spark plugs for a full top end ported engine

[flyin ryan]

Originally Posted by Jeffvette

John, anything that comes into me gets the NGK iridium plugs. I've been extremely happy with them on my 368 and other cars I've used them in.

I use them on my cars as well as on some of the better engines I build. They are spendy but worth it, I feel. Sounds like your creeping up on it Johnny .

[phrogs]

Originally Posted by flyin ryan

I use them on my cars as well as on some of the better engines I build. They are spendy but worth it, I feel. Sounds like your creeping up on it Johnny .

Well I changed the plugs and while It felt a little better anything up in 5th or 5th gear at lower MPH say 40mph and I mash the gas it shakes like the damn car is comming apart.

so looks like Ill be in for a plenum pull to see WTF is wrong.

Anyone have a tech 1a I could borrow? its the one tool I still don't have.

[phrogs]

well heres what I got

I swaped the plug to another cylinder and it was clean in that one, the one in # 6 was getting dirty like carbon or oil?


But I checked the wires and coil packs without pulling the plenum and heres what I have.

1/6 20.6
2/3 21.3
4/7 19.0
5/8 20.2

so I guess its time to check the injectors man this sucks.

[flyin ryan]

Originally Posted by phrogs

so I guess its time to check the injectors man this sucks.

Yup...but gotta be done .

[phrogs]

Ok now I'm really at a loss


Checked the injectors hot they all rear around 15 ohms.

I even changed out the secondary injector relays with my spares and it didn't change anything.

now heres the kicker I was hammering on it this evening just now after I did this nice hard pulls untill around 5K and it stumbles but then keeps going but when Im around 60 in 2nd gear I get a SES light.

checked the code and Its damn 61 secondary port throttle system WTF

[XfireZ51]

Sometimes 61 is accompanied by an Lean O2 Sensor, I think its code 55.
If its not lean then the ECM is shutting down the secondaries due to insufficient vacuum, so differential MAP sensor is sending a signal voltage to the ECM of less than .7v if IIRC.
Secondary vacuum leak? Weak Fuel Pressure?

[rhipsher]

Originally Posted by phrogs

Ok now I'm really at a loss


Checked the injectors hot they all rear around 15 ohms.

I even changed out the secondary injector relays with my spares and it didn't change anything.

now heres the kicker I was hammering on it this evening just now after I did this nice hard pulls untill around 5K and it stumbles but then keeps going but when Im around 60 in 2nd gear I get a SES light.

checked the code and Its damn 61 secondary port throttle system WTF

The old code 61. Don't you love it. Secondary port throttle failure seems to be the most common problem that I read about on here. But I'm sure you are already familiar with the method for chasing down and fixing that. When it happened to me I don't remember my car shaking. But I do remember it running out of breath at 4500rpm's and then the ses light and the H61. The secondaries weren't working when I bought the car. And at that time I knew nothing about the car. Let alone how to fix it. But I found an article about secondary port throttle failure on the corvette action center "with pictures. I like pictures" and it really helped me understand how it works and what to check for. It took me a month to close in on the bad component. And just when I was about to throw in the towel thinking I had made a big mistake buying this car. I found it. A $36 part causing the problem. It was the secondary vacum solenoid. Buttoned the plenum back up and for the 15th time took it out for a drive and crossed my fingers and prepared to mash that peddle. Wow! What a difference. The rest is history. I hope its somthing simple like that.

[phrogs]

Im thinking about just removing the secondaries, I mean I do not have smog check so I really don't care about them being there.

Originally Posted by rhipsher

The old code 61. Don't you love it. Secondary port throttle failure seems to be the most common problem that I read about on here. But I'm sure you are already familiar with the method for chasing down and fixing that. When it happened to me I don't remember my car shaking. But I do remember it running out of breath at 4500rpm's and then the ses light and the H61. The secondaries weren't working when I bought the car. And at that time I knew nothing about the car. Let alone how to fix it. But I found an article about secondary port throttle failure on the corvette action center "with pictures. I like pictures" and it really helped me understand how it works and what to check for. It took me a month to close in on the bad component. And just when I was about to throw in the towel thinking I had made a big mistake buying this car. I found it. A $36 part causing the problem. It was the secondary vacum solenoid. Buttoned the plenum back up and for the 15th time took it out for a drive and crossed my fingers and prepared to mash that peddle. Wow! What a difference. The rest is history. And I have never had another secondary failure again. I'm sure I will eventually but now I know what to look for and how to fix it.

[flyin ryan]

Originally Posted by rhipsher

A $36 part causing the problem. It was the secondary vacum solenoid.

That was the problem on my 90 as well. Secondary Port Throttle Control Solenoid...the thing with the little filter on it, LOL. 'Think' the GM number is 1997222...don't quote me on it .

[jonszr1]

that was the problem on both cars . that little deal with the filter on it .i have a sppare if you cant find one