Everything I've seen so far indicates the EGR valve is on the intake manifold rather than a plate between the carb and manifold. (Apparently, I was thinking of a 1980 Ford 351M in my previous post.)
Note the linked illustration above has the Chrysler logo. Autozone illustrations tend to be more generic in nature, even when they imply they're specific.
The linked illustration is more complete in terms of vacuum system and hoses. It includes PCV, fuel vapor, and other systems, in addition to EGR. In that respect, it's helpful for bringing your engine back to OEM configuration.
Based on that illustration, the picture you originally posted was of the vacuum solenoid valve, vacuum amplifier, and (maybe) vacuum reservoir.
1970 Explorer Class A on a 1969 Dodge M300 chassis with 318 cu. in. (split year)
1972 Executive Class A on a Dodge M375 chassis with 413 cu. in.
1973 Explorer Class A on a Dodge RM350 (R4) chassis with 318 engine & tranny from 1970 Explorer Class A
In addition to Eric's 360, it's applicable to the 318 for MLP.
Griff in Fairbanks wrote:
Here's an interesting article that provides food for thought.
In addition to Eric's 360, it's applicable to the 318 for MLP.
Here's an interesting article that provides food for thought.
In addition to Eric's 360, it's applicable to the 318 for MLP.
Why Griff, you old Hot Rodder.
![[emoticon]](http://www.coastresorts.com/sharedcontent/cfb/images/wink.gif "wink")
My neighbor has a 1970 Dart Swinger. sans engine, trans, and needs a k member for sale. This is making me think things I shouldn't be thinking.
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A complete list of ignition system components in our older Dodge motorhomes is ignition switch, ballast resistor, coil, ICM, distributor, high tension wires, and spark plugs.
Chrysler, along with other manufacturers, started throwing in lots of extra doodads in an effort to satisfy government regulations. But that list is basically it for engines made prior to the early '80s.
Add 12VDC wires and connections and you have everything that could cause your ignition system to malfunction, act up, or otherwise not work well.
12VDC wires and connections are significant. If they're not up to snuff, they could cause components to act wonky when the components are otherwise fine. I've already mention one example of this, in the form of swapped primary wires on the coil. Likewise, loose/dirty/corroded connections will cause intermittent or insufficient current, making it seem like components are failing. While much less common, older wires can cause problems if they're corroded, have broken stands internally, or suffer deteriorating insulation.
Ignition switches are largely mechanical and will wear out over time and use. Being small and inexpensive, carrying a spare ignition switch is an option. (The switch is easy to replace if it's mounted in the dash ... if mounted on the steering column, it involves a bit more difficulty.) However, it's easy to 'hot wire' the ignition so the choice is yours. (Identifying which wires are which provides most of the difficulty.)
I hot wired my '49 Int'l Metro for weeks so I could use it while manufacturing a new sheet metal dash. (The wires were hidden under an old couch cushion on the doghouse.) I twisted the stripped (bare) ends of the BATT, ACC, and IGN wires together and touched the START wire to that cluster to start it. The first three stayed twisted together while I was driving it and I pulled the bundle apart to stop the engine.
We've already discussed the ballast resistor extensively and consensus is you should carry a spare. Like the ignition switch, the resistor is small, inexpensive, and much easier to replace. More importantly, it either works or doesn't -- no middle ground. (Ignition switch tend to signal pending failure by working intermittently.)
In a pinch, if you don't have a spare ballast resistor, you can bypass a failed one. (Jump across the terminals or pull the connectors off and clamp them together.) However, I generally recommend against doing so, limiting it to getting out of remote areas ... with as little time and distance as possible. (To get to cell phone coverage or a land line instead of a part store or repair shop.)
As noted, a spare coil is an option but will probably never be needed. (I know first hand of a fifty plus year old coil working just fine for well over a hundred thousand miles.)
Spare distributor cap and rotor is a good idea. (Do like I do and save the old ones when replaced during routine maintenance.)
If you want to go 'all out,' a spare distributor reluctor and brass gap gauge is a possibility but also probably unnecessary.
Beyond spare cap and rotor (and maybe reluctor), there's not much you can do about a failed distributor without access to a shop and timing light. (I can time an engine by ear but it's difficult to do without lots of practice ... and afterwards I tend to verify with a timing light.)
Spare spark plugs and high tension wires are a final possibility. However, a problem there tends cause reduced performance rather than complete failure, allowing you to get to a better place for making repairs.
All of this becomes much less necessary if you fix issues before they become a problem. Along with regular good maintenance, judicious rehabilitating/refurbishing is advisable on older vehicles.
The throttle positioner was a vacuum dashpot that raised the curb idle slightly higher when egr was in use, which was a real bad idea at low engine speeds, i mean its feeding exhaust gas into the intake, engine does not like it. It leans it out without adding oxygen and in turn reduces combustion temps and the production of Oxides of Nitrogen.
Sooo, the vacuum amplifier used the weak vacuum from a port that had what was called venturi vacuum that raised as the engine speed increased, vs regular manifold vacuum that goes down. Why ported vacuum like was hooked to the distributor advance wasn't good enough i don't know. They didn't want this to run on a cold engine because driveability would be horrible (stalling, hesitating, popping back through carb) so they added the ported temp switch in the thermostat housing to only work above 170 F maybe.
This is not stuff found on most trucks, they got a pass for most of this stuff until late 70s pretty much what griff says
Also, my post focuses on the ignition system. It assumes the rest of your electrical system is in good condition. A good, fully charged battery, functioning alternator and voltage regulator, and good positive and negative/ground cables, wires and connections.
Specifically worth mentioning is the potential impact the starter has on the ignition system. A good ignition system could appear to be malfunctioning of the starter is failing or doesn't have good cables, wires, and electrical connections.
The starter requires a tremendous amount of electrical current. If there are issues with the starter itself or its electrical supply, it will require even more current. The result could be not enough electricity left for the ignition system to 'do its thing.'
Ballenxj wrote:
Why Griff, you old Hot Rodder.
My neighbor has a 1970 Dart Swinger. sans engine, trans, and needs a k member for sale. This is making me think things I shouldn't be thinking.
Why Griff, you old Hot Rodder.
My neighbor has a 1970 Dart Swinger. sans engine, trans, and needs a k member for sale. This is making me think things I shouldn't be thinking.
That '70 Dart would be perfect for the V6 (based on the LA V8 small block) in the 'donor' Dakota in my yard!! I grabbed the Dakota (saved it from the junkyard) precisely for that kind of a project.
The biggest thing wrong with the Dakota is it had a complete idiot for an owner. (The ultimate in 'loose nut behind the steering wheel.') Otherwise, the engine suffers from oil consumption due to deteriorated valve stem seals but few other problems.
VintageMopar wrote:
That is some real dated stuff there.
The throttle positioner was a vacuum dashpot that raised the curb idle slightly higher when egr was in use, which was a real bad idea at low engine speeds, i mean its feeding exhaust gas into the intake, engine does not like it. It leans it out without adding oxygen and in turn reduces combustion temps and the production of Oxides of Nitrogen.
Sooo, the vacuum amplifier used the weak vacuum from a port that had what was called venturi vacuum that raised as the engine speed increased, vs regular manifold vacuum that goes down. Why ported vacuum like was hooked to the distributor advance wasn't good enough i don't know. They didn't want this to run on a cold engine because driveability would be horrible (stalling, hesitating, popping back through carb) so they added the ported temp switch in the thermostat housing to only work above 170 F maybe.
This is not stuff found on most trucks, they got a pass for most of this stuff until late 70s pretty much what griff says
That is some real dated stuff there.
The throttle positioner was a vacuum dashpot that raised the curb idle slightly higher when egr was in use, which was a real bad idea at low engine speeds, i mean its feeding exhaust gas into the intake, engine does not like it. It leans it out without adding oxygen and in turn reduces combustion temps and the production of Oxides of Nitrogen.
Sooo, the vacuum amplifier used the weak vacuum from a port that had what was called venturi vacuum that raised as the engine speed increased, vs regular manifold vacuum that goes down. Why ported vacuum like was hooked to the distributor advance wasn't good enough i don't know. They didn't want this to run on a cold engine because driveability would be horrible (stalling, hesitating, popping back through carb) so they added the ported temp switch in the thermostat housing to only work above 170 F maybe.
This is not stuff found on most trucks, they got a pass for most of this stuff until late 70s pretty much what griff says
VERY good! VintageMopar chimed in. (His knowledge and experience tends to be better and more extensive than the rest of us.)
Leaded gasoline aside, the main cause -- by a wide margin -- of emission, pollution, and smog is neglected or non-existent maintenance.
To deal with people failing to maintain their vehicles, Congress, state legislators, and administrative agencies came up huge pile of regulations. Relatively new vehicles started failing emissions tests so people blamed the manufacturers, not realizing their voting and failure to adequately maintain their vehicles was the real cause.
The manufacturers added doodads to address government regulations, owners' failures, and (most important to manufacturers) falling sales. The doodads sometimes worked when new and regularly maintained. (In case you didn't notice, we're right back where we started, without addressing the actual problem.)
The fact most emissions inspections and testing require "as manufactured" arguably gets in the way and drives up maintenance costs. Even if a 'stripped down' vehicle produces less emissions, it can't be registered in many places because it's not an OEM configuration.
So, we're left with a vicious cycle of good intentions making things worse.
Personally, any engineer who doesn't adhere to K.I.S.S. -- Keep It Simple, Stupid -- should be horsewhipped.
Like ignition switches, starter relays have internal mechanical components that can wear out through repeated use. (I've never had one fail but the potential is there.) If the one currently in your motorhome looks like it came from the factory, you may want to replace it with a new one and save the old one as a spare.
Like the ignition switch, the relay could signal pending failure through intermittent or erratic operation. However, it also could simply fail without any warning.
For those who don't know, a relay is basically a remote switch. It allows a low current switch and wires to control (switch on and off) a high current circuit. (Relays can also be used to perform certain logic functions but that's a topic for another discussion.)
In terms of 12VDC circuits, 'low current' typically means 40 or less amps and usually means less than 10-15 amps. 'High current' typically means 30 or more amps. (Yes, there's an overlap due to variations in definition and use of the terms.)
Before continuing, note starters have two circuits leading to them. One is a 'control' circuit, which is what we're discussing here and is a usually a 'high current' circuit with relatively large (10-12 gauge) wires. The other is a 'power' circuit, with very large (4 to 4/0 gauge) wires capable of handling hundreds to a thousand or more amps. (These wires are sometimes called cables, as in 'battery cables.')
Note: Do not confuse high tension/voltage wires (i.e., spark plug wires) with what we're discussing here. Spark plug wires carry tens of thousands of volts while we're talking exclusively about 12VDC circuits. (There's a distinct difference between voltage and current.)
In very old vehicles (prior to the mid-50s), there were separate ignition and starter switches instead of the combined ignition/starter switches in modern vehicles. (Yes, I just called our roughly 40-year-old motorhomes "modern.")
The ignition switches in those old vehicles were effectively identical to our 'modern' switches, minus the START position. (In most cases, the similarity extended to using a key, instead of a knob or lever, to control the switch.)
The starter switches were massive pushbutton switches, capable of handling the high current needed for the starter control circuit. (The switch for the starter's power circuit has always been, to the best of my knowledge, inside the starter solenoid.) If the starter switch was on the dash, it also meant very large (6-10 gauge) wires leading from the battery into the dash and back out to the starter.
(The starter switch on my '47 Willys Overland wagon was on the starter, with the foot-operated pushbutton poking up through a hole in the floorboards. When it rained, my feet got wet.)
You might think a single switch and simplified starting procedure is the main advantage provided by starter relays. (Old style: Turn on ignition switch and press starter switch. New style: Turn key to start position and release key.)
However, safety is the primary benefit. Relays permitted moving the high current wires out of the dash and allowed shorter, more direct routing. The possibility of a short-to-ground or similar problem increases with wire length. In smaller low current wires, the wire usually acts like a fuse, melting through and stopping the flow of electricity. The same process occurs in the larger high current wires but takes much longer. The result is always spectacular, often with enough sparks and heat to start a fire. (It's never good in a vehicle but especially dangerous in the dash, close to the driver and passengers.)
There's also economics involved. Longer and larger wires means more copper, which means more expense. The 'scenic route' for low current circuits is acceptable, as long as the wires are slightly larger to compensate for the added length. ('Not good' but at least acceptable, given the wire size caveat.) The wires in high current circuits need to be as short and direct as possible.
In my next post, I'll provide pictures, part numbers, and other info on your starter relay. In closing, I will tell you finding your starter relay will require a flashlight or trouble light (aka droplight). It may also involve a significant bit of physical contortion. (They're rarely located in one place ... instead placed wherever is most convenient for the designer/manufacturer.)