Lean burn?

[liquidswords88]

I just got done getting the engine my ty rebuilt. Balanced rotating assembly the whole 9 yards. Long story short I had to use flat top Pistons. I also changed out the heads for a set of l35. I port matched the manifold and the turbo as well. I also went to a 3inch "Jsm" style down pipe and three inch exhaust. The compression ratio ended up around 9.75 to 1. I know this is not boost friendly or pump gas friendly. Before all this work I bought a turbo tweak chip from a gentleman whose name I believe is Eric. The chip was burnt as a stock 92 octane chip. I expected the truck to be lean but was going to turn up the fuel with the chip to its max. Doing that makes no difference. I have been around tinkering with engines long enough to know a lean misfire. The plugs are lean as well. I know the misfire is not ignition related. Everything is new and quality parts. Msd,ngk ur6 plugs, new distributor, gm ignition module, real nice wires that were made for a group purchase for here a awhile ago. New harmonic balancer, blah blah blah. Everything on this truck is brand new.

What do I need to do to get this thing more fuel? Are my stock injectors going to be enough. I am pretty sure my chip can be burnt with a different tune. I am really frustrated with this damn truck. I have datamaster and there is no knock when the misfire occurs. Everything else looks really good. Sorry for the long post just trying to include all the info.

 

[Peter]

Re: Lean burn?

There are some things that would really help understand what's going on. Do you know the fuel pressure, and is it increasing with boost as it should? Since it wasn't mentioned, your truck must not have a wide band O2 sensor and any way of reading it. This would tell you what your AFR really is. Knowing that, there are lots of options available.

 

[liquidswords88]

Re: Lean burn?

Fuel pressure is 42 lbs at idle with vacuum line connected. The fuel pump is brand new whalbro. The truck ran great (except for the knocking and no oil pressure) before the rebuild. I do not have a wideband. I'm not trying to run high boost or go racing here. If all I can safely run is 10lbs I'm fine with that. I enjoy turning the wrench, no so excited about the computer "tuning" side of it. I know for a fact this truck is lean. Real lean, I can smell it and feel it. I have been rebuilding and tuning on snowmobiles since I was a kid. Anybody who messes with 2 strokes knows that lean is fast. Well at least until you go so lean it won't run lol. This typhoon is that lean. When I pull the plugs they don't even look like they had fuel on them. The stock o2 sensor looks like it is rich? Maybe because the misfire is dumping the unused oxygen right into the exhaust? I can drive the truck around with light throttle. It will even run decent up to about 5lbs boost, I'm sure it's still lean there but it does not misfire. All this leads me to believe my problem is in my tune. When bought the tt chip I did not plan on rebuilding the engine.

 

[Don W.]

Re: Lean burn?

Well first Eric's chip AND your injectors have to be matched. IE if the chip is for 50# injectors then you need 50# injectors. Eric can make you darn near anything. That compression might be a bit high but I'm running 9.0-1 without problems. Eric's chip flashes the CEL when it detects knock. Is your CEL flashing?

There are 3 ways to add fuel with Eric's chip. Parameter 1, parameter 2 and the WOT dial. Do you have your instructions?

Need more info as Peter mentioned.

 

[liquidswords88]

Re: Lean burn?

Well first Eric's chip AND your injectors have to be matched. IE if the chip is for 50# injectors then you need 50# injectors. Eric can make you darn near anything. That compression might be a bit high but I'm running 9.0-1 without problems. Eric's chip flashes the CEL when it detects knock. Is your CEL flashing?

There are 3 ways to add fuel with Eric's chip. Parameter 1, parameter 2 and the WOT dial. Do you have your instructions?

Need more info as Peter mentioned.

I turned #1 and #2 up to max. I don't think I have a wot dial. If I do the instructions do not include that info. I have datamaster and when the misfire occurs there is no knock. Turning up the fuel makes little to no difference. I am running stock injectors, the chip is burnt for stock injectors. I had the chip made with the intentions of keeping the engine stock. But since I had to get it rebuilt, I decided to make few changes. From what I have read here the l35 setup should not make a huge difference. The raised compression should require more fuel. Maybe the l35 and 9.75.1 combo is creating a much more powerful "pump"

 

[Don W.]

Re: Lean burn?

Actual compression primarily affects the motor's tendency to knock. Not the mixture. Was the lifter "preload" set correctly?

Is the turbo stock? Is the cam stock? Do you have a cat in the exhaust? What plug are you running? Is timing set to -0- with brown wire disconnected?

Fuel is normally set to about 40# with the vac line disconnected.

IMPORTANT When warm and idling in neutral what are your IAC counts? In DM this is IAC Pos? This should be around 30. Important with Eric's chip and -might- be why you're lean. If wrong this can be adjusted with what you probably think is the idle speed screw but isn't.

If you don't have a WOT dial then you have an earlier version of Eric's chip. Is it this one?

http://www.turbotweak.com/velosytydoc.pdf

Can you post a link to you DM file when it's missing?

 

[liquidswords88]

Re: Lean burn?

Actual compression primarily affects the motor's tendency to knock. Not the mixture. Was the lifter "preload" set correctly?

Is the turbo stock? Is the cam stock? Do you have a cat in the exhaust? What plug are you running? Is timing set to -0- with brown wire disconnected?

Fuel is normally set to about 40# with the vac line disconnected.

IMPORTANT When warm and idling in neutral what are your IAC counts? In DM this is IAC Pos? This should be around 30. Important with Eric's chip and -might- be why you're lean. If wrong this can be adjusted with what you probably think is the idle speed screw but isn't.

If you don't have a WOT dial then you have an earlier version of Eric's chip. Is it this one?

http://www.turbotweak.com/velosytydoc.pdf

Can you post a link to you DM file when it's missing?

I did not do the lifter preload, the engine builder did. A compression check was done while the engine was on the stand. If the preload was too tight compression would be low, it was not. There is not ticking or engine noise that would point to a loose lifter either.

Turbo is stock, cam is a gm 10051147
Hydraulic Roller Tappet
This hydraulic roller tappet is a V6, 90 degree version of L-79 small-block V8 cam for 4.3L even-fire engines. Use only with roller tappet block on engines without balance shift. The duration at lash point in degrees (intake/exhaust) is 318/318; duration at .050" tappet lift (intake/exhaust) is 222/222; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 447/447. Lobe centerline is 114 degrees.

Fuel pressure is being controlled by stock fpr

It does have a catalytic converter.

Ngk ur6 gap 30thou


Iac counts are low 40, I understand how the tps sensor and iac work on these trucks.

I have no brown timing connector, it has been eliminated. Timing is set by setting timing to what datamaster says the ecu is commanding. Again all these things except the cam were in place as adjusted with the previous engine. It ran a 13.42 on datamaster. The previous engine ran great it was just used up by the previous owner.

 

[Peter]

Re: Lean burn?

If it runs well up to 5 psi boost and then misfires, it might be lean. But it could also very well be an ignition problem. This is a classic ignition problem description for our trucks. What's the plug gap? Drop it to .025 just to be sure.
Like Don said, set the fuel pressure with the vac line disconnected. Or for a quick and easy check, just turn on the ignition but don't start the engine. The fuel pump should run for a few seconds and the pressure should hit about 40.

 

[Don W.]

Re: Lean burn?

If IAC counts are low 40s then, IMHO, you need to bring those down to closer to 30. Why not set this closer to where Eric likes it to be since this setting affects how the chip operates?

You should peobably consider an adjustable FPR.

Someone please explain to this village idiot how this works:

"I have no brown timing connector, it has been eliminated. Timing is set by setting timing to what datamaster says the ecu is commanding."

And again can you post a DM log and maybe even a photo of a plug?

And Peter makes a good point. After key on and the FP runs for 2 secs and stops the fuel pressure should hold and not drop. If it does then you need to find out why.

 

[liquidswords88]

Re: Lean burn?

If IAC counts are low 40s then, IMHO, you need to bring those down to closer to 30. Why not set this closer to where Eric likes it to be since this setting affects how the chip operates?

You should peobably consider an adjustable FPR.

Someone please explain to this village idiot how this works:

"I have no brown timing connector, it has been eliminated. Timing is set by setting timing to what datamaster says the ecu is commanding."

And again can you post a DM log and maybe even a photo of a plug?

And Peter makes a good point. After key on and the FP runs for 2 secs and stops the fuel pressure should hold and not drop. If it does then you need to find out why.

Village idiot? I have more intelligence in my farts then you "peobably" have in your whole brain. I appreciate the effort in trying to help me. But why the insults? Does it make you feel better about yourself? I eliminated the est bypass plug. Why would I send you a picture of two wires that have been soldered together? As a matter of fact I ran all new shielded cat6 braided wires to the distributor directly from the ecu. Do you want pictures of that?

Maybe in the future you could save your childish insults for your grandkids. That assuming a woman would marry you, and that your kids would even bring them around grandpa.

 

[fivetodrive]

Re: Lean burn?

Sorry dude but don't bash Don. He is one of the few that actually take the time to help people. You looked a gift horse in the mouth...

Changing the gauge of wire probably isn't helping you either. You changed the gauge from 18 to 23... and removed a helpful tool by soldering the est...

 

[Don W.]

Re: Lean burn?

I was being facetious, referring to myself. I was asking how disconnecting the brown wire and setting timing the way you say actually works. And I meant spark plug. It would help if you could spell. See ya...

 

[liquidswords88]

Re: Lean burn?

I apologize to you Don. Not looking for any favors. I guess this truck has taken its toll on my mind and my pocket book. I'm the first person to willingly face a challenge, but when does it end. Again I'm sorry.

 

[CC801]

Re: Lean burn?

why solder the brown wire together when it needs to be disconnected to set base timing?

 

[0966Sy]

Lean burn?

If you want help around here you better be willing to take some criticism. Otherwise the Facebook page might yield you better results. I honestly think some of your decisions haven't been the most knowledgable with the truck. From the information your giving.

Your base fuel pressure is 10psi to high for stock injectors.

Are you sure the plugs are lean? Post some pictures. Although you have already identified your self as a plug reading expert.

What timing mark was used on your crank pulley if using a double roller SBC set?

Have you verified base timing at 0* and how?

What is your engine vacuum at idle at what RPM?

Sounds to me like your too rich and the chip is trying to pull fuel, what is STFT?

 

[dgoodhue]

Re: Lean burn?

It is pretty likely that your engine is running lean, but you should confirm it with a scan tool datalog. In addition to increasing the airflow with the heads & cam, the higher effective compression with the lower boost level compounds the issue as well for the engine air flow as well as the fueling since the rising rate fuel pressure is tied to low boost levels. Until ~5 years ago, you would have been looking aftermarket ECM or DIY tuning with code $59 to even attempt to get your engine running properly. You maybe beyond the adjustments of turbo tweaks chip as well.

I would adjust your IAC 1st as mentioned above.

You stated that you have a Walbro fuel pump. Was the pump acquired from a trusted Walbro distributor? You may want to put a fuel pressure gauge on the rail anyways to make sure the fuel pump fuel pressure increase with boost. If your fuel pressure is 42psi with the FPR vacuum source disconnected, it should read 47psi @ 5psi of boost and 52psi @ 10 psi of boost.

I would get a adjustable fuel pressure regulator and raise your fuel pressure as needed and record some data logs to verify what is happening.

 

[Don W.]

Re: Lean burn?

I'll accept your apology. Hopefully you can consider some of the advice given by me and others to help you make your truck run correctly.

Looking back I can easily see how what I said could be taken as being aimed at you. This is the trouble with any kind of written word be it email, a post here, or anything else. One needs to be very careful.

Reminds me of a sign I used to have on my desk many years ago:

"I know you believe you understand what you think I said but I'm not sure you realize that what I said is not what I meant."

 

[liquidswords88]

Re: Lean burn?

I have a brash personality and a coarse filter. It has gained me more enemies than friends in my lifetime. But I try to live my life in the light of truth. That being said I found out my problem. Although I could easily pretend this thread does not exist and save myself the embarrassment, I would rather expose the truth so maybe it can be used in a positive manner. Number 2 cyl had a cracked porcelain. I had the plugs out a number of times and never saw it. It was cracked so bad I felt it when I was taking it out. As far as the lean condition, it is gone now? I have a theory as to why but I don't think if follows the rules of how this system works. Maybe somebody can enlighten me. While trying to correct a terrible over boost condition caused by my new three inch exhaust, I experimented with different size reducers I fastened to my tailpipe with self tapping screws. Once I got the back pressure to a point where the wastegate could keep control of the boost I noticed my o2 cross counts where way faster and more steady then with the non reduced exhaust. I think that without sufficient back pressure the exhaust moves past the o2 sensor too quickly and it does not have time to get an accurate reading? Not sure if that is even possible but with the straight three inch pipe the Xcounts were very sparatic and slow. Sometimes it would just sit only changing 10 to 20 mv. Sorry for the long rambling post but I am trying to get all of this out at once. From what I read about the Jsm downpipe I thought that it would make the wastegate more efficient at controlling boost with a better flowing exhaust. Maybe it's the increased compression creating a stronger force to move the turbine? But my truck was boosting to the moon. Not even sure where it would of stopped but the over boost cut out kicked in damn near instantly. This is with a 3inch standard flow catalytic converter. I ended up with a two inch reducer at the tailpipe. I tried a few different sizes, all the way down to 1 3/8!!! It was almost a joke putting that little crapper on there. Boost control is steady as a rock now. I'm running 13 pounds of boost on 93 octane with zero knock. At full tilt the rushing air noise is louder than the exhaust which I am not fond of. Maybe down the road I will consider putting a external gate on it and ditch the converter and reducer. I eliminated the front diff in an effort to lose weight which before the rebuild didn't seem to hurt the launch very much. Now on a boost launch it starts to break the rear tires free before boost is even built and then torches then all through second. So maybe the front diff needs to go back in. It just seems more fun to drive when you can floor it at 35mph and break the tires free on the downshift. Anyways sorry again for the never ending post but I wanted to share.

 

[TYTILIDIE]

Re: Lean burn?

I have a brash personality and a coarse filter. It has gained me more enemies than friends in my lifetime.

So you can dish it out but you can't take it? :rotf:

Funny you implied in an earlier thread that I am a wanna be mechanic and you can't even figure out what's wrong with your truck without everyone here and you build race cars?

 

[liquidswords88]

Re: Lean burn?

So you can dish it out but you can't take it? :rotf:

Funny you implied in an earlier thread that I am a wanna be mechanic and you can't even figure out what's wrong with your truck without everyone here and you build race cars?

You are a wannabe mechanic. My name is Dean Eggart. Do a google search on me. I don't build race cars. Look up my posts. I said I have built a few race cars. Which I have. I know a lot of mechanics. Professional mechanics. If any one of them could make more money doing another profession they would. I work on mechanical things because I enjoy it. I don't want to be a mechanic. I enjoy it too much.