it was running great for a while there, then it started bogging bad.

DOHC ZC, 6psi kit, using jackson FMU and B&M fpr.

cruising and idling, you can feel an irregularity. but when accelerating and when going from cruise to WOT, it hesitates and bogs horribly.

fuel pressure at idle is 38. with vacuum off the B&M, 48ish. vacuum on the B&M, off the FMU, fuel pressure is 58.

i finally noticed as i blipped the throttle, the adjusting nut on the B&M was sliding around. i tightened that, and now the hesitation and bogging is ONLY at WOT.

so hopefully this is all narrowed down to the B&M and it's setting. i'm just not sure how to test what's going on. i don't think disconnecting vacuum from the FMU is the right way to test that. wouldn't i need to introduce pressure at that vacuum line?

or what else should i look for?

 

some people say run the MAP reading AFTER the blower. some say to connect it to the stock location, reading off the throttle body. who's right?!

mines connected to the throttle body (before blower)...

 

c'mon guys, help a brotha out.

i've searched and searched and tried everything i've come across. but no matter what i do, WOT=bogging!

 

what you need is to switch to crome/uber/hondata..I had the same problem and when I switched, it never came back...

 

my map is connected to the intake manifold. i have the spacer looking thing under my map sensor that comes with the map mod.

do you have your timing retarded?
colder plugs?
highest octane gas you can use?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FOUR-G &raquo;</TD></TR><TR><TD CLASS="quote">some people say run the MAP reading AFTER the blower. some say to connect it to the stock location, reading off the throttle body. who's right?!

mines connected to the throttle body (before blower)...</TD></TR></TABLE>


If you are using an FMU with the Jackson boost pressure sensor, connect your MAP sensor to the throttle body.

If you are using an FMU and the Jackson MAP mod, connect your MAP sensor to the intake manifold.

If you are using uberdata/hondata, connect your MAP sensor to the intake manifold.

 

my timing is retarded to 10deg.
still using stock bcpr6e-11.
91 octane.

after some more reading on the high fuel pressures the FMU causes and how stock fuel pumps have a hard time keeping up under WOT conditions, i'm leaning towards my pump taking a **** on me. it does have 195,000 miles on it...

i have a set of DSM 450s and a Zdyne gold SECU, but i can't afford to have it dyno tuned right now. i also bought the Jackson fuel pump upgrade when i bought my kit, but i wasn't going to put it in until i used the 450s because it's hard to get the stock injectors to idle with it.

i'll try some bcpr7es-11 or bkr7e plugs. but with the issues i have, does it sound like my stock fuel pump is shot?

 

I don't know if your pump is shot, but you should be able to install the jackson racing pump with your stock injectors. Your idle shouldn't be affected at all.

 

okay so i'll be installing the fuel pump this weekend, but if that dosen't solve anything...what else would you suggest i look at?

seems like as long as i stay out of boost, the car will drive fine

thanks guys

 

anybody?

 

Well, it's not your timing, so the problem sounds like a fuel issue.

And you say everything ran fine for a while, then suddenly the bogging issue arose? That means you probably have everything setup right.

So it sounds like some part of your fuel system crapped out. If it's not the pump, I'm guessing it's either your FPR or your FMU. Both of those are known to crap out on people. The Jackson FMU's in particular are know to have bad diaphrams.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FOUR-G &raquo;</TD></TR><TR><TD CLASS="quote">

i have a set of DSM 450s and a Zdyne gold SECU, but i can't afford to have it dyno tuned right now. i also bought the Jackson fuel pump upgrade when i bought my kit, but i wasn't going to put it in until i used the 450s because it's hard to get the stock injectors to idle with it.

</TD></TR></TABLE>

Why does it have to be dyno tuned? Get a wideband and street tune it then have it dyno tuned for max whp. We always street tune them a bit before the dyno, as long as you have the proper tools to do it.

 

I street tune all my setups too. But timing is kind of a guess. The dyno detects knock long before you'll hear it.

 

my timing is at 13 degrees and i'm running 6psi. no problems here.

your JR fmu can be going out at well.

 

well i went ahead and installed the JR fuel pump tonight. it made a world of difference, yet didn't fix the problem if that makes any sense.

it raised my fuel pressure 5psi across the board. when i play with the throttle under the hood, the fuel pressure will rise and hold, whereas before it would go up, then back down to the base pressure of 38.

it's driveable now, without having to baby the gas pedal like i was. it'll bog really bad at tip-in still, but then cleans up and just pulls to redline. could all be in my head, but seems to pull even harder now with the pump.

at least i feel alot better about it now. because it feels DAMN QUICK when i get on it and stay on it throuhout the bogging. i'm gonna borrow a hand pump tomarrow and test out my FMU, see what the fuel pressure does when the FMU sees pressure. and i'm gonna try out a PM6 ecu i have lying around too. for ***** and giggles.

but now that i have the pump in, i'd like to just send out my DSM injectors to be cleaned and tested, pop 'em in and load the zdyne with a tune from somebody's setup similar to mine.

thanks for all the input

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FOUR-G &raquo;</TD></TR><TR><TD CLASS="quote">

it raised my fuel pressure 5psi across the board. when i play with the throttle under the hood, the fuel pressure will rise and hold, whereas before it would go up, then back down to the base pressure of 38.</TD></TR></TABLE>


That sounds bad to me. You fuel pressure shouldn't have changed anywhere except under boost. If it's higher now at idle, you need to adjust the FPR. Are you sure your FPR is good?

 

when i'm adjusting my fpr, i know you disconnect the vacuum line to the fpr itself...but do i leave the FMU's vacuum line connected to the manifold or disconnect it and plug the port on the manifold?

 

How is it bad? Any 255 hp pump will raise your base fuel psi unless you have very big fpr. Anything stock size needs a releif hole drilled in it. http://theoldone.com/articles/regulator/

 

He has a B&M regulator. And he has no need to raise fuel pressure at idle.

Also, I refuse to read any of Larry's articles because he makes **** up.

 

put a stock fpr back on and see if it goes away

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tad &raquo;</TD></TR><TR><TD CLASS="quote">put a stock fpr back on and see if it goes away </TD></TR></TABLE>
i'll try anything at this point

until then, i picked up some bcpr7es-11s. i know for my lowsy 6 pounds 0.028 is excessive, but i'm gonna try it! i'll see how that runs and go up from there.

oh yeah, it seems a lot slower with this PM6 ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">He has a B&M regulator. And he has no need to raise fuel pressure at idle.

Also, I refuse to read any of Larry's articles because he makes **** up.</TD></TR></TABLE>

LOL k he put on a BIGGER pump and IT raised his fuel pressure 5 psi at idle. B&M uses the stock fpr it just makes the spring ajustable. The pump will give you more pressure at idle. I would prolly leave it nothing wrong with a bit more fuel.

LOL Larry might not be the best buisness man, but cars here are making 800+ WHP (daily driven street cars!) run his products so who really cares what you say about him, his **** makes power. I'm not a huge Larry fan, but the article I posted is very helpful. If you want it stock pressure buy a bigger fpr like aem or drill it like the articel says.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">


That sounds bad to me. You fuel pressure shouldn't have changed anywhere except under boost. If it's higher now at idle, you need to adjust the FPR. Are you sure your FPR is good?</TD></TR></TABLE>

And why on earth would a fuel pump change the psi under boost and not at idle? A FPR and a FMU are both just restrictions in the fuel system that block it and make the pressure go up. A bigger pump flows more fuel at the same psi and is more efficient at higher psi (well the HP high pressure pump is)

 

Yeah, I don't know about Larry. I just stay away from his products and articles. Some of his info is good and his knowledge is good, but other times it's like he tries to act like he knows more than he really does.


And the way I see it with the fuel issue - you are just slapping a turbo on a stock motor, right? So you have no need to toy with your fuel pressure at idle. Unless you did something like headwork, then you don't want higher fuel pressure at idle. Because you have no way of controlling your injectors, right? You're just going to run rich for no reason. Also, extra fuel pressure puts extra strain on the whole fuel system.

But during boost, your FMU is going to create a huge raise in fuel pressure. Since you can't control your injectors, your only hope of adding necessary fuel is to stuff it through your injectors, which is why the FMU raises the pressure. But that puts a lot of demand on your pump. Adding an aftermarket pump ensures that you can keep your fuel pressure where the FMU is trying to keep it.

So bottom line - when you have no real engine management and get stuck using an FMU (gay) then you only want extra fuel pressure when you are making extra power. Raising fuel pressure when you are not making extra power just makes you run rich and waste gas.

 

well it musta been the plugs. i gapped the colder ones at 0.028, and no hesitation on the quick test drive i took.

now i just gotta figure out why it almost stalls when i depress the clutch when slowing down. the tach sits at ZERO for a second before it bumps itself up. when the A/Cs on when this happens, the ****** stalls. i STILL must have a vacuum line that's hooked up wrong...