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I've been having an issue starting the truck in wet weather, especially after a rain. Cranks and cranks and cranks, but doesn't fire. Eventually, after a LOT of cranking, the engine will barely fire and fail repeatedly. Then, after further cranking, it eventually starts and runs fine. After driving, it can shut down and restart no problem.
Pulling the SPOUT connector gets it fired up after just one or two tries. Definitely something related there.
Pulled codes, got a DTC 211 in stored memory. KOER is 1-1-1.
Yesterday, I checked a few things: Pulled distributor cap - appeared fairly dry, no visible moisture, but the inside was maybe a little slick. Dried it, put it back on, still no start. In heavy rain, the wiring harness for the computer is soaked, but I have a fresh hood-cowl seal installed. The water appears to be coming through bottom of the cowl, maybe under the windshield/opening for the wipers.
Any thoughts? Should it be bone dry there? Do I need to return the ECM?
You have a leak in the cowl area. The wires and PCM connector should be dry. A few recent threads have popped up with the same issue lately. I would be concerned your replacement PCM is getting a bath. At the very least the water on the wires/connector is probably not helping either.
You have a leak in the cowl area. The wires and PCM connector should be dry. A few recent threads have popped up with the same issue lately. I would be concerned your replacement PCM is getting a bath. At the very least the water on the wires/connector is probably not helping either.
I also put a good bit of dielectric grease in the ECM connector and the ignition coil wire. The ICM still had plenty of grease left in it, so I didn't bother adding any. The ECM connector had no sign of moisture.
This morning (super foggy and humid) I opened the hood and made sure everything was still dry, then tried to crank her up. Cranked for about 10 seconds and never got a start. Pulled the SPOUT and it fired right up, stumbled, then ran fine. Put the SPOUT back in, and it ran fine all the way to work. Shut it down, restarted with the spout in. The other day, I checked the base timing and the advance - all seemed perfect right at 10d base.
What else could it be if not an ECM moisture issue?
The Check Engine Light is normally on with the key on and engine off. When cranking, the Check engine light stays on for a couple seconds, then extinguishes, and the engine fires shortly after.
I've noticed that when the engine isn't going to start on these moist days, the CEL never goes off while cranking. Eventually, when it does, the motor begins to fire.
My question: What conditions have to be present for that light to extinguish during start?
Distributor Pickup looked clean. The wires according to the TSB looked to be just fine as well. The weather has been really humid, but no water has been in the engine bay for the last few days.
Checked resistance on the spout connector: .03 Ohms, which appears in spec.
One thing I've noticed is that when I pull the spout and crank, it seems to instantly lessen the problem. I'd think that if I put the spout back in, the problems should return. The advance works perfectly once running. It even starts fine with the SPOUT in after the initial trouble.
My theory is that the battery doesn't have the voltage or too much resistance to accurately control the spout, but the alternator does. Is this possible?
I assume you were measuring the SPOUT circuit from the computer to the ICM?
Correct. I backprobed it from where the SPOUT jumper plugs in.
Originally Posted by rla2005
Did you check resistance with reference to ground. A high resistance would be expected. In the k-ohms I believe.
I'll need help with this one. Where should I put the probes to check this?
Originally Posted by rla2005
With reference to your question "What conditions have to be present for that light to extinguish during start?"
I believe the PIP signal turns off the Check Engine Light (CEL) when cranking the engine or it is running.
Thanks. Since I've seen the PIP signal at the ICM, this one would lead me to believe that the PIP signal is there, but the computer isn't seeing it. I don't understand how pulling the spout would change that though...
Pull the SPOUT plug, put the negative lead of the meter on the negative post of the battery. Put the positive lead of the meter in one of the open SPOUT connector pins. Set the meter to ohms. Verify what the resistance is.
Repeat the above with the positive meter lead in the other open SPOUT connector pin.
A faulty ICM can drag the SPOUT signal down to an unusable level, same for a short or relatively low impedance to ground.
Removing the SPOUT disconnects the computer from controlling the spark/timing. The ICM will trigger on the raw PIP signal (limp home mode).
Have you tried pulling the codes since you installed this "new" PCM? There could be a lurking code in CM.....
Pull the SPOUT plug, put the negative lead of the meter on the negative post of the battery. Put the positive lead of the meter in one of the open SPOUT connector pins. Set the meter to ohms. Verify what the resistance is.
Repeat the above with the positive meter lead in the other open SPOUT connector pin.
A faulty ICM can drag the SPOUT signal down to an unusable level, same for a short or relatively low impedance to ground.
Removing the SPOUT disconnects the computer from controlling the spark/timing. The ICM will trigger on the raw PIP signal (limp home mode).
Have you tried pulling the codes since you installed this "new" PCM? There could be a lurking code in CM.....
Thanks. This morning is foggy, muggy, and the start issue appeared, although not as bad as previously. Ran the resistance test prior to startup and then ran the KOEO test after driving to work.
Resistance from SPOUT pin to -Batt (PCM Side)- 700 Ohms
Resistance from SPOUT pin to -Batt (ICM Side) - 6,030 Ohms
Checked it twice to verify.
KOEO Codes:
System passed, 1-1-1
Continuous Memory Codes
452 - Computer detected an error in the VSS or PSOM signal during the last 80 warm-up cycles.
628 - Converter clutch Lock-Up error (E4OD)
634 - Transmission Manual Lever Position Sensor circuit out of self test.
I had tracked down a hard shift since I bought the truck, but it never got resolved. The PCM didn't store codes, so I thought there were none... I replaced the VSS with an aftermarket sensor some years back, must need to look at it again. MLPS was replaced with motorcraft sensor 2 years ago as well. The hard shift still occurs occasionally and sporadically, typically in hot weather.
Resistance values are reasonable given the PCM and ICM were still connected. Since you are not getting a SPOUT related code I would be confident the signal is not compromised by a short to ground.
Code 634 could be a simple fix. Adjust the MLPS. Code 452 could be from the aftermarket VSS. Kind of common these days.
I am not a transmission guy so all I can tell you about Code 628 is the computer is sensing too much slippage when the converter is supposed to be locked.
Resistance values are reasonable given the PCM and ICM were still connected. Since you are not getting a SPOUT related code I would be confident the signal is not compromised by a short to ground.
Code 634 could be a simple fix. Adjust the MLPS. Code 452 could be from the aftermarket VSS. Kind of common these days.
I am not a transmission guy so all I can tell you about Code 628 is the computer is sensing too much slippage when the converter is supposed to be locked.
Thanks.
Sounds like this is leading me towards a PCM problem... And I already turned in the core
Thinking about going full shade-tree and pulling out the PCM and coating the whole outside with dielectric grease.... If that stops the problem, then I'll at least have confirmation! There's been no water getting in the engine bay since my weatherstripping fix, so it's just humidity at this point.
Sounds like this is leading me towards a PCM problem... And I already turned in the core
Thinking about going full shade-tree and pulling out the PCM and coating the whole outside with dielectric grease.... If that stops the problem, then I'll at least have confirmation!.
I believe that will be a bigger mess to deal with. Open up that "rebuilt" PCM and inspect.
Resistance values are reasonable given the PCM and ICM were still connected. Since you are not getting a SPOUT related code I would be confident the signal is not compromised by a short to ground.
Code 634 could be a simple fix. Adjust the MLPS. Code 452 could be from the aftermarket VSS. Kind of common these days.
I am not a transmission guy so all I can tell you about Code 628 is the computer is sensing too much slippage when the converter is supposed to be locked.
Thanks.
The MLPS was *slightly* misaligned. Got it fixed up and it seems to have fixed the code. Got a motorcraft VSS installed. When I compared it with the aftermarket one, the visual difference was notable. Shift problems haven't returned, and I'll pull codes this afternoon.
This morning was another wet morning, but she fired right up with no problem. Hopefully it will pick up a code or something next time it happens. The fun of intermittent problems....
Next time it happens, I'll try cranking, check for codes, then pull the ECM to inspect.
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