Multitude of questions (Z32 Maf+Tune/Nistune/idle problem/TPS/FPR)

[Prophetic]

To start, I did do a search for each of these questions but they either lead me to threads where one thing was solved and another wasn't, or the threads were never replied to with a satisfactory answer.

First the idle problem: The car is fine when cold, but as it warms up it starts to idle really low (400-500rpm) and when rolling to a stop it has a tendency to drop REALLY low (200-300) and sometimes die completely. After reading multiple threads the three major ideas that I came up with are: Maf/TPS/Battery. My battery is a new optima red top but HAS been jumped 4 times since I've owned it (Usually from leaving lights on in the morning when getting to work.) So I've all but eliminated that, if someone thinks that really might have killed it then I guess I need to search for a new battery.

#1 Would it be possible to put a Z32 maf on RB20DET with a socketed ECU and only need a minor tune? I'm looking to fix my idle problem as opposed to making power atm. The reason I want a different maf on to fix the idle is I figure I will upgrade the maf sooner or later (other mods kind of ask for it) and I figure if it's cost-friendly I should just do this if it will fix my problem also.

#2 Is nistune 'nooby friendly' I'm not very mechanically inclined but would I have to have someone dyno tune for the simplest things, or is it as simple as clickclick done? (ala z32 maf) I would obviously have someone experienced install nistune for me.

#3 I can't seem to get a reading of voltage on my TPS. I tried to do it where the white middle wire is and the volt meter doesn't show anything. Sits at 0. I tested it on the battery and the volt meter works fine so I'm not sure what the problem here is? A lot of threads mention the TPS as the culprit for a bouncing or low idle but would the car work AT ALL if it was completely dead? I unplugged the side part for a short 15 second drive and my RPMs sat at 1.9k, so I assumed if it was actually dead it would do something like that?

#4 I have a walbro 255lph pump in my car, second one in under 6 months. The first one apparently died, or was close to according to the techs at racing greed. When I replaced it my cold start problem went away but the idle problem stayed (had hoped it would fix it) I was wondering if I should be putting an aftermarket FPR in to help with this?

List of mods on car:

Exoticspeed FMIC (don't remember size, if it's truly important I can look it up
Deatchwerks 444cc injectors
Walbro 255lph
3" exhaust
K&N air intake cone; assuming it replaced the OEM one? Sensor cone is attached to looks stock but again I have nfi what I'm talking about!
socketed ECU - tune done by techs at ztune
manual boost controller set to 14.5psi
yellow jacket coils, put on 12k km ago.

I think that's everything?

Any help in this matter would be greatly appreciated. This problem has been very persistent (couple months now) and I would really like to get rid of it and start enjoying my car again.

Also if anyone has a spare stock rb20 maf that they wouldn't mind lending me for a day or two I'd be greatly appreciative. I could then test if that is the problem and try and save myself some money in eliminating problems.

Sorry for the huge text bomb and beating a dead horse with questions that I know have been asked before, but again like I said either the answers weren't straight forward enough (I'm dumb.) or I'm dumb.

Thanks!

[Skym]

1.) Need to change MAF voltage translation table on ECU for Z32 MAF. This affects load scaling across the top of fuel, ignition maps and each cell on those maps needs to be checked, adjusted on dyno. Not an easy bolt on mod. Usually you change injectors, fuelpump, MAF at same time.

2.) It's easy to use. But you need to learn how to tune an engine and that includes having experience with the engine your tuning.

3.) Idle contact pin inside TPS bends over time, so doesn't touch idle contact anymore. That means ECU doesn't switch to idle tables, etc that are used when slowing car down. The result is engine could overfuel (TPS makes ECU add fuel above what fuel map injects to make sure engine doesn't go suddenly lean when throttlebody suddenly opens), revs drop below idle rpm and sometimes don't recover. I've been through 2x TPS on my car and pulled one apart, played with idle, WOT (Wide Open Throttle) contacts (didn't work when refitted to engine). It's a use, dispose type of sensor.

If you have Nistune tuning software, consult cable, idle contact button light's up in Nistune tuning software when idle contact is engaged inside TPS. Also can see TPS voltage displayed on screen via gauge. Makes it easier to set TPS properly.

4.) If they run fuelpump at 100% (run full voltage to fuelpump) it can wear brush type fuelpumps (Stock, Walbro, etc) out quicker. Normally there's a voltage regulator to fuelpump that drops voltage to fuelpump, which reduces load on alternator at idle when light's, aircon, etc are on, makes fuelpump quieter, doesn't heat up fuel, makes fuelpump last longer, etc.

I've found on my car that misadjusted or faulty TPS was the cause of dropping below idle rpm, not recovering.

With Faulty MAF on my car, engine idled at 1500rpm when warm and had MAF error code on ECU. Sometimes MAF can have faulty solders inside square box part of MAF or MAF sensor needs cleaning with CRC MAF cleaner. Also wires can fall out of MAF or ECU plug if wires are pulled on when removing plugs from ECU or MAF. Sometimes ECU plug is not seated correctly (gets bent) and causes problems.

Also sometimes people raise idle rpm via AACV to temporarily solve TPS problem (not a good idea). But they don't put ECU into idle adjustment mode, readjust idle rpm back to 650rpm properly and causes problems when you try to adjust AACV back to correct idle rpm. Both ECU (idle rpm at 650rpm on idle rpm table when engine is warm) and AACV (adjusted to 650rpm) are meant to be calibrated so they both are at 650rpm.

[M13]

Here is the way I look at it with MAF.


You are putting in the Z32 MAF to allow ecu to read more air due to higher air volume for more power.

If you are doing power mods affecting possibly affecting AFR, you shouldn't skimp on tuning for the new MAF along with dyno tune.

adjusting just MAF and procrastinating tuning for later is not much better than not putting in the MAF at all the first place.

[Prophetic]

It really sounds like the TPS then, I guess I'll try again with a different multimeter and see what happens.

Continuing with question #4 and your reply, Skym:

Should I bring the car into a shop and ask them to look at the voltage going to the fuel pump? I was surprised when my first fuel pump went and the car is acting like it did before minus the cold start problem so I would hate for it to happen again because of voltage.

And maybe you answered it but I missed it, but is a larger/upgraded FPR necessary when the fuel pump has been upgraded?

@M13: I realize that short-cutting isn't really a good idea but the question was more is it a large undertaking to adjust for the MAF? I would get it dyno tuned but as I only have a socketed ECU I was more curious if that will still be adequet atm or if I will have to upgrade to nistune for it to be a worthy upgrade (counting all the other mods I have also, of course.)

Another reason I was curious if it would be minor is if I get it done I'll have it dyno tuned but I don't want to spend $400 on dyno/tuning time for a single upgrade when I could just wait, get nistune+other things, and spend the same amount and get more bang for my buck.

So really I guess I should have said is how long/easy is it to adjust the tune for the z32 maf on a socketed ECU?

[Prophetic]

Also another thought: Are the symptoms I described charastic of an O2 sensor going, and if so any way I could test if it is that easily?

I'm really just trying to narrow stuff down right now, so I can start with the cheapest fix and work my way from there. If it ends up costing a lot, that sucks, but I don't see a problem in replacing 15year old+ parts in the process if there is a slight chance they are the problem.

[Skym]

Problems are part of modifying any car.

Monitoring fuelpressure, A/F ratio on dyno is a good idea to check fuelpump.

Can wire in a Kenny Belle Boost a pump, which can replace voltage regulator and does the same job as voltage regulator -

http://www.kennebell.net/accessories/boostapump/boostapump.htm

From what I can remember, Walbro fuelpumps are sensitive about voltage. It's what can make them not provide enough fuel at higher rpm's, which is why dyno run with A/F ratio check, fuelpressure check is a good idea (piece of mind).

I noticed some tuners have found a bigger enough lph fuelpump can cause problems with stock FPR (age related failure or wasn't providing enough pressure in fuel rail) or Nismo FPR. One tuner found out, removing vacuum line to Nismo adjustable FPR (raised fuel pressure) solved the problem. But I gather he was running a huge lph fuelpump. As far as I know, Nismo sells replacement / upgraded FPR's.

Larger FPR allows like, according to some around 10%??? more fuel from stock or upgraded injectors. It's a band aid fix at best. Proper way is to upgrade injectors.

With o2 sensor, I think it was hold at 2000rpm and note how fast ECU switches between rich, lean voltage triggers (how fast voltage fluctuates from lean = Ov to rich = 1v). If too slow (can't remember the amount of seconds, but should be obvious), o2 sensor needs to be replaced. Or unplugging o2 sensor should give you an idea if it's the cause. If engine is running lean, not a good idea to unplug o2 sensor.

[Prophetic]

Really appreciate the help, Skym.

Do you by any chance know the part number for the TPS? Does that include the plugs that extend from the TPS by any chance or are those a separate part to themselves?

[M13]

well since you have socketed ecu, that means you'll have to get a ROM burnt to adjust for the new MAF.

You could drive this but you'd never know what your AFR is on boost unless you had wideband.

If you don't, you should dyno it to see afr on boost to be safe.

Basically it's just more money and the way I see it is to do all at once and tune at once. Doing things partially for power is kind of pointless and waste of money as you'll have to do it again anyways or your motor goes.

[Prophetic]

I'll probably just save during the winter and get nistune/maf done at the same time.

And the reason it's been done half at a time is because my injectors were leaking awhile ago so for the same price as oem replacements I was offered installed brand new deatchwerks 440cc at ztune. I figured why pass up a deal like that when I already need the work done anyway. Same as the fuel pump, it was work that was being done already so I just upgraded at the time. Was less for power as it was convenience. Power was just a happy side-effect.

[cobrAA]

Kinda on-topic. I already have 4 gauges in my car and I might add another one this winter. but I still don't have a Air fuel gauge. However my car is already dyno tuned. Whatever... would installing nistune in my car could be a good idea as a tool for monitoring thing without having 20 gauges in my car?

I don't want to tuno it myself simply monitoring my stuff..

[Skym]

I'll post it in this thread.

Nistune tuning software was re designed / updated to run on car PC for car show purposes.

I was thinking of 7" touchscreen Mustang tablet PC (mini MFD, similar to R34GTR) with Nistune (gauges in Nistune tuning software for injector duty, MAF voltage, TPS voltage, wideband A/F ratio, etc) -

http://www.iepos.com/mini-mustang.htm

Wideband connects to tablet PC USB port. Then have spare USB port for Consult cable.

But where to purchase one from, retailer or direct from above??? Also it has solid state hard drive, so car bumping around (hard suspension) won't affect hard drive.

Then just need basic oil pressure, oil temp, exhaust temp, boost gauges on dash.

[cobrAA]

I'll post it in this thread.

Nistune tuning software was re designed / updated to run on car PC for car show purposes.

I was thinking of 7" touchscreen Mustang tablet PC (mini MFD, similar to R34GTR) with Nistune (gauges in Nistune tuning software for injector duty, MAF voltage, TPS voltage, wideband A/F ratio, etc) -

http://www.iepos.com/mini-mustang.htm

Wideband connects to tablet PC USB port. Then have spare USB port for Consult cable.

But where to purchase one from, retailer or direct from above??? Also it has solid state hard drive, so car bumping around (hard suspension) won't affect hard drive.

Then just need basic oil pressure, oil temp, exhaust temp, boost gauges on dash.

We had the same idea. I thought with a carpc it could be possible to do a MFD for half the price of one with even more option but where should we put it? In front of the vent?

[Skym]

On a custom stand infront of air vents. Or the 2x slots where stereo, etc goes. Or custom mounted in glovebox (better if parking on street).

[cobrAA]

On a custom stand infront of air vents. Or the 2x slots where stereo, etc goes. Or custom mounted in glovebox (better if parking on street).

Custom mounted in the glovebox : I don't think it will be useful while driving. I think the best is to have it mounted where the stereo goes but I can't let go my radio deck or my 3 gauges. so i'm stock with only 1 din open. Ummm maybe I will stick with a mini dell laptop at 300$.

[Skym]

Some mount rally timing gear on the dash inbetween the middle, passenger side air vents.

Also some recommend the Emachines Netbook ($200 in US?). Supposedly is one of the fastest Netbooks with 10.1inch screen.