Long story short, a couple months ago, my A-1000 fuel pump vapor locked. I went in to a full 1-4 pull, and caught the car going lean through the gauges on the back half of the pull. I pulled off and the car immediately overheated and smoked poured out the breather on the valve cover.

Did a pressure and leakdown test, and #5, and 7 are down on PSI. 145psi in #7. Put new LS9 headgaskets on it, and ran it. The car needed to be retuned and was running lean, so my tuner retuned it to a safe level. The option was given to me to pull the motor or leave it and run it with #7 being hurt. The car made 4 pulls, made 790rwhp(down 20hp but much hotter than previous dynos). I decided to not pull the motor.

Ran the car for 2000 miles now, lots of very, very hard pulls. The car still smokes out of the breather all the time and burns a little oil, but no smoke at all out the back. It is the top rings most likely, which my tuner said. Now, last night, I had a race with a fast truck and made a couple pulls. It was too fast to keep an eye on the gauges. Tonight, I made a pull with a buddy, and the car is way, way lean. High 13's. Aborted and stomped on it quickly again to make sure, and got out of it early both times. Some times the A/F on my car has a slight delay, so I wanted to make sure.

Will a damaged ring that gets worse cause a car to continually get leaner, meaning that the tune needs to be adjusted until either the motor pops or it is fixed? I'm having a hard time figuring out why the car is running leaner now even if I am getting a little more blow by from one cylinder, and yes, the meth is spraying. Thanks.

 

If a cylinder misfires, it will spike your wideband lean. If it continues to misfire, it will hold a leaner reading. Why? Because widebands don't read fuel. They read oxygen content. A cylinder that doesn't burn the fuel due to a misfire (or any other reason) will pump elevated levels of oxygen into your exhaust. That's probably what's going on, but I would stay out of it just in case. You don't want to be wrong and cause further damage.

Good luck and congratulations on your upcoming wedding!

 

What are your fuel pressure and injector duty cycles doing when the car goes lean? Are you convinced that you don't have a fuel pump on it's way out?

 

Just another reason why I prefer running Bosch -044 pumps inline on hobbs switch.

Sorry to hear ur new setup is hurt, I'd say don't keep beating on it. Pull it apart and fix it before u end up with a inspection hole in the side of ur block. Heck u could just pull it and swap in a $500 truck 5.3 that comes with dish pistons and run it 700rwhp until ur forged motor is refreshed and ready to go back in.

 

Bret, thanks for the advice and wishes. I'm going to send the car in to my shop over while I'm on my Honeymoon. I'm scheduled to run but might back out depending on the car. I need the dope to hang with anybody up there, and that is a long haul with no trailer since I'll be bringing up the rear of the pack. Probably just spectate. I'll see you up there in a few weeks, bud.

Ken, we have tuned the car plenty of times. The original reason for the fuel pump failing was the A-1000 vaporlocked, causing the car to go lean and damaging the motor. There is a new Magnafuel pump in the car now that is boost referenced. I'm pegged on injectors(72lb), but I am picking some up from a buddy(FIC 1000). With dumping a ton of meth, I'm in the high 70's on duty cycle, over 100% with no meth. I'm more convinced on it being an engine issue rather than a fuel issue. The car has been beat on hard on and off the track.

Josh, I'm boost referenced on a hobbs switch now. That is actually not a bad idea to throw in a 5.3 in there. A buddy of mine actually mentioned that. However, I have no desire to drive the car in the summer, unless on a date night after 8pm on weekends. I live inside the inner loop in Houston, and like Dallas, there is no real use for these cars at this power level in 100* and 80% percent humidity for 4 months that are coming up. I'd rather drive my civic honestly when it is that hot. My living conditions do not allow me to do any real labor on my own(high rise) so I have to pay until I buy a house.

I'm thinking the best bet is to redo a compression test, add the new injectors and bigger blower and see how it turns out if the compression is still the same on the motor. Pull the motor around June, and have it back ready for September/October to start going back out to the track. If there is an issue with the pump or other part of the fuel system, my tuner will find it right away. I have quite a bit of confidence in them.

 

are you sure the meth is spraying when you see it lean right now? if your spraying a ton of meth, in order to get the AF to a sane level on the meth, your tuner likely had to pull a ton of fuel out of the tune, therefore when the meth fails to come on, you will have a very lean condition

 

Good point.

 

Hit the dyno real quick and confirm fuel pressure, meth pump flow and pressure, IDC matches readings from the dyno previously, add c16 for race day, and go have fun.

Oh yea, and pull all the plugs. That is what I do. You've missed enough events man!

 

Mark are you sure the secondary fuel pump is coming on and STAYING on? I hate those hobbs switch setups... They work well...WHEN they work....BAPs are the same way.

I think I'm going to do a hobbs switch as well as a micro switch on the gas peddle to get two signals to the secondary fuel pump....Hopefully one of them will always work..LOL

I hope your engine isnt hurt but...with that much blow by, it doesnt sound good...

 

It is possible to tune around that if it's set up properly. With proper thresholds set, you can yank all of the timing out and add or remove fuel as well if the IAT's spike.

Also if you spray enough meth, it's possible to run so lean without it that there's not even enough fuel to create enough heat and energy to detonate or burn anything up. The car will just nose over. Not saying he was set up this way or anything.

 

That's my 1st resort and the reason why I like to tune the Meth box set on #7 or #8 so if something goes south the car is "starved" for fuel and feels like a slug. I like to pull timing thru IAT table as well, but cooler than normal IAT's and it becomes a 2nd resort. I've always liked the idea that you "kill" the power when Meth quits so the driver knows right away something isn't right and let's out of it.

 

If your engine is having a lot of blow by, and you lost compression in the wounded cylinder. It basically means you likely lost a ring land, broke a ring or a combination of the above. With saying that driving it more, will likely cause scoring of the cylinder wall. As you may already know these engines have pretty thin liners, and scored cylinders can be just honed out providing that the walls are not scored to deep. If however the scoring is severe enough then the only options are to sleeve the cylinders or a new block.

 

yes i know this, i am a tuner lol i use the IAT timing table method, but if he is spraying a shitload of meth (which many people do) then this could be an issue...

 

if the motors breathing heavy than you prob got a hurt motor

 

The problem is that the IAT signal just doesn't run up instantly when the METH nozzles run dry. They ramp up fairly fast but not nearly as fast as it needs to be when you are at WOT leaning on that engine hard, and when detonation at that level occurs damage comes in milliseconds.

 

I've read the same thing. Guys running nitrous and using the IAT as a timing retard are asking for trouble. ECT is a much better sensor to use but these are not the same circumstances.

Are there are alternatives to the IAT sensor that could be spliced in and report the IAT in real time?

 

the IAT is more effective at adding or not adding timing on the initial hit of Meth, but its not as effective if the meth fails... the IAT does report in real time, the issue is if the meth fails, the IAT can still be cold a little bit after the meth has stopped and that short period can lead to detonation

 

use a fuel that doesent need meth.

 

this is exactly what i was thinking. Air pocket in the meth line or meth pump going south, have seen this many times, and it does exactly what the OP is describing.

We also tune it to yank out timing when the meth doesnt spray. we use aftermarket IATs that react faster also just for added security.