vg30det missing under load

Idles fine, free rev's fine, but flattens off under load. Anyone know what it could be?

vac leak, dirty MAF
bad plugs
could be alot of things
do a tune up on her, change your fluids, change your tranny fluids, then work from there

Could be weak spark thats being blown out by the boost, i'm pretty sure you can test each coilpack with a multimeter to check its resistance and the same goes for the ignitor chip.

A quick search for a link finds this:
[url]http://www.aus300zx.com/forum/showthread.php?p=265307#post265307[/url]

Good luck :thumbsup:

what grade gas u running???

shoudlnt matter, the VG can run on anything

[QUOTE=Yokotas13;65035]shoudlnt matter, the VG can run on anything[/QUOTE]



not true...my y33 did the same thing because I ran base gas....the guy who bought it from me filled up out in town and it stopped doin it. It's a turbo engine....u need to run high octane. I was just too cheap to pay 4+ dollars a gallon.

[QUOTE=DEE;65122]not true...my y33 did the same thing because I ran base gas....the guy who bought it from me filled up out in town and it stopped doin it. It's a turbo engine....u need to run high octane. I was just too cheap to pay 4+ dollars a gallon.[/QUOTE]

Haha, I dream of petrol being that cheap, at the mo super unleaded in the Uk is 103.9/Litre and rising which in $ terms means $7.76/Gallon :sad: :thumbsup: 
:smiley:

[QUOTE=DEE;65122]not true...my y33 did the same thing because I ran base gas....the guy who bought it from me filled up out in town and it stopped doin it. It's a turbo engine....u need to run high octane. I was just too cheap to pay 4+ dollars a gallon.[/QUOTE]

i run base gas, on a tuned y33 with a bunch of mods, no problems at all

turbo motors need premium gas.  
it could be a boost leak too.  So manything can go wrong with a boosted car.  I have owned a lot of them.  What car is it in?

[QUOTE=Yokotas13;65206]i run base gas, on a tuned y33 with a bunch of mods, no problems at all[/QUOTE]

where are you located though? in Asia base gasoline is ALOT better than here in the US... in Taiwan everyone fills up midgrade with 95 octane and my friend says midgrade in japan is 98


sounds like it could be a maf problem or a knock sensor problem

So many possibilities.  Anymore info on the problem?

Did you ever figure out what the probem was?

if youre still looking for ideas it might be a good thing to ohm out your injectors to.  i know they use the same ones as my SR and they dump out all the time.

I just had the same problem w/ my VG30det , after exstensive diagnosits, it end'd up being 2 bad coilpacks and a few old vac lines that came off. The biggest problem was the coilpacks

I'm guessing boost leak. Since under load the leak will cause less fuel to be expelled causing the hesitation since boost is being produced..which is the reason why at idle you have no issues.

[quote=elpresidente;80955]I'm guessing boost leak. Since under load the leak will cause less fuel to be expelled causing the hesitation since boost is being produced..which is the reason why at idle you have no issues.[/quote]
 
Hey that would hake sence, but my VG30det can non-intercooler, just one alluminum T pipe going straight from the turbo up to the 2 throdel boddies

[QUOTE=Bippu_Ten;81102]Hey that would hake sence, but my VG30det can non-intercooler, just one alluminum T pipe going straight from the turbo up to the 2 throdel boddies[/QUOTE]
That just means you have less places to check for leaks...haha.  Makes the job a lot easier.  One of my friends in Yokota was chasing a boost leak for 2 weeks.  I found it in 5 minutes. through testing and crimping vacuum lines to see where in the bay the leak was occurring.  Do you have good vacuum?  What is the vacuum pressure reading?  I guess more importantly..do you have an aftermarket boost gauge?

turbo with no fmic or intercooler is a no no.  i say check your spark plugs and coils. and def. you got to run higher grade gas on turbo motors. you will see the improvement in performance. hell my n/a needs 91 to run smooth, smooth enough to were when the car is started by my passenger and im not in the car yet, i have the urge to turn the key. meh.

Stock VG30DET in the Cimas/Ceds etc are not intercooled. Seems to go alright in standard form, but of course adding an IC is one of the first mods for these cars.

Ya mine came non-intercool'd which eliminated all the turbo lag, but since then Ive added a FMIC, runs great !