@RB04Av Would improper length push rods cause underwhelming performance and/or a severe lean condition?

 

Too short, too much valve lash and a lot of noise. Too long, all valves hung open and no compression.

 

I thought I read on ls1tech before that the timing mark orientation was different than a typical SBC or BBC. Both marks on the gears were to be spaced up.
not dot to dot.

also, The op said the injector nous light was faint. Doesn’t that point towards harness or ECM?

 

I'll go check the FSM but I'd never heard any videos claim other than dot to dot.

The vendor for the cam has been very disappointing with their post sale support. They can't provide me with a copy of the cam sheet. They don't have a clue what length pushrods for completely stock long block using this cam. They sold the cam in kit form with implied stock length 7.40" pushrods. If the pushrods aren't correct, I'm out of $100 with that screw up.

You are also correct that my noid light is super faint. I did do a test against another running rig(02 Tacoma) with the exact same noid light. Both of them were beyond faint compared to the noid light direct across the battery.

 

12 12 or 6 12 is the same apart from firing 1 or 6.

 

Not sure how many times we have to say this. Twin_Turbo just did, again.

Both dots up and dot to dot ARE THE SAME THING. If you assemble the motor one way, EITHER of the 2, and then turn the crank exactly one turn (kinda like it will be doing on a regular basis anyway?), it will then be at the other. Both dots up is #1 & #6 TDC and #1 firing, dot to dot is #1 & #6 TDC and #6 firing. The 2 firings alternate for each revolution of the crank. We typically build em dot to dot because it's easier to see and not make a mistake lining it up. But that is NOT #1 firing, it is #6; and once the motor is together, IT DOES NOT MATTER.

It is the same as the old SBC or BBC, or ANY NUMBER of other motors as well. THE SAME.

I agree exactly with G Atsma's description of the effect of the wrong push rod length.

 

As said in this thread, and on all the multiple threads before this one...
Be sure to click the download button...

 

Check compression & or do a leakdown test. Check pushrod length and get correct pushrods if needed. Report back

 

Compression test was done. Passenger side was 180, 180, 185, 175. Driver side was 175, 185, 180, 180.

 

Compression looks plenty good. In the right range, reasonably consistent among cylinders.

You say "lean condition". When is it lean? it means different things at different times.
.

• All the time = injectors are too small
• High speed / high power = fuel pump is inadequate or weak, or filter is clogged
• Idle = vacuum leaks
• Cruise = O2 sensor problem (they're telling the ECM it's too rich, so the ECM pulls out fuel, and even though the ECM thinks it's happy, the engine is too lean)
• Acceleration = fuel pressure regulator set too low
• And so on...

When?

Datalogging can help.

 

Good question. I have used HP Tuner for logging of all 'regular' sensors like o2. I am using an AEM wideband o2 for checking lean/rich.

According to AEM, it is running lean almost 99% of the time... as in so lean it won't display a number lean. VERY rarely can I get it to get 'rich' and it involves being reved up (4500ish rpm) and full release of gas pedal.

I can also say without a doubt it isn't related to injector size. When I did the cam swap, I left the rig sitting for ~2.5 years. The stock LQ4 injectors got sticky. I bought replacement injectors that claimed to be stock replacements for the 6.0L. As it turns out, they weren't stock replacements for the 6.0L, they were stock replacements for the 8.1L. I ran the cam tune as is for a 6.0L injector and I also ran a modified tune for the 8.1L injectors. In both cases, the results were the same. I have since bought real 6.0L injectors and used the 6.0L cam adjusted tune with no better results.

I have pretty much hosed the whole upper end of the engine with carb cleaner checking for leaks. I mean that almost literally. Around the maf, around the elbow to the throttlebody, the whole throttlebody, around each of the intake runners, around the block off for the air injector at the front of the intake, and around the brake vacuum port at the rear end. Nothing changed.

 

Is the OP using stock lifters or did he swap to LS7 or aftermarket lifters?

 

The lifters are the one that came with the engine(2004 LQ4) At the time, no research showed that a replacement was needed.

The pushrods were swapped to hardened stock length. In reading, this was recommended due to stiffer valve springs.

The valve springs were upgraded to BTR #SK001S (for stock rocker arms). In reading, this was recommended to resolve valve float issue at higher RPMs.

 

I used LS7 lifters and a BTR stage 2 cam and 7.4 inch pushrods on my 5.7. I'm not sure what style lifter was stock in 2004.

 

OP, can you clearly state the current issue/symptom with as much detail that it could be duplicated by a local shop if you asked them to diagnose it?

Is this a correct summary of current status:
1. Cam installed at 106* ICL using a degree wheel?
2. Not sure what the recommended ICL is due to no cam card?
3. Not clear what the correct push rod length is?
3. Concerned running lean based on AEM O2 sensor state showing LEAN most of the time?

 

I found that the difference between LS7 and the lifter I have(stock LQ4) is the amount the lifter body shrouds over of the roller. Otherwise, same size. I talked with the cam shop and they confirmed 7.4" pushrod for the cam is correct for stock head/head gasket LQ4. I verified by doing "hand" test of pushrods; found the 'loose" cylinder and was able to spin the 7.4" pushrods a hair but the rocker didn't have any looseness. *edit* I found was able to hand spin a 7.4" pushrod with zero lash. This doesn't account for lifter preload.

Unfortunately, I don't have any local "good" shop. Certainly not one I'd trust with an 'open ended" diagnose.

What would cause a noid light to be VERY light? Is there an ohm reading I should have for the injector power and injector to PCM? What about ohm reading from pcm to ground?

 

Noids are usually light. Unless you wide open throttle it. Then you'll see them brighten up.

Ohm out the wire from the injector clip to the pcm, the trigger is a ground trigger and the hot side is from a fuse so ohm out the hot side and also check for battery voltage.

I will say though, if it runs you're likely barking up the wrong tree testing injector signal, since it requires injector operation to run.

 

It runs but badly.

If it isn't the injector circuit causing a problem, I'm at a loss. I've tried three different PCMs that were all SERV#: 12586242 with the same tune. I've pulled apart the PCMs to look inside for corrosion or burnt circuits. They looked clean as do the external pins for main plug

I'm on second factory harness... this one is mostly unmolested. Only adjustments are things going into cab like power, MIL, and diag port(think c1/c2/c3 plugs).

This is third set of injectors and the results are still poor. I've been told that running 8.1L injectors with a 6.0L tune should run pig rich. Even with that tune, I am running un-registerablely lean.

Sadly, I'm one man diagnosing so I can see the noid light while trying to engage the drive by wire pedal

Is it possible for a cam or crank sensor to have within range settings that are incorrect? In the past, I've had o2 sensor stuck that didn't trigger a MIL but would fail smog(86 s10)

 

If you think it being lean is causing your problem a quick test is to try additional fuel, spray some brake clean into the intake through a small vacuum hose and see if it smooths out. If it does then that tells you it is lean.

Have you checked fuel pressure and volume yet?

 

Thank you for the input. I'm 100% sure I have a lean issue based upon a wideband o2 down the pipe. It runs reasonable(not choppy at idle)

I believe lean is the issue of lack of power and I'm fairly certain that the lean condition isn't from the tune(check in HP tune, stock vs cam adjusted/purchased) I would expect that putting along at 2000 to 2500 rpm and mashing the gas would at least put me back in the seat more than same test with a 4.3L S10 truck.

I will give the direct carb cleaner in vacuum a test. I have gone over everything with carb clean to verify no vacuum leaks.

I have checked fuel pressure and it was low 50s at power up, at idle, and no load rpm. I do not have a method to check volume. The pump is a few years old but stock 99 Camaro assembly(LS1)