Built Motor Problems, CAN'T DRIVE

[HolyShiznit]

Ok long story short buy my "shell sponsored" built motor fired up but I am having massive problems:

I tried to start it up today after getting through some other issues. It fired right up idled and was fine free revving. However when I got the courage to back it out and put load on the motor it went insanely rich. I revved it up to 2grand to clear it's throat and get rid of the excess fuel and it was fine. Then I tried to pull forward, no dice. Basically anytime I put load on the engine it went pig rich. It had a weird vaccum at idle -394mm/HG on the AVCR. Well now it won't even idle smoothly. It's REALLY rough and has -234mm/HG it is also idling really rich now. It sounds like it is searching for idle but having mad problems. I tried leaning it out with the SAFC now nothing. I tried a billion different in and out settings also. I even tried unplugging the damn SAFC II so that it could not affect the car's A/F and it still was "searching" and running rich.

For the record I called and was on the phone with Ivan for 10-15 minutes doing nothing but troubleshooting wiht him. He was kinda out of ideas.

Background: 9:1 supertech's, Crower Springs/Retainers, JWT ECU tuned for 72lb injectors/Z32 maf, 75lb injectors being used, SAFC II, AVCR, T3/T04, Tial 38mm wastegate, Spearco FMIC, MSD SCi, MSD blaster coil 2, etc.

This is NOT the first time the car has seen boost. Everything was working until the motor detonated to death on 87 octane, motor was removed and was built. I am so lost as to why it would go pig rich under load, and even more confused why it's all fubared now.

I dunno who could help at this time as me, my shop, Ivan, and my friends are stumped but after 4 months of having the car down for reasons not even my fault I am getting to my last straw of patience. I only have one more month to get it running/tuned/played with before college starts again.

[Structure240sx]

whats new besides the motor? anything with the fuel system? ignition?

do you use a normal boost gauge? i cant really relate right now to the numbers that you are giving from the avcr.

i assume this is with a wideband. what kind of numbers are you getting?

[HolyShiznit]

I have a Greddy boost gauge and the AVCR. 500mm/HG is "normal" idle for a KA-T. The ignition was changed from the stock everything to MSD SCi and Blaster Coil 2, BOTH of which are being used and we are definitely getting spark. The distributor is a stock S13 along with the stock cap/rotor. I have a PLXM-300 that when it did idle fine and I tried to put load on it it went from 13.9-14.4 to 11-10-rich. Now it just stays at 10.3-rich while it "searches". Keep the questions coming I know that this stuff comes down to pinpointing the nitty gritty, I just don't know who else to turn to. I WAS the big Nissan guy in my town so I am doing 95% of this one my own.

[toki]

check your MAF, check all of your s-afc settings, check your fuel pressure. and then check them again.

[HolyShiznit]

Fuel pressure was 35 when it idled. I tried the SAFC settings a billion times and even unplugged it so the SAFC cannot alter the car. I need to check the MAF voltage. I don't know why the Maf would have gone bad but it did just sit in the back of the car for nearly 4 months.

[virus77]

check all you intercooler pipes for leaks, also check your mafs.

[HolyShiznit]

I sprayed the entire engine, intake manifold, every vacuum line, bov (recirculated), intercooler couplings with carb clean and it did nothing.

[rn240sx]

I just don't know who else to turn to. I WAS the big Nissan guy in my town so I am doing 95% of this one my own.

How much of a load r u putting on the motor b4 it went pig rich...?? Are we talking instant load or a couple of seconds worth of load then pig rich..??

Im sure your very frustrated with this problem, believe me ive been there done that with idle problems trying to figure out why its all messed up, everyone throws idea's and nothing fixes it. Hell i went almost 2 weeks with the same idle problem and eventually found the problem and fixed it, but enough of my stories...

Did u add anything to the motor since the rebuild..?? Or did u pull the motor out, rebuild it and drop it back in and NOW u have this problem..??

[WDRacing]

Check the MAF voltage on the SAFC. I had a MAF work one day then not the next.

Did you inititalize the SAFC?

WD

[fabio420]

Sounds like MAF to me.

[grimple1]

sounds like something electrical.

Are the ignition components new too?

[virus77]

I sprayed the entire engine, intake manifold, every vacuum line, bov (recirculated), intercooler couplings with carb clean and it did nothing.

Ive seen it a million times that carb cleaner doesnt do **** to the idle and there is a vacuum leak. Especially in your intercooler pipes. When boost builds it makes whatever leak there is even bigger than it was so you will leak your boost out and get a very rich mixture, not drivable actually. Either that or if you mafs is off it will cause an extremely rich or lean condition so check its voltage. My money is still on boost leak. Last time on my car everything was on fine at idle but I forgot to tighten one of my clamps and everytime boost would hit it would leak like madness, I pressure tested the system and sure enough it was gushing out air faster than my shops air compressor could fill up the pipes.

[HolyShiznit]

See this is the problem, I can't even get it close to boost, I am just trying to BACK the car up or pull it forward, any sort of slight load such as slipping the clutch a little to move the damn car resulted in the extremely rich situation. Now it won't even idle or rev freely. It sounds more and more like the MAF, soemthing REALLY weird with it. I am going to check it thoroughly today because honestly that's the only thing I can think of that would cause it to go this weird.

The new ignition is working fine, we are getting good spark and it's hitting everything right.

EDIT: What should the Maf Voltage be for a Z32 maf btw?

[dsylvia]

im having an idling problem with my fully built KA-T also. except when i drive, it becomes lean. not good.

make sure your fuel pressure is set to 43.5psi (with the vacuum line off). im pretty sure thats what the base fuel pressure is for your program.

call JWT and talk to ben in the tech department. he's been a big help to me. even though i havent been able to find the problem, he's given a bunch of ideas.

[toki]

gah. it's your MAF, fuel system or your s-afc. i'm calling it now.

shoe in mouth if I lose, continuation of my boy genius status if I'm right.

[klattr1]

do you have an air filter in front of the mafs or just wide open temporarily? if not, that can cause some funkyness.

also, did you pull each plug wire to see if you notice no difference in sound of motor? if theres no difference in sound, that means there's a problem coming from that cylinder. and also check injector clips good as well.

when it goes "rich" under any slight throttle does the car just die?

[Colton]

how close is the mafs to the turbo? If it's to close you could be disturbing it's air flow causing stumbling when load is applied, but I'm leaning towards mafs.

this happened to me when I went top mount (SR), I ran the mafs far to close to the turbo and it wouldn't boost and it would stumble with load applied.

[HolyShiznit]

This set-up has been running for 2 years now, only thing that was changed was the ECU program, engine internals, ignition, and the AVCR added on. The MAF is about a 9-12 inches away from the turbo, it has a filter on it and it ran fine this way before the gas incident.

I spent ALL day looking over stuff. I pulled the spark plugs and the tone changed with each one so I know that all the cylinders are fine. I unplugged the MAF and the car immediately died. I am almost 100% sure it's not the MAF at this point. The vacuum problem is still there. I think that's what is causing the rough problem and the immediate richness. I popped off the recirc tube from my greddy type S and revved the engine a little bit and held it there and the bov was actually sucking IN as I was revving it up. It shouldn't be doing this correct? Because that would mean that as the air was drawn in and the maf was reading it the bov would appear to be sucking the air back out and towards it...

Anyways keep up the help guys I am trying my best.

[nissanfanatic]

Check the daughterboard on the ECU. It can come loose sometimes in shipping and cause funkyness.

[HolyShiznit]

I understand that could be a problem but I have a vaccuum problem right now. The car runs very rough while "idling" the richness isn't an immediate problem right now. I need the car to stop being so rough and the vacuum problem to be fixed up.

[klattr1]

maybe a tooth off at the distributor?

[C-Kwik]

Check your cams to make sure they are positioned correctly. I had missed the mark by a tooth before and it caused a seriously rich condition. I speculate there was too much overlap at the time and it was getting a lot of reversion which caused a rich condition. It fouled a set of plugs real bad when I did this.

[HolyShiznit]

It's only rich when I either, try to move it forward/backward or rev it up quickly and let off the throttle. Right now it idles at an OK A/F it's just got a weird vacuum and it sounds rough, like it's off somehow. Dunno how to explain it. You guys are all helping honestly though, if this thing ever runs NICO will get a big star from me.

[toki]

you car shouldn't die if you unplug the maf. it should start up and idle with no maf signal. ......

and then go extremely lean and stall if you give it any throttle. that is what happens when you have no maf signal (or *dun dun dun* an improper one!) Very lean/very rich might feel the same under these limited circumstances.

[HolyShiznit]

Ok guys I spent another full day doing nothing but trying with the car. Here's what I found:

MAF is goodIgnition is goodUpgraded Ignition is goodMechanically cams/cam gears, timing chain, etc etc is goodTiming....NOT GOOD

I found that the car was just ridiculously retarded on timing. I pulled out the distributor and lined the rotor and everything to exact FSM procedures and tried again but for some reason I can't advance it far enough to get to 20 degrees. It's almost as if at idle something is "pulling" the timing. Could the coolant temp sensor do this? Only thing touched in the cooling department is an electric fan and a Nismo Thermostat installed with the build. Please help it's so close but this is holding me back. I had my 240 buddy come out and help me and we both set the distributor to EXACT settings and it's like we just couldn't reach it. Something is pulling out timing. For example advancing it as far as it could go (with the nut still holding the distributor in) only resulted in around 10ish degrees of timing at idle. This is going off the marks on the crank pulley of course.

Anymore help would be appreciated.

[klattr1]

what rpm was it idling at cuz it needs to be at 750 rpms and to set it, the motor needs to be warm and then remove the TPS?

[HolyShiznit]

Did all of that twice. I have had that stupid TPS unplugged, the idle air motor cranked, and the car warmed up so many times today it makes my head spin.

[C-Kwik]

It's only rich when I either, try to move it forward/backward or rev it up quickly and let off the throttle. Right now it idles at an OK A/F it's just got a weird vacuum and it sounds rough, like it's off somehow. Dunno how to explain it. You guys are all helping honestly though, if this thing ever runs NICO will get a big star from me.

I should elaborate. My car ran fine when the cams were off. Seemed to idle normally. I took the car out for a spin. Got to the first corner and it stalled while slowing down. Called up my friend and had him come by and pick me up. I grabbed some tools and pulled the plugs to find them fouled. Put a new set in and babied the car back to his shop.

If the cams are somehow off, it may cause a strange vacuum reading depending on how it is off. I can't, for the life of me recall which gear the distributor is tied into, but it is possible if the dist is inline with the upper chain, then a misalignment there may be a mis-timed chain. The lower chain may actually be off. Maybe both chains have mis-alignment issues. Maybe try and line up the crank pulley mark with the pin and check to see if the rotor is pointing where it should.

[egan]

Check the daughterboard on the ECU. It can come loose sometimes in shipping and cause funkyness.

yeah, seriously, this happened to my friends sr enthalpy tune. pull out the ecu and open it up and see if anything is loose. your symptoms are just like his.