current to pull in the relay, but once you jumpered the relay, it would stay engaged. I cleaned the bolt, reassembled it, and all is fine. I now now have both an extra wiper motor and switch. Feel free to tell my I'm a dumb-@$$.
Fortunately, the wiper motor in the other 1985 D88 is noisy and I was planning to replace it anyway. The lesson learned is that ground paths through structural connections aren't always adequate, and usually don't show up in the troubleshooting charts. I'll also add that the wipers worked when it was dry. The problem was that when humidity was high (like, if it were RAINING), the moisture caused the resistance between the bolt and the ground strap to increase JUST enough to cause a problem. As a troubleshooting step, a temporary jumper from the wiper motor ground strap to the "-" terminal on the battery would have pinpointed the problem very quickly.
Joe, it is refreshing hear that even you can have an experience like that.
So, similar to the recent guy with a bad engine but it can't be the engine but the starter won't spin the engine over...
Isn't this the perfect example of how and why to put a voltmeter from the item using power to the battery (-) and read the voltage drop, thus providing the clue that the connections from Power User to (-) are all OK.... or not, and if not, then test each connection until you find the one with a sizable VD across it.
Isn't this the perfect example of how and why to put a voltmeter from the item using power to the battery (-) and read the voltage drop, thus providing the clue that the connections from Power User to (-) are all OK.... or not, and if not, then test each connection until you find the one with a sizable VD across it.
Thus the "teaching moment".
It's really a crappy design. The ground strap from the motor housing sits under the bolt head on top of the rubber isolator. The bolt compresses the rubber when you torque it down, contacting the ground strap and completing the ground path. As the rubber compresses and relaxes, the clamping force between the ground strap and the underside of the bolt head reduces. Add in oxidation on the bolt, and the resistance in the ground path goes up. Seems to me that an extra inch of ground strap, routing it AROUND the rubber bushing so the strap contacts the firewall bracket directly, solves this problem (but adds a couple of pennies to the manufacturing cost of the wiper motor). The 1980s cars aren't exactly GM's best work, and there are a LOT of cases of inadequate wiring design failures in these cars.
I'll also add that for Chris' troubleshooting method to be effective, you must use either a high-impedance VOM or an incandescent test light. The Chinesium VOMs like the ones Harbor Freight gives away for free with a coupon won't show the resistive loss at such a connection without the current draw across the joint and will give a false positive reading. The test light will glow dimly, thus indicating a resistance problem.
Several years ago, I ran a business that had several businesses within it. We had a full service wrecking yard, a body shop, a mechanical shop, a parts store for both new and used parts, and a towing company. It was great and they all would compliment and of course complicate each other at times.
We had a guy who would just run errands all over a large metro area. He would put on a few hundred miles a day on a pick up hauling parts all over. We at that time had a couple of early 80's (which it was the mid 80's then) Chevy pickups with the 5.7 diesel engine. They got about 25 mpg and when used that much they seemed to just run forever. not much for power but cheap to run. We had one that we were going to retire and so we looked for another truck. We found one that was a very low mile 2 wheel drive half ton that was white just like the one we wanted to retire. The one we found had a crunched pick up box and was a 350 gas engine. So, we bought it and put the box off the one we were going to retire on it. A few hours of work and it looked good as new. He drove it for about a month or so and it was a great vehicle. The owner of the company needed to use a pickup for some work at home, so he took it home and used it for a week or so. He brought it back and complained at how bad it was running and decided we needed to put a new engine in it. Our shop was so busy we could not get to it for a few weeks. So, he offered to me and one of the other managers who was a close friend a good chunk of change if we would change the engine on our weekend. So, we both took him up on it. We had one of our drivers drop the truck and engine off at my house. Saturday morning we changed the engine. Pretty easy 350 for 350, we were done in about 5 hours. The replacement engine was the same year and had been drive tested in a wrecked truck, had a full compression test, oil pressure test and all the usual inspections. After we started it up we drove it and it ran good but lacked power and seemed to smoke some. We drove about 2 miles and we thought man this thing runs crappy. We had the windows down and when we came to a stop sign the smoke rolled up on us and it was so obvious what was wrong. It smelled like diesel. We took it back home and sure enough the gas tank doors still had the diesel fuel only" stickers on it. We back tracked and the boss had gone to a service station and had them "fill it up". he did not go to the card lock and put the gas in himself. So, we changed the engine for nothing. We drained the tank and filled it up with fresh gas and in a few miles it ran great!
Classic. I've lost count of how many electrical problems have been caused by ground problems, you would think by now it would always be the first thing I would check but - no. All part of electricity being magic smoke inside the wires...
I'll also add that for Chris' troubleshooting method to be effective, you must use either a high-impedance VOM or an incandescent test light. The Chinesium VOMs like the ones Harbor Freight gives away for free with a coupon won't show the resistive loss at such a connection without the current draw across the joint and will give a false positive reading. The test light will glow dimly, thus indicating a resistance problem.
Yes, if we could get a list of things you can buy from Harbor Fright that would be fine for everyday use, I think it would be less than 1% of the store inventory.
Yes, if we could get a list of things you can buy from Harbor Fright that would be fine for everyday use, I think it would be less than 1% of the store inventory.
That's not exactly true. You need to understand the limitations of a tool and use it appropriately. You wouldn't use a 1/4" drive ratchet to torque a harmonic balancer bolt.
I have a bunch of those free VOMs, pretty much one in every vehicle. They work well for finding 12V and checking resistance. I've had one of their transmission jacks that I got on sale for $149 about 10 years ago. Works great. I've got one of their rolling A-frame cranes. I upgraded my engine hoist with one of their air-over-hydraulic long stroke cylinders. I use their spray gun cleaning kit a lot.
That's not exactly true. You need to understand the limitations of a tool and use it appropriately. You wouldn't use a 1/4" drive ratchet to torque a harmonic balancer bolt.
I have a bunch of those free VOMs, pretty much one in every vehicle. They work well for finding 12V and checking resistance. I've had one of their transmission jacks that I got on sale for $149 about 10 years ago. Works great. I've got one of their rolling A-frame cranes. I upgraded my engine hoist with one of their air-over-hydraulic long stroke cylinders. I use their spray gun cleaning kit a lot.
Well, I have had more problems with items I have purchased there than anywhere else. Bought an upright compressor about 5 years ago that leaked oil, got an electric cutoff tool that had the center stripped out, and some jack stands that I wouldn't trust my worst enemy under. I have owned the same transmission jack you speak of and never had an issue with that. But that was one time use for me and I sold it. However, I did purchase the same one again and it sits in the box brand new in the garage now. Seems to be working fine.
My favorite purchase from there: My son's huge TV remote control. That is amazing. And it still works...
As we talk about ground issues. One thing I started doing some time back, is when there is a ground I put in one of those grounding teeth washers to ensure a better connection. The ends of many ground wires has one kind of built in. These don't always get the bite needed to ensure the ground.
I bought one of those multipacks of that kind of washer and keep it with my electrical stuff. That and dielectric grease.
As we talk about ground issues. One thing I started doing some time back, is when there is a ground I put in one of those grounding teeth washers to ensure a better connection. The ends of many ground wires has one kind of built in. These don't always get the bite needed to ensure the ground.
Funny you should mention that. The 1960s/70s cars had conical star washers under the heads of the wiper motor mounting bolts. The 1980s cars do not. As I said previously, I've been very disappointed in the quality of the electrical systems in my 1980s GM cars. The conductors and connectors are undersized in many cases, leading to problems. On the CCC 307 motors, as an example, there is a square four-terminal connector between the engine harness and the HVAC harness near the distributor. One of those terminals holds a large gauge red wire that powers the blower motor on high speed. On every 307 car I've owned, this terminal has been overheated and needed to be replaced. Same thing for the single wire connector that feeds the HVAC control panel on the 1980s B-body cars. And don't get me started on the undersized contacts in the power seat switches on these cars.
Funny ... the first wiper issue I ever had was on a '92 Subaru. On the highway, 200 miles from home and tools. Found a scrap yard and asked them to install a replacement. As the guy's pulling my old one, I ask him to check it (I'm distracted, I'm supposed to be at a customer's) So he just jumpers the thing .. flup flup flup. 30 seconds later he's installed a jumper lead for ground, put some cash in his pocket and I'm on my way. Ever since then, ground is the first thing I check on anything electrical. Won on that score half a dozen times so far.
But be sure to put Sir in front of that...you've earned knighthood status here. Now to convince the wife...
Sorry couldn't resist. Is isn't often you get the chance to call "The Great One" that, and at his own request to boot...
You've also learned from the greatest rule...shut ones pie hole and open ones ear hole.
Your understudies (ME) have learned much from you, setting ones ego aside and being able to admit fault and learn from it... Ive been caught many times with the proverbial pants down here either due to lack of current data or cerebral hemorrhaging.
I have had too many stories like this being a trouble shooter most of my life. Ive definitely learned from each one... Its not plugged in doh... or is there power present or is there fuel present etc...doh moments! Those moments usually occur because were in a hurry, then we all go GAH! you dumb-@ss!
Good to see you have those moments Joe.
Steve
Attached are some tools which can be very useful to enhance those DOH moments!
Chineasium Junk! Yes a great laugh, but sadly full of truth and us dumb @zzes line up to get into the hell hole. What really isses me completely off it that I cant rip the dam ad out of hot rod or Hemmings when Im in the outhouse cuz they strategically place a cool car pic on the back sides of the GD ad! Hate China! I dont even buy bungee cords there any more(thats all I ever bought there to start with) because they last about 6 months. Any one have a USA source for bungees!
Not to sound like someone's mom, but BE F$*KIN' CAREFUL with those Chinese bungie cords!
Only some of them have steel hooks inside the plastic.
They still have strong elastic, and the hooks can and DO break, sending the end flying unexpectedly.
A coworker of mine had to help a guy who'd just had one blow his eye out, so these things can cause serious damage.
I put made in USA bungees in the Googler and there seems to be some out there. The round elastic cord type. More expensive but not that much more, especially when you factor in longevity. The chinese junk last literally 6 months holding the tarps over the wood pile. I have some USA made flat bungees that I know are at least 20 years old. Yes the safety factor also goes out the door when you walk into hazard freight.
May 21st, 2016, 04:37 PM
