VQ25DE powered A32, knocks like hell

[VT-Ten]

Hi All,

I need some help here. My ride has been knocking since last month and i dont know why. hope that sifus out there can give me a pointer or two.

it all happened when my car starts "shivering" when at idle. It turns out that 2 ignition coils has gave way. changed that and 1 week later i heard some faint knocking when going uphill. Sent for check and diagnosed with knock sensor faulty. Got it replaced but still knocks after a few days. sent for check again and knock sensor faulty (again?). got it changed for the 2nd time and god help... it still knocks even on low engine load. and believe me, i wish all the roads in this world is downhill, cause it knocks sooooo badly when going uphill.

My mech saids that the ECU might be faulty. given that it's a 3.0L ECU (specs of my car at the bottom), it know it will cost me an arm, a leg and a ball to get it replaced......if i'm lucky enough to find one.

Consulted a few friends and they say e-manage with ignition harness can resolve the problem. I'm not sure if it could, as emanage still relies on ECU to do the calculation at the end of the day. your thoughts?

is there any A32 owners out there that has the same problem as mine? please give a pointer or two. i'm really at my low waves now (no $$) and i would prefer to spent the least to resolve this problem. here's the spec of my car

A32 3.0L year 97
VQ25DE engine kosong
gearbox, ECU, fuel rails, injectors, air flow are retained from 3.0L

Thanks in advance.

Cheers.

 

[Ultimate Cefiro]

how long did u swapped ur engine??

 

[VT-Ten]

since aug last year

 

[Ultimate Cefiro]

1st.... maybe its bcoz u swapped the 2.5L engine kosong right away w/o changing other parts (i.e. ECU, fuel rail, injectors etc.), the 2.5L engine of course will consume less fuel theoritically, but ur 3.0L ECU will "order" your 3.0L to inject the amount of fuel that is sufficient for 3.0L engine, which in other word, more than the amount needed for 2.5L engine. dats y after a period of that engine for running too rich, it actually will deposite more unburnt composites in the engine and therefore knocking occurs.....

yes try to change back to the 2.5L ECU, it is a must, even my fren last time oso swapped the engine kosong from 3L to 2.5L like you do, and his car A/F is too rich, always can smell the fuel fume even in his car..... well it is juz my RM0.06 anyway~~ hope this will help... gd luck....

 

[seizai]

1st.... maybe its bcoz u swapped the 2.5L engine kosong right away w/o changing other parts (i.e. ECU, fuel rail, injectors etc.), the 2.5L engine of course will consume less fuel theoritically, but ur 3.0L ECU will "order" your 3.0L to inject the amount of fuel that is sufficient for 3.0L engine, which in other word, more than the amount needed for 2.5L engine. dats y after a period of that engine for running too rich, it actually will deposite more unburnt composites in the engine and therefore knocking occurs.....

yes try to change back to the 2.5L ECU, it is a must, even my fren last time oso swapped the engine kosong from 3L to 2.5L like you do, and his car A/F is too rich, always can smell the fuel fume even in his car..... well it is juz my RM0.06 anyway~~ hope this will help... gd luck....

RM0.06 no more accept, must rond up to RM0.05

btw i dun think he hv 2.5 ecu since wat he bought is engine kosong only

 

[VT-Ten]

thanks for the replies guys.
yea i dont have 2.5L ECU. but im also confused of how can a car running rich will knock? i tot knocking only occurs when engine is running lean? pls enlighten me. thx

 

[Ultimate Cefiro]

i dun think it is knocking izit? shud b JERking instead of knocking.... since it is going uphill..... how abt flat road?? normally too rich will cause miss firing.... and thus less combustion take place as the spark is covered by too much fuel.... anyhow, might get 2.5L ceffys part easily nowadays since more and more JDM ceffy is being chopped.... happy hunting....

 

[sb3]

Hi All,

I need some help here. My ride has been knocking since last month and i dont know why. hope that sifus out there can give me a pointer or two.

it all happened when my car starts "shivering" when at idle. It turns out that 2 ignition coils has gave way. changed that and 1 week later i heard some faint knocking when going uphill. Sent for check and diagnosed with knock sensor faulty. Got it replaced but still knocks after a few days. sent for check again and knock sensor faulty (again?). got it changed for the 2nd time and god help... it still knocks even on low engine load. and believe me, i wish all the roads in this world is downhill, cause it knocks sooooo badly when going uphill.

My mech saids that the ECU might be faulty. given that it's a 3.0L ECU (specs of my car at the bottom), it know it will cost me an arm, a leg and a ball to get it replaced......if i'm lucky enough to find one.

Consulted a few friends and they say e-manage with ignition harness can resolve the problem. I'm not sure if it could, as emanage still relies on ECU to do the calculation at the end of the day. your thoughts?

is there any A32 owners out there that has the same problem as mine? please give a pointer or two. i'm really at my low waves now (no $$) and i would prefer to spent the least to resolve this problem. here's the spec of my car

A32 3.0L year 97
VQ25DE engine kosong
gearbox, ECU, fuel rails, injectors, air flow are retained from 3.0L

Thanks in advance.

Cheers.

VT - Ten, Our ceffies r ultra sensitive when comes to electronics , hence if u have swapped to the engine kosong which is only 2.5L compared to ur previous 3L, i suppose most if not all of the components especially ur ecu will not be compatable to the 2.5L. It will get the engine started but it won't run properly.
Since you are low on ur budget , i suppose u could start your diagnostic repairs by chnaging your spark plugs , different petrol brands and bring your car to a kedai potong shop to swap ECUs . You will have an option to purchase the ecu only if it could solve your knocking,idling hunting problems. But if swapping the ECU does not solve ur problem, then you have to swap other items such as TPS sensor, MAF, temp sensor , o2 sensors , MAP snesor and see whether it solve ur problem. Oh yes ! please check ur intake manifolds (upper and lower). They tend to leak air due to ageing ovetime

Good luck

sb3

 

[XTEC]

hi vt-ten, u may try to clean ur EGR system. if EGR choke will cause engine knocking. this happen to my.http://www.aa1car.com/library/egr.htm and location of EGR of nissan A32 http://nissan4u.com/parts/maxima/el_a32/1997_12/type_6/engine_mechanical/egr_parts/

hope will help

Bump: hi vt-ten for my case, when cucuk with computer for diag no error code for this EGR system reported. when open for clean it just totaly choke from manifold thru whole EGR system.

 

[deacon]

btw a piggy back ecu probably won't help, better to get full stand alone. Running off a faulty ecu will not help.

 

[rskathi]

hei bro,i had the same problem after 3 month changing the engine from 3.0 to 2.5, i have replaced the injectors, ecu, knock sensor all air hoses and tried different type of spark plug but knocking still there. i have been driving with the prob for more then 1 year.till now i had some engin over temp problem. i checked that the termostat was stuck close. its located on the left side looking toward the rear. follow the hose till the connection to the engine.remove the hose and the metal join on the engine with 3 connecting bolts. in there you will find the termostst. you have to change it in 1 set but what i did i removed the valve which is hold in, with 2 screws and installed the metal join without the termostat. and wallah there you go.......the knocking and jerking of the engine was gone.i have been using my car with no problem for the past 2 day.

i realised that the termostst was poory working until it failed... just completely .

well you can try it yoursely it simple to remove and replace. you need a size 10 spanner and socket with short extension....

Hi All,

I need some help here. My ride has been knocking since last month and i dont know why. hope that sifus out there can give me a pointer or two.

it all happened when my car starts "shivering" when at idle. It turns out that 2 ignition coils has gave way. changed that and 1 week later i heard some faint knocking when going uphill. Sent for check and diagnosed with knock sensor faulty. Got it replaced but still knocks after a few days. sent for check again and knock sensor faulty (again?). got it changed for the 2nd time and god help... it still knocks even on low engine load. and believe me, i wish all the roads in this world is downhill, cause it knocks sooooo badly when going uphill.

My mech saids that the ECU might be faulty. given that it's a 3.0L ECU (specs of my car at the bottom), it know it will cost me an arm, a leg and a ball to get it replaced......if i'm lucky enough to find one.

Consulted a few friends and they say e-manage with ignition harness can resolve the problem. I'm not sure if it could, as emanage still relies on ECU to do the calculation at the end of the day. your thoughts?

is there any A32 owners out there that has the same problem as mine? please give a pointer or two. i'm really at my low waves now (no $$) and i would prefer to spent the least to resolve this problem. here's the spec of my car

A32 3.0L year 97
VQ25DE engine kosong
gearbox, ECU, fuel rails, injectors, air flow are retained from 3.0L

Thanks in advance.

Cheers.

 

[doraemon98]

hei bro,i had the same problem after 3 month changing the engine from 3.0 to 2.5, i have replaced the injectors, ecu, knock sensor all air hoses and tried different type of spark plug but knocking still there. i have been driving with the prob for more then 1 year.till now i had some engin over temp problem. i checked that the termostat was stuck close. its located on the left side looking toward the rear. follow the hose till the connection to the engine.remove the hose and the metal join on the engine with 3 connecting bolts. in there you will find the termostst. you have to change it in 1 set but what i did i removed the valve which is hold in, with 2 screws and installed the metal join without the termostat. and wallah there you go.......the knocking and jerking of the engine was gone.i have been using my car with no problem for the past 2 day.

i realised that the termostst was poory working until it failed... just completely .

well you can try it yoursely it simple to remove and replace. you need a size 10 spanner and socket with short extension....

Bro... post some photo la shows which bot your spanner should stuck into... :hmmmm: