Intermittent Full Power Mode

[johnboy89]

Hi All,

Looking to get some help on an intermittent issue (91 ZR-1) I'm having with the full power light going out on me.

Light will go out on me occasionally, although even when it's on doesn't feel like my secondaries are kicking in sometimes.

So far I've tested the switch, manually actuated the secondaries, installed a new vacuum pump and tested for leaks.

If the power light goes out is it tied into the permissives for the secondary actuation, coolant/oil temp etc. and is this what’s causing my light to go out occasionally?

Thank You :)

[MuRCieLaGo]

Why do you even have a "Full Power" light on a 1991? I thought it was only there on 1990s...

[GOLDCYLON]

Why do you even have a "Full Power" light on a 1991? I thought it was only there on 1990s...

You are correct the "Full Engine Power" light only comes on for the 90 Model year in the Drivers Information Center (DIC) however the full engine power script still remains in the DIC however has no light bulb for it in the 91 and up models.

I believe the OP is referring to the green LED next to his power key ? Are you getting any Service Engine Soon codes? Have you scanned the car for codes?

If your car is displaying any SES codes it won't go into full power mode

[Marc Haibeck]

Some time ago I encountered that problem. If the green light is not on, the secondary port throttles will not be enabled.

I replaced the key assembly and the problem did not recur. After the car ran correctly for a few weeks I reinstalled the original key assembly to confirm that the key assembly was defective. The problem did not return. Was there a resistive connection on one of the two cable connectors? You could try unplugging the cables and reconnecting them. It's easy to do.

[Dynomite]

Some time ago I encountered that problem. If the green light is not on, the secondary port throttles will not be enabled.

I replaced the key assembly and the problem did not recur. After the car ran correctly for a few weeks I reinstalled the original key assembly to confirm that the key assembly was defective. The problem did not return. Was there a resistive connection on one of the two cable connectors? You could try unplugging the cables and reconnecting them. It's easy to do.

Kevin successfully reconditioned the Full Power Key as I also did......
See item #2 CMHSL LED, Full Power Key and Alternator Pulley (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-3.html#post1581564081)

Using needle nose pliers I bent the "blades" shown in red to their new position shown in yellow (the bending taking place at point A and point B). This allows the cam of the switch to fully contact the yellow "blades" while fully closing the silver contacts located in the top right corner of the photo of the Full Power Switch.

The original position of the "blades" shown in red actually did not stay in contact with the cam requiring jiggling the switch back and forth until contact was made of the cam with the "blades". Then vibration would break that contact and you have a non working Power Switch or intermittent working Power Switch in which the silver contacts on the top right would not stay fully closed. You could feel that the Power Key was loose with no resistance in the Full Power Mode indicating there was no contact with the "blades".

I used a bit of white grease on the cam and cam pin.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/f5821e0f-739a-46db-812d-3de36ee7501f.jpg

[johnboy89]

You are correct the "Full Engine Power" light only comes on for the 90 Model year in the Drivers Information Center (DIC) however the full engine power script still remains in the DIC however has no light bulb for it in the 91 and up models.

I believe the OP is referring to the green LED next to his power key ? Are you getting any Service Engine Soon codes? Have you scanned the car for codes?

If your car is displaying any SES codes it won't go into full power mode

That's correct I'm referring to the green LED next to power switch. I meant to add in my original post no SES light or codes.

Some time ago I encountered that problem. If the green light is not on, the secondary port throttles will not be enabled.

I replaced the key assembly and the problem did not recur. After the car ran correctly for a few weeks I reinstalled the original key assembly to confirm that the key assembly was defective. The problem did not return. Was there a resistive connection on one of the two cable connectors? You could try unplugging the cables and reconnecting them. It's easy to do.

I pulled the key apart last night checked connections and redid solder joints. I'll test later today to see if it resolved issue.

Kevin successfully reconditioned the Full Power Key as I also did......
See item #2 CMHSL LED, Full Power Key and Alternator Pulley (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-3.html#post1581564081)

Using needle nose pliers I bent the "blades" shown in red to their new position shown in yellow (the bending taking place at point A and point B). This allows the cam of the switch to fully contact the yellow "blades" while fully closing the silver contacts located in the top right corner of the photo of the Full Power Switch.

The original position of the "blades" shown in red actually did not stay in contact with the cam requiring jiggling the switch back and forth until contact was made of the cam with the "blades". Then vibration would break that contact and you have a non working Power Switch or intermittent working Power Switch in which the silver contacts on the top right would not stay fully closed. You could feel that the Power Key was loose with no resistance in the Full Power Mode indicating there was no contact with the "blades".

I used a bit of white grease on the cam and cam pin.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/f5821e0f-739a-46db-812d-3de36ee7501f.jpg

I actually found this article and my switch is different in that I have contacts inside like a relay. I thought I remember reading somewhere they changed the switch to a momentary in 91?

[Dynomite]

I pulled the key apart last night checked connections and redid solder joints. I'll test later today to see if it resolved issue.

I actually found this article and my switch is different in that I have contacts inside like a relay. I thought I remember reading somewhere they changed the switch to a momentary in 91?

Did you take any photos of the switch apart/key apart?
If what you did fixes the issue for the 1991, post up the fix for the 1991 :thumbsup:

I think this is one more case where there were changes between 1990 and 1991.

Just found out the Clutch Hose between Master and Slave may be another change between 1990 and 1991. 1991 appears to be a SS Braided hose with swedged end fittings and 1990 appears to be a combination two steel pipes and short length rubber hose in between :dontknow:

Paul may verify this shortly :handshak:

I may have to modify/upgrade..........Differences between 90', 91' and 95' ZR-1s and Engines (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1583614819)

[johnboy89]

Did you take any photos of the switch apart/key apart?
If what you did fixes the issue for the 1991, post up the fix for the 1991 :thumbsup:


Unfortunately I did not take any pictures, but it's not the same as you have above. Appears to be a better design also.

What I did do though appears to have fixed it, although I didn't see anything wrong.

I was able to get datamaster to connect for me tonight and I did notice that I had trouble code 66 "Valet mode switch open or shorted". I went for a run without clearing the code and feel as though the secondaries did not open, seeing how I never went above 5100RPM. Not sure if there are other ways to verify that in datamaster?

Does anybody know if this code will stop the secondaries from opening? Did NOT have a SES light on.

UPDATE 4/12: Drove car to work this morning and secondaries appear to be working, so the DTC for the valet switch must have been it? :)

Thanx



http://i104.photobucket.com/albums/m161/johnboy89/datamaster_zpscuxkljvm.jpg