So now that I have everything fixed, gonna work on tune and knock problem...

C

Chrisssssssss

Member
Joined
Jul 27, 2008
OK everyone,

May be an earful here, but I will tell you everything I know and all my observations so that it is all on the table. All help is appreciated. I just wanna get my car running right!!

I have been struggling with knock problem ever since I got the car. Now that I have everything fixed that would impact a proper tune: Cracked drivers side header rewelded, exhaust rehung properly, turbo to downpipe bolts replaced and properly secured, oil changed, new o2 sensor, seafoamed, spark plugs and wires done... that's about it.

OK, I have verified by a fuel pressure gauge routed to my windshield that I have fuel pressure that increases 1-1psi with boost - hovers around 38ish with vac line on and 46ish with it off, so I don't think that fuel pressure is the problem. I have a walbro 340 hotwired. Fuel filter was replaced last year, no improvement.

I have a tt 5.6 chip (TT5.6 36# street 91 (octane I assume) 19*-17* 15-16psi) matched to my 36# injectors - or what are supposed to be 36# injectors. However I see something interesting on the side - they say 24 on the top of them all - I just noticed this today. They have other numbers on them, but this is what they look like and the 24 that I am referring to you can clearly see in the pic. Does this mean that they are 24# injectors? Just wondering:




The issue is that I am getting knock. Lots. The car I got from my dad in california with 91 octane avail to them. I live in BC canada and use Chevron 94 exclusively so I think that at these low boost levels and octane levels - this should be a walk in the park with no knock at all. I only have the boost set to like the lowest around 12-13 psi or so and still get LOTS of knock. Doesn't matter whether I roll into it or punch it off the line. Even with low boost as I am rolling into it - knock starts to show. Even on non WOT acceleration around 7-10 psi - still will start to show knock. I get knock ALL the time.

My scanmaster shows 726 at 12.7* KR when I hit the recall button. This was at BASE tune with no adjustment of the chip. These numbers seems to be all over the place whenever I do a WOT but this was what I just got.

The rest are as follows:
816 0.0
AF 04
L8 31
bat 13.7
int 128
bL 132
mph 00
clt 200
ats 130
r 750
tps .44
IAC 26
cc 13 (these were not moving at the time that I was in park idling)
nal 00

I have tried messing around with the chip with timing and fuel - I don't really know what I am doing there, do I thought I would ask here now.

There is one thing I will mention - I hear the car make a knocking type noise (that I can video and add if necessary) upon a hard acceleration (close to WOT) in first gear mainly, that I can kinda make go away if I play with the timing and take a few degrees out. That mostly does not register on the SM as knock though. I can hear that noise and get no knock whatsoever registered - sometimes I do but I don't know if that is what I am hearing or something different altogether.

I know that this is long, but I would like to give everything out so that it may be easier to pinpoint. I just want my car to be right.

Any and all thoughts and help are appreciated!

Chris
 
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Likely, wrong chip for those injs...I assume you changed the chip your dad had in the car, when you got it. Y/N? You still have the old chip? Any markings on it?
If those are 24# injs, they are short on flow for even a stock engine. [OEM is 28pph],Bosch 0280 150 218.]
Tomco is not what I would classify as a "hi performance" inj.
Any other numbers on them?
All 6 have the "24" on them?
ALSO: STAY off the pedal until you get the knok fixed......Or, you will be back to "fixing" a lot more than what you've already done. IE: a new block, head gaskets, etc.
Idle temp at 200* is too high.
Air temp @ 130? Is this after driving, in the hot weather, or?
 
Hey Chuck,

Normally the car idle temp is low. I just raced it up and down the street a few times and parked in the driveway. Usually sits around 170. I didn't change the chip, my dad had this chip in the car when he got all that work done. He also has a thrasher chip that is set for the 36# injectors too I believe. That is the only common number on those injectors. I just noticed that when I took the pics. They are supposed to be 36# injectors. That's what was told and billed for, but How can I tell from looking at them? The green color? Dunno. I am planning on going with an alky setup with 60# ones when I can afford it and then get the chip to match. I will look at the other numbers on them when I can.

Is there any way that this knock can be false? downpipe hitting firewall maybe? Loose motor mounts leading to the exhaust or downpipe hitting somewhere?
 
Just my opinion , I would buy a new set of injectors , 42lbs or 60lbs both will work fine from Turbo Tweak and a matching chip at the same time so you will be getting a discount when you do that , then you will know where you are from a starting point , you probably have old technology injectors and chip and with today's gas it will be to aggressive timing in the chip you have . That will cause your knocking going on for sure . I will stop here as more things can cause KR but you need to start with a clean slate and go from there.
 
Depending on what your goals are, I would get the 80# injectors and chip from TT as they are the same price as the 60's. It'll leave you more room to grow, and you'll be done buying injectors pretty much forever unless you go to E85. Cheers!
 
"Is there any way that this knock can be false? downpipe hitting firewall maybe? Loose motor mounts leading to the exhaust or downpipe hitting somewhere?"
Above are places I'd look. Check the upper, rear of the pass A-arm, too.
What plugs are in there?
Have you pulled them, and taken a looksee?
Cam going flat?
Cam sensor timed correctly?
 
I think that pmoore is onto something there... I am using a 36# chip with 32# injectors. That could be a problem... I have a couple more chips at home. I am gonna have a look and see if there is one that is for 32# injectors. I am gonna investigate this more today. I will phone my dad and see what he has to say.
 
If you can verify what lb injectors you have, TT can burn a chip for them. I wouldn't do too much experimenting with unknown chips as you've already had enough knock to be scary. That can get expensive in a hurry; ie rebuild engine. Ask me how I know this!
 
Order a new chip for the injector part number you have at the boost level you plan on running


Sent from my iPhone using Tapatalk
 
Ok, so here's a bit of an update...

I took a look at all the chips that I have. I also talked to my dad who owned the car before I did. He got some work done at a place although I am not gonna name it - but it is in the LA area and very well known for GN's. Apparently came highly recommended as there were like 4 other GN's in there when it was brought down there. My dad remembers ordering 36# injectors and that's what was on the work order/invoice (although I cannot find it at the moment) and I swear seeing 36# on the list. That's why I always had it in my mind that it had 36#. He had the TT chip installed at the same time as these injectors, as well as the scanmaster. However he said that the car never ran right with the TT chip. He was experiencing a lot of knock and stuff so he put the older thrasher chip back in and it seemed to help a bit. Now I know why he was having problems with the TT chip. It's burned for 36# but by what I see here, I think they are the 32#. Here's another angle...



These have the markings on them that you can plainly see.D1720BA and D1720AA but also has 2468 which looks like they are 32#

Soooo... here's a pic of the chips that I have. Will any of these work well? I don't think so...



I have the car actually running not too bad right now. I have the TT chip in and have it MAX'd out on the fuel settings. I think I am gonna send it in to Turbo Tweak there and have him reburn it for the correct injectors.

HOWEVER I have also another thought. I am thinking on buying a set of 60# and TT chip that matches with Alky. I have someone offering me the chip that is burned for 60# w/alky and the 60# injectors. All I have to do is get Alky kit. I have emailed alkycontrol and priced out a kit. Would this be the better way to go? I am planning on still getting an alky kit, but is the 60# overkill? I may as well do it now and get it over with. I am not going E85 at all because it just simply isn't available up here so 60# will be way plenty in case I upgrade the turbo somewhere down the line.

With the stock turbo, should I just get the Alky kit, leave the injectors as is, and just get the chip reburned for the injectors I have with alky? Is the 60# redundant overkill with the stock turbo?
 
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