Intermittent Code 61 Ideas

[Paul Workman]

The casual reader of this and other ZR-1 boards quickly pick up on the fact that the 15-20 year old vacuum circuit is one if not THEE most common nags associated with the LT5s.

Parts not used don't cost anything and they seldom break!



I'm using Marc Haibeck's secondary elimination chip b/c it has several other drivability features really worth the $$: The fans come on early, the idle, especially on startup is handled nicely, fueling and spark advance minimize power loss when the engine is at normal op temp, and a couple more features too...Not to mention no more finicky secondary naggings! Eliminating the damn things is a consideration. And, there just might be a few more ponies in there when the throttle rods and plates are out of the air stream!



P.

[GOLDCYLON]

Originally Posted by Pete

When your on the throttle does it shut down at 3k?
If so check your power switch make sure it works/stays on.
Put a scanner on the car check the volts on secondary MAP it needs to be below 3.6 volts.
Otherwise you have a vacuum leak search and find leak,also check vacuum actuators put vacuum to them make sure they open by 7" of vacuum and stay open,they don't usually go bad but if your in there might as well check them.

Just a thought you sure you plugged in the electric plug to the vacuum solenoid. Done that once
Since then i yanked the secondaries.

Pete

Hi Pete no it does not shutdown at 3K. My Power key is defeated at the Prom level so its always on. The pump works and I now have the answer to what that Brrrraaaaap sound is when I turn the key before I start the car. I thought that was a Battery ECM sound to be honest. I pulled the rubber hose to the pump and it immediately started pumping when I tried to block the tube next to the oil filter.

I checked the hose connection at both MAPs I am convinced one of the Metal vaccum actuators is toast and time for a plenum pull. Jim check valve is also a certain possibility.

[GOLDCYLON]

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:

Great pic. I remembered that when I replaced my ECM holder about 6 months ago. I had no idea where that line went too until I traced it down. However dood... where the hell is your brake fluid lol?

[Pete]

If you need the vacuum actuators,i have 2 brand new actuators i will sell $250 for both.

Pete

[GOLDCYLON]

I'll keep that in mind thanks Pete

[Dynomite]

Originally Posted by GOLDCYLON

I checked the hose connection at both MAPs I am convinced one of the Metal vaccum actuators is toast and time for a plenum pull. Jim check valve is also a certain possibility.

When you say toast ......do you mean you think the bellows is leaking or the acutator is stuck and not working......or.....the vacuum line connection is leaking?

Do the secondary actuators look like they are functioning when you look down through the plenum?

I know you are aware of this but......
I checked the secondary actuators using a dull sewing needle alongside the pin C17 (pink with black stripe 1991) where it is connected to the ECM. I used a small aligator clipped electrical wire attached to the sewing needle. I turned on the ignition switch and then grounded the other end of the aligator clipped wire while looking straight down (each side) between middle two intakes using a flashlight. As you ground the end of the aligator cable you will see the vacuum actuator pull the secondary linkage

Paul Workman......I am thinking of your suggestion eliminating the secondary actuator control system and having Marc program/reprogram my chips (yes I have a couple)

In your last post in that thread http://www.zr1.net/forum/showthread.php?t=9370&page=8 was that idle issue taken care of....did you have Marc program the chip for secondary injectors on at idle? Are the secondary injectors programmed in sync with the primary injectors or how does that work?

Originally Posted by Paul Workman

It IS as simple as removing the secondary vacuum pump associated hardware, actuators, and even the throttle plates too!
P.

I assume you mean each throttle plate in each secondary and elimination of the shafts also using your shaft removal technique?

I would pull the shafts and plug the holes....Marc program the chip accordingly

Did you eliminate the secondaries before or after porting and did the fact you eliminated the secondaries have any effect on how you ported the injector housing?

I just sent Marc an e-mail

Back to you GC

Originally Posted by GOLDCYLON

Hi there GC needs a little help. I getting an intermittent SES light that wont hard set but always leads back to a code 61 (Secondary port throttle system error). Thanks Daryll

[GOLDCYLON]

I think one or both of the metal actuators are leaking. Or the pump is not compensating for a low pressure demand in 6th gear. I suspect this is causing the intermittent Code 61

I have found all the charts in the FSM and will pull out the Tech 1A this weekend. Flying out of town again tomorrow but will be back soon. At least it appears it can be diagnoised to just before the point of a plenum pull. Hopefully its something simple.

[bdw18_123]

Originally Posted by GOLDCYLON

Great pic. I remembered that when I replaced my ECM holder about 6 months ago. I had no idea where that line went too until I traced it down. However dood... where the hell is your brake fluid lol?

There is fluid in the reservoirs, it's just low. Was like that when I bought the car.

[Paul Workman]

Originally Posted by Dynomite

Paul Workman......I am thinking of your suggestion eliminating the secondary actuator control system and having Marc program/reprogram my chips (yes I have a couple)

In your last post in that thread http://www.zr1.net/forum/showthread.php?t=9370&page=8 was that idle issue taken care of....did you have Marc program the chip for secondary injectors on at idle? Are the secondary injectors programmed in sync with the primary injectors or how does that work?

No, I haven't latched the secondary relays; still controlled by the ECM. Neither I nor anyone with the secondaries removed has had an SES event (yet) that would shut down the secondary injectors. But, once I get the LT5 back in, it will be back on the radar as a "todo" this season.

I assume you mean each throttle plate in each secondary and elimination of the shafts also using your shaft removal technique?

Yep. Use the Dorman 555-108 freeze plug and a socket way smaller than the plug to drive the plug in place. (Thank Pete for that bit of info)

I would pull the shafts and plug the holes....Marc program the chip accordingly

Did you eliminate the secondaries before or after porting and did the fact you eliminated the secondaries have any effect on how you ported the injector housing?

I pulled the secondary hardware after porting the top end, before semi-porting the heads (in place). The secondary ports on the heads are at 36mm (stock). The secondary plates would not necessarily have had to come out, but I did remove them for better air flow, and because I radiused (is that a word?) the transition between the IH and the head, somewhat, to soften the bend between IH and the head.

The primary side is another question: That too is 36mm at the IH outlet. So, the head is opened up quite a bit to mate with the IH. From what I gather, most simply go down into the head, maybe a half inch to blend. I was working in a phased approach: always intending to port the heads, at a later date (Phase-II). As an interim step, what I did was create a smooth transition from the input of the head all the way down to the valve guide; about 3-1/2". (Man! I do so wish in retrospect that I had dyno'ed the car before pulling the heads (to fix a valve issue). I'd bet a steak dinner the net result of the P&P with the taper in the heads was worth significantly north of the 30 or so hp gain that is typical for a P&P.)




As for the heads,

I just sent Marc an e-mail

Back to you GC

>>

[tomtom72]

Good morning guys!

Yes, that MAP under the ECM bracket is what our ECM uses to monitor the state of vacuum during secondary operation. The vacuum hose attached to it originates at the T-ee fitting at the left actuator. Also, now I'm not 100% sure on this but I'll post it as a "beware" kind of thing.

The MAP under the ECM I think is a different part number. Not sure, but I remember doing something and trying the electrical connector on my spare MAP sensor from behind the plenum, and it seemed not to want to plug into the MAP's socket???? This is a big "not sure about this" on my part. I think I was just doing a let's see if this works thing, and I couldn't get the plug in my spare plenum mounted MAP.....I was kind of surprised, but I have never revisited this issue to nail it down I will this weekend if I have a chance, now that I'm thinking about it. I was doing my own diagnosis of a hard 61 about three years ago, and I brought all my spare parts with me to the garage I rent so as not to forget anything I might need. As usual, I was in a hurry to get the 61 cleared up as it was a week before my first Carlisle and I wanted to take the Z. My 61 was the ECM.


Tom