Like that's your only exhaust leak...

Shouldn't cause what you're describing. I've got a '95 auto ECU you can try also, completely stock.

 

Well lately, i have been having MAJOR power loss. To the point where if i go WOT at 3000 in 3rd, the car would take probably a full minute to hit redline. 1st and 2nd gear are the same midrange loss (2.5k-about 5k) then jumps to redline like it clears up.

I have VQ30 timing
Gutted UIM
PFTB
AFPR
stock 3.0 manifold and warpspeed y

problems ive noticed
bad o2 sensors
exhaust leak at flexpipe(never known to slow my car up)
small exhaust leak between manifold and ypipe
CPS(flywheel) was rechecked and no codes

Ive change my MAF 3times, changed ECU's, PCV valve,Air Filters, uninstalled VAFCII.

I have done some wiring on my MAF before but reconnected everything as normal, but as far as that exposed wire that goes around the singal wire, i just grounded it to the MAF ground. Also cleaned the CPS(flywheel) and IAT.
still cant figure it out. WHAT IS IT!!???!!!


few videos, i will paypal $20 to anyone who can figure it out for me.

 

Also, if i pat the gas, it jumps(as normal) but will drop to about 1.5k-2k and sit there for a sec, like im holding the gas or something than drop down to about 850rpm.
what would cause that?
and there is no hose connecting the front valve cover to the intake system

FYI, 3 of the videos, i was WOT before i started recording

 

Would be interesting to see a datalog of your WOT runs...

Maybe when you get that EB installed.

 

New thread really necessary?

 

well the last one was for another problem and it seemed since i didnt bring this problem up until further down the thread, it got less attention. Also, its getting to the point where i might get rid of the car if i cant figure it out AND im offering money

 

if your selling ill take all 5spd parts and give you my auto trans and whatever else

 

Vulture.

Besides, it's far more involved going 5MT to 4AT than the reverse.

 

it was auto before, we can both use each others cars as parts car

 

I've spent considerable time contemplating the 4at swap with a xxxx4B

Anyways, so if I understand this right you have NO hose connecting the front valve cover to the intake piping, but you DO have the pcv valve on the rear valve cover connected to the upper manifold right before the TB on that bend in the elbow right?

If so, bingo, problem solved, MASSIVE amounts of un-metered air bypassing the maf, as well as causing a rather large vacuum leak that you had to account for @ idle with your tb and iac settings.

If not than a big to seeing the a/f, as well as knowing.... WTF is your fuel pressure bro'? I/we know you have an afpr from the swap, but we can't geuss your FP

Link to the original thread?

 

whoaa I dont have a hose connecting my front valve cover either but do on the rear as you said. I'm working to get a midpipe so I can reconnect all of it as I now realize its causing a vacuum leak but I didnt realize it could be effecting anything at WOT.
Do I want to make my connection for the valve cover on the engine side of the MAF or the air filter side of the maf?

 

i have my afpr set at about 34psi

original thread
http://forums.maxima.org/all-motor/5...ower-loss.html

 

fuel pressure should be more around 51 if I recall correctly. checking.

okay I couldnt find it but I remember at one point nismology IIRC said that the fuel pressure didn't need to be 52 but could be a little lower. 34 sounds too low to me though.

 

well i know that 51psi is the constant psi for 5.5 motor and ecu, i think the ecu adjust the injector rather than relying on vacuum for fuel psi. Since im using 4thgen ecu, i BELIEVE i need my fuel psi between 34psi-41psi

 

Im going to put a stock UIM on today and see what happens.. hope it solves the problem

 

That's about right. That's what I use - 43 psi above an idle...

 

ok, ill turn the Fpsi up to about 43psi. about to check my sparkplugs? Could these cause problems?

 

Well I just had my fuel psi at 50psi at idle and the car ok but mad rich, so I lower it to 35 at idle and 45 at wot and it is alot smoother and faster

 

change my UIM ou for the stock one and plugs look fine..set the fpsi at 43psi and the sammmmmme problem.

could anyone tell me what the voltage I suppose to be for the signal wire and power wire at the maf and ecu at idle and wot?

 

Pin 3 on the MAF should be seeing battery voltage under all conditions I believe.

1-1.7 volts on pin 1 at idle.

Not sure at WOT though.

What do you mean at the ECU?

 

ok.is the ecu voltage suppose to be the same at the ecu but I guess so..

I was reading the FSM and it said something about a joint connector around the singal and ground wire..like a shiel around it that was connected to a joint connector then grounded...what Is this

 

What section and page?

The signal wire for the MAF is shielded to prevent interference, the shielding splits off to a ground wire at the ECU.

 

put jwt ecu back in same problem. Cleaned CPS under crankpulley too.


But i DID discover that my o2 sensor fuse was blown soo, this means?? I replaced it, should i expect an immediate change in power or it(ecu) has to relearn them(o2 sensors)?

and would sparkplugs cause that much of a powerloss at only a certain rpm, EVERYTIME?

If this isnt the problem, it goes up too $50 to whoever can figure it out

 

Threads merged.

 

O2 sensors do absolutely nothing in open loop, so don't worry about those.

Plugs shouldn't cause that sort of driveability problem, no. Worth pulling a few out to see what they look like, though. Still don't have a wideband?

 

the only time my car acted like it had no ***** in the midrange but pulled like normal on the high end is when I had a coilpack misfire. (which didnt throw a code btw)

 

It's causing unmetered air to enter the engine, it's going to lean out your a/f and ever so slightly advance your timing. You need to connect that anywhere between the tb and maf, so on the engine side not the filter side.

You need to fix that ASAP.

As for FP, I've also figured 30 to 32 psi @ idle w/vacuum connected was the magic number TO START WITH for running 3.5 injectors on a 4th gen ecu, and when I dyno'd the '02VI car last friday @ 32psi the afr was geourgeous allthough just a hair on the rich side, like I'm talking 12.8 - 13.0 all across the board!

 

wow, maybe i need to turn mine down then. Im going to start checking coilpacks but ive honestly forgot how to check for good ones.

The car feels a little better now with the o2 sensor fuse in, lowend has got better but when i accel. about 70% throttle, i can feel it miss and hesitate/ a few dead spots.

So now im guessing its either coilpacks or CPS(flywheel).

Can anyone give me a solid answer about the CPS and distance from the flywheel? It starts fine, like as soon as the key is turned it starts, but could it be doing that and still be messing up the timing/ign. firing system?

 

Your saying this assuming I have left an open hole in the intake or something, correct? I have no midpipe basically..just straight tube from the filter to the maf.

my fuel pressure is allot higher than that though, closer to 50 IIRC. 13.5 is what to aim for a/f-wise right?

 

I had something similar this weekend and it was a bad coil but it was on my 3.0. My idle was crazzzyyy felt like I had a parachute attached to the car holding me back, didn't get a code either my CEL flashed then went off. I'm not an expert my any means as others are but might as well check everything right

 

For the most part yes, (13.5) Some will say 13.2, others will say YOUR car's sweet spot is unknown. I think there's a thread in the 1st page about that But regardless, if you tune with an afc just get it as close to that red colored line as you can, those things are garbage imho.

I know you have no midpipe, but what you should do in the meantime is cap off the pcv port on the manifold side and just leave both valve covers open while you wait for your midpipe to arrive. After you cap that rear port off on the mani drop the fp way down and see what you think. After capping that port you might have some idle settings to readjust of course.

 

damn i've been running the car like this for a long time. I'm just going to get a midpipe asap and connect it back to how it should be. What is the benefit of dropping the fuel pressure though, I dont understand why you run them so low.

afc is all I got mayn.

 

you should check your TPS sensor. Had a similar problem and it was my TPS sensor as the car would not pull. What codes do you have?

 

I run them so low because it will run rich otherwise. The 3.0 ecu and 3.5 injectors don't match, it will run rich unless you go even slightly lower than stock 3.0 settings

 

ahh because you dont like to run afc's I got you.

 

doesn't the car go to open loop after the rpm he's having a problem with? check your o2 sensor readings with a multimeter. @ normal operating temp @ 2k rpm out of 5 cycles the voltage should go above .6v at least once and below .3v at least once but never exceed 1.0v. so if your saying your sensor 1 bank 1 and 2 codes are coming up. id check that.

 

well changed the plugs again and added a midpipe for the front valve cover to connect to, went out for a test drive and shattered 3rd gear.. so once it gets rebuilt again ill do more trial and error.(car WAS way more responsive, BUT problem was still there)

but as for my TPS. the signal wire gets .7 volts closed and 4volts at WOT. so i believe its working fine.

Going to check my knock sensor AGAIN, even though i dont have a code, change out my CPS sensors again and Camshaft sensor again to see what happens..

Only thing i can think of if those dont work is the exhaust leak sigh

 

how did you shatter 3rd gear? what exactly broke? the synchro?

I hope when I put my midpipe back on it feels a little better, I assume so since then I'll have the IACV in as well.

 

Given what I've seen with these things, most likely broke the actual gear.

Aaron...







That reminds me, know of any 5 speeds for sale?

 

yea, i think i actually broke the gear.. was going through the gears, didnt even go to 3rd hard, as soon as it got in, i heard a crack and pop and the rpms shot up.. took it out of 3rd, put it back in..Car acted as if it was in neutral.

Ill look around for you, i think i might