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1998 ford windstar nightmare

posted Mar 22, 2016 11:42:39 by bdazsvt03
To start this off. The van shut off driving down the road. No symptoms at all. Once it stopped. I got out and heard clicking coming from under the hood. Popped the hood checked it out and it was the fuel pump relay and the IAC motor. The service engine light is dimming constantly and there is no communication with DLC. DLC checked out with power and grounds just for good measure. So i went after the PCM grounds and all seemed ok. SCOPE DOES SHOW SOME SPIKING so i removed all grounds i could find and cleaned then with no change. I do not have fuel pressure. I have spark, i have injector pulse, i have 5 volt reference at dpfe and tps. I am having trouble finding an accurate wiring diagram. I use alldatapro. And found a mitchell but they all say it has a CCRM. 1998 does not.there is a wire that monitors the fuel pump from pcm i have eliminated the fuel pum because it has been unplugged at the harness and relay still clicks. The green and yellow wire going to the inertia switch is dim and pulsing as is the white and blue signal wire from iac. I dont want to call a PCM i am not a parts changer i am a diagnoser! Any ideas would be helpful. I have some other info i can provide as to what i have done. This is getting to l9ng. Thanks
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17 replies
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bdazsvt03 said Mar 22, 2016 11:56:18
Also pulled plugs on all sensors. I feel like i am missing something!!!!
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cheryl hartkorn said Mar 22, 2016 22:48:46
check under the cowl!! windstars are known for water leaking on the pcm and causing issues
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Noah said Mar 22, 2016 22:48:58
Did you also volt drop test the power wires at the PCM? Possibly a main relay crapping out?

Probably doesn't matter but 3.0 or 3.8?
Massachusetts, USA
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cheryl hartkorn said Mar 22, 2016 22:50:32
also what do you mean seem ok? did you use a test light to "load" test the grounds at the pcm?
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bdazsvt03 said Mar 23, 2016 10:00:29
Yes i checked PCM pulled it out and everything is dry took cover off and was dry.

The PCM relay is good. I did volt drop tests on all pcm power and grounds.

I scoped grounds and they are within spec.they are a little spikey on the scope so i removed and cleaned all of them that delt with PCM. No change

It is a 3.0
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Noah said Mar 28, 2016 01:53:31
Did you get anywhere with this one bdazsvt03 (ohhh, now i get the SN!)?
I have an all data diagram if you need it.
Just curious, are there any other power feeds that seem to be pulsing? Like the fuel injectors or MAF?
Massachusetts, USA
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bdazsvt03 said Mar 29, 2016 11:08:03
I actually had a medical emergency with my mother so i backed off. The only things pulsing are the signal wire from the iac valve and the (im assuming at this point the fuel pump monitoring circuit and control. It is a green with yellow tracer which is the same as goes to the inertia switch. The pump runs fine if i remove the relay and jump it. Also if i disconect the harness that goes to the rear of the van the fuel pump will stop whirling but the relay is still going nuts. As for the all data i have alldatapro and the sheet is wrong. I have a pre september model. (Off the top of my head,date)
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bdazsvt03 said Apr 01, 2016 01:26:53
So here is an update. The control wire for the iac and the control wire for the fuel pump are the two wires causing the whole issue i assume since they are both acting up at the same time and are 2 pins apart the PCM is the problem.
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Noah said Apr 01, 2016 02:16:10
The control wire for the iac and the control wire for the fuel pump are the two wires causing the whole issue

So the light blue and orange wire that controls the fuel pump relay is switching from high to low? (ECU pin #80) I only ask because you first only mentioned green/yellow wire to the inertia switch. That wire goes right from the fuel pump relay to the inertia switch and ultimately the fuel pump. The leg of the circuit to leads to the computer like you said is a monitor. I don't believe that a computer problem on that circuit could activate and deactivate the fuel pump relay.

I noticed the power feed for the fuel pump relay and the IAC come from the PCM Power main relay, as do the power feeds for the MAF and injectors. That's why I was asking about those earlier.

The no communication and flashing CEL are scary, but the power feed from the PCM power relay is also a computer power, so it could fit.
Still could be a bad PCM, hard to call to make sometimes.

I hope everything is okay with your mother.
[Last edited Apr 01, 2016 02:27:06]
Massachusetts, USA
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bdazsvt03 said Apr 01, 2016 10:45:07
Everything is ok with my mother she has had to make some life adjustments and move in with my family. What i found with the green and yellow was a splice with all three green and yellows together. I cut the splice to remove the fuel pump and monitor and i was still getting the fuel pump relay clicking. I pulled the engine compartment fuse panel and flipped it upside down and the wire that is pulising is the blue and orange to the fueel pump. It is the control for prime when koeo. That wire goes strait to pcm. I did voltage drop test and continuity and it is perfect as is the white with blue wire on the IAC. The green and yellow wire was throwing me off because it was the easiest to get to so i started chasing it because it was linked to inertia and pcm and fuel pump. Everything tested out on the PCM relay, wiring and the relay itself including tue wire from pcm relay to fuel pump relay. I went soley after the fuel pump relay. The red wire is fine on every sensor every place i can get to it. As is the 5v ref wire. The onlything pulsing is the white and blue from IAC and blue orange pump control. Its odd and the first time i ever seen it like that in two places. In the beginning i went after pcm grounds. Which by the way all of them are probably at a little higher resistance as stated before early in the post due to the pump control and IAC cuting on and off. Now that i know all reds are good and the problems are coming from 2 seperate control wires i feel pretty confident its the PCM. If you dont mind look over the info we have talked out and check that diagram let me know what u think.

Thanks for the help i dont ask for it to often but its better to trouble shoot with someone else.
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Noah said Apr 01, 2016 11:58:43
If that blue and orange wire is being pulled low then high repeatedly, it sure sounds like a PCM issue. That one only goes to the PCM and the relay, like you said. If you're confident in the powers and ground at the computer, I would say it's time for a new computer.
Massachusetts, USA
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PaulDanner said Apr 02, 2016 20:25:48
Just briefly read through this, just tread carefully if you are calling a bad PCM. They do not fail often on these. But as cheryl hartkorn said, these are known for water intrusion.
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Noah said Apr 04, 2016 11:58:50
I think the only thing u would add is that I have seen IAC motors on ford engines that are shorted out have low resistance wipe out computers. May be worth checking the resistance of the IAC, or even manually energizing it and doing an amperage measurement to make sure you don't fry a new PCM.
Massachusetts, USA
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bdazsvt03 said Apr 04, 2016 17:39:18
Noah the iac i believe is fine. It is actuating with the voltage pulse. So it is doing what the computer tells it. And let me add those two pcm contols look crazy on my scope
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bdazsvt03 said May 24, 2016 13:47:12
I forgot to update. I replaced PCM and everything works as it should
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