R32 Problems

[jessehu]

hello everyone,

i recently got a 1990 gtr r32, and I'm having some problems with it.

1. extremly bad fuel consumption. my r32 can only do 3kms on 1 liter when I'm driving very gentle(shifting before 3k rpm). the car is slightly moded, according to the previous owner, the engine was rebuilt(with stock parts i think), kakimoto exhaust, custom turbo downpipes, apex intakes, boost restricter off, boost on 8psi, hks intercooler and stock turbos.

after i got the car, i put new ngk sparks in, and found the tip on those sparks i took out are really black(fuel), so i checked injector, but they are fine.

my question is will it be the o2 sensors, fuel pressure regulator, fuel pump or fuel filter?

and will a flashed ecu do this?(previous owner don't know if its flashed or not)

2. hicas. the hicas light on cluster comes on after a few km drives on highway, but goes away if i shut the car off and start again. if i jack the car up right after the light comes on, both rear wheels can be shacked right and left by hand, almost like the hicas is not doing anything, but if the light is off, wheels are perfectly good.

my question is whats wrong with my hicas?

i already ordered the hicas lock bar, I'm gonna install it either way, but when installing, is it better to take the whole hicas system off from the car or can i just loop the hydraulic line?

3. rear differential. my rear differential makes very big noise when wheels are turning and i happen to find a $300 used one for r32 from getjdmcars.com, its not here yet, but my question is, does the differential on r32s break ofter? should i upgrade it to a cusco 2way or 1.5 way one?

thats all questions i have now.

thanks for viewing and answering.

[BOOZTJUNKEY]

1. Will most probably be a dodgy o2 sensor not leaning fuel the way it should so just replace them first

2. Hicas system is over 20 years old and the hicas rack is probably just old and shit ! Just put a lock bar on it and don't worry bout hicas anymore ! I personally dont like it but each to there own

3. Is ur diff shimmed can u describe the noise ? Is it like it is lockin the wheels an chirping ? Or is it like its really sloppy lights up the inside wheel ?

never really herd or a gtr diff blowing just becoming sloppy and usually u would just shim it to tighten it ...

preety sure they are 1.5 way or something similar standard

[jessehu]

1. Will most probably be a dodgy o2 sensor not leaning fuel the way it should so just replace them first

2. Hicas system is over 20 years old and the hicas rack is probably just old and shit ! Just put a lock bar on it and don't worry bout hicas anymore ! I personally dont like it but each to there own

3. Is ur diff shimmed can u describe the noise ? Is it like it is lockin the wheels an chirping ? Or is it like its really sloppy lights up the inside wheel ?

never really herd or a gtr diff blowing just becoming sloppy and usually u would just shim it to tighten it ...

preety sure they are 1.5 way or something similar standard

thanks for answering!

for o2 sensors, i see 2 around turbos and i know theres one more around catback, which one should i replace or should i replace all of them?

for hicas, i am installing the lock bar, but I'm not sure what should i do with those hydraulic lines, and can the whole system be removed completely?

for rear diff, I'm hearing "thump, thump, thump, thump" noise while driving around 10-30km/h, any speed after 40km/h it turns into a whining noise.

turning doesn't change the noise.

while turning rear wheels by hand, i can hear something like metal grinding noise.

a mechanic told me to shim it but i thought its not gonna last long so i ordered a used one.

the cusco 1.5way cost around 1.5k,, is it a good upgrade? or should i spend money on engine?

thanks a lot

[blind_elk]

1. How old is the battery?

If the battery is old, it will lose a lot of charge on startup. The alternator then starts pumping heaps of amps back to the battery to get it recharged. The ECU sees this amperage as some sort of error, and switches to a sort of limp mode that burns fuel like it was going out of fashion.

(the "O2 sensor" in the cat is the cat temperature sensor).

Have you had the injectors sonic cleaned?

Not "I ran injector cleaner", actually removed, cleaned and flowed in a sonic bath.

2. Try doing the HICAS diagnostic.

3. You have oil in the rear diff? Change the diff oil? (although it's probably shagged by now)

[BOOZTJUNKEY]

The clunking in the diff maybe caused by worn our shims not putting enough preload on the gears making them lose and and creating the clunking sound you describe which I think the most likely cause I would not by another one just pull it out and inspect and then get it shimmed shims from Nissan are only like 13 bucks if ur mechanically minded u could do it yourself ...

If not take it to a shop It should be around the 500 mark to get the work done I think whic is cheaper than a cusco as stated above factory gtr is a 1.5 way anyways ( I think )

As for sensors replace the 2 just after the turbos they are ute o2 sensors the one on the cat is actually a different sort of sensor it is connected to your light on your dash and will measure ur exaust gas temp it will tell ur ecu if it gets to hot meaning it's leaning out to much which indicates more servere problems which is a story for another day

With the hicas Just loop the lines so they run back to the pump ( bypass the hicas when u lock it ) if u buy a proper lock bar kit they should give you parts and info required for the job

[jessehu]

1. How old is the battery?

If the battery is old, it will lose a lot of charge on startup. The alternator then starts pumping heaps of amps back to the battery to get it recharged. The ECU sees this amperage as some sort of error, and switches to a sort of limp mode that burns fuel like it was going out of fashion.

(the "O2 sensor" in the cat is the cat temperature sensor).

Have you had the injectors sonic cleaned?

Not "I ran injector cleaner", actually removed, cleaned and flowed in a sonic bath.

2. Try doing the HICAS diagnostic.

3. You have oil in the rear diff? Change the diff oil? (although it's probably shagged by now)

both battery and alternator is new,

the mechanic checked my car said injectors are fine so didn't sonic clean them

im installing the hicas lock bar either way, just want to know what do i do with the original plugs and hydraulic line.

the diff oil was changed recently and its still making noise

thanks

[jessehu]

The clunking in the diff maybe caused by worn our shims not putting enough preload on the gears making them lose and and creating the clunking sound you describe which I think the most likely cause I would not by another one just pull it out and inspect and then get it shimmed shims from Nissan are only like 13 bucks if ur mechanically minded u could do it yourself ...

If not take it to a shop It should be around the 500 mark to get the work done I think whic is cheaper than a cusco as stated above factory gtr is a 1.5 way anyways ( I think )

As for sensors replace the 2 just after the turbos they are ute o2 sensors the one on the cat is actually a different sort of sensor it is connected to your light on your dash and will measure ur exaust gas temp it will tell ur ecu if it gets to hot meaning it's leaning out to much which indicates more servere problems which is a story for another day

With the hicas Just loop the lines so they run back to the pump ( bypass the hicas when u lock it ) if u buy a proper lock bar kit they should give you parts and info required for the job

i already ordered a $300 used rear diff for r32, so i guess this is cheaper.

i just want to know that incase the used one breaks too, should i upgrade it to a cusco 1.5way one? is it any good?

for o2 sensors, can i buy 2 widebands and put them in? can they connect to factory ecu or do i have to get a aem power fc or some sort?

thanks!

[blind_elk]

the mechanic checked my car said injectors are fine so didn't sonic clean them

You can't tell by looking at them. What were the flow figures like? What was the spray pattern like?

[luke gtr]

For the hydraulic lines, justjap sell a bypass pipe.

Goes between the 2 bolts near the rack.

Easy to install, do it at the same time as the lock bar.

[DVS JEZ]

Does the car have an aftermarket ecu or fuel pressure regulator?

Can u check ALL of the intercooler pipes and vacuum lines. If one or more is off the mapping will be out.

Check air flow meters

Set base ignition timing

Set TPS adjustment