ECM CODE 61

[gorgeousgeorge]

I finally got the ECM CODE 61 with the method once Bob Saveland shown me(ALDL diagnostic port jumping) and my LT5 engine speed is limited to just 3000 rpm.

I have read the shop manual and now I understand that the CODE 61 refers to "Secondary Port Throttle Valve System". NOT a tiny work to fix..

I am suspecting "Secondary Port Throttle Valve Solenoid" failure or "Electric Vacuum Pump" failure. How would you think about this trouble? Is there any other cause concerning CODE 61?

Thanks in advance.

Yoshifumi Honda
91 Z
Nagoya, Japan

[gorgeousgeorge]

Z51JEFF, XfireZ51,

Thank you for your replies.
I inspected my car this morning with the ignition ON and engine OFF. The electric vacuum pump (located under the passenger side headlight) were winding loudly, and IT NEVER STOP until ignition key being off.

It is most likely I have some vacuum leakage under the plenum. Removing prenum is not easy for me but I have to go ahead with this issue.. I will keep reporting about this trouble.

By the way Z51JEFF, what is P.M.?

Yoshifumi Honda
91Z
Nagoya, Japan

[VetteMed]

P.M. is Private Message.

[gorgeousgeorge]

VetteMed,

Thanks

Yoshifumi Honda
91Z
Nagoya, Japan

[Demps]

Trace the hose with a flashlight under the plenum from the pump. You may see it off.

Another trick is to turn the key again. With the pump running, pull the drivers vacuum line in plenum between 3/5 and Plug with your finger. Does pump stop? Yes check valve is bad. Put vacuum check valve in the connection and a small piece of gas hose to mate to the plenum nipple until you can get under plenum.
Ted

[gorgeousgeorge]

Ted,

Thank you for your reply. I will look for lose vacuum hose connection.

About another trick you told to "pull the drivers vacuum line in plenum between 3/5...".



Does 3/5 mean cylinder#? Is the hose you mean the red circled hose in the picture above?
Does the check valve exist behind the nipple of a plenum?
Does your trick means that add another check valve in line if the original check valve is bad, so that I can fix this problem without removing plenum?

Sorry for disturbing you. I am relatively new to the ZR-1 world and I sometimes do misread English. That?s why I ask this to you



By the way, do I have to check the line of RH, between 4 and 6?

Thank you.

Yoshifumi Honda
91Z
Nagoya, Japan

[Paul Workman]

Originally Posted by gorgeousgeorge

Ted,

Thank you for your reply. I will look for lose vacuum hose connection.

About another trick you told to "pull the drivers vacuum line in plenum between 3/5...".



Does 3/5 mean cylinder#? Is the hose you mean the red circled hose in the picture above?
Does the check valve exist behind the nipple of a plenum?
Does your trick means that add another check valve in line if the original check valve is bad, so that I can fix this problem without removing plenum?

Sorry for disturbing you. I am relatively new to the ZR-1 world and I sometimes do misread English. That?s why I ask this to you



By the way, do I have to check the line of RH, between 4 and 6?

Thank you.

Yoshifumi Honda
91Z
Nagoya, Japan

Here is a picture to show the secondary vacuum system. From the picture you will see that the vacuum line between #4 and #6 on the passenger side is not part of the secondary system.



I would start by checking the vacuum pump first by pulling apart the vacuum connection on the line between the vacuum pump and the plenum. With the pump running, place your thumb over the end of the line and see if the pump stops. If it does, then the pump is working correctly.
Next step is what Demps suggested. If, as he said, the pump continues to run, then there is a check valve problem, or maybe a connection loose? At that point, removing the plenum is your only option. (Removing the plenum sounds a lot more difficult than it is! It is really quite easy.)

Let us know what you find, and we'll continue to troubleshoot.

P.

[Demps]

Paul's picture and explanation are great.

If you plug the drivers hose (one you circled) and the pump stops, the check valve is bad. You can put one in-line at that location until you can remove the plenum.

This may help the code 61 and can keep vacuum in the system if the check valve is the only thing bad.
Ted

[gorgeousgeorge]

Craig-san,

http://www.corvetteactioncenter.com/...diagnosis.html

Thank you for your sharing the interesting link above. I have been at my office from 8:00 a.m. and not worked yet this morning because I was too busy to read through the article

My friend mechanic has a handheld vacuum pump and we will try to inspect vacuum circuit for leaks or worn parts, including valve actuator, vacuum reservoir and vacuum solenoid.

I will let you know the detail here or by e-mail and would like to talk with you about which parts to replace.

Thank you.

Yoshifumi Honda
91Z
Nagoya, Japan

[HAWAIIZR-1]

Ted,

Thanks for the vote of confidence and I'm always willing to learn so another plenum pull will be great.

Yoshifumi-san,

Don't get fired from your job.........lol.

I can send you the DVD for the plenum pull since I might not be able to get to you in the next week. It was crazy to have all this household goods today and I am exhausted from all day of this and can barely walk around all this stuff. I did find the DVD for plenum pull though.

I'll get in touch by email.

Take care.

Craig