Engine Performance problem
1995 Chrysler Le Baron 6 cyl Front Wheel Drive Automatic 69000 miles
The engine has a long history of stalling out. (This time it can be kept running by shifting into neutral and keeping the accelerator open but this is not drivable). Over a couple of years many $ have been applied to the problem (some new sensors, distrib.,etc.,etc). I have wired in a ground wire to all engine grounds, as suggested by several Lebaron Club members and the car ran fine for a couple of months (about 700 miles) when the stall began again, as it usually does. The key switch code system now reads 12 (OK), 54, (no fuel sync signal) and 55 (OK). I was told by a shop that #54 is a "general" code and they will have to run a diagnostic with their "reader" to learn what is wrong. I have had this done several times and am thru with that approach (throwing in new parts until the problem goes away).
I bought the '95 GTC Lebaron Conv. (from a woman's estate). It appeared to be in excl. cond. W/40K mi. in Rockport, TX a Gulf Coast town. It now has 68K mi. and is my "toy" car. I suspect that the coastal climate may have started an electrical corrosion problem but none apparent on the body.
The picture was taken here in Austin, TX, Dec. 20/ '10 w/my gnddtr age 15 from San Diego, CA.
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.
February, 25, 2010 AT 3:30 PM
Thank you Randy. I will follow all of your suggestions and believe you are on the right track. So far I have disconnected the battery overnight and after starting the engine (normal start) all conditions were normal through total engine warmup at idle. No fault codes were recorded.
Before I proceed with the " coasting" test I want to finish grounding the fuel pump and conducting the " pinching or blocking" the fuel return line test. I will keep you informed and will gladly pay for this assistance if it is required. Would my having your e-mail address be of any help in ease of communication?
DHuber6024@gmail. Com Thanks again Doug
February, 25, 2010 AT 11:29 PM
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 : )
February, 28, 2010 AT 3:47 PM
Randy: Doug Huber here.
Thanks for your suggestions. I attempted all but the coasting test. Rather than " pinching off" the fuel return line I tried the alternate: removing the vacuum hose from the fuel pressure regulator and plugging it. The engine ran fine through warm up and starts and stops. No smoke was observed as I revved the engine up.
The code 54 remains even after removing the negative terminal from the battery. I take this to mean that the fault still remains. The following short history may help.
The stalliing problem has been ongoing during the 20,000+ miles we have driven it. The car had a new MAP sensor installed following a lengthy $400 testing program. About two months ago the car stalled again and had to be towed to a repair facility. They wanted to start throwing parts at the car and there was no way I could speak to the mechanic. They apparently did some diagnostics testing with no discussion with me and said they needed to replace the CPM (which had already been done some time previously) with a used one costing $186 plus another $125 labor. I paid the $91 bill and asked that the car be left so I could tow it away. I tried starting the car and it ran and stumbled badly. While it was running, I raised the hood and found the mechanic had removed the electrical connection from #6 injector and installed a small light bulb fixture which was flashing on and off. Also, he had removed the cover on the CPM connector and pierced an orange wire (apparently so he could read the voltage) running to the #7 pin. The orange wire runs to the distributor and other places according to the Haynes manual. I reconnected the electric lead to the #6 injector and drove the car home.
I cleaned the CPM 60 pin connector and receiver with electrical spray in spite of the fact that the pins looked clean. Then I ran a ground wire from the negative battery post to every grounding spot in the engine compartment. No fault codes were read with the key on/off system. My son drove the car after this commuting on a 30 mile daily run daily for 800 miles. Then it stalled once again and now we have #54 code still to deal with. It appears to me that I need to get the car to some shop that will take the time to talk to me and/or buy my own diagnostic tool and try to do the job myself.
I would really appreciate your further suggestions. It's a hobby car, in beautiful shape, but it is forcing my attention to a new hobby. The car's beharior is forcing me to consider donating it to a museum or sadly, an automotive parts recycling facility (junk yard). Thank you again. Doug
dhuber6024@gmail. Com in Austin, TX
March, 1, 2010 AT 6:36 AM
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.
March, 8, 2010 AT 5:26 PM
Randy, Doug here. Sorry for the long delay. Those scanners are far too expensive for me but I need to keep trying to find out why the car quits running somehow. Following your suggestions, the car seemed to be ok so I took it out on the highway to do the " coasting test". All went well so on the way back home the car stumbled again at a red light where I had to turn. I was able to keep it runnining but after the turn it flat out died and wouldn't start so I coasted to a side street and parked. The engine wouldn't start and still has the 54 code. Another tow job to get the car home. I put the original CPM back in, but no start, still shows 54 code.
My question' is it possible to get the CPM and Sensors TESTED? I Haven't gotten a straight from the shops, they just want to throw parts ion a logical sequence based on experience. Thanks Doug
March, 8, 2010 AT 6:55 PM
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.
March, 14, 2010 AT 6:52 PM
Thank you for your 3/08/10 reply. I also have been unable to locate a camshaft position sensor in the Chilton Manual for the '95 which is very limited in scope.
Following your suggestions, I reconnected the battery (new last September), eliminated the flashing security lights (lock and unlock the driver side door), tried to start the car which cranks over well and tested again for codes using the key system. This time I got 12 (OK), 11 (a new one " no camshaft position signal detected during engine rotation" ), 54 (no fuel sync signal during engine rotation), and 55 (OK).
I think this tells me that I got no spark and no fuel. Is this right?
I probed the distributor connector power side (had to disconnect it to do so). With the switch on I got the following results which I recorded as each was done: The orange wire - no voltage - supposed to be 8.0.
Black/light blue tracer - near or zero - supposed to be 0.2 volts or zero.
Grey with black tracer - 4.9 volts -supposed to be 0 or 5 volts.
Yellow - 4.9 volts - supposed to be 0 or 5 volts.
But the grey and yellow are supposed to pulse when the engine is cranked and they don't.
In reviewing the previous work, I noticed that you may have wanted the distributor connected up during the voltage tests.
Regarding your paragraph that starts " check the 5 volt power supply": I cannot detect which wires are the 5 volt power supply wires to check for short to ground. The only wiring diagrams I can find are those partial ones shown in Chiltons' " Chrysler '88-'95 Repair Manual # 8672 (#20384). Is there anywhere I can get the complete wiring diagram for this '95 GTC so I can figure it out?
I probed the ignition coil input voltage, which I presumed would be 12 volts, but there was no voltage at all. And again the car doesn't start. To me, it appears that the distributor is still a suspect fault. It was suspected 3,000 miles ago as the source of the stalling and was replaced by a mechanic with a rebuilt one after which the ran for a while. Is it possible to replace the sensor(s) in the distributor without removing it from the engine (which I am lothe to do unless necessary)?
At this juncture, I am considering spending another $150 for a new used " internet" PCM taken off a running car.
I just went out to read the codes, the car wouldn't start and the only code showing are 12 and 55 with check engine light still showing. What a mess!
Thank you for your help. Doug
March, 14, 2010 AT 8:17 PM
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.
March, 17, 2010 AT 8:00 PM
Randy, Doug here: Thank you for your 3/14 reply and suggestions.
Making minimal progress. There is definitely no voltage on the orange wire leading to the connector for the distributor. There is continutiy in the orange wire from the PCM. The 8.0 voltage could not be detected at the pin in the PCM either. All the wires were carefully inspected and no sign of abrasion, etc. Could be found.
Since I am completely in the dark as to the source of both the 8.0 and 5.0 voltage circuits I cannot proceed without your assitance in locating the souce of them. I would appreciate very much your offer in " fashioning" the simple 8 volt supple for the distributor and possibly also a 5 volt supply so I can test the various sensors. I will monitor the key codes during the process.
In the event the above testing shows that the distributor is working and, hopefully, all the sensors I suspect the next step would be to just go ahead and buy a used PCM. This will assume there are no key codes showing.