Intrepid Auto Repair
“A run of very bad luck” is the only way to describe my efforts to put my Intrepid back on the road. I had replaced the water pump well over a year ago. While I was in the front of the engine I replaced the timing belt and main oil seal along with belts and hoses. I was doing the “right thing.”
Six months later I was driving to work and noticed a faint haze behind me. I exited the Interstate as quickly as possible. Inspection revealed that when running there was a thin stream of oil pouring from the front of the engine. Since my wife’s car was recently made available by our purchase of a mini van, I started driving it instead.
Over time I took the Intrepid apart and eventually determined that the cheap painted metal front main seal I had installed had been forced out of the block by the oil pressure. This was after replacing the two cam shaft seals and the PCV valve. (I thought that perhaps the oil leakage was caused by, or at least exacerbated by, pressure in the block.) I replaced the main seal again. This time with a teflon coated seal.
By now the Intrepid had been sitting for almost nine months. Now that it was fixed, I was ready to sell it. To prep it for sale, I replaced the EGR valve (the check engine light had been on even before the oil seal was blown out). After replacing the EGR valve, I cranked the engine to make sure it was running correctly and that the check engine light did indeed go out.
I was a little impatient. I used my ODB II reader to erase the error code instead of waiting for the engine to warm up. I cranked the engine again with the intention of bringing the engine up to normal operating temperature. As I was gathering my tools the engine made an unpleasant sound and died. I tried to start it again and when it didn’t start right away I thought, “Oh, well. Something else to fix,” and promptly forgot about the incident.
Thinking back, I don’t understand how I forgot such an important detail. I was trying to sell the car after all. I did, though….
I had received several calls from people interested in the Intrepid but none of them ever showed up to look at it. I reduced the price in the ad just before trying to move it into the garage to remove the trailer hitch. Having forgotten about the engine dying, I was surprised when I couldn’t get the car to crank. The battery was low so I thought perhaps the combination of a cold engine and low battery was the culprit. I charged the battery overnight.
The next evening after work, I re-installed the charged battery. The battery was still too weak to turn the engine over more than a few times. Undaunted I dropped the old battery in the trunk of my wife’s car to avoid a $5 charge on a new battery.
Five miles, four turns, a wayward mini van and a brick wall later I found myself without a drivable car. I didn’t like my wife’s car but it didn’t deserve to be forced into a brick wall. I’m pretty sure I didn’t deserve to be forced into a brick wall, either. Even more determined now, I called up a friend and, with the Sherrif’s deputy’s leave, took my old battery on to the store.
Still no good. The new battery spins the motor fast and long but the engine will not crank.
I go through the basics; fuel, fire, fuel and fire. The first look indicates a nice blue flame and the plugs were wet. Normally I’d think that the wet plugs were indicating no spark. However, since the car had been sitting for nine months and had only been started a few times, I decided that the fuel must have gone sour. I checked and it did smell a bit sour as it came from the fuel rails. It smelled very sour at the fill hole. Following the first conclusion, I drained the old fuel and put in five gallons of premium.
Same story. The engine would not start. This is where the fun begins….
Back to the basics…I once again checked for fire. This time I saw that the fire was not continuous. Number one would fire once and stop. I checked others and they did not fire at all! Now my thoughts move on to the computer (or PCM–Powertrain Control Module, as Chrysler calls it). However, given its cost and the rarity with which the PCM’s go bad, I had to check everything first.
Following the Haynes manual, I began the methodical task of testing all the sensors and devices. Both the cam shaft and crank shaft sensors were doing fine. The primary and secondary coils of the ignition module where within spec for resistance. Twelve volts was being applied to the coil when the ignition was turned on. Everything required to let the PCM know when to ground the ignition coils was in place. Frustration.
It was at this point that I started remembering that the engine had died suddenly the last time I had started it. I still didn’t remember the fatal noise. Given the timing of the engine failure (just after I had replaced the EGR valve) I began to suspect that perhaps the new EGR valve solenoid had in some way damaged the PCM.
After checking parts stores and finding prices of $170 plus and relatively long delivery times I decided to check junkyards. I found one late Saturday evening. They were already closed so I’d have to wait until Monday to buy the PCM.
In the mean time I once again checked all the sensors and devices. In addition to repeating all the previous tests I used a test light to test how the ignition coils were being grounded while the engine was being cranked over. One of the wires was being grounded permanently. Another wasn’t being grounded at all. The third was being grounded either once and then no more or a few times and then no more. I found this particularly strange.
Having checked all the sensors and devices and seeing the strange ignition coil grounding behavior, I estimated a 90% certainty that the PCM had failed. I was haunted, however, by the remaining 10%.
First thing Monday morning I arrived at the junkyard. They did indeed have a matching PCM. I also picked up the solenoid portion of the EGR valve while I was there just in case the new one had caused the supposed PCM failure.
Once I had the used PCM in place I tried to start the car. Still no good.
As I stood looking at the engine I reviewed what I had been through up to that point. I had checked the crank shaft and cam shaft sensors. I had tested the ignition coils. I had done everything right! But still the strange ignition coil grounding behavior persisted. The 10% had come back to bite me–the PCM wasn’t the problem. Supreme frustration!
I recalled something my friend had said when I started cranking the car over with the new battery. “It doesn’t sound quite right,” he’d said. I agreed but didn’t think much of it at the time. There are lots of things that can make a car sound “not quite right” including the stange PCM behavior I was observing.
Having done everything else, I finally broke down and pulled the timing belt covers off. Lo-and-behold, the driver’s side cam shaft was about three teeth out of time. Finally! I quickly came to the conclusion that since the cam shaft that had the position sensor on it was out-of-time the PCM didn’t know what to make of the signals it was getting!
I quickly pulled the timing belt tensioner off and re-timed the engine. Leaving the alternator and A/C belts off, I jumped in and cranked the engine hopefully.
Vroom! Yahoo! moorv… Uh oh. Not good.
The car would start, run for just under three seconds and die. If I left the ignition on and tried to restart the engine, it would hit but not start. If I turned the ignition off before restarting the engine would start, run for just under three seconds and die. Repeat.
Once again I check fire and fuel. The car was firing perfectly even when it wouldn’t run. That left only fuel.
I could hear the whir of the fuel pump at all the right times so there wasn’t a problem with the fuel pump running, at least. This left two possibilities; either the fuel pump had been damaged in my ferver to empty the fuel pump (no, I hadn’t pumped the tank dry using the fuel pump, but I had checked fuel flow many times through the fuel rail access port) or the fuel injectors were being shut off (a la PCM).
Trying to cover both possibilies in the shortest time possible, I called the junkyard to arrange to get my old PCM back the next day and I visited Autozone to get a fuel pressure tester and, just in case, a fuel pump. Things were going reasonably well, I felt, after such a horrible sequence of events.
It didn’t take long to determine that the fuel pressure was just fine. It was the PCM, then, and a long sleepless night before I could confirm.
At the junkyard the next morning they didn’t take too long to locate my old PCM. They assured me that the PCM I had purchased had come from a running car. Whatever. I knew I was taking a chance by getting it at a junkyard.
Vroom, vroom, vroom! What a relief. After the stress of being without a ride and working feverishly to get the Intrepid back on the road I felt like I had only just walked away from the accident. I feel better now that I have my Intrepid working again.
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Details: The timing signal wasn’t correct so the PCM didn’t know how to signal the ignition coil to fire. The driver’s side cam had jumped a few teeth (why or how was a concern for later) causing the cam position sensor signal to no longer coincide with the crank position sensor signal. The ultimate result was that one of the three grounding wires going to the ignition coil was staying on all the time, one would be off all the time, and the other would sometimes toggle once and stop or sometimes toggle more than once and stop.
The preceeding involved a 1997 Dodge Intrepid with a 3.5 L engine.