BACKFIRING AT 4K

6 Shooter

Well-Known Member
Were the heads, cam, and headers replaced, same for same? Or going from single port to split port? The broken sensor in the head is a cylinder heat temp sensor.
 

moman327

Member
same for same ( split port wise) even on the data plates on both cars were o2 but there were differences( now the new heads are pp with larger valves bigger cam intakes)
 

Phil II

Cone Destroyer
That's probably the cylinder head temperature sensor (cht). It's how the pcm senses coolant temperature and is needed for closed loop operation.
 

moman327

Member
could that be a cause of the issues i have been having. I also never got any codes about that and temp was always in normal range. the plastic was snapped of the brass nut part just dangling behind the head. Autozone/ advanced autos website says it can affect gas mileage. Is that true
 

Phil II

Cone Destroyer
More or less it is true. I don't know how the relationship exactly works, but it does affect maximum allowable ignition timing. Less timing means less power and less economy (to a point).
 

moman327

Member
ok so i have my car up and running no longer back firing at 4k or higher. Now Im having a new problem. wants to keep stalling out on me. Now I am waiting to get a proper tune from bama (free tunes)so I dataloged this morning and sent it to them. But I think I have a fuel delivery issue runs ok at higher rpm but will stall out when i come to a stop. Had this issue last year and it was a pump. A friend of mine said I could need bigger injectors now doing some reading I don't think I have maxed them out but not sure so here is what I have done to it and it was running ok for the first few days now cant stay alive i raised the drive idle and neutral idle to almost 800 rpm

cam 228/236 .572/.606 w 1.7rr 110 lsa
ported polished heads with larger valves
stock upper
stock lower
stock tb
cai
shorty headers
pypes cated x
flowmaster catback

also has new
maf( stock)
tps
o2s
cht

my friend is also telling me i need to put a larger stall converter in. Lacks some getup and go but runs great from 2k on ( so if you want to chime in on that as well)

if anyone wants to look at the datalog to see what they think I will gladly send it
 

Phil II

Cone Destroyer
I think your current issues are at least mostly due to the cam swap. I think no-one could say if your prior problems are solved since you made dramatic changes instead of specific troubleshooting until all was resolved. I'm just pointing that out.

Your cam specs are really similar to mine. Which is huge, bordering on pointless. I have the benefit of a roots blower but I also don't see great engine response below 2000 rpm. This is mostly due to the cam duration.

I used a high stall torque converter for something in the neighborhood of 1 to 2 years. It worked great, but I hated how it drove. Swapping to a 5 speed is one of my favorite mods, right next torque arm suspension.

You will definitely need a new calibration. BAMA might work out, or maybe get you close. I suspect they will not have enough talent for your motor. Its outside of their primary customer base.

I believe 6 Shooter continues to use the automatic setup and could share a lot on that.
 

moman327

Member
OK SO IT FIRED UP AT LUNCH LET IT IDLE WHILE FOR A WHILE AND AFTER 5 MINS SHE DIED PRESSED IN RELIEF FOR THE FUEL LINE AND HAD NEXT TO NOTHING .

FUEL FILTER IS NEW AS WELL. BTW

IM THINKING FUEL PUMP EVEN THOUGH IT IS A YEAR OLD ( SAM SYMPTOMS AS ID HAD LAST YEAR)

SEPARATE NOTE DO YOU THINK STOCK INJECTORS ARE ENOUGH FOR MY SETUP.
 

Phil II

Cone Destroyer
Can you catalog? Track your fuel pump and injector duty cycle to see if they are insufficient. You could also check the fuel rail pressure sensor is ok. If it failed there typically there is a smell of gasoline in the vacuum line. Lastly a mechanical fuel gauge can be attached to the fuel rail to verify your electronic indications.

Your ecm may not be able to keep your engine idling indefinitely without tuning.
 

6 Shooter

Well-Known Member
Couple of thoughts. The motor dying at a stop sign is often related to fuel starvation. Going real lean PLUS the transmission staying in the 3 gear all the way down to 10 mph or less and not downshifting into 2nd sooner. Had the same problem and fixed the downshift shift points for the fix. And yes, IMHO, your injectors are too small for the extra air flow from the heads, cam, etc. You should probably be looking at 24 lb injectors IF you are NOT using any forced induction. And with those changes, you will need a tune to get rid of the drivability issues. Kinda surprised that the exhaust valve has a higher lift than the intake valve. Often they are almost equal or the intake may have a slightly higher lift to allow more time for more air.

Post the year of car and the type of fuel system; return or returnless.
 

moman327

Member
it is a 2002 with stock returnless fuel system. i tried swaping out the frps ( had one that was used for a few months cause i thought that might have been the issue in the first place) that is what is on it right now. car wont run long enough to data log anything new. i had short term and long term trims on the"last drive" before this happened. i am going to get the 75gph fuel pump for the focus from advance auto gonna cost me like 40 after a speed perk and another 20% OFF unless anyone has objections to it. if so let me know. plan on ordering it tonight if no objections.


thanks again guys for all the help and the continued support

on a side note
i have been upgraded to a sr cailbrator at bama so maybe this will work out. name sounds familiar to a name i have seen on here but want to make sure before i get happy lol
 

moman327

Member
http://shop.advanceautoparts.com/p/...l-pump-e2386/15770117-P?searchTerm=fuel+pump+

this was the pump I am looking at i looked it using a 2004 svt focus

also after doing a little investigation i think i have our member ortiz on my tune now found a post where he said he was moving to pa to work for a major mustang company doing tuning. And the person on the case has the name i remeber when i talked to him on the phone a while ago when i was originally going to do the head and cam swap. looks like i hit tuning jackpot i sent him a pm this morning but it seems i am in good hands with bama
 

6 Shooter

Well-Known Member
30s would be better.

Post your 4-digit PCM code.

Agree with the focus fuel pump. After switching to the Focus pump, in the tune, need to multiply the entire voltage table by 0.80. This will lower the voltage table by 20% to accommodate for the higher flowing pump, vs the stocker.
 
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6 Shooter

Well-Known Member
The key to getting injectors is to locate the EXACT set of value files which correspond to the injectors. A mismatch will be tuning hell or sloppy idling, down low in the throttle range, and maybe some lag on tip-in (on the gas). So, would first decide about who is tuning and what software they are using. Then, ask the question IF they have the specific value files for the injectors you are interested in. For example, many tuners use the SCT software. And, SCT has a number of value files for specific fuel injectors. For example, SCT has 3 sets of value files for 30s -- Accel Slope only, Ford Racing injectors, and a generic set for 30s. Personally, I would lean toward the Ford racing due to the specific value file for the specific injector. But, could be an extra $100 vs those Boschs posted. So, be sure to ask the tuner IF he/she believes the generic 30s value file would work well with the Bosch 30s. Further, ask HOW many times he has tuned the Bosch injectors with the generic value files. A tuner can always make due with the generic value files, but the quality of idle ability most are not happy with when the idle varies up and down over 100+ rpms.

One other point, it may be that Bosch website will have a set of value files for their injectors, so do a little research to find out. Look for high slopes, low slopes, minimum pulse width, and fuel injector break point, as a minimum. You do not have to understand the numbers, just look to see that those 4 categories are listed, as a minimum.
 
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moman327

Member
SOOO
I WAS ABLE TO DATALOG AGAIN FOR A SHORT TIME BEFORE IT DIED SENT IT TO THEM AND THEY SAID I HAVE A VACCUM LEAK / EXHUAST LEAK BEFORE FRONT O2S( I HEARD THE EXHAUST LEAK DIDNT KNOW IT WOULD BE THAT BIG OF A DEAL) SO I AM GOING TO TRY TO GET THAT FIXED FIRST AND SEE IF IT CLEANS UP IDLE AND DRIVING ISSUES BEFORE I DO THE PUMP ( THEY SAID IT WASNT TRYING TO MAX THE PUMP OUT) I CAN SEND DATALOG FOR YOU GUYS TO LOOK AT IF YOU WANT
 

moman327

Member
I HAVE CONFIRMATION BTW THE TUNER AT BAMA I AM WORKING WITH IS ORTIZ!! LOOKS LIKE I AM IN GOOD HANDS IN THAT RESPECT. I DO PLAN ON UPGRADING THE FUEL PUMP AND THE INJECTORS. JUST WANT TO GET IT UP AND RUNNING FIRST AND THEN CONTINUE TO ADD THINGS WITH TIME AND MONEY. I WAS OUT OF IDEAS WHEN I PUT EVERYTHING ON IT THIS TIME (AND SINCE I WAS DOWN AND BOSS LENT ME A CAR SO I FIGURE DO IT WHILE I COULD ALL AT ONCE) THANKS FOR INFO ON THE INJECTORS TOO I WILL LOOK INTO BUT NOW THAT I DON'T HAVE TO RUSH I FEEL BETTER AND CAN DO MORE RESEARCH TO DO THE RESEARCH INSTEAD OF JUMPING RIGHT IN OR SAVE UP MONEY AND JUST GET THE FORD ONES TO START WITH.
 
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