Boost Problem? Misfiring?

[acidburn1204]

I'm using a 3S-GTE and had just transplanted this engine on my MR2.

At 0.5bar which is the stock boost, everything was going fine n smooth. Redline is at 7000rpm.
After increasing the boost to 0.7 the rpm seems to stall for awhile at 5000rpm then continue as per normal. A wierd GRRR sound appears and the boost drops by 0.2 when this happens, b4 continuing to speed on to 7000rpm as per normal. After explaining this to my friend he said that its mis-firing. wat does this mean? and how do i fix it if? If its not misfiring, then wat is the problem?
At first it only happened on the 3rd,4th and 5th gears. After some time now, its also happening on 2nd gear. In other words, getting worse... and more frequent.

I just had my car for less than a year so i'm new to turbocharged engines, its technical functions...etc.

Really need some help on this. Thx

 

[Rein]

might be running too rich.
can you describe more specifically about what other mods have you done to the car. How are u managing your fuel? R u using safc, fuel regulator or standalone ecus?
give us more details and we might be able to figure out the prob.

 

[ezwong2002]

I'd say change your spark plugs to a better ones... such as DENSO IRIDIUM plugs.

 

[GSR5559]

there is possibilities of fuel running too lean oso cus as you said u increase the boost to 0.9 bar..
as i remember my fren boosting at 0.6 bar using stock injectors no prob den he increased the boost to 0.9 bar without changing any injectors..
den wen he tried to go till red line, there is a certain RPm wher it will be kinda sluggish and can hear poping sound coming out from the exhaust wif black smoke..so to solve the prob , he change to bigger cc injectors..
den now can boost till 1 bar without any probs..

or

u can check ur fuel pump, spark plugs,plug cables...

jus my 2 cents

 

[TE27levin]

miss fire? yes.. cos ur engine start to retart the ignition.
engine start knocking, knock sensor detact and retart your ignition to protect ur engine. it should be cause by running lean, weak fuel pump or bad fuel filter. it also can be cause by TDC ignition timing is too high. and one more maybe u using the wrong spark plug cos turbo need cold plug. hot plug will also cause detonation.
if u keep on holding the throttle.. u will see broken piston ring, broken con-rod or blew piston.

 

[acidburn1204]

All,
I have SAFC and i'm using stock injectors.
My spark plugs are already DENSO iridium's.
Two weeks ago i had the fuel pump changed to supra's fuel pump.
At the same time i also changed tthe plug wire to a new 1.

GSR5559,
ya i think theres sum black smoke and the sluggish RPM

 

[GSR5559]

GSR5559,
ya i think theres sum black smoke and the sluggish RPM

mebi try changing a bigger cc injectors .. mebi can solve ur prob..jus my 2 cents..
like wht te27 said oso culd be the possibilities of running too lean or mebi too rich ..
but i guess it is too lean..too rich will make ur car laggier ..u feel heavy i guess.

 

[TE27levin]

check ur ignition timing, it might be too high.
too lean will cause black smoke cause ignition timing will retart when detected knock, fuel will not be burn and shot out from exhaust.

 

[GSR5559]

Originally posted by TE27levin@Sep 3 2004, 09:54 AM
check ur ignition timing, it might be too high.
too lean will cause black smoke cause ignition timing will retart when detected knock, fuel will not be burn and shot out from exhaust.

yeah too lean will cause knocking..but dude TE27 Levin..ive experienced before engine running too lean and it will produce black smoke wen sudden full throttle..
wht about too rich of fuel ? wht is the outcome ? pls explain more..TQ

 

[Rein]

too rich will cause alot of black smoke also.....
cept that the rpm will stall at high rev.....eg if you're too rich at high rpms, u rev till 5k, lotsa a black smoke and rpm cannot exceed 5krpm....exhaust keep popping onli.....

 

[GSR5559]

Originally posted by Rein@Sep 3 2004, 05:46 PM
too rich will cause alot of black smoke also.....
cept that the rpm will stall at high rev.....eg if you're too rich at high rpms, u rev till 5k, lotsa a black smoke and rpm cannot exceed 5krpm....exhaust keep popping onli.....

pphh..means it is around the same wif running too lean rite?
cus if lean oso produce poping sound from the exhaust and black smoke..
but i think running too rich will be better den too lean cus it might make ur engine lifespan shorter..as an example oni le..
but the best is running jus nice for each RPM..
TQ rein

 

[Rein]

too rich also not good.....when u're running too rich, ur engine very heavy, and the crankshaft on alotta load....not good for engine bearings.....
that's wat my mech told me lar....

 

[GSR5559]

oic..yeah too rich or too lean is not good for engines..thats wht i learn..so the best settings is balance..
tq for da info rein..

 

[kschu]

buy an AFR n check ur fuel lah whether it's lean or rich..............it's owes goot to b rich a bit than lean all d time

 

[acidburn1204]

I already have an AFR. The meter indicates LEAN (max.) How do u set it to rich or lean?
ya the exhaust keeps poppin and rpm unable to exceed abt 5000rpm. when poppin, theres black smoke... Theres also black smoke upon sudden full throttle
But having sum black smoke upon full throttle is quite normal i heard..
And the ignition timing is supposed to be set by the SAFC rite?
Does it have anything to do with the fuse?
REAL hEaDaCHe....... its really fucking up the cars full potential when performing a drag or street race.. <_< wat do i do man guys? just wanna get this over with..

Now its even worse... not even stalling or lagging anymore. When it reaches 5krpm, theres a sudden shut down for a few seconds; RPM drops then continues again. Does this prob affect or damage the engine in any way? That is wat worries me... i also have a AVCR, if it helps in any way?

Thanx for ALL the info man

 

[GSR5559]

wah..serious shit man..for how long uve been driving like dis..dun tell me dat wen ur car is facing this prob u still go for a drag..might as well settle the probs first den oni go and drag like there is no tomoro..
if im not mistaken SAFC can set ur fuel..for AVCR , it oni can play wif ur boost level and etc which im not reli sure..but if ur SAFC cant set ur fuel den get a bigger CC injectors to solve this prob..and if u continue driving wif sudden full throttle alwiz causing poping sound all the time,..i think one fine day u have to say goodbye to ur engine (touchwood)..
so get it done quick..or else in future u will face more probs like wht TE27 said, broken pistons and stuff lidat..
Good luck

 

[Danny]

u have safc but u do not have an air/fuel ratio meter also no use, u woudn't know how to set the proper air/fuel ratio settings.

 

[GSR5559]

worse comes to worst go dyno le..ahaha..

 

[Danny]

yea dyno tuning will yield the best results.

 

[phat7]

Hi Bro,

My 2 cents worth. Try checking your grounding cables. After changing the engine on my fd i had a similar problem. After consulting a few japanese websites i found that the problem actually lay in the grounding itself. I tried cleaning all points but the problem still was there. I did a complete swap for the grounding wire and the problem decreased. The problem completely went away after installing one aftermarket grounding kit.

good luck.