Imperial Journey

In the last article Electrical 9: Up Gauging we largely finished upgrading the Imperial wiring. But the story wasn’t done. Bypassing the ammeter leaves no way to know the state of the charging system, so I planned to add a voltmeter.

This led to buying a <$20 multifunction digital gauge that included a clock, inside and outside temperature, and a voltmeter. Trying this out on a test drive produced immediate concern – the voltmeter said 12.3V when the system should have been over 13 volts. This indicated that the system isn’t charging, and driving the car would just run down the battery. A deeper dive was clearly called for.

Time to grab the good multimeter and connect it to the battery. This showed 12.7V, a reasonable value. The cheap, straight from the Far East multifunction device was inaccurate – shocking! The next step was to fire up the engine. If the charging system was working the voltage at the battery should jump to 13.2-13.4V. With the engine running the voltage stayed absolutely flat – no change at all. Krud. The charging system was actually bad.

Three things could be bad: the voltage regulator, the alternator, or the wiring. And they were all new. In fact, the voltage regulator was an upgraded solid state regulator that should work better than the old electro-mechanical regulator.

Still, the symptoms looked like a voltage regulator. The fastest way to get a new one was through Amazon, so an order was placed. I still needed a voltmeter, so I also ordered a dual USB with voltmeter that plugs into the cigar lighter. The new regulator arrived, was installed, and no change. The new voltmeter seemed accurate when compared to the digital multimeter.

Again, krud. OK, check the alternator wiring against the service manual again. There are only three wires and it is straightforward; everything looks correct. OK, that leaves the alternator. While getting ready to order another new alternator (the alternator was replaced during the rebuild) I remembered that I had saved the old alternator. I was even able to find it. OK, install the old 35 amp alternator, verify that it works, and then order another 65 amp alternator.

Fire up the engine – and no change. Still no charging. Krud. The possibilities are two bad voltage regulators, two bad alternators, or bad wiring. I spent a couple of days checking everything – tracing the wiring, checking the wiring, jumpering around the wiring with direct connections, running various tests, and in general pounding my head against a brick wall.

While reading up on charging system tests for the 87th time I realized that I had done an alternator test wrong. The test is to connect the FLD (Field) terminal on the alternator directly to the positive post of the battery. If the alternator is good it will over-charge the battery, producing over 14V. You don’t want to do this for long, as it will destroy the battery and the alternator.

When I performed this test the first time I had left the wiring harness connected. This acted like a dead short, producing sparks and instantly heating my test wire. Thinking about it, this shouldn’t have happened. This time I disconnected the wiring harness from the alternator, connected a test wire, and started the engine.

With considerable fear I touched the test wire to the positive post of the battery – and nothing dramatic happened! OK, a good sign. Hold the test wire on the battery terminal and the voltage reading starts going up, quickly exceeding 13.6V and clearly charging the battery. Now this is a very good sign! It shows that the alternator is good, strongly suggests that the wiring is correct, and points a finger at the voltage regulator.

Next question: is the new 60 amp alternator also good? Time to re-install the new alternator and re-run the test. With the new more powerful alternator the voltage quickly exceeded 14V. With the alternator good and the wiring good, pretty much the only thing left is the voltage regulator.

Two bad voltage regulators? Shouldn’t happen. For the third voltage regulator I ordered a premium regulator from RockAuto. More expensive, but hopefully better quality.

When the third voltage regulator arrived I bench tested it with a regulated power supply. Unlike the other two voltage regulators, this one showed 12V on the output FLD terminal; the others showed 0V in this test. An encouraging sign, so time to install this regulator.

With the third voltage regulator installed I once again fired up the engine – and watched the digital multimeter rise to 13.3V! The charging system is working. And the USB/voltmeter in the cigar lighter is also showing 13.3V.

The only thing left was to confirm these results. The voltmeter showed a consistent 13.3-13.4V during a test drive, exactly what it should be.

This one had me tearing my hair out. I don’t expect to get two bad parts in a row – I don’t “expect” to get one bad part in a row! I learned more about testing alternators and voltage regulators, so should be able to figure out something like this much faster in the future. Another lesson is to order parts from reputable sources.

With the charging system working I can call the electrical upgrades done.

Update 1:

The next morning I headed out on a longer test drive. Immediately after starting the voltage went to 15.3V and the voltmeter started saying “tilt”. Not good – this looks like the voltage regulator is shorted out. Pulled the car back into the garage, hooked up the good multimeter, and it was reading 15.6V at idle. Since this will fry the battery, the alternator, and what is left of the voltage regulator I started troubleshooting the charging system (again).

The voltage then went to battery voltage, like it was before I installed this new regulator. I checked across the IGN and FLD terminals and it showed an open circuit. The regulator is dead.

What is going on here??? Three bad voltage regulators? Mentally going through everything I had done I began to question how I tested this regulator. I had hooked it up to a bench power supply which could have put up to 10 amps through the regulator. In fact, this was likely – one of the resistors on the voltage regulator got so hot from the test that I burned my hand when I picked it up. Could I have almost burned out the regulator, leaving it good enough to work initially but damaged enough to quickly die? Unfortunately this seems like a distinct possibility… It looks like the only thing to do is try another regulator.

Update 2:

The fourth voltage regulator arrived and I installed it. It looked perfect while running the engine briefly. So far so good… It is really hot this afternoon so I don’t feel like a longer test drive. Will try to get out tomorrow for a good run.

Update 3:

On the test drive the next day the voltage went back above 15V again. Krud.

Time for more research. A recommended upgrade is to go to a later model electronic voltage regulator which Chrysler used in the 1970’s-1990’s. This later model regulator works with the new style alternator I had purchased, so I went ahead and ordered one.

Update 4:

The new(est) voltage regulator arrived. It is wired differently than the older style voltage regulators, so I made a temporary test harness with the new wiring connections that would let me try it without making permanent changes to the existing wiring harness. With the test harness ready, I installed the new alternator and the new voltage regulator, connecting them with the test harness. After a careful review of the wiring I started the engine.

And watched the voltage immediately go to 17V-18V. Not Good! Quickly turn off the engine.

This is getting ridiculous! I’m getting frustrated and out of ideas. Back to the Internet for more research.

I found some articles that suggested this behavior could be caused by a short in the alternator field windings that control the output voltage. This can be tested by checking the resistance between the field terminals and the case of the alternator – this should be an open circuit with infinite resistance.

Get the alternator on the bench, dig out the multimeter, and start checking. Hmm, Field Terminal 1 to case is measuring 4 ohms. Field Terminal 2 to case is measuring 0.3 ohms. Could this be the problem all along – the new alternator is bad???

Time to order another new alternator. Might as well order another new voltage regulator while I’m at it. Just in case the alternator problem managed to fry the voltage regulator. Stay tuned for the next update!

Update 5:

I ordered the new alternator and voltage regulator on Wednesday; supposed to arrive next Tuesday. Then got the order confirmation with new shipping information – now next Friday. Bummer, I didn’t want to wait that long. Thursday (yesterday) I got a package delivery email – and the new parts were on my doorstep! One day shipping as a (pleasant) surprise.

There are some indications that I might have originally received a new style alternator that was internally configured for the old style voltage regulators. Chrysler alternators were mechanically compatible over about a 30 year period – they all just bolt in. The switch to new style voltage regulator occurred in 1970. To make sure everything was new style I ordered an alternator and voltage regulator for a 1972 Imperial.

Time to repeat this familiar drill: pull out the old alternator, install the new alternator. Pull out the old voltage regulator, install the new regulator. Connect the wiring, including the test harness for the new style voltage regulator. Double check the wiring. Hook up the multimeter to check voltage. Check the wiring again. Start the engine…

And the voltage looked good. Encouraging, but we’ve been here before. Back the car out of the shop and head out on a test drive. This time the voltage stayed rock steady on 14.5 volts! This is at the high end of the normal range, but it is within the normal range and is expected at startup. Over a 30 mile test drive the voltage dropped to 14.4 volts and stayed there. When idling it would drop to 14.2-14.3 volts.

Things are looking good – this is exactly where the voltage should be. The next step is to do a permanent mount for the new voltage regulator and then replace the test harness with permanent wiring. Followed by another test run! Not that I’m paranoid or anything… Actually, at this point, I AM paranoid about the alternator and voltage regulator!

It looks like the underlying problem was a bad 60 amp alternator. This might have killed the voltage regulators, or it could have been something I did.

The engine is hot after the test drive so I will just put this job off until Monday.

Update 6: Success!

The final step was to install the voltage regulator in its final position and replace the test harness with production wiring.

As seen in this picture there is little room for the voltage regulator and poor access. Despite this I was able to locate it and drill new mounting holes. I really need to get a right angle drill. And smaller hands…

The new voltage regulator requires two wires. I really didn’t want to run another wire – adding wires to a sleeved harness is a lot of work. The new voltage regulator doesn’t have the dedicated ground wire that the old one does – so why not repurpose the old ground wire as the new field wire? This simply required putting new terminals on each end of the wire – along with updating the labels on the wire so I won’t confuse myself in the future.

To ensure that the voltage regulator is well grounded I added a new ground wire from the updated chassis ground system to the case of the voltage regulator – this is the same ground that the headlights are using. I checked the grounding of the alternator to chassis ground and it was good, around 0.3 ohms.

With everything connected and the wiring double checked it was time for the first moment of truth. Fire up the engine and check the voltage. 14.5V-14.6V – just a touch high, but within specs.

I’ve been here before, so on to the real test – the test drive! After a good test drive, including Interstate driving, the voltage registered a steady 14.4V-14.5V. Again, on the high side but within specs.

I’m declaring success and moving on to the next project.

Next electrical article: Electrical 11: Connections Evolved

Next article: I take the Imperial to my First Cruise Night!

After finishing the headlights in Electrical 7: Headlights it was time to track down why the heater blower motor wasn’t working. The symptom was a blown fuse as soon as I pressed any of the heater buttons. No power means the motor doesn’t work.

After changing several fuses I confirmed that the problem was in the blower circuit. It looked like something was creating a dead short. This could be from the new wiring harness, or I could have pinched something when re-installing the heater plenum.

The speed control for the blower motor goes through a big resistor mounted on the firewall in the engine bay. I started the underhood troubleshooting by unplugging one of the wires from the resistor.

Umm, why does this wire say NEUTRAL SAFETY SWITCH???

Krud. In the new wiring harness both of the wires for the blower resistor plus the wire for the neutral safety switch are all brown and come out of the wiring harness at the same location and have the same connectors on the end.

This is why it is critical to READ THE FREAKING LABEL (RTFL) when you are connecting devices!

Yup, the wire connected to the neutral safety switch says HEATER BLOWER MOTOR.

Connect the wire labeled NEUTRAL SAFETY SWITCH to the neutral safety switch. Now plug the wire labeled blower motor into the blower resistor. Hmm, its a bit too short. OK, wire up an extension with a new plug and plug it it.

Now to check the blower motor: No blown fuse! And the heater blower runs at low, medium, and high speeds. There wasn’t any rejoicing this time – I was too annoyed with myself for making such a stupid mistake.

The last thing was to try to start the car and make sure the neutral safety switch still worked. The Imperial fired up immediately, so that part is still good.

All that work labeling all the wires and then I don’t pay enough attention when actually hooking everything up. At least the problem was obvious when I finally looked. Grumble.

On a side note: If you are going to be doing a lot of electrical work it is a good idea to buy fuses in bulk. The retail price of automotive fuses can be over $1.00 each. Or you can get them for less than a dime by ordering 50 or a hundred at a time – for example, 20 amp mini fuses for eight cents apiece. Since it is easy to go through several fuses when tracking down a problem (at least for me…) it is good to have a box full of fuses available.

The next job is to figure out why the alternator isn’t charging.

Next: high current upgrades in Electrical 9: Up Gauging.

Previously: Electrical 7: Headlights

When we last saw the Imperial it was running great on a short test drive. It was now time for a serious drive!

I started out slowly, driving around the block while watching the gauges and paying close attention to any possible signs of problems. So far everything was going great…

Next step was to drive some back roads. Still the same, everything was working great. OK, time to live dangerously, so I headed for the Interstate.

This time the Imperial pulled onto the Interstate with plenty of smooth power – no signs of hesitation or loss of power. This car likes the Interstate. I ended up putting 70 miles on the car today, mostly cruising at 65-75 mph keeping up with traffic.

The car rides smoothly and tracks straight. It is fairly quite, with most of the noise coming from wind. This was expected, as it needs new door gaskets and window gaskets. New gaskets will be installed after bodywork is done and it is painted.

Even better, the gas gauge works! It started on full, and then went down at what looked like a reasonable rate. On the way back home the gauge was showing just under 3/4 of a tank when I stopped for gas. Filling the tank took 8 gallons. With a 23 gallon tank, just under 3/4 of a tank should be 7 gallons if the tank and gauge worked perfectly. Considering that a fillup may fill the tank over its rated capacity, this is a near perfect result. I still want to check calibration at a half tank and quarter tank, but things are looking good!

Even better – gas mileage was 11.1 mpg! After a 1,000 mile break in period I will probably be getting around 12 mpg on the highway. While horrible by any sane standard this is still good gas mileage for this kind of car.

The test drive wasn’t perfect. The alternator may not be charging correctly; I need to look into that. The temperature gauge is still reading warm, not hot, but warm. This also needs more research.

Today was much better than being towed!

Next: Doing the (mini) Splits

Electrical 6: I Need Power! described the installation of the new fuse/relay box and rough wiring. The next step was to complete the headlight wiring by installing a Weather Pack 4 pin connector on the new wiring harness.

I may have slightly overstated the status of the headlight wiring… While the new wiring is indeed 12ga, it doesn’t run all the way to the headlights. There is a separate run of wire from the main harness to the headlights. Recall that one of the defining features of 1961-1963 Imperials is the podded headlights.

The wiring runs up from the bottom of the headlight through the base, into the pod, and then through a connecting bar between the two pods. There is minimal space for the wiring – getting four 12ga wires in here will be a real challenge. So I decided to punt on this for the moment by re-using the existing headlight wiring and building an adapter between the new wiring harness and the existing headlight wiring. The headlight wiring will be updated when I have the headlights out for painting or when I send them out to be re-chromed.

While re-using the existing 16ga three wire setup isn’t ideal, the remaining 16ga wire is short and the upgrades to the rest of the system help a lot.

The existing headlight connector is a 3 pin Packard 56 connector. Of course I have 1 and 2 pin Packard 56 connectors, but no 3 pin. Not a problem – cut the existing connectors off of the old wiring harness leaving a 3″ pigtail. Then crimp Weather Pack connectors onto the ends of the old wires and install in the mating shell for the new wiring harness. As long as everything is opened up, go ahead and spray the old connectors with contact cleaner. Viola, or maybe even voila, and the headlights are plugged in and working.

In this picture you can see the four 12ga wires of the new harness going into the sealed Weather Pack connector, the three 16ga wires from the original harness, the the three wires going to the headlight. Also shown are the green and yellow wires to the parking and turn signal lights.

The headlights are now substantially brighter than they were before. Thanks to the relays and new wiring I no longer have to worry about the old wiring or the old headlight and dimmer switches. The headlights had already been upgraded from the really old incandescent bulbs to the somewhat less old sealed beam halogens. A planned upgrade is to replace these with modern H1/H4 lights – this will probably be done when the headlight pods are rewired.

A couple of other notes on the headlight wiring: 35 amp relays were used; this makes sure that the relay is not the weak point of the system. Even using 65 watt bulbs, the four high beam headlights will only be pulling a total of 20 amps. 100 watt HI beams could be a problem, but even then they could be split across two relays. And 100 watt bulbs would probably melt the pods!

This particular Bussmann fuse/relay box was chosen because it supports circuit breakers as well as fuses. The headlights will use these automatic resetting circuit breakers for maximum reliability and safety.

Next: is the Imperial ready for the road? Find out in Cruisin’!

Next electrical: chasing a problem in Electrical 8: RTFL

Not a great day – the Imperial died in the middle of a test drive and had to be towed home.

As a break from the electrical work covered in Electrical 5: Boxing I had decided to put some miles on the car to break in the engine and suspension and to try to work out a problem with losing power under acceleration. Bad idea! The loss of power got steadily worse, ultimately stopping completely in the middle of the road. Fortunately I had gotten off the Interstate and was looking for a place to park. Unfortunately I hadn’t found that place when it quit completely.

Fortunately a kind gentlemen in a pickup truck (hi, Ken!) stopped and asked if I needed help getting towed off the road. He hooked up a tow strap and pulled me 1/4 mile over the top of the hill and into the parking lot of Westward Orchards in Harvard.

First things first, so I headed in to the store, bought a coffee, told them I had broken down, and asked if it was OK to stay in the parking lot for a while. “No problem!” was the answer – this was a case where it was better to ask permission than forgiveness. OK, this was actually the second thing – the first thing was thanking Ken profusely for his help!

There wasn’t a trace of gas in the fuel filter – bone dry. This confirmed my suspicions of a fuel delivery problem. Looks like a blockage in the lines or a bad fuel pump. Or maybe air leaking into the lines. Nothing that can be fixed in the parking lot, so time to call for a tow. Thanks to the miracle of cell phones this is easier than it used to be. Fortunately it only took 45 minutes for the tow truck to show up, and a half hour later the Imperial was back home.

Blocked lines don’t make any sense – the fuel tank, fuel sender, fuel lines, fuel filter, and fuel pump are all new and were working up to this point. The fuel pump is brand new with less than 100 miles on it, but it is the most likely suspect.

NAPA didn’t have any of these fuel pumps in stock, so I had to order a new fuel pump. While waiting I dug out the original fuel pump and installed it. I had replaced the original pump to avoid problems like this from happening…

With the original fuel pump back in place – nothing. Not a drop of gas. Stubbornly remains bone dry. Krud.

OK, time to troubleshoot the entire fuel system checking for blockage or leaks. All of the lines are clean, all of the connections are tight, the fuel hoses are securely clamped to their fittings, and the fuel tank vent is fine. Blowing air through the lines showed that they are open with no trace of blockage. In fact, after I removed the input line from the fuel pump gasoline continued to dribble out of the line, siphoning from the gas tank. Clearly gas is getting to the fuel pump. The fuel filter and lines to the carburetor were checked and were also open.

Once again the evidence is pointing to the fuel pump. And I have another new pump on order. But this still doesn’t make sense – failure of two pumps that were working is unlikely…

Sigh. More diagnostic work is needed. I’ll update the Blog when I find something.

Update (12July2021)

Some online research revealed that a common problem is wear of the pushrod that goes between the camshaft and the fuel pump. This pushrod connects the fuel pump lobe on the cam to the pump lever in the fuel pump.

The pushrod is supposed to be 3.22″ long. It is fairly easy to remove – remove the fuel pump, unscrew the retaining plug, and the pushrod drops out. OK, it drops out after grabbing it with needle nose pliers and wiggling it a bit…

Fire up the trusty digital calipers and measure the length: 2.942″. The pushrod has worn 0.278″ – over a quarter inch of wear! You can easily see the wear – there is a thicker section in the middle of the pushrod that rides in the bore and reduced sections at each end. These end sections should be the same length. You can clearly see that the right side is shorter than the left side. You can also see some wear toward the right side of the middle section.

There is no way the fuel pump could work with this much wear – it is amazing that it worked at all! The pushrod should have been replaced when the engine was rebuilt; I’m disappointed the shop didn’t do that. If I ever rebuild another Chrysler big block I will know to check the pushrod while the engine is out of the car. Or better yet just replace it as another wear part in the engine.

A new pushrod is on order. Hopefully this is the only problem; wear on the camshaft would be really bad. Will update again after the new pushrod is installed.

Update 2: 29July2021

After a bit of a comedy of errors (my errors…) the new fuel pump finally pushrod showed up. Installation of the pushrod and fuel pump was actually quite easy. Then the moment of truth:

Crank the engine over for several seconds. Go to check the fuel filter. And there was gasoline in the fuel filter! Crank the engine some more and it started and ran. And there was much rejoicing!

At this point I changed the oil and filter in case there was any metal from the pushrod in the oil.

Fired the engine up and drove the car around the block a couple of times. It is running great! Running smoothly, plenty of power, and no hesitation. I had other commitments and couldn’t spend much time driving the car, so putting some quality miles on it will have to wait for another day.

On another note, all of the electrical wiring is working (see the thread on Electrical for details). This is a pleasant surprise, as I had expected to have to track down and fix at least a few mistakes.

Next: Electrical 6: I Need Power!

In Sounds of Silence we made tremendous progress on the interior – but weren’t quite ready to really drive the car.

I didn’t trust the tires that came with the car. They weren’t the right size for the car, were who knows how old, were rather worn, and two of them had slow leaks. Not confidence inspiring for running a 5,000 lb. behemoth down the Interstate! Or for driving on twisty New England roads.

With the Imperial ready to go, it was time for new shoes. The Imperial came with 8.20 x 15 tires. This is an obsolete size, which was replaced by L78-15 (not an exact fit) and later by modern metric size tires.

Somewhat surprisingly the original 8.20 x 15 tires are now available, even in the original whitewall. This wasn’t the case a few years ago. Companies like Coker Tire offer tires such as American Classic Radial that is basically an improved version of the original factory tires. They also offer bias ply tires which are the same as the original factory tires and offer a factory experience including a smooth supple ride, poor handling, and rapid tread wear. The bias look radials are expensive.

I’m planning on taking some long trips in the Imperial, so a modern radial tire is attractive. The closest size is P235-75/15; this tire is ~3% smaller than the factory tire and has a wider footprint. Several companies make this tire. I’ve had good luck with Michelin, and ultimately decided on Michelin Defender LTX.

The Defender is designed for light trucks and SUVs, so it has the weight capacity for the Imperial. Today’s SUVs are basically luxury cars and expect a smooth and quiet ride, so this should work. Reviews of this tire indicated that it is quiet and has a good ride, as well as good ratings for traction on dry roads, in the rain, and in light snow. It is also half the price of the Coker radials. The Defender isn’t available in whitewall, but I can live with blackwall.

BJ’s had the tires on sale. As far as I can tell, BJ’s always has tires on sale… In any case the Imperial is now sitting on four new tires.

I’ve only had the chance to take a fairly brief test drive, but I think I’m going to like these tires. With the new suspension, new sway bars, and front end alignment, handling was already improved even with the old tires.

With the Michelins the handling is more positive. The tires respond more sharply to steering input, there is less roll in corners, and the overall feeling is more secure. The ride is quiet (thanks to all the sound insulation), and smooth. There is some roughness going over bumps, which I think is largely due to the new shock absorbers; will see how it feels after I have a few thousand miles on the car.

At this point I would say the work has turned out well. Changes include all new suspension parts, front disk brake conversion, heavier front sway bar, added a rear sway bar, rebuilt power steering box, new shock absorbers, and new tires.

Previously the car was scary to drive – leaning and lurching in the corners, vague steering feel, considerable roll when turning, pulling to one side when braking, and noisy. It now corners flatter, is smooth, doesn’t make noise, and brakes straight. It isn’t a sports car, but it is much more confident and comfortable to drive.