Knock at no boost?

[E.Murray]

I just did valve seals, put in a Forge wastegate and added an AEM wideband O2. Took it for its first drive and got the engine light flashing (TurboTweak chip) at me for knock at about 1/8 throttle and maybe 1 lb of boost. Then the turbo hose to the intercooler blew off (again at no boost) before I even got to the next driveway. What did I do wrong?

 

[E.Murray]

Re: Knock at no boost?

After doing some research, it looks like I set the valves too tight. Could that cause this (i.e. intake not fully closing so cylinder pressures made it back through intake)?

 

[Don W.]

Re: Knock at no boost?

Turbotweak chips have to be calibrated for the WB you're using. What readings are you getting? Is the WG setup correctly. Are you reading the factory ga or a "real" gauge. If you blew the turbo hose off, assuming clamps were tight, then you're overboosting. Pretty much regardless of what everything else reads.

Remove the turbo hose. How does it drive?

 

[E.Murray]

Re: Knock at no boost?

I did flip the switch on the chip so it would use the WB (contacted Eric before installation to make sure I had it right). I didn't notice the reading when it was knocking. The whole drive was maybe a half mile. I did look at the AFR when driving back (as gently as possible) and it was a little over 16 with barely above zero throttle input.
As far as boost, I have an AEM gauge and believe it to be accurate. As I said, I was just feathering the throttle at 20-25 miles an hour, so I don't think it was possible to get boost. The wg should be out of the equation, I would think. The hose blowing off was the bizarre thing in my mind, too. It's possible I forgot to tighten the clamp, but it came off with a loud bang, so I don't think it just fell off. I may be grasping at straws with the valve thing, but since that's the only thing I know I did wrong, I was trying to think how that could cause the issue (since the turbo shouldn't be able to do that as slow and gentle as I was driving). Ideas?

 

[Don W.]

Re: Knock at no boost?

16 is way lean. Probably why it's knocking. You need to figure out why. Is fuel pressure at 43 with the motor idling and vac line off? Do you have a FB gauge? Does FP follow boost pound for pound? Any codes? If the valves were to tight to the point they were being held open it's unlikely the motor would run, or if it did very poorly. What was your system to adjust them? Also like I asked how does it drive with the turbo hose off? Also is your timing set correctly?

 

[E.Murray]

Re: Knock at no boost?

Where is a good place to tap in to get fuel pressure? I have a gauge I used to use on an old SBC (somewhere...). In the TurboTweak chip, it did have a lot of extra fuel being added before. I suppose that disconnecting the battery wiped that, so I should go reset all those parameters.
As far as the valves, I mis-read the Chilton manual. It said to tighten the nuts while turning the pushrods until the lash went away, then turn an extra turn. I thought it meant until I could no longer turn the rods (instead of no longer move them up and down). I've adjusted valves on aircooled VW and lots of dirtbikes and ATV's but never anything with hydraulic lifters, so this was new to me.
On the timing, I did check it when I got the truck to verify 0 degrees. I haven't touched the distributor, so I don't see how it would be off.
I'm going to re-do the valves, add the fuel back through the chip, and check fuel pressure. Then I'll report back. Thanks for the help.

 

[Black Knight]

Re: Knock at no boost?

Where is a good place to tap in to get fuel pressure? I have a gauge I used to use on an old SBC (somewhere...). In the TurboTweak chip, it did have a lot of extra fuel being added before. I suppose that disconnecting the battery wiped that, so I should go reset all those parameters.
As far as the valves, I mis-read the Chilton manual. It said to tighten the nuts while turning the pushrods until the lash went away, then turn an extra turn. I thought it meant until I could no longer turn the rods (instead of no longer move them up and down). I've adjusted valves on aircooled VW and lots of dirtbikes and ATV's but never anything with hydraulic lifters, so this was new to me.
On the timing, I did check it when I got the truck to verify 0 degrees. I haven't touched the distributor, so I don't see how it would be off.
I'm going to re-do the valves, add the fuel back through the chip, and check fuel pressure. Then I'll report back. Thanks for the help.

There is a port on the drivers side front of the fuel rail where you check FP.

With the valves I was having the same trouble getting them adjusted properly, too tight, too loose, I ended up adjusting them with the engine running.

Was the brown wire under the dash by the ECM unplugged when you verified timing?

 

[E.Murray]

Re: Knock at no boost?

Adjusting with the engine running seems like it would be a real pain. But if I have to, that's where I may end up. Thanks for the info.

 

[Don W.]

Re: Knock at no boost?

As you know you have to adjust the valves with the cylinder at TDC compression stroke. Here's an old reliable system to do that.

With valve covers off rotate motor while watching the valves of cyl number 4. Just when the exhaust closes and the intake opens you're at TDC compression for number 1. Adjust number 1 valves. Next in the fireing order is number 6 so you watch number 3 And so on. 5 watch 2, 4 watch 1, 3 watch 6, 2 watch 5.

Write it this way:
165
432

Works for virtually any even fire 4 cycle motor.

I believe 1 full turn is incorrect. Someone can verify. I think it's only one half turn AFTER tightening to where the push-rod won't spin.

 

[E.Murray]

Re: Knock at no boost?

Wait. That's what I did - 1/4 after I couldn't turn the pushrod (saw the 1/4 thing on here). So that's right? Yes I adjusted with them at tdc. I thought lash was up and down movement??
The reason I thought I was screwey was that they all seemed very loose when I started. I ended up having to turn the ones I didn't disassemble over a full turn, which worried me since it was running fine before I tore into it (was just doing seals on pass side while ic was off). Should they have all been that loose to begin with? It had been sitting a couple weeks, so did they just loose their hydraulic pressure?

 

[dgoodhue]

Re: Knock at no boost?

Wait. That's what I did - 1/4 after I couldn't turn the pushrod (saw the 1/4 thing on here). So that's right?

Zero lash is approx when the pushrods has the first sign of resistance (when spinning). If you tightened the rocker until you couldn't spin it the its too tight.

 

[codename Bil Doe]

Re: Knock at no boost?

^This. To tighten until the pushrod doesn't turn is way, way too tight. Should be moving the pushrod up and down to find zero lash. When you get close to no play between it and the rocker/lifter you're there. I like to go back and forth at that point to feel what is closest to zero lash.