3.5 Swap midrange LOSS!!
08-09-2008, 10:50 PM
#1
3.5 swap power loss?!!
VIDEOS AT THE BOTTOM FOR THE EYE lol
well pretty much I just finished the 3.5swap and my car runs fine.. lots of power up to 6000rpms but once it gets to 6000 it falls on its face! I mean it literally won't pull to 7200 as if the fuel cuts at 6000 because the A/F reads as normal until 6000 then it drops past LEAN and doesn't read anymore. I've even tried addin as much as +20% of fuel and as little as -5% of fuel and still does the samething.
Any idea of what it is cuz it runs like sh*t after 6000
well pretty much I just finished the 3.5swap and my car runs fine.. lots of power up to 6000rpms but once it gets to 6000 it falls on its face! I mean it literally won't pull to 7200 as if the fuel cuts at 6000 because the A/F reads as normal until 6000 then it drops past LEAN and doesn't read anymore. I've even tried addin as much as +20% of fuel and as little as -5% of fuel and still does the samething.
Any idea of what it is cuz it runs like sh*t after 6000
Last edited by ghostmax301; 08-28-2008 at 10:01 PM.
08-11-2008, 03:40 PM
#7
you said the a/f reads "LEAN", do you have a ricer narrowband wideband readout (those are the "light show" ones that just blink back and forth bet'n RICH and LEAN) or a legit wideband?
if its a wideband, whats the ACTUAL a/f ratio?
if its a wideband, whats the ACTUAL a/f ratio?
08-11-2008, 09:35 PM
#8
well i have a stock fpr right now, waiting for my AFPR to come in. As for the A/F gauge, Yes, sadly its a narrow band but i have it hooked up to the signal wire of the front bank o2 so i can ATLEAST have some type of idea of whats going on. But i DO plan on getting an electric cutout and WBo2 as my next mods before anything else.
08-12-2008, 10:44 AM
#9
I still don't understand completely what's going on. Is there like a pseudo-rev limit at a certain RPM where you just can't pass it no matter what, even in neutral? Or does the motor feel like it falls flat on it's face like the USIM does past 5.5k?
08-13-2008, 05:00 PM
#10
[quote=ghostmax301;6570310] Yes, sadly its a narrow band but i have it hooked up to the signal wire of the front bank o2 so i can ATLEAST have some type of idea of whats going on. quote]
using a narrowband for tuning is really not recomended. i would deffently get a wideband asap!!
using a narrowband for tuning is really not recomended. i would deffently get a wideband asap!!
08-18-2008, 05:54 AM
#12
just an update,
I have my AFRP in now set at about 39psi. The only reason I set it that high at idle was because if I revved the can in neutral, the fuel psi would drop to about 32psi. Also,I changed my plug and ALL of them were flat black on the end of them and it wasn't rubbing off? was that from running rich?
The WBo2 sensor is the next buy. Funds are tight right now so I going to have to hold off for a week or 2 untill I get it.
Going to the track on some Hoosiers on friday,ill let yu guys know what happens. From my past runs, and experience driving others car, im expecting a 13.3-13.8 @ 99-104
I have my AFRP in now set at about 39psi. The only reason I set it that high at idle was because if I revved the can in neutral, the fuel psi would drop to about 32psi. Also,I changed my plug and ALL of them were flat black on the end of them and it wasn't rubbing off? was that from running rich?
The WBo2 sensor is the next buy. Funds are tight right now so I going to have to hold off for a week or 2 untill I get it.
Going to the track on some Hoosiers on friday,ill let yu guys know what happens. From my past runs, and experience driving others car, im expecting a 13.3-13.8 @ 99-104
08-24-2008, 11:39 PM
#13
ok, soooo. Went to the track................14.40@95
car seems to be running good, NO driver error..WTF IS GOING ON???!!
Only unnormal thing going on is the fuel PSI dropping so much as i rev? Is it suppose to do this or do i possibly have a bad fuel pump?
car seems to be running good, NO driver error..WTF IS GOING ON???!!
Only unnormal thing going on is the fuel PSI dropping so much as i rev? Is it suppose to do this or do i possibly have a bad fuel pump?
08-25-2008, 09:05 AM
#14
well I went and fixed the small vacuum leaks today and the car runs even worse... it deffinently feels like somethings literally holding the car back..as if there was a towel over my MAF or something..anyone know what's going on?
08-25-2008, 10:03 AM
#15
your fuel pressure goes down as you rev the car higher? That should not happen. It should go up.
08-25-2008, 10:15 AM
#16
What's is the purpose of the vaccum on the afrp? I was going to unplug it when I get off and see if it still drops? but I swear I can't find anymore vacuum leaks
08-25-2008, 10:41 AM
#17
yep, I Have it set at 40psi(just because it drops soo low at redline ) and when I rev it..it'll be around 28-32psi.
What's is the purpose of the vaccum on the afrp? I was going to unplug it when I get off and see if it still drops? but I swear I can't find anymore vacuum leaks
What's is the purpose of the vaccum on the afrp? I was going to unplug it when I get off and see if it still drops? but I swear I can't find anymore vacuum leaks
That's not good.
I am guessing it needs the vacuum to know what the engine is doing to know how much fuel to supply. I would double check your install on the FPR.
**also I should probably say that any advice I am giving about this is based on my boosted engine. I have never used an AFPR on an N/A engine, so if I am off hopefully someone else will speak up. But I know even before my engine goes into boost when I just blip the gas my FP rises.
08-25-2008, 11:10 AM
#18
well the sad thing is,my afpr didn't come with installation instructions but it had a fuel fitting on the side and ont the bottom. vacuum port on the other side and adjustment screw on the top...I have the feed going in through the side port an the return going out through the bottom..does this seem correct? when I raise the Fuel PSI,the idle raises so I think its hooked up right
08-25-2008, 11:26 AM
#19
well the sad thing is,my afpr didn't come with installation instructions but it had a fuel fitting on the side and ont the bottom. vacuum port on the other side and adjustment screw on the top...I have the feed going in through the side port an the return going out through the bottom..does this seem correct? when I raise the Fuel PSI,the idle raises so I think its hooked up right
I have an AEM regulator so I would have to look at mine before I could comment on your current set up.
08-25-2008, 12:08 PM
#20
which regulator is it? I am sure the instructions are probably online. It may be hooked up right but you probably want to check it since it sounds like you are running out of gas up top.
I have an AEM regulator so I would have to look at mine before I could comment on your current set up.
I have an AEM regulator so I would have to look at mine before I could comment on your current set up.
. Im leaning towards getting a 255lph fuel pump and hoping the solves the problem. Might even go grab one from the junkyard(stock) to make sure if it is my fuel pump
08-25-2008, 04:16 PM
#22
If you need a stock fuel pump, I've got 10 or so in my box. They're Z/G pumps, but AFAIK the same thing.
08-25-2008, 04:42 PM
#23
perhaps the reason ur fuel pressure dips is simply because your fuel pump is going out. Thats really what it sounds like to me. Our cars are no longer 2yo and trouble free, things do take craps over time on 10yo+ cars, including fuel pump.
You shouldnt even be making a big deal about running a 14.4. After all, last I saw, you still had an old fuel pump thats possibly taking a crap (replace it with at least a Walbro 190, that worked fine for me All-Motor), you have no idea where the a/f is so of course, no idea how bad the tune is (and yes, as YOU already know, 97% of 3.5 swaps here run like crap [relatively] due to lack of tuning
).
Upgrade the fuel pump, get a wideband, tune it, THEN go back to the track and see some real #s.
Best of luck!
You shouldnt even be making a big deal about running a 14.4. After all, last I saw, you still had an old fuel pump thats possibly taking a crap (replace it with at least a Walbro 190, that worked fine for me All-Motor), you have no idea where the a/f is so of course, no idea how bad the tune is (and yes, as YOU already know, 97% of 3.5 swaps here run like crap [relatively] due to lack of tuning
). Upgrade the fuel pump, get a wideband, tune it, THEN go back to the track and see some real #s.
Best of luck!
08-25-2008, 08:55 PM
#25
http://forums.maxima.org/all-motor/3...all-motor.html
Note the HP levels.
Was your car doing this before the swap?
Note the HP levels.
Was your car doing this before the swap?
08-26-2008, 09:38 AM
#27
08-26-2008, 09:42 AM
#28
I really think a higher capacity pump would be band-aid'ing the issue. You're not putting out the kind of power that would max the stocker out.
http://forums.maxima.org/all-motor/3...all-motor.html
C'mon guys. You really think the stocker can't keep up in neutral? 
Check that AFPR out..
http://forums.maxima.org/all-motor/3...all-motor.html
Originally Posted by ghostmax301
I have my AFRP in now set at about 39psi. The only reason I set it that high at idle was because if I revved the can in neutral, the fuel psi would drop to about 32psi.
Check that AFPR out..
Last edited by nismology; 08-26-2008 at 10:00 AM.
08-26-2008, 10:16 AM
#29
I really think a higher capacity pump would be band-aid'ing the issue. You're not putting out the kind of power that would max the stocker out.
http://forums.maxima.org/all-motor/3...all-motor.html
C'mon guys. You really think the stocker can't keep up in neutral? Check that AFPR out..
http://forums.maxima.org/all-motor/3...all-motor.html
C'mon guys. You really think the stocker can't keep up in neutral?
Check that AFPR out..
08-26-2008, 10:33 AM
#31
FWIW after we put a GSS342 in Merlyn's A33B, it seemed...quicker, for lack of a better word. 99% it was a placebo effect, of course.
08-28-2008, 01:37 PM
#32
got the walbro 255lph in..Same problems....topend feels a lot bettr and fuel psi doesn't drop anymore towards redline,it raises but the car feels like a napkin or something is stuck over my MAF if I het it at 3000 the car won't pull for about 5 secs...it'll sit between 3k and 3.5k for -5sec UNDER WOT.
could this be a CPS or CKPS going bad? Im only getting codes for B1 & B2 S1 o2 sensors and a misfire code..
but once it passes about 5k,the car wakes up dramatically..
any idea what it might be? timing issue from the CPS?
could this be a CPS or CKPS going bad? Im only getting codes for B1 & B2 S1 o2 sensors and a misfire code..
but once it passes about 5k,the car wakes up dramatically..
any idea what it might be? timing issue from the CPS?
08-28-2008, 02:06 PM
#33
also,the car just started acting like this recently..when I first did the swap it ran perfectly.also I have a small vacuum leak(not enough to disturb the ilde though,I idles at 800) and I have changed the brak in oil yet(1000miles on it,don't know if that makes a difference)
08-29-2008, 09:23 PM
#37
Damn man now this is weird lol
to answer this, no. I dont even have my o2s connected. They've been bad since I was on the 3.0 2yrs ago. But then again... I've been tuning from idle to redline since. You're not tuned at all, so who knows.
COULD it be air/fuel related? yes it could, but without a wideband to see the a/f, there's no way to know. What if you're running ubber rich in that dead spot then lean out to a manageable a/f at 5k or wherever it is that it picks up? what if its the OTHER way around that its ubber lean then gets to a good enough a/f to rev strong?
Things that affect A/F under WOT are MAF, RPM, TPS, and ECTS.
What codes did you say you had? You mentioned earlier of having codes but what are they exactly?
08-30-2008, 12:52 AM
#38
what's all under the ECTS? also, im going to check the TPS and change out my ECU.
I entered midrange powerloss on the free search and got a lot of results that help 90% but still hasn't fixed the problem, the people that have had the same problems,even with 3.5 swaps are losing it at the same spot 2.5k-5k but EVERY other rpm Is fine (0-2.5k&5k-6.8k) and it led to the MAF.
I did some work awhile back on the ECU im using right now and though I messed it up,just a coincidence, I was wiring up a J30 maf.. so ill try a ECU tomorrow that I know is goode and see what happens... ill keep you all updated
I entered midrange powerloss on the free search and got a lot of results that help 90% but still hasn't fixed the problem, the people that have had the same problems,even with 3.5 swaps are losing it at the same spot 2.5k-5k but EVERY other rpm Is fine (0-2.5k&5k-6.8k) and it led to the MAF.
I did some work awhile back on the ECU im using right now and though I messed it up,just a coincidence, I was wiring up a J30 maf.. so ill try a ECU tomorrow that I know is goode and see what happens... ill keep you all updated
09-01-2008, 09:49 AM
#39
question about the CPS and fywheel timing ring.
Does th CPS have to be an EXACT distance away from the flywheel to have optimum power? My car starts fine so im guessing its the correct distance away but wonder if it were a specifc distance away it should be?
Also,I know the KS can throw a ghost code but would it not throw a code at all if it was going bad or was bad? I took it out and it has no visual defects or cracks in it. the harness that connects to the engine harness was actually clipped and connected to the engine harness with butt connectors. anything wrong with that?
Im asking about the KS because I've noticed it was just very noticeable around 2.5k-5k(power loss) but have realized its lost power all throughout the rpm range.
still haven't changed ecu yet..can find a good one now lol
Does th CPS have to be an EXACT distance away from the flywheel to have optimum power? My car starts fine so im guessing its the correct distance away but wonder if it were a specifc distance away it should be?
Also,I know the KS can throw a ghost code but would it not throw a code at all if it was going bad or was bad? I took it out and it has no visual defects or cracks in it. the harness that connects to the engine harness was actually clipped and connected to the engine harness with butt connectors. anything wrong with that?
Im asking about the KS because I've noticed it was just very noticeable around 2.5k-5k(power loss) but have realized its lost power all throughout the rpm range.
still haven't changed ecu yet..can find a good one now lol