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P0200, misfire, backfire, VERY rich, lack of power after cam swap in 04 LQ4(6.0)

I just ordered up an OTC noid and see how it does.

SLOWPOKE693 said:
Do you have a scanner that reads injector milivolts? With the scanner hooked up and the engine running back probe each injector and see if the voltages from scanner and volt meter match? Might be able to unplug one at a time and go directly to the pins but having one injector down may have other affects so id try the backprobe deal.
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I do not have a scanner for injectors. Is there a brand/model I should be looking for?
 
I'm out of the loop on scanners these days and couldn't really recommend one. I'm still using an old OTC Genesis that I bought in like 2009. Its outdated as hell but it works for what I need it to do.

I'm sure you can probably buy some Bluetooth or whatever thingy to plug into the diagnostic port and link to your phone but id be lying if I told you I knew a thing about those.
 
You running a fuel rail with a fuel pressure regulator on it, or is it returnless and only has 1 line?

if it has one... Have you pulled the vacuum hose off the regulator while its running to make sure the diaphragm isn't split and leaking? If it was, it would run like shit and use a ton of gas like you described. :confused:
 
I did a couple more quick tests on my current noid light. I believe it is actually in good shape. I tried it directly across the battery and it was bright as a dash light. I then tried it from the injector power to the battery ground; also bright as a dash light. I then tried it from the injector PCM ground circuit to the battery ground; super faint blinking.

SLOWPOKE693 said:
You running a fuel rail with a fuel pressure regulator on it, or is it returnless and only has 1 line?

if it has one... Have you pulled the vacuum hose off the regulator while its running to make sure the diaphragm isn't split and leaking? If it was, it would run like shit and use a ton of gas like you described. :confused:
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My fuel system is composed of:
Stock 1999 Camaro fuel pump assembly
Runs to a 2000(???) Corvette fuel filter/regulator - return goes to fuel pump assembly *EDIT* Red is NOT true
Fuel output of pump goes to an Earl fuel filter then a tee
One end of the tee goes to the return of the fuel pump assembly
Other sends gas to single input fuel rail on engine

The fuel pressure regulator is part of the Camaro fuel pump assembly.

Here is fuel pressure numbers at the fuel rail Schroeder valve:
Key On Engine Off: 53/54 psi
Idle and ~4500rpm: 59 psi
 
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Any chance you got the lines on the fuel filter messed up or its bad? I used a vette fuel filter to add an external pump and fuel cell to a JK. I had to double and triple check to make sure it got hooked up right.
 
SLOWPOKE693 said:
Any chance you got the lines on the fuel filter messed up or its bad? I used a vette fuel filter to add an external pump and fuel cell to a JK. I had to double and triple check to make sure it got hooked up right.
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I misremembered my current setup. I've adjusted the other post to reflect current state. I do not have the vette filter/regulator. The Camaro fuel pump assembly has internal fuel regulator. I do have an Earl fuel filter of some sort. I will disassemble it tomorrow and assess.
 
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LJ, i have the same setup in my scout and have my stock cam in the box the new cam came in if you end up going down that road. My LQ4 is from a 2000 and im NV4500 as well so if you want to check some stuff with me running numbers as well let me know.
 
Thank you very much for the offer. I'll send you a PM. But right now, the noid makes it look like I am back to fighting electrical.

Chops24 said:
LJ, i have the same setup in my scout and have my stock cam in the box the new cam came in if you end up going down that road. My LQ4 is from a 2000 and im NV4500 as well so if you want to check some stuff with me running numbers as well let me know.
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I pulled the fuel filter I had and it doesn't appear to be plugged.

I am running an Earl 230106ERL which is rated for 70+ PSI and is 35 micron. They came a flow rate of 4-5GPM. Is this too fine a filter?

I've also got a Summit SUM-230102 which is rated for 70+PSI and is 40 micron. They claim a flow rate of 130GPH(a bit over 2GPM).
 
I ran a quick test with the Summit filter with no filter in it. No change to driving.

In doing some further study, I have another follow up question:
At what point should new/different length push rods be used with a new camshaft assuming a stock long block? Valves are stock with BTR platinum valve springs.

The cam is advertised as 208/216 with 0.561"/0.561" lift. I was lead to believe that stock length push rods would be fine(7.40") Now I have some doubt.
 
Unless the new cam uses a larger base circle than stock or has huge lift #'s, I would think stock length pushrods would be fine with the rest of your stock valvetrain. No? Whats making you second guess yourself?

What length does BTR recommend in your application?
 
I'm not sure what made me look into the push rods... but once I got off onto that tangent, I found one symptom of an improper length push rod is lack of power.

The cam isn't a BTR unit but some other company(not willing to out them just yet) but they have been largely unhelpful post sale. The cam card that came with the cam is currently MIA. The company has refused to send me a copy of the cam card. I am currently 'fighting' over information for push rods... the answer so far is "measure for them". If I have to measure them, why offer the MFing cam in a kit form with push rods:rolleyes:

Unfortunately, I have no idea what "huge lift #s' really mean. Stock cam is supposed to be .467"/.479" while my new cam is supposed to be .561"/.561".

I do have a push rod measurer on order.

I do have a BTR cam in another LS and have the cam sheet for it. It is unclear where the base circle is called out but the lift numbers are similar to the above.
 
Lil'John said:
I'm not sure what made me look into the push rods... but once I got off onto that tangent, I found one symptom of an improper length push rod is lack of power.

The cam isn't a BTR unit but some other company(not willing to out them just yet) but they have been largely unhelpful post sale. The cam card that came with the cam is currently MIA. The company has refused to send me a copy of the cam card. I am currently 'fighting' over information for push rods... the answer so far is "measure for them". If I have to measure them, why offer the MFing cam in a kit form with push rods:rolleyes:

Unfortunately, I have no idea what "huge lift #s' really mean. Stock cam is supposed to be .467"/.479" while my new cam is supposed to be .561"/.561".

I do have a push rod measurer on order.

I do have a BTR cam in another LS and have the cam sheet for it. It is unclear where the base circle is called out but the lift numbers are similar to the above.
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You outed them in the first paragraph of this thread. Are you running stock heads and valve train?
 
M92PV4U said:
You outed them in the first paragraph of this thread. Are you running stock heads and valve train?
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Head and valves are completely as they came from the factory. The valve springs are the BTR springs. I believe the retainers are also stock.

removed company from first post:homer:
 
The cam company reached out again with some more information/ideas.

They confirmed that their cam works with stock 7.4" pushrods when the heads are stock. I was able to confirm that they provided no lash; barely able to spin the pushrod when on the "flat" of the cam... there was no rocker movement.

I'm back to thinking I'm fighting something in the fuel controlling circuits because the noid light is super dim.

The noid light using the fuel injection power is very bright when grounded directly to the battery. That tells me the power circuit to the injectors is good to go. Any disagreement on this?

That leaves the wires to the PCM that control the injector or the grounding on the PCM. Is there a known good ohm reading for the PCM to injector wires? Same question with regards to grounding out the PCM. Is there a known good ohm reading for the PCM?
 
On the flat side of the cam, you should have lash when tightening the rocker. From zero lash, you should get a full turn on the bolt. If you are tight and at zero lash, you need some 7.425's

But keep in mind, this is not going to cause your issue. This would cause a noisy drivetrain and slightly low on power.
 
waynehartwig said:
On the flat side of the cam, you should have lash when tightening the rocker. From zero lash, you should get a full turn on the bolt. If you are tight and at zero lash, you need some 7.425's

But keep in mind, this is not going to cause your issue. This would cause a noisy drivetrain and slightly low on power.
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Fawk... you are right. When doing pushrod measurement on LS, you use measurement tool until no lash. Then use that measurement and add 0.070" for lifter preload.:homer:
 
Lil'John said:
Fawk... you are right. When doing pushrod measurement on LS, you use measurement tool until no lash. Then use that measurement and add 0.070" for lifter preload.:homer:
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You don't need a tool... .070 is too much. More like .050 preload. One full turn past lash.
 
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