Im Baffled R Still down on power

H

hyperturbo400

Guest
Please heellppp!!
After driving for 45mins car wont pull and holds back, can here turbo
spooling but i get poor acceleration and it makes a strained sort of
sound when it dumps, also engine temperture gage flickers back under
acceleration and dont know if this is linked. iv done a check and it
shows 55 all clear!! :cry: engine spec is below if this helps.
rebiult with JE 87mm forged pistons
Roller bearing hybrid T28 turbo
HKS 1.2mm metal head gasket
Pace front mount intercooler
Blitz sus filter
HKS irridium plugs
mongoose system
boost i think is set at 0.9bar
My car is a 91H with no cat and i always run on optimax.
Any help or advice on what to check would be greatly appreiciated :?
 
S

stevenrsturbo@aol.com

Guest
sounds pretty obvious,, but check battery voltage and earth for good connections?
 
Fast Guy

Fast Guy

Moderators
Staff member
hyperturbo400 said:
also engine temperture gage flickers back under
acceleration and dont know if this is linked.
Click to expand...
It could be, if the ecu detects abnormal engine temperature readings, it gives the ecu a preset value to work from. It might be worth checking it out to see if there's a dodgy connection or broken wire maybe.
 
H

hyperturbo400

Guest
re still baffled r down on power

Thanks for the advice, just bought a new battery earth lead to replace the old one, will see if this helps and let you know tommorow
 
S

str_motorsport

Guest
i also have a similar problem with my gti-r.
when driving for a while on low boost and rpm, the car will start to run badlyespecially until 5000rpm.
it seems to hold back, lack or fuel or overfuelling?
with my wideband connected i haven't find anything strange.
i have checked all ground wires and power supply to fuel pump etc...
no fault codes at all.
it seems that the problem is related to engine coolant temperature, becaus when i have this problem, if i start the cooling fan(i have an additional safety switch and the heater at full speed and temp) the problem disappears.
i have repalced the coolant temperature sensor, fitted 550cc injectors, z32 maf, my daughterboard and chip,new plug leads, new coil, new fuel pump, new fuel pump power and ground wires, but the problem is still there...
any ideas???
 
H

hyperturbo400

Guest
Hi there,
Got this reply from that technical guru Ray which may offer up some sugestions to the problems.(I hope you dont mind me copying and pasting to this forum Ray:wink: )
I will be checking these out tommorow and will let you know how it goes.

It sounds like you know what's what but I'll suggest a few things anyway.
Assuming no massive overheating issues ...

a) look for intake air leaks. Check the AAC & air hoses although these
problems tend to be there from startup.
b) check for 'blowback' in the crankcase ventilation system (blocked oil
mist condenser etc causing the block to pressurise)
c) melted plug/s or wrong gap/heat range (too hot?)
d) weak HT (coil is about to pack up or leads are breaking down under
heat/stress)
e) erratic HT - can be caused by using aftermarket HT leads that cause
interference with the flywheel sender unit
f) boost pipe leak or damaged frontmount
g) failing fuel delivery - faulty in-tank pump or fuel pressure regulator

More unlikely but nevertheless worth checking;-

h) MAF voltage readings/earth
i) MAF contamination "on the go" - DON'T touch! It'll break. Just find the
cause of the contamination, eliminate it and the MAF will clear itself (hot
wire system).
j) Wastegate control valve actuator valve malfunction (you'll only get 0.5
bar if this fails)

I've also read recently that a 55 doesn't always mean OK - so maybe you're
getting knock or that the knock sensor isn't being very co-operative.

How-to's for all this stuff are in the 6+year's worth of archive -
http://autos.groups.yahoo.com/group/gti-r/messages and enter keywords in the
Search box. If you need pics, visit www.gti-r.com, the "Reference/Info"
section is the place to go. A lot of these checks can be done fairly quickly
at a reputable garage with a Sun-type diagnostic machine - even better if
they have a 4wd dyno.
 
K

kyepan

New Member
hyperturbo400 said:
Hi there,
Got this reply from that technical guru Ray which may offer up some sugestions to the problems.(I hope you dont mind me copying and pasting to this forum Ray:wink: )
I will be checking these out tommorow and will let you know how it goes.

It sounds like you know what's what but I'll suggest a few things anyway.
Assuming no massive overheating issues ...

a) look for intake air leaks. Check the AAC & air hoses although these
problems tend to be there from startup.
b) check for 'blowback' in the crankcase ventilation system (blocked oil
mist condenser etc causing the block to pressurise)
c) melted plug/s or wrong gap/heat range (too hot?)
d) weak HT (coil is about to pack up or leads are breaking down under
heat/stress)
e) erratic HT - can be caused by using aftermarket HT leads that cause
interference with the flywheel sender unit
f) boost pipe leak or damaged frontmount
g) failing fuel delivery - faulty in-tank pump or fuel pressure regulator

More unlikely but nevertheless worth checking;-

h) MAF voltage readings/earth
i) MAF contamination "on the go" - DON'T touch! It'll break. Just find the
cause of the contamination, eliminate it and the MAF will clear itself (hot
wire system).
j) Wastegate control valve actuator valve malfunction (you'll only get 0.5
bar if this fails)

I've also read recently that a 55 doesn't always mean OK - so maybe you're
getting knock or that the knock sensor isn't being very co-operative.

How-to's for all this stuff are in the 6+year's worth of archive -
http://autos.groups.yahoo.com/group/gti-r/messages and enter keywords in the
Search box. If you need pics, visit www.gti-r.com, the "Reference/Info"
section is the place to go. A lot of these checks can be done fairly quickly
at a reputable garage with a Sun-type diagnostic machine - even better if
they have a 4wd dyno.
Click to expand...
good link mate, perhaps we should make that a sticky in the problem solving.
 
H

hyperturbo400

Guest
Just thought id update you all,
Carried out all the checks as advised and everything seemed OK, replaced car battery and earth strap and believe it or not the problem has gone away!! :D (Just hope it stays that way, as i am still strugling to beleive that it was something so simple,£3.99 lead and a £35. battery)
No doubt ill be back if it rears its ugly head again.
Thanks for you help :D
 
G

GartracS2

Guest
my consult unit could have picked that up for you ;) It saves lots of fooking about.
 
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