Scorpio High Idle🙄

[espacef1fan]

I did a search and learned a lot but no one seems to have the same problem I’m having.

So 89/auto.

It starts(reluctantly, the gas is old as hell so no surprise there?)

It will not idle down however. On initial start it’ll go to 12-1500rpm then climb to 2000ish rpm.

Trouble shooting I’ve done so far and other symptoms:

Ran codes:
-Code 23 (TP/FIPL sensor out of range)and code 67 (PNP or clutch switch circuit failure) are present KOEO.
-IAC, TPS, and ECT sensor wires are less than .6 ohms.
-TPS and connector replaced with TSB kit.
- replaced IAC with 2.3T IAC, same result.
- swapped EVU with another ECU(same codes/symptoms)
- car will idle down during KOER test but idle up after wards.
- idle drops to normal with ECT unplugged
- car stalls with IAC unplugged but can be kept running.
- hesitation on revving, similar to broken accelerator pump on a carbed vehicle.


What’s next?

[zxr250cc]

Hi all,

Look for a vacuum leak? Was the car sitting a long time? Mice nibble on anything like the vacuum hoses for the engine?

Cheers

[espacef1fan]

The car had been sitting but I’ve had no luck finding any vacuum leaks, to include capping off the manifold port.

I’ve never seen it run good as it’s something I saved from a field/back yard.

[espacef1fan]

So far all I can think to do next is:
-Revisit vacuum leak search.
- Try to reset base idle with iac unplugged(need to find procedure for that)

[espacef1fan]

What’s the normal TPS voltage range the ECU is looking for?

I’ve messed with the idle stop screw so it may be causing an issue?

[zxr250cc]

Hi all,

The XR, which is a different engine obviously, likes a 1.0 volt reading IIRC.

Others in here what setting do you use? Ranger 2.9 liter pickups use the same system?

Cheers

[zxr250cc]

Hi all,

How to adjust TPS in Fords:

https://www.therangerstation.com/tech/t ... tion-test/

Cheers

[Ed Lijewski]

I'd install a new ECT; its role in engine manage is key. (And MAP sensor and ACT sensor just as part of a tune-up on an unknown engine maintenance history). The EGR valve could be carbonated up (equivalent to a vacuum leak). The trans shift modulator (passenger side of trans) operates via vacuum so check the hose end length near it. The hose ends at the vacuum ball typically lose grip after some years; clip off ~1" from each end.

Good luck!

YMMV

[Ed Lijewski]

Edit above:

The throttle body should be thoroughly cleaned (bore/butterfly and passages).

I think the butterfly should close completely at idle (re idle screw) .

YMMV

[espacef1fan]

I'd install a new ECT; its role in engine manage is key. (And MAP sensor and ACT sensor just as part of a tune-up on an unknown engine maintenance history). The EGR valve could be carbonated up (equivalent to a vacuum leak). The trans shift modulator (passenger side of trans) operates via vacuum so check the hose end length near it. The hose ends at the vacuum ball typically lose grip after some years; clip off ~1" from each end.

Good luck!

YMMV

I’ll definitely have a look at the EGR .

I’d simply not thought about that as all my other cars don’t have an EGR valve for one reason or another.

Is there anything special about the ECT or ACT sensors or will rockauto specials suffice?

I’ll also remember to mess with the vac modulator plumbing if nothing else to ensure the trans is happy.

[espacef1fan]

Edit above:

The throttle body should be thoroughly cleaned (bore/butterfly and passages).

I think the butterfly should close completely at idle (re idle screw) .

YMMV

The reason I ask about the idle setting is the code says out of range.

I’m wondering if I’ve closed it too far and if the ECU doesn’t self calibrate like modern stuff.”, so it needs a minimum starting voltage to pass KOEO tests.

[Ed Lijewski]

I'd install a new ECT; its role in engine manage is key. (And MAP sensor and ACT sensor just as part of a tune-up on an unknown engine maintenance history). The EGR valve could be carbonated up (equivalent to a vacuum leak). The trans shift modulator (passenger side of trans) operates via vacuum so check the hose end length near it. The hose ends at the vacuum ball typically lose grip after some years; clip off ~1" from each end.

Good luck!

YMMV

I’ll definitely have a look at the EGR .

I’d simply not thought about that as all my other cars don’t have an EGR valve for one reason or another.

Is there anything special about the ECT or ACT sensors or will rockauto specials suffice?

I’ll also remember to mess with the vac modulator plumbing if nothing else to ensure the trans is happy.

WVE (formerly Wells) and Standard Products sensors from RA have worked well for me in both Merk models, and are very inexpensive on RA.

YMMV

[Ed Lijewski]

Edit above:

The throttle body should be thoroughly cleaned (bore/butterfly and passages).

I think the butterfly should close completely at idle (re idle screw) .

YMMV

The reason I ask about the idle setting is the code says out of range.

I’m wondering if I’ve closed it too far and if the ECU doesn’t self calibrate like modern stuff.”, so it needs a minimum starting voltage to pass KOEO tests.

Your Code 23 re FPIL and that weird Code 67 definition suggests you're using a list of codes applicable to some other version of the Cologne 2.9. Search for a an earlier Two Digit ODB-1 Code List without these things which the Scorpio 2.9 doesn't have.

Re TPS found out of range it seems possible that an idle screw misadjustment would be read by the ECU as out of range at idle, especially as you said you installed a new TPS. The Scorpio TPS is non-adjustable (unlike the XR TPS). And its ECU doesn't self-calibrate. I've never touched/adjusted the idle screws on my two Scorpios, an '88 and an '89.

YMMV

[brokencase]

As always each time you fix something, disconnect battery and wait a bit and reconnect and re-capture codes to see if you actually addressed the issue.

I think your TPS is bad. Unless you have proven that this particular error code is gone.

One almost never messes with the idle screw on a Scorpio. It is factory set for the life of the vehicle. This is not like a carburetor adjustment.
Why? Because the EECIV controls idle with the idle control solenoid. idle control solenoids can go bad. Mine did.

[zxr250cc]

Hi all,

I posted this over in the XR section and it is specific to OBD 1 codes:

https://www.therangerstation.com/tech/o ... ord-codes/

The early V6 Ranger used the same engine, as we know.

Hope this helps.

Cheers