so ive been breaking in my motor im at about 650 right now drove it to about 550 600 with no boost or very very little just to get up hill an stuff. At about 575ish i started to run it like the book said normal not hard not to soft. its a large streetport with a hks fcon and a fcd. so tonight i was getting on it a little to get up a hill by my house about 5psi an the car did a little hesitation let off an went away. So i pushed the clutch gave it a little rev an the hesitation wasnt there when i reved. So i looked down an my a/f said idle to rich. My apexi timer said 14.3to 14.1.

Didn't get on it a little til i was a few blocks from home. it was good first second i boosted about 5 6 psi an it hesitated agian. left off an it went back to 14.3. Agian i tryed it an it like hesitated right when i let off in second. It feels like its taking for ever to get to boost but im only at about 1/2 throttle so that could be why to.. But every so often my af just goes to 20.0 an then i rev a few times an goes back to 14.3. could it be my fuel pump takin a poop i changed my fpr to a afpr an set it to the book but i have no hold pressure. I think the book said 18psi an it drops to 0 could this be a sign of a bad fuel pump..

 

might be fuel pump, but 14.3 is a little on the lean side.... it should be in the 13s or 12s

 

yeah i know thats why i was kinda leaning tord my fuel pump.. cause i was reading that 14.3 is what idel is or thats what wikipedia said. then anything after that would be considered lean. an anything under is rich so im thinking maybe my pump is taking a poop or my fcon isnt adding fuel i dont wanna drive it so idk...

 

Yes, 14.7:1 is a perfect a/f ratio, as in Stoichiometric ratio. Therefor, in an ideal world, with a perfect engine that has no flaws, holds 100% of the compression, doesn't burn excess oil etc. etc. with ideal atmospheric pressure and temperature, you would recieve a complete burn and the maximum power delivery.

This, however, is not an ideal world, and you no longer have a perfect engine. As a matter of fact, it never was perfect.

Shooting for lambda (14.7:1) will most likely be a very bad thing to do, as a small change in wind could change the atmospheric pressure of the air (i.e. being forced into the system) which could potentially cause detonations in your car. You really should aim for the 12 to 13 area. This will help shield you from any sudden lean situation that the computer can't compensate for.

If it wasn't meant to be this way, the professional tuners would all tune to lambda.

 

In the turbo Dodge world, we generally tune for around 11.5-12 AF ratio as a safe tune. May not apply to the rotary though.

 

Get a high flow pump.

Your motor just needs to be broke in, and having such a big port like that, theres a good chance of that kind of hezitation to happen when your boosting low because its trying to fill the gap from a bigger port with air.

Go ahead and get the pump, break your motor in, then get it to where you can drive it how you want to so you can accualy open the car up. Most likly the hezitation wont be there because you'll be boosting higher also with the throttle body wide open or just far open will suck much more air in.

I dont think you have anything to worry about.

 

Also, if this dosnt cure the problem, tune your car to its own liking, not every motor is the same. A/F ratio numbers from what people say can only give you a good idea of what you need to be around, but it needs to be tuned to what makes it run at its best.

 

for sure man ill do that... im getting a new turbo soon so im going to be upgrading my secondaires. but fuel pump i have a walbro i got for free from a friend he never used it. but ive heard bad things about walbros. i opened it up a little later an its still there but not as bad as like 1/4 1/2 throttle but its still there. when i get into boost air fuel goes up to about 13.2 ish

 

Again, we have a bunch of people supplying improper answers, due to lack of knowledge and lack of information in the original post...

First, how are you measuring A/F ratios? Wideband?

Second, you say it went into the 14s when you let off the throttle? If that's the case, then it's perfectly normal.

A misfire will cause a super lean reading. So any of those 20:1s could have just been a momentary misfire.

Also, if the stock emissions equipment is in place, the air pump will pump air into the exhaust and effect the sensor reading.

 

Like i said, you'll be fine.

 

Why? Based on the information presented in the thread, there doesn't seem to be any extra need for a fuel pump. Under low boost, 12:1 is perfectly acceptable. No point running 11s until 8 PSI or so.

No, not at all. Hesitation means something is wrong with the car.

On a freshly built engine, plugs should be checked. Assembly junk will ruin a new set of plugs very quickly.

Again, any hesitation is a problem. If the car is hesitating, going to WOT is a stupid idea. Ignition misfires under boost will eat a set of apex seals.

Neither do I, but not for the reasons you suggest.

I've been watching the answers you are providing to questions lately. Many of them are inaccurate or jump to odd conclusions. Please reread the rules regarding misinformation.

 

The reason i suggested a fuel pump is because i didnt know if he had an aftermartket one or not.

Also, the hezitation he described sounded small. So I figured it would be because hes not opening the car up enough.

Also, I simply suggest sharper tuning to the A/F.

And you didnt have to put me in my place in a public thread.