More knock- datamaster

graham1524

graham1524

Well-known member
I just replaced the fuel pressure regulator with an adjustable one from kirban and it made such a big difference. I did another log now that its replaced and I am still getting some knock on the top end. The knock showing on datamaster has decreased significantly, going from 12,000 in a log to under 2,000 now.

Here is the link to the file if someone could please look at it.

https://rapidshare.com/files/2621236465/breakfast.uni

Thanks,
Graham
 
Don W.

Don W.

Stab it and steer it
Re: More knock- datamaster

Others are much better at this that me but my first impression is you're getting, IMHO, way to much spark retard. Don't go by knock count, look at how much spark is being retarded. Also it doesn't appear that you're hitting full throttle. (TPS% in the 82 range) So it would appear, to me at least, that you're still running lean.

What are your mods?
 
graham1524

graham1524

Well-known member
Re: More knock- datamaster

It's completely stock. What would be some possible causes of it to be running lean still?

and I'm working on getting a wideband
 
Don W.

Don W.

Stab it and steer it
Re: More knock- datamaster

OK. First I think you should check timing. Next you're gonna have to check fuel pressure. Somewhere along the line figure out why DM doesn't show full throttle. Start by making sure you are getting FT in the first place. IOW have someone hold the pedal down and look the the throttle body and see if it's going to FT. Just some places to start...
 
johnboy89

johnboy89

Member
Re: More knock- datamaster

I took a quick look at it and your mv are very low when you are in boost indicating you are lean. What did you set the PSI to on the regulator????

I would be very easy on the throttle until you get it fixed, you're seeing almost 12 KR with about 5 PSI boost at times.
 
graham1524

graham1524

Well-known member
Re: More knock- datamaster

Don W. said:
OK. First I think you should check timing. Next you're gonna have to check fuel pressure. Somewhere along the line figure out why DM doesn't show full throttle. Start by making sure you are getting FT in the first place. IOW have someone hold the pedal down and look the the throttle body and see if it's going to FT. Just some places to start...
Click to expand...

Tested it today and it does go to 100% TPS

I tried setting the AFPR a little higher and see how that went but it did not go well, actually got a lot worse. The base fuel pressure is set to 42 with the vacuum line unplugged.

The plan tomorrow is to look at the spark plugs and I'm double checking the timing later this week.
 
It's just a six

It's just a six

Super Member
Re: More knock- datamaster

I would set the fuel pressure to 45-50 psi. It should help, not get worse.

What are the intake manifold temps?

You could add one gallon of Xylene to 10 gallons a gas. Just to see if the knock goes down.
Need to see where your timing is for sure first.

How much boost is it showing?

Sometimes guys think there Sy/Ty is stock & found out the preveious owner/s have installed a different or custom chip.
 
graham1524

graham1524

Well-known member
Re: More knock- datamaster

It's just a six said:
I would set the fuel pressure to 45-50 psi. It should help, not get worse.

What are the intake manifold temps?

You could add one gallon of Xylene to 10 gallons a gas. Just to see if the knock goes down.
Need to see where your timing is for sure first.

How much boost is it showing?

Sometimes guys think there Sy/Ty is stock & found out the preveious owner/s have installed a different or custom chip.
Click to expand...

The highest IA temp is 111 F

The highest boost it shows is 7.3 and thats after it pulls the peak timing

I can double check the chip tomorrow. What exactly am I looking for to verify that it is a stock chip?
 
It's just a six

It's just a six

Super Member
Re: More knock- datamaster

graham1524 said:
The highest IA temp is 111 F

The highest boost it shows is 7.3 and thats after it pulls the peak timing

I can double check the chip tomorrow. What exactly am I looking for to verify that it is a stock chip?
Click to expand...

Do you have a aftermarket boost gauge? Just to see if the boost level is the same as the datamaster is showing?

111F is not bad.

Do you have a Lowes or Home depot near you?, they should have some Xylene.
 
Last edited:
graham1524

graham1524

Well-known member
Re: More knock- datamaster

It's just a six said:
Do you have a aftermarket boost gauge? Just to see if the boost level is the same as the datamaster is showing?

111F is not bad.
Click to expand...

No i dont. But its funny because I've used both datamaster and tunerpro and only datamaster reads boost. Tunerpro will read zero the entire time and also shows more knock. And I am certain that I set up the tunerpro correctly.

I've spent the night reading up. Hopefully I'll get somewhere
 
Don W.

Don W.

Stab it and steer it
Re: More knock- datamaster

I wonder. Are vac lines stock/original? If so then I'll almost bet you have a leak in the line that provides vac/boost to the MAP and to the FPR. Comes off the back of the upper intake. A leak in that line would provide inaccurate boost readings AND insufficient fuel pressure under boost causing a lean condition, contributing to knock.
 
graham1524

graham1524

Well-known member
Re: More knock- datamaster

Don W. said:
I wonder. Are vac lines stock/original? If so then I'll almost bet you have a leak in the line that provides vac/boost to the MAP and to the FPR. Comes off the back of the upper intake. A leak in that line would provide inaccurate boost readings AND insufficient fuel pressure under boost causing a lean condition, contributing to knock.
Click to expand...

I did the bike innertube vacuum test today and found that a lot of air was being leaked from the connecting hose between the intercooler and the TB I took it off and fixed it and now there is no air leak there. Other than that i have the sportmachines silicon vacuum lines which are new so no vacuum leaks elsewhere.

After i fixed the leak i took it for another test drive and the truck ran better. And by better i mean it pulled less max timing than before. The base fuel pressure is still set around 42 and according to datamaster I am still running a little lean. I will try and add more pressure in the next couple of days to see what the results are. Also, do you think I could benefit from the fuel pump hotwire? I've been doing a lot of reading and that was a recommendation I've come across a few times.

Here is the new run that looks better..... or at least getting a little progress
https://rapidshare.com/files/3373470031/test2.uni

Thanks so much for the help
Graham
 
randy merritt

randy merritt

Donating Member
Re: More knock- datamaster

DM file indicates running in closed loop at WOT. Should be open loop. Is this a stock chip?
 
RealFastV6

RealFastV6

@jb_and_his_coffee
Re: More knock- datamaster

Would have to be an aftermarket chip if you have a 3 bar map sensor (per your DM file) ?
 
RealFastV6

RealFastV6

@jb_and_his_coffee
Re: More knock- datamaster

graham1524 said:
I bought it from someone on here and was told its a 2 bar map. Is there a way to test this?
Click to expand...

My fault - I *ass*umed datamaster would display as 2 bar if your file was recorded as 2 bar. It's probably fine, I had mine set to 3 bar.

To answer your question, just check the part number on the sensor.
 
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