1995 Chrysler Le Baron I have been having stall-out problem

Hi Doug, Randy here. I was in Austin two years ago. Went to Houston with a friend, then visited his sister in Austin for a day.

Two things to look for. At engine startup, the engine speed should go to around 1500 rpm for a couple of seconds, then back down to around 800 rpm. If this "idle flare-up" happens, the Automatic Idle Speed motor is working. If it doesn't occur, the dealer can use their DRB3 scanner to command the idle speed to increase up to 2000 rpm. If there is no change, they will pull the motor out to watch if the valve moves when commanded to. If it does, suspect carbon is plugging the air passage around the throttle blade. This was real common with the 3.0L engines years ago when fuels weren't as clean as they are today. Cleaning the passage was not terribly difficult.

Something to not overlook, although it might not apply here, if the battery was recently disconnected or run dead, "minimum throttle" must be relearned by the engine computer before it will know when to control idle speed. The conditions that must be met include higher than normal manifold vacuum for at least seven seconds. High vacuum occurs when releasing the throttle after snapping it open, but the only way for that to happen for seven seconds is by coasting.

With the engine warmed up, drive at highway speed, then coast for at least seven seconds without touching the brake or gas pedals. At that point, when the computer sees a steady voltage from the throttle position sensor, it will know it's at idle and will memorize the reading. From now on, anytime it sees the same voltage, it knows it must be in control of idle speed.

No two sensors are exactly the same. When it was replaced, the new sensor might read slightly lower at idle. Usually the computer will immediately put the new lower value in memory. If the lowest reading is higher than with the old sensor, it will never reach the value that tells the computer it's at idle. The computer will think you are holding the gas pedal down a little, so it won't try to control idle speed. In this case, it will be necessary again to do the coasting procedure.

I'm happy to hear you don't want to throw parts at the problem hoping one will stick, but there are two other things you might look at. If fuel pressure is a little low, not enough fuel will spray through the injectors. GM has a lot of trouble with fuel pressure regulators, but for Chrysler products it's almost unheard of. You might try pinching off the fuel return line and observing if the stalling still occurs. That's the smaller of the two fuel lines by the right strut tower. You'll likely see black smoke out the tail pipe because pressure, and the resulting fuel delivery, will be too high, but at least it won't stall. Removing the vacuum hose from the regulator and plugging it will also raise fuel pressure. A hint that pressure is low might be found by reading the short and long term fuel trim values. Low pressure causes a lean mixture, and the engine computer will be adding fuel. The numbers displayed on the scanner will be very high positive.

You could try a new MAP sensor too. Before the engine starts, its reading represents barometric pressure. After the engine starts, higher manifold vacuum results in a lower voltage from the sensor. As long as that voltage is between.5 and 4.5 volts, the engine computer will believe the sensor and deliver fuel accordingly. Less than.5 volts or more than 4.5 volts are not acceptable values, and the computer will turn on the Check Engine light and memorize a diagnostic fault code. However, the sensor could report an incorrect value that is still within the acceptable range. It will not set a fault code in that case. It could take a few miles before the engine will run right after replacing the sensor. The engine computer is always comparing the sensor readings to each other and will take some time to learn the characteristics of a new one.

One more thing to consider is a plugged pickup screen in the fuel tank. This is grasping at straws, and it doesn't exactly fit your symptoms, but it happened to me a few years ago with my '88 Grand Caravan. The largest volume of fuel is moved by the pump when coasting since there is less resistance to flow by the regulator. The higher volume causes a pressure drop by the plugged screen. That pressure drop results in not enough fuel spraying from the injectors. The engine will stall at around 20 - 30 mph. After sitting for half a minute, the engine will start again. The clue here is the faster you drive, the better the engine runs. When this happened to me, it took me four hours to nurse it through Minneapolis rush hour traffic with three interstate bypasses full of road construction. Had I known at the time what the problem was, I could have unplugged the regulator hose to at least keep the engine runnng. This also happened on the hottest day of summer. Two days later it ran fine. The problem didn't show up again for six months. When my students finally removed the pump, the screen was full of rusty colored mud. Again, this doesn't exactly apply, ... I think.

Caradiodoc

You can get my e-mail through my information page, but I'm going to dump Verizon if I keep losing information. Can't get a live understandable person to complaint to through phone or internet. Very not customer-friendly.

By communicating through this forum, other users can find answers by searching through previous posts, and more importantly, other people can post additional information about your problem or they can correct me if I would ever make a mistake. We know that isn't likely to happen though. I made a mistake once in 1969. Thought I was wrong, but someone pointed out I was NOT wrong, therefore, I made a mistake!

Caradiodoc :)

The light you found under the hood is called a "noid light". It is used to quickly show if the engine computer is firing that injector. It's made specifically for that purpose. Regular bulbs won't respond fast enough.

I know a lot of mechanics pierce wires to measure voltages, but this causes a real big problem later with corrosion from moisture getting in. I would recommend putting a tiny dab of RTV silicone sealer on the hole to prevent that. Rather than buying a whole tube, I would drive to a repair shop where the folks know you, and ask a mechanic for a little bit of this sealer and explain what you're doing with it. Every mechanic has a half-used tube of the stuff, and they might even just give it to you. Once opened, the better stuff cures right in the tube after a few weeks, so it's wasted.

A little dab the size of a finishing nail head is more than enough. Chrysler has two RTV sealers, (room temperature vulcanizing). The black stuff stays more rubbery but will not bond if there is any oil or transmission fluid residue. The gray stuff gets a little harder and will bond even if the surfaces aren't perfectly clean. Either one will work fine. There are other brands of this stuff with other colors. They all will work fine for sealing a wire.

Rather than piercing the wire, he could have easily back-probed the terminal in the connector with a paper clip. That's what I taught my students to do. I made a really big deal of inspecting my prepared broken cars for signs of pierced wires to impress on the kids how important is was to follow professional procedures. They were required to remove any sections of wire they pierced and replace them before continuing on with troubleshooting exercises. Sealing the hole later is fine to prevent problems, but it is not acceptable in my class because it is treated as a quick fix for unprofessional conduct.

It sounds like the guy who did this to your car was expecting it to come back into the shop, so he might have planned on sealing the hole later. Still, ... There's a better way to measure voltages.

As a point of interest, since the mid '70s, a lot of GM cars used aluminum wire to save weight. The insulation was translucent and you could see the wire inside. I worked on a few of those where someone had pierced the insulation and corrosion had caused a break in the wire. Usually that only took a few weeks to occur.

I think there has been some confusion in my interpretation of the symptoms. By "stalling" I took it to mean the engine stopped running due to engine rpm too low when pulling up to a stop sign, and it would easily restart. Now it sounds like you mean it quits running while you're driving and won't restart. If that's correct, and you have a code 54, try a different distributor. There are actually two different sensors in it. I can't remember if they each operate at different engine speeds, or if one identifies which cylinder is getting ready to fire and the other one is for precise spark timing.

Many years ago, Toyota had a bunch of trouble with this type of optical sensor. When the PVC system plugged up or stopped working, pressure built up in the bottom of the engine from normal blowby. The pressure forced engine oil vapor past the rubber seal around the distributor shaft. The vapors condensed on the optical sensor. I can't remember what the symptom was, but I don't think it was as simple as stalling while driving.

This sensor is not a common failure item, but you're well beyond looking for something common.

As for buying a scanner, the investment won't break the bank, but in this case, I would recommend a Chrysler tool. There are a lot of aftermarket units out there but none will ever do everything the manufacturer's unit will do. Some of the better ones are the Genysis and various models by Snapon, but they work on many brands of vehicles, so you'll be paying too much for things you don't need. They both include so much unnecessary stuff that they cost more than the two Chrysler scanners. The Chrysler DRB2 has cartridges that work for '94 and older vehicles, but mine work just fine on my '95 Grand Caravan. I sold one for $600.00 at the nation's second largest old car show swap meet about 50 miles from my house, and I have one more that I no longer use. I also have a Monitor 4000 that I bought new and updated once for '92 models. It was made by the same company that made the DRB2, but it does fewer functions but on all three domestic manufacturers. Cost was a lot lower because of the decreased functionality.

Now I use Chrysler's DRB3. It really does a lot of stuff, but because it's a newer model, it only works on vehicles back to 1998. I will never own anything that new, so I use it with two plug-in cards that lets it work back to '94 or '83 models. The '94 card also gives it the capacity to work on the engine / emissions systems of any '96 or newer brand and model car sold in the U.S. This complete kit can be purchased over the internet for a little over $6200.00, but it includes way more stuff than you'll ever need. It has cables to connect to any Chrysler car or truck back to 1983, (but you would need the extra cards), a huge carrying case, books, etc. If you go through the dealer's parts department, you can order just the scanner, the needed card to do '94 to '97 models, and one cable for around $3900.00.

Besides reading fault codes from any of the many computer modules, you can watch sensor values in real time, actuate things like the fuel pump or radiator fan, observe inputs such as brake light switch and neutral safety switch, and there is a record / playback function. That is really useful for intermittent glitches such as momentary sputtering that doesn't last long enough to troubleshoot. When a problem occurs, you press "record" and it will record all the sensor values beginning a few seconds before the button was pressed.

Another dandy function you won't find on any other equipment is "last cutout" for the cruise control. How do you find the cause of a cruise control that stops working for an instant, but within seconds, you can press "resume" and it's fine? The recorded reason could be "brake light switch", "ignition switch", or "something similar. For "ignition switch" for example, you would look for an intermittent problem in the power wire for that circuit. You obviously didn't turn off the ignition switch while you were driving. For the "brake light switch", you would check its adjustment or suspect pitted contacts.

The DRB2 does all these things too, but you have to have the right cartridge. The latest '94 cartridge works on all domestic Chrysler vehicles up to that year, (and most '95s), but older cartridges only work on the few model years they were made for.

Holler back for more information on scanners if you have an interest in finding one.

Caradiodoc

Code 54 is related to loss of signal from the camshaft position sensor. Just to verify, you have the 3.0L V-6 engine. There is no reference to a crankshaft position sensor for this engine, but I only have a service manual for a '91 model. There are no wiring diagrams for a '95 on Chrysler's web site.

The next time the stall occurs, leave the ignition switch on, pop the hood, and measure the voltage on two wires in the distributor connector. The orange wire must have 8.0 volts and the black wire with light blue stripe must be near zero. Typically it will have 0.2 volts. If both of those are correct, measure the voltage on the other two wires. An older pointer-type voltmeter will work best. The voltage should be either zero or five volts, but they should pulse when the engine is cranked. If they remain steady, replace the pickup assembly in the distributor. Before doing that, it would be smart to measure the voltages on the other end ofthe same wires in the Engine Computer's connector. As an alternative, unplug the distributor connector and measure the voltages on those other two wires in the car's harness. Expect to see 5.0 volts on both of them. If you find 0 volts on one, suspect a break in that wire or a corroded pin in a connector.

Here's the same reply from a Chrysler troubleshooter to a mechanic for the same problem:

Check the 5 volt power supply to the sensors for a short to ground. A short to ground on the 5 volt power supply to sensors such as: MAP, TPS, A/C PRESSURE TRANSDUCER, EGR POSITION, etc. Will cause the vehicle to die out and may cause the PCM to be a no response with the DRBIII. It may also cause many other faults as the 5 volt supply feeds several sensors. The 5 volts may be shorted externally as in wiring or you may have a shorted 5 volt supply within the sensor itself. Unplugging each sensor one at a time while monitoring the 5v signal is the easiest way to check for a shorted sensor. When using this method of unplugging each sensor on the 5 volt line, be sure to turn the ignition key off and back on when rechecking the 5 volt supply output. This holds true for the primary 5 volt supply and the secondary five volt supply.

Caradiodoc

I think you found the clue that's going to solve the problem. That orange wire must have 8.0 volts when the ignition switch is in the "run" position. There are three possibilities as to why it's missing:

1. The wire is broken / corroded between the distributor connector and the Engine Computer. If you can remove the cover from the computer's connector, find the wire there and back-probe it to see if the 8.0 volts is there. If it is, but not at the distributor connector, the wire is broken. Since it's intermittent, suspect a corroded connector pin in a connector as the most likely cause. If corrosion is the problem, you will usually see a little voltage at the distributor connector if it is unplugged.

2. The wire could be shorted to ground. The computer will turn the 8.0 volt supply off to protect it from excessive current. The supply will not turn on until the short is gone / removed / repaired, and the ignition switch is turned off and back on. That resets the 8.0 volt supply. Look for wires rubbing over sharp metal brackets or the fat harness under the battery tray is sliding back and forth and some wires are rubbed through and touching bare sheet metal. If you suspect the wire is shorted to ground, unplug the large connector for the Engine Computer, then use a test light or ohm meter. Use the ohm meter to measure between the orange wire in the distributor connector and the NEGATIVE battery cable. Low or 0 ohms is proof of a shorted wire. It should read open circuit on any meter scale. Alternately, use the test light with the clip lead connected to the battery POSITIVE post, and the probe to the orange wire. If the light lights up brightly, that is also proof the wire is grounded. Leave the light or meter connected while you move, wiggle, and reposition stuff. Watch for the short to go away, then look in the area you're monkeying in.

3. The 8.0 volt supply could just be dieing in the Engine Computer for no external reason. You might find this by just monitoring the voltage while you do nothing else. Don't try to start the engine. If the supply dies when nothing is moving, vibrating, or heating up, suspect the computer. I can help you fashion a simple 8.0 volt supply that should operate the distributor. If that stops the stalling, the computer would be the first suspect, or look closely at the connector pins for the orange wire's terminal to be stretched open or corroded.

Caradiodoc

Well, at least we know the 8.0 volt supply is the problem. Don't worry about the 5.0 volts on the signal wire. That will come back when the 8.0 volts is there to power up the distributor.

Since the wire is good, there are two possibilities. The 8.0 volt supply is dieing in the computer. That's where it originates. Or, the distributor is shorting the 8.0 volts to ground. If the distributor is the cause, the 8.0 volt supply will come back if you unplug it, then turn the ignition switch off and back on.

There is one thing that would be helpful to know. When the 8.0 volt supply is missing, do you have 5.0 volts on the signal wire? If it is there, that tells me it is independent of the system that supplies the 8.0 volt supply. If it is missing, building your own 8.0 volt supply probably won't work.

To build a cheap, quick 8.0 volt supply, you will need two resistors. 8.0 volts from a 12 volt battery is real easy to come up with by doing simple math, but things will change when connectong the distributor. For that reason, it will be an experiment. The lower the resistor values, the less the distributor will affect the voltage but the hotter they will get so you'll need higher power ones. Higher value resistors won't get so hot but the distributor will affect the voltage more.

We're going to divide the 12 volts into 8 and 4 volts. Since 8 volts is twice as much as 4 volts, the resistors must have the same ratio. Each resistor has two leads. If you used an 8 ohm and a 4 ohm resistor, connect one lead of the 8 ohm resistor to ground, and one lead of the 4 ohm resistor to the battery positive. Connect each resistor's second lead together. That's where the 8.0 volts will be.

The total of the two resistors is 12 ohms. 12 volts divided by 12 ohms equals 1 amp of current flow. That's a bunch for such little resistors. You will get the same 8 volts with higher value resistors as long as the ratio stays the same. Higher total resistance results in lower current so you can use lower wattage resistors because they won't get so hot. 80 and 40 ohm resistors would be a good choice. These resistors are available at stores like Radio Shack, but they come in standard values so you'll have to pick the closest ones. A 100 ohm and 47 ohm should provide close to 8 volts.

Even if this works, it will just prove the distributor is ok if it doesn't stall. What I don't know is if the computer is the cause of the loss of the 8.0 volts, what other functions might be affected? I guess what I'm thinking is I don't know if this will work.

Reread a ways back and I see your mechanic was poking around on that orange wire so he must have been on the same trail. It looks like their suggestion about replacing the Engine Computer is something to consider. Chrysler actually had very little trouble with them between the mid '80s to mid '90s so I would be comfortable finding one in a salvage yard. If you have a "Pick-A-Part" type yard, computers will run less than 40 bucks. I'm about to make a run to a few "Pull-A-Part" yards in Indiana and Kentucky. I could hunt for a computer, but I don't have a car to test it on. I think this would be the best thing to try next.

Caradiodoc

I'm not getting automated messages either right now, but it's because my Verizon e-mail service has been down for "maintenance" for over two days. I'm gonna have over 300 e-mails when it gets working again!

Your computer is on my list, but I don't have any way to test them. The ABS should not be a factor. What I might need to know is which transmission you have. The three speed or the computer-controlled 4 speed. The easiest way to tell is to look at the gear indicator on the dash. If there is a big "0" around the letter "D", it is the 4 spd overdrive transmission.

Either way, I know there are hundreds of them at the salvage yards around you. I found a spare for one of my Caravans for under 50 bucks. You might have to look at some of the smaller yards. The big expensive places often don't keep anything over ten years old.

Caradiodoc