More spark retard after fixing exhaust leaks and trying race gas.

**94ndta** · 07-31-2015, 08:19 AM

Originally Posted by MKCoconuts

I've never heard of too much fuel causing knock. I will have to look into that because now I'm curious.

Another way to test for a leaky injector is to unbolt the rail, lift it just enough the bottom of the injectors are visible and turn the key on, but do not start it (obviously), and see if you get any drips. This visually confirms a leaky injector.

A less mess/safer way is to hook a fuel pressure gauge up to the rail, turn key on, then shut off and see if the pressure drops. If it drops any more than 10 psi in a short amount of time you either have a leaky injector, return line leak, or bad check valve, but since we are on a leaky injector hunt, that would be the issue. A significant fuel drop off would cause trouble starting as well.

Has Solomon said anything regarding your tune/datalogs?

Solomon said there is nothing he can see from the scans I am sending him that would indicate any issue with the tune, I have a ton of data logs, and have sent him a handful.

I have already tested fuel pressure, and it is great, and hold pressure for a long time after I shut the car off. I think it took an hour for it to drop 5 psi.

**shownomercy** · 07-31-2015, 08:27 AM

A false lean condition would cause PCM to dump fuel, but you said you checked for exhaust/intake leaks correct?

**94ndta** · 07-31-2015, 08:38 AM

Just cleaned the MAF, and inspected for intake leaks, but will do it again. Only thing I haven't checked is the intake itself I guess.

only exhaust leak I have is at the collectors, which I have spent a small fortune on different gaskets to try to stop it, only thing I can think of is having the flanges machined or a new y-pipe.

**shownomercy** · 07-31-2015, 10:22 AM

If it is truly sucking in unmetered fresh 02 and skewing 02 sensors, can you disable 02 sensors, run it OLSD and see if it pings still?

**gmpowered** · 08-03-2015, 01:13 PM

Originally Posted by 94ndta

Just cleaned the MAF, and inspected for intake leaks, but will do it again. Only thing I haven't checked is the intake itself I guess.

only exhaust leak I have is at the collectors, which I have spent a small fortune on different gaskets to try to stop it, only thing I can think of is having the flanges machined or a new y-pipe.

What type of flanges are you running? A fix i tried goes like this, sandwich starting with the header flange, gasket unwelded flange, gasket flange. Works to seal leaky collectors. Its the tits for warped flanges. Worked on my car.
Here is a PIC and discussion. http://67-72chevytrucks.com/vboard/s...d.php?t=181718

Good fuel pressure and hard warm starts tends to make me think opti.
Most leaky collectors are downstream(sometimes exhaust reversion can affect them at idle) of the 02s the leaks would have to be at the header/head. Probably not the fueling issue, looks like a misfire.

**gmpowered** · 08-03-2015, 01:32 PM

Originally Posted by shownomercy

If it is truly sucking in unmetered fresh 02 and skewing 02 sensors, can you disable 02 sensors, run it OLSD and see if it pings still?

Worth a shot.
You could unplug maf and o2s to see how it runs on SD.
Try the above mentioned. It will rule out exhaust leaks maf and 02s. It will run different in SD, but knock and fouled plugs are what you are looking for.

Then if nothing helps.

I would
#1 Buy an ohmmeter
#2 test opti test coil find specs for injectors then ohm check them. How to's are on shoeboxs website.

You could just throw money and time at it till you hit the problem.

The pics of the plug show a rich or no spark condition. Injector spraying with no(or weak) spark or too much fuel.

Previously stated that being rich can cause knock, i have not seen this on an N/A lt1. I have seen it First hand on boosted applications or nitrous use. Not to say it cant happen N/A,

**94ndta** · 08-04-2015, 11:11 AM

Originally Posted by gmpowered

What type of flanges are you running? A fix i tried goes like this, sandwich starting with the header flange, gasket unwelded flange, gasket flange. Works to seal leaky collectors. Its the tits for warped flanges. Worked on my car.
Here is a PIC and discussion. http://67-72chevytrucks.com/vboard/s...d.php?t=181718

Good fuel pressure and hard warm starts tends to make me think opti.
Most leaky collectors are downstream(sometimes exhaust reversion can affect them at idle) of the 02s the leaks would have to be at the header/head. Probably not the fueling issue, looks like a misfire.

This is exactly what I need. Thank you! I'm not sure how I would get a flange to work with this style of y-pipe. There is a good 1/4 in space between the collector and the y-pipe, but it is flared out. I don't know how I would get the flange to fit over the flared out part.

It gave knock and had a hard time starting when the plugs were not fouled. I am wondering if I tried starting it too many times (with it not starting) while trying to figure out if I fixed the knock.

As far as it being the opti, I really hope it's not. It has done this since I switched to a vented opti with my h/c swap, and is a brand new delco. I won't be able to work on the car for a while, and will make note of a few things in this thread and report back.

**gmpowered** · 08-07-2015, 12:07 PM

I didn't realize you were using the ball and socket type flanges. HA that fix wont work.
I had the even shittier slip fit, cut them off and welded flanges on. Thinking this will fixya! Then they leaked lol. So I tried that and it worked.

Solomon can be a pain in the sense that he knows his work is correct, and he is not a mechanic. So it sucks but he will not really get into diagnosing with you as it could be anything.
From reading other help threads i completely as a DIY tuner, understand how and why he is the way he is.
I think he feels he is just the tuner and YOU are the mechanic. He has a REP for that, and sour feelings towards him because of it.
But His tuning from my experience with him and my personal knowledge he is spot on. He has a TON of knowledge and proven theory behind how he sets up his tunes.

You have some decent money and time into the car, keep taking your time and iron out the little issues. You'll get there.

**Rhett954** · 08-07-2015, 12:50 PM

if you are using a ball and socket collector try wire brushing it clean, then clean it off with brake cleaner, then coat everything with a thin layer of permatex ultra copper. I did this with the slip fit on my kooks and in the past with paper gaskets on other headers.

**94ndta** · 08-07-2015, 08:46 PM

I'm not using a ball and socket style. It is a flat triangle shaped flange against another one , but the y-pipe is flared slightly. There is a good 1/8-1/4" of space between the two flanges.