twin64

I just finished a DOD and VVT delete using Texas Speed parts consisting of their 212 218 low lift cam 112 LSA and 111 LCL. I installed their long tube headers and ORY. I had Justin at Blackbear update my tunes and have sent him logs.

The issue I am having is it seems to be igniting the fuel in the drivers side header. It doesn't do it on the passenger side. Cruising is fine. Accelerating gently while driving doesn't do it. Every time from a dead stop it does it. If you try to kick it down and take off it does it.

The engine feels lazy. Would someone with EFI live like to take a look at the logs and see what you think? Justin asked me to clean the throttle body which I will do tonight.

twin64

Here's another log.

BudRacing

iTrader: (3)

Check your plugs. There's a chance you cracked one.

twin64

I swapped the plugs from drivers side to passenger side last night. It made no difference.

BudRacing

iTrader: (3)

My next step would be to take a temp gun to each primary to find an outlier to ID which cylinder may be causing it. Or you could just pull plug wires one at a time to see which one doesn't cause a change.

twin64

You can hear different cylinders do it depending on how hard you are trying to accelerate. If you are taking off really easy it will be just one cylinder, and the harder you try to take off the more cylinders will do it. If I do a rolling stop chances are it will take off just fine. If I do a complete stop chances are it will do it, clean up around 2k rpm, shift do it, clean up then be fine through third. That is all with very light throttle. Try and open it up some and it is terrible.

I can check the primaries at idle, but I don't think that is going to show anything. I will try it with power braking it and see if it will act up.

Thanks for your help BudRacing!

BudRacing

iTrader: (3)

So you're getting a random multiple misfire and it's not throwing a code?

If it never ran right after the cam swap, how was the cam installed? Dot to dot?

If it were throwing a code, my guess would be the P0300. Lots of things to check for causes.

What causes the P0300 code?
Spark plugs that are damaged or worn
Spark plug wires and/or coils that are damaged or worn
Distributor cap that is damaged or worn (only if applicable to the vehicle)
Rotor button that is damaged or worn (only if applicable to the vehicle)
Fuel injectors that are defective
EGR valves or tubes that are clogged
Ignition timing that is off
Vaccum leaks
Fuel pressure that is low
Head gasket(s) that are leaking
Distributor cap that is cracked
Camshaft sensor that is faulty
Crankshaft sensor that is faulty
Mass air flow sensor that is faulty
Oxygen sensor that is faulty
Throttle position sensor that is faulty
Catalytic converter that is faulty
PCM is faulty

twin64

Justin has turned off a lot of the misfire diagnostics in the tune. I don't think it is a misfire as much as a very late ignition event. I would think with a misfire we could see it in the O2 sensor.

Cam was intalled dot to dot.
Stock OEM wires with 107K miles.
Plugs have 15k miles on them.
The injectors were fine before the cam swap.
Timing looks good in the logs.
All vacuum lines are hooked up.
I haven't put a fuel pressure gauge on it but there wasn't an issue before the cam swap.
Head gaskets were new MLS gaskets when I did the swap and no signs of leaking.
Cam sensor is a new GM that cam with the new gear cover for the 3 bolt 4X cam gear.
Crank sensor didn't have an issue before the swap and not getting a code now.

twin64

Just an update.

I decided that there was a possibility, even though I was 99.99% sure it was dot to dot, that I had misaligned the cam during the install and was one tooth off. I came to this conclusion by adding 16 degrees of timing to my tune file and it pretty much cleared up the firing through the header with the exception of coming off idle from a dead stop. So this evening I pulled the front cover and the cam and crank were in fact lined up dot to dot. Just to verify I moved it one tooth in either direction and it was obviously way off from being dot to dot.

After finding this I decided I needed to degree the cam in. The cam is supposed to be ICL 110, duration @ .050" 212, and Lobe lift .324". The measurements I ended up with were ICL @ 123 degrees, duration @.050" 194 degrees, and a max lift of .202". These measurements were taken with the dial indicator placed right above the push tube on the rocker arm.

My question before calling Texas Speed Monday is could the location where I placed the dial indicator have that much effect on the measurements? The measurements are so far off that it is hard to believe, but I triple checked my work, the dial indicator returned to zero every time the valve closed, and the dot on the crank gear was straight up which agreed with our measured TDC.

1CAMWNDR

iTrader: (21)

Something is way, WAY off. .202" lobe lift is only
.343" valve lift with a 1.7 rocker..... And only 194° duration? Either that cam is QUITE wrong, or your degree wheel and indicator were not set up right.....