Alright I spent the day finishing up on my install of my 370's, Z32 MAF on the charged side and JWT ECU and I have major problems now...

I got the car started but the idle wont stay still..its goes from 900 down to 400 then back up to 700 then back down...up and down, up and down..almost stalling...when I come to stop sign or a light the car usually stalls if I dont keep gas on it

I took the car out for a ride and under boost the car feels good but once I jsut cruize under light to NO load, the car bucks foward every 5-7 seconds, very slightly, but very noticable..

Vacuum at idle is very good around -20 and fluctuats with the screwey idle...I Checked for any kind of vaccum leak and I cant seem to find any....could my plugs be fouled ??

Please if anyone could help me I would appriate it..here is the setup
Z32 MAF
JWT-ECU
370 cc injectors
AEM FPR
3" charge pipe

Im lost on what to do now..

-matt

 

Play with the fuel pressure via the AEM at idle. Lower it and see if it stabilizes the idle some... If so - you know what to do.

 

I have it set at 34 psi at idle...Ill play with that alittle bit..I was just out by the car and had it idleing checking a few more things, and its not as bad..its still up and down, up and down, then almost dieing, but it not as bad as when I first started it..

What do you think the bucking it while im cruizing..? its definetly related to the idle problem

-matt

 

It could be a few things... if the car is running so rich that it's bucking like that - the o2 sensors won't do anything.

My bet is in this order.
1) Vacuum or coupler leak on the sc
2) Fuel related - although I haven't experienced issues with it BUCKING... it either has really bad power or it bogs.
3) Bad maf?

 

Well the idle is a tad bit better but not all fixed....I lowered the base fuel pressure below 30 and the idle got worse ...I then raised it up to about 40-42 and it got better but not really a whole lot better...I have it at about 32 right now and it seems ok but not totally fixed.

The weird thing is that my vaccum is reading perfect at -19 - -20 and thats what is soo confusing to me

I checked all the T-bolts and they are all tight on the intake...I did a 3" custom charge pipe with all new silicone couplers and all new T-bolt connectors...

The Bucking I am feeling is definetly there...Its almost like something is holding the car back and then letting it go...its very strange....when Im say in 2nd just starting to drive up the street, and say I let off 2nd and cruize, the car will hesitate alot and buck like the car is holding back and then letting it go...Very Strange

Im thinking it may have soemthing to do with the MAF or even the TPS...The TPS is fairly new (well off of a used newer car) ...the TPS would be something that may be causing this bucking but I didnt really mess with that when I had it off the car so that doesnt seem all that right...the MAF could be the culprit but IDK..

Im at a loss for words !!!!

-matt

 

I agree on checking the tps - it may just be adjusted incorrectly.

 

Well would a bad MAF affect the idle of the car ?? and possibly make the car buck if thast what is wrong with the car ??

How do I go about checking the tps ?? The tps, in my mind, may be what is causing this problem, but why now ? i really didnt do anything do that at all...just took the TB off and put it back on the car

-matt

Could be plugs be fowled ??

 

Yes the maf would do both.

Checking the tps: http://vbxmaxima.8m.com/tps.html

Pull ur plugs and see if they are fouled... they'll be black if they are

 

Do you think its a problem with the ECU ?? possibly the injectors ??

Under Boost the car seems fine...idle and cruizing is when the car acts really funny

I just went back out to the car, started it back up and it still wants to die and the idle is up and down up and down...very strange

-matt

 

Could it be the ECU ??

One thing I did notice is that when I start the car it goes right down to low idle...it doesnt stop up in the high RPMS like it used to do before...no real cold idle start

The sqrewy idle is still present and the bucking while cruizing is definetly still there ??

-matt

 

I pulled the ECU and put in my stock ECU and the idle still is loopy....just driving around my back yard, clutch in, and the idle up and down up and down

I cant think of anything else that could be bad...

any help anyone ??

-matt

 

Alright so the car runs like crap yet you still take it out and go into boost?
I'm sure you'll have to wait a couple days as all the boost gurus are out on vacation so it seems.

 

maybe the injectors are not seated right. Did you lube the o-rings up before putting them in?

 

yea I lubed them up properly...they all seated into place...If they werent seated properly I would most likely smell gas or not be able to get the caps on the top...this doesnt seem to me to be fuel related...

I have a feeling I missed something like a lose bolt somewhere or soemthing...or the MAF is bad...I will know more when I mess around with it tomorrow...

I was also thinking and i was wondering maybe the upper intake manifold gasket isnt seated right onto the LIM...just pondering some thouhgts right now, but other then that, im clueless...

-matt

 

Just a quick thought, is the MAF pointing in the right direction???
Have you let the car idle for more than 10 minutes before taking it out for a drive?
Im saying that because the JWT ecu needs to learn the car....

 

They may not necessarily be seated right - you do have 2 o-rings on each injectors right? And those injectors go into another rubber o ring style seal yea? Just because the top of the injector is flush and it can get screwed in doesn't mean you didn't rip the lower, small o-ring - you wouldn't be able to tell other than the car running like crap. That larger o ring closer to the connector would stop gas from leaking out.

Check your ecu, make sure your screw that you use to pull codes is fully counterclockwise as well.

 

Yea 2 O rings on each like injector...yea I had the Fuel rail off and I replaced all 6 of those Fuel Rail isolators...I dont think any of the O-rings were ripped but it may have happend...I did lube them pretty well with 3 in 1 Oil....

The Ecu Screw is set correctly...the check engine light is on when I turn the key to ACC which is right

Yea the MAF is pointing in the right direction
I did let it idle when I first started and it barely wanted to stay idleing...I then checked for codes, reset the ECU and took the first ride


Well im just totally confused now..I went out now when the car was completely cold and started it..It starts right up and just idles horribly...almost like it wants to stall, then kicks back up...then idles low, then kicks back up...

-matt

BTW I mounted my AEM FPR upside down on the wheel well, do think that would cause a problem or no ??

 

I read your setup, but do you have an SAFC hooked up?

 

Does not sound like an injector to me leaking to me, although one could be stuck. Did you have the injectors sitting around for a long time before you installed them? Sometimes if injectors sit for a while they can get stuck, it takes a few hits with some voltage to get it firing again. Just a possibility.

Sounds more like a MAF or vacuum issue to me. Check all the wiring you spliced for the Z32 MAF. I would not be sticking in the stock ECU with the Z32 MAF and then get into boost, not a good idea.

One thing I have heard in the past is the JWT chip not being correctly seated in the daughterboard.

 

No I sold that when I purchaced the kit


yea the injectors were sitting around for about A LONG time so that could be a possability...whats the fix for that ??

Ill check the wireing again for the MAF....I checked it nearly 5 or 6 times...could the MAF be bad ??

No I nearly plugged in the stock ECU to see if that would fix the ideling problem..I didnt go for a ride and boost with the stock ecu, im not that stupid ....

Well if the JWT is not seated correctly, what does that mean ???

It keeps acting the same way..Im really confused on what it could be....vaccum is steady at 19-20 and idle up and down up and down up and down

-matt

 

I was just out by the car for the first time today, nice and cold and started it...same thing...even when I originally started the car, the idle was up and down up and down..even when it was up around 1600 rpms it was up and down...once it warmed up it definetly got worse...400-850 up and down up and down....

The car is VERYYY smooth running, thats why I dont think its an injector problem...the idle just keeps jumping up and down...I dont understand what could be the problem...


-matt

 

Yes, the MAF could certainly be bad. It is a 10yr old used part right, not a new one?

Is the vacuum going up and down with the idle or is it steady?

The believe the chip in the ECU is just stuck into the daughter board with prongs or it might be solderd. But that one is a long shot

 

yea the MAF is a used part

The Vaccum does not stay steady when the idle is up and down...it moves very slightly...from 19-20...maybe 18...it moves ever soo slightly...

Im confused on what to do now...should I jump to conclusions and purchase a different MAF

the car runs alright just a loopy idle

-matt

BTW: Could it be that the MAF is on the charged side and JWT insists on not putting the MAF on the charged side and it can ONLY be on the NON-Charged side ?? but there are many members that put in on the charged side with no problems at all

 

Well I had the car running and it was osolating still..i tried unplugging the MAF while it was running and the car stopped oscolating and idled around 1000 with minimal ocolation...

Then I shut the car off and unplugged it then started it and the engine light came on and the car ran the same it was before...oscolating..

Im really confused on what to do next

-matt

 

Check your pcv valve. Paul (requin6) was having similar problems and he fixed the problem by changing the pcv valve. $8 from napa. I am having idle issues as well but that didn't fix it for me. Im getting a hissing sound from the passenger side firewall area. I can only hear it when the blower is disconnected. Once it warms up all is well which takes about 15 min. Does your max run ok after you warm it for a few miles?

 

NO...it still oscolates bad...this isnt a slight problem, something is definetly wrong...

Brand new PVC valve, and I switched it back to the one I was running and still the problem

-matt

 

Don't you just hate these annoying a$$ problems. Did you try letting your car sit running for awhile to let it get used to everything? Have you checked around the intake manifold for leaks? Make sure all of your sensors are plugged in, maybe one came loose pulling all the stuff out...

 

yea I triple checked everything then checked everything all again twice...so everything is plugged in and tight...And I did let the car idle for about 10 min at one point seeing if it would fix itself and get used to the program...but no dice...
NO codes witch is bizarre and I did reset the ECU once to see if that would fix it

I was wondering maybe it is a leak around the manifold gasket, how do I check for something like that ??
It kinda feels like there is a pretty large vaccum leak cause wheN I come to a stop the idle dippss way low and sometimes stalls..(i havent been driving the car alot, I took it out twice less then a mile long)..

-matt

 

Hey Matty, I'm having the same exact issues, bucking while cruising, bucking while trying to boost...My car is a 3rd gen VE30DE...My brother said to replace the coils, since its a 12 year old car..I have the Z32 maf, 370cc injectors, walbro pump, nismo afpr(set at 40, stock is 34 but car still does the same idle, up and down, etc and sometimes stalls)...Vaccum is at -19-20, but decreases when idle lowers to a point where the car stalls.

Does my Fidanza flywheel have anything to do with the loopy idle, mine is at +-650 rpm....

 

No it defiently doesnt have anything to do with the Fidanza..Ive had the flywheel for more then 20K miles and Never an issue

I put in my Z32 MAF (charged side), JWT-ECU, 370's, and the 3" charge pipe, and Im having the problem...Something I installed is causing the problem...

I have the ECU to take care of the injectors and the MAF now I need to troubleshoot and figure what is wrong

-I put in the stock ECU, started it, and the problem is still there, so I guess the ECU is fine
-I pulled the connector on the maf sensor out while the car was running and the loopy idle seemed to go away...idle was at 1K was wasnt loopy as much..the MAF is wired up properly but may be bad

Next step i guess is to wire back the A32 MAF and put in the A32 epprom and see if the loopy idle still is there..I have a feeling its the manifold gasket, but not sure how fast it would stall or how bad it would run if it was off a tad bit...
the injectors also may be an issue here, or just a BAD MAF

-matt

 

Nobody has any ideas ??

Stephen Max, Iansw where are you guys ??? Im about to put all my stock stuff back in..

I need help !!

-matt

 

bump up to the top...

Anyone have any ideas..

I put in Z32 MAF, JWT, 370's, 3" charge pipe and now im getting a very loopy idle, almost impossible to drive the car...the bucking while driving is very noticable...almost like a hesitation, then the car goes...

Idle is loopy right when i start the car

-matt

 

have you double/triple checked all your vacumn lines to make sure none are crossed and hooked in the wrong locations? Thats the only thing I can think of besides a bad MAF causing the lopey idle.

 

I know it sucks, but at this point I would swap the old stuff back and see what happens. At least just do the ECU and A32 MAF and leave the 370's in, the car should run like that with base fuel pressure turned down to 30psi or so.

That is why I hate installing several mods at once, trouble shooting is a PITA.

 

what are the torque specs on the manifold bolts?

 

can it be a O2 sensor problem

 

Well would a bad MAF cause a loopy Idle ??
What do you mean by "Crossing the vaccum lines" ?? I had the 1) sourse or vaccum 2) BOV 3) MEVI canister 4) AEM FPR 5) Cartech FMU all on a 5 way vaccum splitter...the only change I did was take the Cartech out, and changed to a 4 way splitter...I dont think anything else really changed other than that....


The specs are 13-16 Ft lbs...I set it at 15...
What are the symtoms of a bad manifold gasket ?? anyone know

Thats not even a slight possablitly...The car was running perfect before I did all these things...I either messed up on something or something like the MAF is a bad part

 

All of my problems i was having was a result of a bad manifold and egr gasket so i would go ahead and replace that becuase i think your suppose to replace it everytime you remove the manifold(at least that is what i was told)

It may not be the main cause of your problems, but like mike said you have to go through and start eliminating things. Trust me i know how you feel, been there done that

 

They were both replaced....

Im thinking the gasket may be "off" just a tad bit"

-matt

 

Yes a bad MAF can cause the idle to be rough and screwy. On my 02 before the MAF went the car started acting strange like that. What I meant by the vacumn lines is possibly having a couple crossed and hooked up into the wrong locations. Im not too good at explaining these things.