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Notorious 2005 Ford Escape, PCM repaired coil drivers, now it will not start
Series of events leading up to current issue:
truck started losing power when we hit around 55mph
No codes
When the temperature dropped the issues got worse, finally the car stalled, all the lights came on, we were able to start it back up and limp it home with loss of power and chugging
Codes pulled up showed a couple misfires and PCM issue
Replace all plugs, all ignition coils, sent the PCM to get repaired, diagnosed with coil driver 4 fried, all coil drivers were replaced PCM was on a simulator for 24hrs, diagnostics ran on pcm pulled up vin, odometer, etc. all systems check ok.
Installed everything, truck cranked but would not turn over- built in diagnostic system read: Lamps ok, lift gate closed, fuel ok, then listed, service emissions, service 4x4, service charging system, service brake system. If you try to get information on the fuel (economy, mpg, etc) it states: fuel information computer not available.
The odometer is correct, the gauges work, the anti-theft recognizes the key and remote.
We took the manifold back off to noid test the wires to the ignition coils. When we tried to crank the engine - Nothing - tried to trouble shoot, made sure all fuses, relays, and electrical connections were good etc, still nothing
Put everything back together, hit the nurse switch, tried to crank the engine - nothing - in system diagnostics still reads the same and the key and remote are still recognized.
We would love to know what we may have missed!! Any help would be appreciated!!
truck started losing power when we hit around 55mph
No codes
When the temperature dropped the issues got worse, finally the car stalled, all the lights came on, we were able to start it back up and limp it home with loss of power and chugging
Codes pulled up showed a couple misfires and PCM issue
Replace all plugs, all ignition coils, sent the PCM to get repaired, diagnosed with coil driver 4 fried, all coil drivers were replaced PCM was on a simulator for 24hrs, diagnostics ran on pcm pulled up vin, odometer, etc. all systems check ok.
Installed everything, truck cranked but would not turn over- built in diagnostic system read: Lamps ok, lift gate closed, fuel ok, then listed, service emissions, service 4x4, service charging system, service brake system. If you try to get information on the fuel (economy, mpg, etc) it states: fuel information computer not available.
The odometer is correct, the gauges work, the anti-theft recognizes the key and remote.
We took the manifold back off to noid test the wires to the ignition coils. When we tried to crank the engine - Nothing - tried to trouble shoot, made sure all fuses, relays, and electrical connections were good etc, still nothing
Put everything back together, hit the nurse switch, tried to crank the engine - nothing - in system diagnostics still reads the same and the key and remote are still recognized.
We would love to know what we may have missed!! Any help would be appreciated!!
0
Comments
What is your level of tooling as far as things like a digital oscilloscope, and low amps current probes?
Everyone knows the mantra of you have to got have spark, fuel and compression to get a cylinder to fire. The troubles like what you are experiencing comes from the fact that fuel has to be in the right amount, the spark has to be strong enough and at the right time, the compression has to include fresh air so that there is oxygen for the fuel.
When checking for spark, are you using an ST-125 spark checker? (The second one in this video)
It takes 25000 volts to fire the ST-125, if it doesn't fire, you test the circuit as "no-spark" and you'll go right at the problem. The other tool that showed spark is actually misleading because while you have some, it isn't necessarily enough to fire the plug in the cylinder.
For the injector pulse, how are you confirming that the injectors are in fact being triggered and in fact delivering fuel? A noid light isn't enough to confirm an injector pulse and can again mislead you into thinking the circuit is working correctly when it really isn't.
Lastly, compression. As I mentioned, you have to include fresh air into the equation and there are a lot of times when you have a misfire occur, the catalysts fail and restrict the exhaust. Without a path for the exhaust the engine stops pumping fresh air and so you don't have the oxygen required to burn the fuel. This is why I asked if the spark plugs are wet with fuel or not. In the shop we have several options from using the pressure transducer in a spark plug hole to measure the cylinder pressure during all four strokes and we will see the exhaust pressure rise. (best way) It's worth mentioning at this time its also possible the cylinders are simply washed down with fuel dropping the compression. If the compression is low a little oil into each one should help restore compression enough that you can get this to fire and clear up.
Now another way is to pull the up stream O2 sensors and if possible attempt to start with that exhaust open. This has some concerns that have to be taken because of the risk of fire and component damage. If you have to try this, you want to hear the engine fire and immediately shut it back down. You are also required to make sure that this check cannot damage anything if the engine does fire up before trying especially since the exhaust is likely to be loaded up with fuel and there will be components near the O2 sensor opening that could easily be caught on fire! You have to take precautions before trying to see if the engine will fire this way such as shielding for the gasses (flame) that will escape and be ready to extinguish any fire should you get some. It is preferred that instead of an open exhaust that you acquire a gage that can be threaded into the O2 sensor hole in order to directly measure the exhaust pressure. Anything higher than atmospheric pressure cranking is showing a problem, some pulsing as each exhaust stroke occurs (less than 1/2 a psi needle movement) would not be an issue.
plugs are dry
We have a multimeter and a probe, no scope... nothing to fancy in our garage, I worked at a parts store and built a wealth of knowledge and have helped my bf (along with the wonderful internet) learn how to do most of our own repairs.
Other than that it is a normal starter circuit.
you can hear the click in the starter relay but the starter itself does not click.
there is power to pin 7.
Still no crank, no start
Inboard diagnostics say information not available on all major systems
What will cause the computer to not have communication?
What scan tool are you using? Professional level tools have broad capability and cover almost all of the systems on the car. The Ford IDS of course communicates and has full function support for every module that the car could have. Many aftermarket DIY level tools are very limited and may only connect to two to four of them and quite often don't support half of the functions that the car is capable of.
We would like to know what may be stopping the pcm from displaying the status of the different major system on the instrument cluster in the display window that is under the rpm gauge
Here is one plausible scenario, this is NOT what I am saying is wrong this is what could be going on and how it would be proven.
Upon connecting a scan tool all of the modules on the car respond except for the PCM. The codes that are retrieved include a loss of communication for the PCM. If you follow a trouble tree at this point it will have you checking powers and grounds to the PCM and other resistance based continuity checks. I teach advanced routines to techs all around the country. I would have them go to the easiest sensor that they can access and measure to see if the 5v reference is present. If they see 5v, that means the PCM is powered up and they can now concentrate on the communication network first. If they see less than .5v then powers to the PCM and the reference circuit must be checked. The thing here is a shorted sensor, or a grounded (pinched) to ground 5v reference could pull that 5v reference output voltage to ground and that does shut the PCM down. If the voltage at the reference wire is higher than 5v, then the ground circuits for the PCM become suspect. During these checks the PCM itself is always suspect and there are legitimate ways to prove if it has failed or not, but again it all starts with what you find with a scan tool.
As I started out saying, that was one example, another would have the PCM communicating and generating a trouble code(s) for specific circuit failures. Trouble codes don't tell us what part failed, they tell us what test the computer is running that is failing. We have to know how the computer runs that test, and then we test the circuit the same way that the PCM did to efficiently come up with a solution. Your earlier post stated that the PCM was sent out and repaired, it's plausible that you have a connector issue and maybe even a damaged PCM connector pin. Without testing correctly, everything is still in play from my point of view. Just like in math classes in high school, the more variables that are in the equation, the tougher that it is to solve but it can still be done if you have a good game plan and the right routine.
We need to see what codes are setting, then we can move to the next step. Otherwise you are basically relying on luck to hand you the solution and eventually that might work, but the safer bet is that without a good game plan your going to be stuck right where you are.
We have a chilton manual but it does not list the pin locations for our 150 pin harness, we did find a diagram on line but there was at least one pin location that was not correct. Would you know where we could find a reliable diagram of the pin list and a reliable diagram of the engine with the sensors locations listed, and a list of what type of voltage each sensor should have?
Without a scan tool, there us a high probability that you are going to be unable to advance through this.
If that helps anyone be able to target an issue for us, that would be helpful.
At the very least I would like to figure out if the no crank issue is PCM, electrical, or mechanical.
Very few people that you are going to talk to have ever diagnosed these kinds of vehicle issues and there are precious few that do it on a regular basis. If you watched them they would make this look easy, but the skills that they put to use were very hard earned and how it looks betrays how difficult it really is.
You won't find the steps that I will tell you to follow in service information. The service manual "assumes" that the technician has no idea how the system really works and that's why they concentrate on resistance tests which require disturbing the circuit to perform. The problem is disturbing the circuit to do any testing risks temporarily fixing a connection issue and that makes the problem hide which results in the car not being fixed the first time and that causes many of the reports of multiple visits before a solution is found, if ever.
The first check I want you to make is go to the easiest sensor to reach under the hood and with the key on, try to measure the reference voltage to that sensor. It should be 5v. If you see 5V then the PCM is powered up and operating and you simply have a communication issue. If you see a voltage higher than 5V, especially if it is much higher then the PCM has lost a ground connection. The next step is that all of the ground circuits need to be measured at the pins that connect the PCM to ground and confirmed to be close to 0v.
If you measure less than 5v at the reference voltage pin for the sensor, then you have to confirm the power supplies to the PCM, and that means all of them. Some are permanently supplied power and some are switched sources. Once those are confirmed to be OK then you need to measure the 5v reference for the sensors at the pin that it is sent out from the PCM. If it is less than 5v you need to start unplugging every sensor under the hood that it supplies. As each sensor is unplugged, watch for the 5V reference to return. Once they are all unplugged and if the 5V reference didn't return, turn the key off. Disconnect the PCM connector and now use the ohm meter and measure the 5V reference circuit to ground. If you have an open circuit, then it didn't get pinched to ground and you have confirmed that the PCM itself has failed and needs to be sent back out.
BTW, pin 13 in the data link connector is only for reprogramming and the scan tool sends an 18v signal out to the car to let the different computers on the circuit know that a reprogramming function is being performed. When using a full function scan tool and a loss of communication we add a break-out box in-between the scan tool and the diagnostic connector so that we can see the communication waveforms as we attempt to access other modules that are on the same data-bus. If we can communicate to other modules that confirms the bus is operational. If we cannot then the diagnostics follow that loss of communication routine.