IDLE?

Technical and Repair Discussions
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PostPosted: Sun May 10, 2020 3:51 pm
Hello Forum,

I searched for that issue but could not find anything here in that forum.

just converted my srf2 to srf3.
The engine "runs" great and I did everything per instructions- fuel pressure, let the engine warm up at idle to have the ECU learn the Lambda sensor and so on. I also went into the map and told the ECU what 0 and 100% throttle is.

The engine revs nice but every time I go off the throttle it stalls. This is happening in the garage at any engine temp. I only drove the car through the neighborhood, I never raced it.

I can think of 2 things:
1) Since the gen2 engine never had that issue (assuming the idle air controller is the issue), the calibration is wrong.
2) The idle air controller went bad while not using it.

Does any of you have an idea how to test the idle air controller? Do I just put 12V on the connector and see if the cone is moving?
Or do you recommend going to Ford and buy a new one?

Thanks.
svenmueller_77
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PostPosted: Sun May 10, 2020 8:00 pm
I think a lot of folks had this issue after the conversion. When I had the isssue, my CSR hooked up to the ECU and did a little tweaking until the idle became steady and the car would no longer stall. I had installed a new throttle body for my new engine, but sometimes the old throttle body is the issue.

Unless someone else has instructions for the tweaking, your friendly CSR should be able to help.
Kurt Breitinger
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Chassis 494
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PostPosted: Mon May 11, 2020 9:57 am
I too had idle issues in the beginning. At the time, the top portion of our throttle body was available and I purchased one. It’s held on by two bolts. If you carefully remove it, it might just need cleaned. I replaced mine as it showed wear. I still needed help on fine tuning it over the phone with my CSR via my laptop tied to the ECU.
This throttle body is no longer available and that is why Enterprises is working on a new version.
Good luck!
Mark Fick
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PostPosted: Mon May 11, 2020 10:11 am
The Idle Air Controls do go bad, especially if moved over from a GEN 2 engine. Mine did and my local auto parts store had them in stock. $55. Someone correct me if I'm wrong -- I believe it's off a 1987 Ford Escort. That may not solve your issue, but it should be eliminated as a cause before delving into the ECU settings.
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PostPosted: Mon May 11, 2020 6:27 pm
Thanks for all the good and quick responses. I ordered a Delphi IAC for around 55$ shipped. Our local Ford dealer gave me a list with Dealers all over the US which have a Motorcraft version (about 100$) still in stock. Later this week I will see if that fixes it and will reply to that thread. PN is F5DZ9F715BA. Thanks and stay healthy.
svenmueller_77
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PostPosted: Mon May 11, 2020 8:35 pm
I forgot to add that the website FordPartsGiant.com has the IAC for $47.38 plus shipping. IAC's are still available. Throttle bodies I heard are not. Replacing it should help mucho!
Mark Fick
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PostPosted: Tue May 12, 2020 12:25 pm
Have you successfully completed a full warm-up cycle required to set the IAC? It's not unusual to have issues with idle until this has been completed successfully (IAC is calibrated). Manually tweaking the throttle to keep it rrunning will not allow this process to complete successfully, even if you do get to full temperature.

In a discussion with Mike Davies chasing down idling issues, he provided a simple trick to work around the idle problem during the calibration process. Take a tie-wrap and put it between the throttle control and the stop on the throttle body, which will crack open the throttle body enough to run up to temperature without touching the throttle. Going through this process corrected the calibration of the IAC, allowing it to idle correctly.

If it fails to idle after going through this process then the IAC is probably defective (or the wiring to the IAC is bad).
Bob Breton - SRF 51 - San Francisco Region
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PostPosted: Tue May 12, 2020 6:25 pm
Hi Bob,

yes I did that procedure up to 180F or 190F don't remember exact what the temperature was. The car was idling well at 1200rpm before and after this procedure. But the IAC could have been "stuck" from the old days of being used in the gen2 1.9l engine. The part is supposed to come on Thursday and I will report back afterwards.
svenmueller_77
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PostPosted: Tue May 12, 2020 6:57 pm
You may also want to check the voltage from the connector to the IAC to confirm there's a good electrical connection. As I recall, we just used a continuity lamp to confirm that there was voltage from the hot side of the connector when disconnected from the IAC. Hope the new IAC solves the problem.
Bob Breton - SRF 51 - San Francisco Region
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PostPosted: Thu May 14, 2020 8:28 pm
Today I received a nice Delphi Bypass valve. I was surprised that it was basically like the Motorcraft version but with a ground away part number.
After installing it I ran the engine to 190F and shut it off. This was all idle above roughly 140F to 190F. The rpm went from 1200 to 1050min-1 so maybe there was some calibration going on? Not sure. After shutting the engine off I started it up again and revved it a few times to 3000rpm. When I went off the throttle it stalled. Did this a few times and it wasn't even close to "catch itself" and stay running.
I did disconnect the connector from that bypass valve and the engine did not even start up. It fires and turns off right away. There is also 12V on the connector when the ignition is turned on.
Lambda is 0.97 at idle, the fuel pressure is 30psi when the engine is turned off and 34psi when idling.
Any idea is highly appreciated. Thanks.
svenmueller_77
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