2005 F90TLRD Another ISC Issue

[99yam40]

he had the wires/pins out of a connector, So there maybe a problem where he put them back

[username]

he had the wires/pins out of a connector, So there maybe a problem where he put them back

I doubled checked wire location in IAC connector several times. They are correct. Not likely a bleed over of current within the connector to another wire, but possible. I did order a replacement and when I splice it in I’ll check voltage at each wire behind connector.

[username]

Just spit balling here. I might try disconnecting one sensor at a time and see if I drop voltage on the green/black wire just in case that voltage is getting sent back on the ground circuit from failed/faulty sensor.

[rejesterd]

Maybe start with the pulser coils, per the service manual. It's odd that your YDIS report didn't show a value for timing. It was null.

[username]

Maybe start with the pulser coils, per the service manual. It's odd that your YDIS report didn't show a value for timing. It was null.

That’s a good point. I went back through all the files I have recorded recently and none show a timing value. Non running files have the BTDC or ATDC column empty. And running shows only the acronym for timing without a value associated with it.

I don’t have a test harness, but maybe I can back probe or fashion one.

Thanks.

[fairdeal]

And running shows only the acronym for timing without a value associated with it.

Engine Monitor
Monitor Item Result Unit
Engine speed 2671 r/min
Intake pressure 39.37 kPa
Intake pressure 11.57 inHg
Atmospheric pressure 996.2 hPa
Atmospheric pressure 29.5 inHg
Ignition timing TDC deg

???
What do you call "halfway between 1 degree BTDC and 1 degree ATDC"?

[username]

???
What do you call "halfway between 1 degree BTDC and 1 degree ATDC"?

Good call and sometimes the obvious needs to hit me in the head

[username]

I found and ordered a 4 pin connector at Amazon for the ISC. I just received it today and confirmed it's identical with the exception of wire color. Thought I would post it so it may help others someday. Common to Denso 4 pin alternator connector.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[username]

New (used) ECM. No change. I have a fishing vacation coming in two weeks and I’m tempted to use it with the ISC disconnected. I’m really stumped here. With the ISC discounted it idles all day long at 10-1100

[TownsendsFJR1300]

With the ISC discounted it idles all day long at 10-1100

That Idle RPM is REALLY hard on your LU shifting into gear..

And LU's ain't cheap...

.

[username]

That Idle RPM is REALLY hard on your LU shifting into gear..

And LU's ain't cheap...

.

I know you’re right!

[username]

Wanted to post what I realized yesterday after someone somewhere else asked if I had a photo of the wiring at connector before “fixing”. It was also suggested here that I should double check it. I did, like what feels like a 100 times. But I was checking against the service manual wiring diagram. I wouldn’t even have considered it was incorrect. Why would I?

So....had a wire at ISC with no continuity. Repaired that one wire and still had issues. Ordered new ISC valve and while waiting for it I de-pinned and “fixed” the complete connector following my manual’s wiring diagram. I wasn’t crazy about how the connector turned out and ordered a new connector and spliced that in again by the manual.

installed new ISC and still had issues. The problem shifted to high idle all the time at start and an ISC that appeared to operate in reverse when tested. Well, that’s because it was. When asked if I had a photo I looked at my phone and of course I did and I couldn’t believe it was different than the manual. I did a quick cut and splice before the heavy rain yesterday. Idle was normal after start up. 1100 for a second and fell to 700. I only let it run for a few minutes cause I had wire hanging out there. But I think I got it. I wanted to close this out. I see it all the times on tech boards where issues aren’t closed out and I didn’t want to be that guy.

[username]

Wanted to post what I realized yesterday after someone somewhere else asked if I had a photo of the wiring at connector before “fixing”. It was also suggested here that I should double check it. I did, like what feels like a 100 times. But I was checking against the service manual wiring diagram. I wouldn’t even have considered it was incorrect. Why would I?

So....had a wire at ISC with no continuity. Repaired that one wire and still had issues. Ordered new ISC valve and while waiting for it I de-pinned and “fixed” the complete connector following my manual’s wiring diagram. I wasn’t crazy about how the connector turned out and ordered a new connector and spliced that in again by the manual.

installed new ISC and still had issues. The problem shifted to high idle all the time at start and an ISC that appeared to operate in reverse when tested. Well, that’s because it was. When asked if I had a photo I looked at my phone and of course I did and I couldn’t believe it was different than the manual. I did a quick cut and splice before the heavy rain yesterday. Idle was normal after start up. 1100 for a second and fell to 700. I only let it run for a few minutes cause I had wire hanging out there. But I think I got it. I wanted to close this out. I see it all the times on tech boards where issues aren’t closed out and I didn’t want to be that guy.





Pics of actual and manual.

[TownsendsFJR1300]

Question, in the initial post, the engine started with having a very high idle (suddenly)..

I know you re-wired the ISC correctly but what / how was the initial cause? Was it a bad ISC initially?

[username]

Question, in the initial post, the engine started with having a very high idle (suddenly)..

I know you re-wired the ISC correctly but what / how was the initial cause? Was it a bad ISC initially?

I think that is correct. After correcting JUST the one wire with no continuity the original valve still idled out of spec. After rewiring all wires in the connector Incorrectly is when the issue shifted to a reverse operating on new valve. I plan on putting the old ECM back on and see if it’s good. Same with the ISC valve. It won’t be until after my vacation coming up on the 15th.