Code 61 during colder outside temp

[Wigert]

Originally Posted by 32valvesftw

The code appears after 5 mins on the highway in the morning? Heres what I think, when one first starts the car it runs in closed loop mode and does not utilize the inputs from all the sensors. when the coolant gets up to temp the engine runs in open loop and takes input from all the sensors. So I don't think its really temperature causing the issue, its just allowing the computer to show it you.
Im no expert on the secondary systems on these cars, so I can only suggest pulling the plenum and checking things.

Yes after around 5 minutes, but only in the morning. Nothing during the rest of the day...

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[Wigert]

Originally Posted by Paul Workman

Dom, It does sound "electrical". But, like the open vs. closed loop I think you're "180 OUT" (old electronics term means 'backwards') on the short vs. open (circuit). (SHORTS = something is gonna get HOT and burn...or melt a fuse @ the very least. OPENS = NO current flowing, e.g., a light switch, resulting in NOTHING is getting HOT.)

OP: Expansion and contraction with the changes in temp is more likely (I think) to cause an open when very cold, and reconnect when the metal expands with the rising temp. (Shorts vs. Opens: Shorts = high current and something will get HOT. Opens too can result in no voltage, but NO current. Nothing gets hot. (Just sayin!).

Starting with the vacuum pump (under the right headlight), is it working when very cold?

My approach would be to verify the vacuum circuit is sound and functional (See Marc Haibeck's site for his articles - one on vacuum leaks, but specifically on how to activate the secondaries while observing the actuators viewed from outside of the motor (i.e., w/o pulling the plenum).

Then verify the connector to the vacuum solenoid switch (under the plenum) is in good condition and the connection to the secondaries MAP sensor is also in good condition. (Note: the secondaries MAP sensor is attached under the ECM on a 90, but under the plenum on 91+

Course there IS a final solution to the whole vacuum and secondaries issue... (Do I have to say it??).

When I say cold weather in the morning I mean around 10 degree celius. As far as I tested befor the vacuum pump starts and stops as it should in the morning. But I shall check again.

Marcs article seems very useful.

I assum you mean elimination of the secondary system

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[S.hafsmo]

Does it still happen if the car is not in full power mode?

[Wigert]

Originally Posted by S.hafsmo

Does it still happen if the car is not in full power mode?

Good question! I shall test it tomorrow.

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[Paul Workman]

Code 61 detailed:

From the symptoms you describe, I think a vacuum issue can be all but completely ruled out, except for the possibility of the vacuum (switch) solenoid leaking, which has to be checked out before scratching a vacuum leak off the list completely.

That leaves the VACUUM SENSOR, the ECM, and the attending wire and connections to be eliminated from consideration - saving the ECM for last.

Good luck!

[Wigert]

Originally Posted by S.hafsmo

Does it still happen if the car is not in full power mode?

Yes the SES light still comes on even with the valet key in the off position.

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[Wigert]

Originally Posted by Paul Workman

Code 61 detailed:

From the symptoms you describe, I think a vacuum issue can be all but completely ruled out, except for the possibility of the vacuum (switch) solenoid leaking, which has to be checked out before scratching a vacuum leak off the list completely.

That leaves the VACUUM SENSOR, the ECM, and the attending wire and connections to be eliminated from consideration - saving the ECM for last.

Good luck!

Good writeup! Then I should start checking electric connectors etc. I have seen a lot of oxide on for example the connectors to the headlights. Maybe something similar has occured for the secondary system.

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[S.hafsmo]

Then I'd try to disconnect the vacuum hose going to the vacuum sensor under the ECM (If the car is a 1990). Don't think you can reach the hose on a later model, as the sensor is moved to below the plenum.
If you can disconnect the hose, and the problem persists, at least you know that the solenoid isn't applying vacuum to the secondarys when not supposed to.

[Wigert]

Originally Posted by S.hafsmo

Then I'd try to disconnect the vacuum hose going to the vacuum sensor under the ECM (If the car is a 1990). Don't think you can reach the hose on a later model, as the sensor is moved to below the plenum.
If you can disconnect the hose, and the problem persists, at least you know that the solenoid isn't applying vacuum to the secondarys when not supposed to.

It is indeed a 1990, but I do not follow your suggestion. Do you mean that I should disconnect the hose and drive without vacuum in the secondary system?

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[Paul Workman]

Originally Posted by Wigert

It is indeed a 1990, but I do not follow your suggestion. Do you mean that I should disconnect the hose and drive without vacuum in the secondary system?

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No. What S.hafsmo was driving at was a method of verifying the vacuum solenoid is not leaking.

As stated in the FSM write-up, IF the secondaries are commanded CLOSED, but the VACUUM SENSOR detects vacuum when it shouldn't. (B/c the SOLENOID vacuum switch is suppose to be blocking vacuum from the SENSOR and the SPT actuators when the SPTs are commanded CLOSED.)

And, b/c you have a 90, you can disconnect the vacuum line from the VACUUM SENSOR which is easily accessible directly under the ECM. NO plenum removal required.

(Note: At this point, I have my fingers crossed, cuz I've never actually done this particular test - just going by the FSM and logic.

The THIRD time I had the plenum off b/c of another SPT issue, I went "COMMANDO" so to speak and took Pete P's suggestion and removed every last bit of the SPT system. Turns out as one of the best "mods" I've done so far, and I NEVER regretted it for a heartbeat!! There's NO drivability downside!) "Parts that aren't there seldom break and they don't cost much!"

Oh, some romantics pine over the loss of function of the FULL POWER switch and the novelty of it....WAXERS....and endeavor to maintain the SPTs uniqueness. But, I like the INSTANT throttle response, the reduced coking especially on the secondary intake valve, and NEVER EVER having a CODE 61 ever again.)