Intermittent Code 61 Ideas

[John Boothby]

By scantool are you refering to a Tech 1? I do have one with correct ECM cartridge. The system is holding vacumn. The pump comes on for a few seconds when the key is turned on and then shuts off and stays off.

[XfireZ51]

Originally Posted by John Boothby

By scantool are you refering to a Tech 1? I do have one with correct ECM cartridge. The system is holding vacumn. The pump comes on for a few seconds when the key is turned on and then shuts off and stays off.

I wouldn't mind having a Tech 1 myself. Yes, it's a scantool. When you go Key On and secondary pump cycles, what is the reading for the Diff MAP sensor voltage? If the pump is shutting down, that tells me sensor is reading correctly and signaling ECM that there is sufficient vacuum to run secondaries. That would lead me to think it's not MAP sensor. If secondaries were not operable you would get a code 55? I think as well. If just getting code 61, then it's a Lean O2 condition which is shutting down the secondaries. So the issue is why is A/F going lean.

[FULLPWR]

Hey John,
I just replaced both on my 90 with ACDELCO's,

under the ECM
the acdelco box it came in states the same no. for ac/gm
ACD# 16232241
GM# 16232241


MAP SENSOR back of plenum
ACD# 213-1545
GM# 12569240



Luis

[Dynomite]

Originally Posted by tomtom72

Daryl, I know you don't want to hear this but an intermittent 61 usually is vacuum related....usually. Figure the control solenoid is an on - off switch, so electrically it has to set a hard code if that side of it fails. If the vacuum side has a soft failure, like crap in it, then the 61 becomes intermittent. Likewise if the pull off canisters have soft failure in the rubbers, then maybe an intermittent 61 happens. Oh, also the second MAP sensor under the ECM where the ECM monitors the level of vacuum during secondary operation...that could also be the source of a 61, or any of the vacuum hose connected to any of the stuff under the plenum for the secondary system....which then goes back to the pump & any issues it could have.
JMHO
Tom

Originally Posted by bdw18_123

So that's what that is. I saw that under the ECM on my '90 ZR-1, looks the same as the primary MAP sensor (minus the silver bracket). Was wondering why there was a second one. Good info, thanks Tom!

Here is a picture of the one on my Z:

Originally Posted by FULLPWR

Hey John, I just replaced both on my 90 with ACDELCO's, under the ECM the acdelco box it came in states the same no. for ac/gm
ACD# 16232241
GM# 16232241

MAP SENSOR back of plenum
ACD# 213-1545
GM# 12569240

Luis

Just putting all this together

[John Boothby]

Thanks bro's!!

[GOLDCYLON]

I want to close this post out. I had broken #5 secondary port throttle valve shaft. It was broken in two at the center screw point. Must have been a factory fatigue flaw. Or maybe I hammer the secondaries too hard

Thanks to the ZFDoc for getting me back on the road and to Andrew for supplying with the secondary parts. Next go around the entire secondary system is coming out

[GOLDCYLON]

Originally Posted by Dynomite

I assume no broken parts were sucked into the cylinder
Sounds like you already started to remove your secondary with another option on how to remove secondary valve shafts

Luckily no the parts were just floating around