Car idles pig rich, Dies with any throttle??????

[NolimitZ32]

As some of you know I just got my car put back together, I got everything wired and triple-checked every detail I could think of but I am still having problems. So here is all the info.

MODS:
660cc Injectors
EGR delete
Adjustable FPR (set at 40psi +/- 5 @ idle)
FMIC
SAFC2
AVCR
E-mance chipped ECU (supposedly custom base map for my setup)

Here is the problem: The car starts, it starts with issues and usually needs a little bit of cranking but it starts every time I try. It idles 900-1200 RPM as it warms up and then settles at about 1000rpm (which is high, FSM says 700rpm for idle). The vacuum at idle when warm is steady at ~17mmHg. If I hit the throttle and stay on it, it dies every time. If I tap it quick and let off it will drop to ~400rpm then bounce back up to ~1500rpm and then settles out at ~1000rpm half the time, the other half the time if I held it open a second too long it dies out. I have tried setting my SAFC to -40 on LO throttle from 800rpm to 3200rpm. The injectors are at 1.2 % at idle and when I flick the throttle they will jump to 100% or more and then back down to 1% - 2%, The voltages all look normal, all the injectors ohm out perfect, the TPS shows .4V - .5V at idle and 4.5V - 5V at WOT. The ECU randomly throws a Code 13 (Coolant Temp Sensor) this code comes and goes. I dont think the Code 13 is the reason for all this non-sence but I guess at this point anything is possible. Sorry for the novel guys but I'm at the end of my rope please HELP!

Thanks in Advance
Anton

[evildky]

step 1, take out the safc
step 2, take out the e-mance ecu
step 3, take out the afpr
step 4, go get nistune
step 5, rent a dyno
step 6 ,make big PAR!

You've got a lot of crap going on. A properly tuned chip doesn't need an safc or afpr, and if it does it's not a very good chip and you might as well be running the stock one! That chts code comeing and going is playing havoc with your fuel maps, when it sees that code it goes into enrich mode dumping in all kinds of extra fuel. I'd have a really good look at the connector, they get corroded or the clip itself gets cracked or broken and you loose connection. You can't expect to get the car to run consistantly if you can't keep random codes from popping up. On the high idle I'd take a good look at the cost start air valve, we just did a plenum on a buddies car and the cold start air valve decided to crap out when it all got put back together. I knwo this isn't what you want to hear but there is no reason to run an afpr. The safc is so limited in what it can do it's jsut a waste fo money, and the ecu chip, either it's right and you don't need the other crap or it's not and it's a waste fo money.

[NolimitZ32]

Thankyou sir, the afpr went on because the stocker looked like s***, it was crushed from shipping so that was why I bought the afpr plus it comes with a handy fuel pressure gauge. the SAFC is there more for monitering purposes then anything ive had it for a long time now, got it off a DSM buddy cheap so thats gonna stay until I can get something like NISTUNE which I am strongly considering doing at this point but i wanna give Jason a chance to right his wrong IF its infact the chip, I cleaned the coolant temp sensor connections ond the efi harness is brand new so shouldnt be any problems there. Whats a cold start air valve, I mean I understand what it is but the Z32 have the IACV and a AAV which one are you referring to there? Also do you think the timing being off would have these effects?

Thanks
Anton

[evildky]

the beauty of a mas air flow engine managment system si that when you do all the fun mods you've done the only change needed is the req fuel to compensate for the larger injectors, the scaling takes car of the rest, granted most "performance" chips might have a slightly better fuel curve and timing curve but the major issue is just the req fuel that done correctly should scale the fuel across the ve table

as for the cold start air valve, I'm not sure what they call it on the Z32, for some reason they have different names for the same part found on other cars, anyhow it's the one between the ballance tube and the aicv, on my buddies car it was stuck open, causing the fast idle, and it won't cause a code because it's just simple voltage to it

[NolimitZ32]

Ok i'll check it out, thanks a bunch dave. I am am talking to the local NISTUNE dealer rightnow about getting nistune and about his tuning services, gotta start saving up

[NolimitZ32]

So the SAFC was to blame, there is something wrong with either the unit or the harness, I took it off last night and the car runs great.

[DMeN Z]

This is your cold start air regulator
http://www.conceptzperformance.com/Cart ... 75.112.246
Located on the rear end of your plenum. Driver side. Sorta under your IACV. Gook luck! (if its not fixed I mean haha)

[NolimitZ32]

Thanks man, but yeah pulling the SAFC fixed it.

[evildky]

This is your cold start air regulator
http://www.conceptzperformance.com/Cart ... 75.112.246
Located on the rear end of your plenum. Driver side. Sorta under your IACV. Gook luck! (if its not fixed I mean haha)

so it'c called a cold start regulator, and it's not under the aicv, it's beside it

[NolimitZ32]

Here's the new problem, it now idles fine and wants to go but misses and dies if you try to drive it. can it be running so rich that its fouling the plugs in a few minutes?

[evildky]

so idle is good, and no codes? right? tps dialed in? iacv working? it should close when you open the throttle

[NolimitZ32]

so idle is good-YEP (it misses a little bit, because its so rich but there is no huge knock SAFC2-dialed in w/ knock correction factor)
no codes-YEP none at all
tps dialed in-YES SIR
IACV working-YES AGAIN, used it to set idle at about 800rpm, it idles at about 800-900, it tries to drop to 750 but when it gets below about 800 it starts to miss and pushes the idle back up, even if you let is sit and idle for 20 min it will still hunt a little.

I'm thinking the map is super rich, the plugs foul out in 10 min of driving, and if I get it anywhere above 4k (yes its in break in period, yes I've taken it above 4k no I'm not romping it everywhere, just did it a few times to check drivability) it fouls the plugs immediately and doesn't want to drive home.

[evildky]

I though you determined the safc was garbage and pulled it?

[NolimitZ32]

I pulled the airflow wires out and connected the factory ecu wires back together, in the mean time i'm using the SAFC to keep an eye on all the sensors, its basically become an expensive multifunction electronic gauge. the knock corrction is on the SAFC itself not for the ECU, it has to be dialed in so the safc will read correctly.

[evildky]

I recomend you pull it, you have no codes but a mysterious rich condition and the safc is still hooked up that has been known to cause problems........

[NolimitZ32]

i didnt realize there were cases like that, And I dont see how it could hurt anything because the rest of the wires are just sensor outputs and ground, i'll pull it completely off and see how it runs, at ths point anything is worth a try.

[NolimitZ32]

UPDATE: engine shows 90psi on all 6 cylinders (holds 90psi with absolutely 0 drop overnight) getting leak-down tester this weekend to confirm, All electrical checks out, #5 does not fire ever (injector works, plug is good, coil is good) My main question is, if the VTC is screwing up would it be a reason for the cylinder compression to be low? like if the car is for some reason engaging the VTC when it shouldn't, would the increased duration on the intake cams/valves be enough to cause low comp numbers?

[evildky]

so #5 isn't workign, is it lacking spark or fuel? if it's spark then you ahve a dead channel in your ptu most likely

as for low compression, was this a dry test or a wet test?
did you have all plugs out at the time of the test?
did you have the tb's help wide open for the test?
had your gauge calibrates? it's odd that they all came up 90psi, so either there was some restriction causing them all to read low, the engine is evenly worn out, or the gauge is a bit otu of wack and yout 90 psi might be 125 on someone elses gauge

the vtc does very little, it just asjusts the intake cam timign at higg rpm's shouldn't be enought o make much of a difference in a stating cr reading

[NolimitZ32]

1) #5 has spark and fuel, confirmed working injector and confirmed good signal from ptu both at ptu and at coil. coil is good but when I pull the coil connector during idle the rpms dont drop, there is no change which indicates to me that its not firing.
2) Test was done wet on a cold engine w/ autozone loaned gauge, it looks almost new I have no way to know if its calibrated correctly which is why I'm getting gauge set and leak-down this weekend to confirm findings.
3) TB's wide open for test, all plugs out, balance tube off the car, engine fresh off a rebuild, block was blueprinted, all clearances (rings,pistons,bearings)were checked 5 times over, rings were installed per FSM.

Reason I asked about VTC is because thats the only other thing I can think of to make the compression so low, due to valves staying open into the compression stroke.

?????? Does anyone know if the exhaust cam gears have a specific side or if they are interchangeable between the DS and PS head?????????????

[evildky]

how about mechanical timing? you positive you got the tming belt on right? having the crank 1 toothe off could explain the consistant low compression numbers

also testing a cold engine could mean a lack of oil to seal the rings

and I'm pretty sure the exhaust cams gears are identical, I'd open that sucker up and reset the timign belt, remember the dots ont eh backing plates and oil pump housing are just in the ballpark, the dots ont he belt have to line up wiht the dots on the gears!

[NolimitZ32]

The timing belt was put on right, like with everything else I was meticulous about getting on there correctly and rechecking it. I even counted the cogs. Everything is right on, only thing I can think of is that I got sent an over-sized HG and now its f*** with my comp.

[evildky]

how think is the HG? still shouldn't mess with static compression readings

you might have been meticulous but something isnt right or you would be driving instead of postin, if I were you I'd open it up and rest the belt, it's only a few hours work

[NolimitZ32]

The HG was supposed to be standard because the heads and block are still factory mating surfaces. The reason I'm saying HG is because 1mm extra thickness of HG doubles the size of the combustion chamber at TDC which would explain the HUGE drop in static pressure. The belt is open I'm waiting for tomorrow to reset it so I have daylight, also doing the leak-down tomorrow.

[evildky]

an extra 1mm makes for aobut .25:1 decreace in CR, and shoudl make less than 5psi difference in the static compression

[NolimitZ32]

Actually by my calcs an extra 1mm thickness in the HG would ad about 1.7 kgs to the compression or actually take away, so instead of 8.5:1 it would be 6.8:1 or 100lbs of compression which makes almost perfect sense. Either way, I haven't touched the car in about a week, I'm too bummed to do anything with it right now so when I get around to it i'll post up what the problem is.

[evildky]

I'm pretty sure you math is wrong on that one but I'd have to look it up, there si a great engine utility for nissan engines that comes fomr australia that does allt he math for you and covers dang near all the nissan engiens of the last 40 years

[NolimitZ32]

I did the math negating the difference in the uncompressed volume, because then the 1mm is only about 1% VS compressed where its near 20% difference. Either way, any idea where I could get a hold of this utility?

[evildky]

I checked and it looks like that extra 1mm should lower the CR by about 1 point

so a 7.5:1 engine should still have mroe than 90 psi static, the L28ET stock is a 7.3:1 and it's standard is 125 psi IIRC

I must be honest taht fact taht you don't knwo your compression ratio worries me a bit

here is the engine utility, it does not have the VG in it but you can add it, this is what I used when designing the pistons for my long rod L30ET http://www.ozdat.com/ozdatonline/enginedesign/

did you ever reset the timing belt?

[NolimitZ32]

TT comp ratio is 8.5:1 by the FSM, it says the static pressure should be 145-185psi, but does not differentiate between NA and TT which would obviously have different compression numbers because the pistons are physically different. Compression ratio measures compression inside the cylinder vs atmospheric pressure at sea level. I am about 24 feet above sea level, at 8.5:1 compression my compression should be 124.95 psi (8.5X14.7=124.95) and (7.5X110.25psi) or am I wrong in my computation, this should be clean compression with air only in the cylinder as the introduction of fluids such as gasoline will raise the comp. I mean if I did something off the wall please let me know but as far as the physics of it is concerned I'm pretty sure all my calcs are correct.

No I haven't touched the car since last week, my life got a bit turned upside down these last couple of days so I've done nothing on the car.

Dave thanks for all your help man, its good to have another good head thinking through all this crap, make the process of figuring things out much easier. And I'm going to go read the Thermal Dynamics book and get deeper into this, who knows maybe this'll be a blessing in disguise, maybe i'll get another bachelor out of this hahaha.

[evildky]

CR's aren't quite that simple, that assumes that there is a given volume of air at a given pressure and that is is simply compressed, when in fact your egnein si spinning at around 300 rpm while cranking and there are intake and exhaust valves openign and closing effecting just how much air is in said cylinder, in any event i think we can both agree that you should be seeing more than 90 psi on a propperly rebuild and assembled engine