Kid

I'm hoping you guys can help me with a really irratating problem I have had for 8-10 months now. I don't even know where to start. My car starting to have low RPM problems, boost problems, and just problems.

Ø I all ready had these mods in it:
o Walboro 255 (used... was installed from my Evo 3)
o HKS FCON V Pro
o Tomei 262 Pon cams
o Tomei Gears
o Tomei Head Gasket
o ARP head studs
o SARD FPR (used...also from my Evo 3)
o There are more but that is mostly from my motor
Ø After all been installed, it seemed my car was running all right for awhile (maybe about two weeks). All of a sudden it would start having low RPMS. At the same time boosting would start to jerk my car maybe around 4000-5000 RPMs.
Ø After troubleshooting for awhile, I noticed my water temp would start to go above 110 degrees Celsius. Japanese friend told me sometimes broken water temp sensors can usually affect the cars RPM which could mess the tuning. After telling me I changed the water sensor and the car ran fine. I was really thinking that was the problem.
Ø 3 days later the problem came back.
Ø I did so many things to look for the problem even doing the unnecessary stuff:
o Changed the fuel filter
o Changed the coil packs
o Changed the coils
o Changed spark plugs
o Changed FPR (Went Areomotive)
o Re arranged the vacuum lines (but it is running FCON so it couldn’t be that)
o Bought a brand new Walboro (old one was 7 years old)
o New filter on pump
o Checked engine compression (just in case…it was good)
o Steel braided fuel lines
Ø My car has been back to the car garage 3 times now. 2 times so far for a re-tune. The last time they took it back, they put the old fuel pump back in, changed the coil wires. The low RPMs seem to have gone away, but when I boost the car jerks badly. I had a stock Altezza beat me today. It was horrible.
Ø Please if anybody has an idea of what it could please let me know. I’m typing this half tired so I am probably missing some information. I will put more into tomorrow. I was hoping somebody had a similar problem before with a good idea for a fix.

I hope this is the right section to post this topic.

Kid

You know.... I was reading this thread:

https://www.evolutionm.net/forums/ev...e-3000rpm.html

You think maybe the camshaft position sensor is bad?

S0rc3r3r

Not certain if this applies but worth a mention:

Fuel Cuts
Cars affected: Lancer 1800 RS/GSR, Evo 1-9
Symptom: A very sudden de-acceleration due to the fuel being cut to the injectors,
similar to your foot slipping off the accelerator except it will recover almost
immediately. It occurs if over boost is detected while accelerating hard (common at
roughly 4000rpm in 2nd, 3rd or 4th gear but possible at other rpm and gears). Also it
is more common if the outside air temperature is colder.
Problem and Cure: Fuel Cuts are the Engine Management’s way of stopping serious
over boost situations occurring. Instead of detecting the actual boost pressure the
ECU (Electronic Control Unit) uses information from the Air Flow meter to work out
the boost pressure. The ECU will cut the fuel at roughly 1.3 bar boost pressure (18.8
PSI) on the Evo 6 (approximately 1.5 bar on the Evo 7) but the specific cut point is
dependant on atmospheric conditions at the time so it will not be the same from car
to car. Fuel cuts are more likely to occur in winter as the air is colder and therefore
more dense. Early Evo models may have a lower cut point that is in relation to their
standard boost pressure level setting.
Fuel cuts commonly occur after fitting an upgraded aftermarket induction kit and/or
exhaust due to the increased air flow they create but fuel cuts have occurred on
standard cars before. It is also possible for fuel cuts to occur due to a faulty
Wastegate Actuator but it is not that common (see elsewhere).
Do not live with fuel cuts! The sudden cutting of the fuel sends a shock through the
engine and drivetrain which in itself can be harmful. You can temporarily 'drive
around' fuel cuts by avoiding using full acceleration or if very worried keeping below
4000rpm at all times (as if you were running in the engine).
The cure for fuel cuts depend on what is causing it and also what you intend to do
with your car. If you believe the over boost is due to any upgraded parts that have
been fitted then the boost level can be dropped fairly easily by a manual alteration to
the Boost Control system, although dropping the boost obviously partially defeats the
object of fitting performance parts. If you intend to modify your car further then you
will require an upgrade to the Engine Management to either eliminate the cut point or
‘work around’ it. It is not recommended that you use a ‘Fuel Cut Defenser’ as they tell
the ECU that the fuel cut point has not been reached by electronically reducing the
air flow signal and this can lead to a lean mixture as the ECU will reduce the fuelling
to suit. If you are having problems with fuel cuts then consult a qualified
garage/mechanic that knows about Evos and also let them know what you intend to
do with the car in future.
Approximate cost of repair: Depends on the fault. Adjusting the boost level down
slightly will take 30 minutes with no parts required. A new Wastegate Actuator is
approximately £200 inclusive (plus fitting approx. 1 hour)

S0rc3r3r

additional things to check:

Rusted Wastegate Actuator
Cars affected: Evo 4-6 (possibly earlier Evos and the Evo 7 onwards)
Symptom: Lack of boost or excessive boost levels with possible fuel cuts. It can be
intermittent or erratic.
Problem and Cure: The location of the Wastegate Actuator and angle of the actuator
arm promotes water entering the Actuator diaphragm assembly. This can lead to
early failure of the actuator due to rust build up. Early symptoms maybe hard to spot
without a Boost Gauge fitted.
The only cure is to fit a new Actuator. The fitting of an aftermarket actuator of
different design should prevent any further problems.
Approximate cost of repair: A new Wastegate Actuator is approximately £200
inclusive (plus fitting approx. 1 hour).

S0rc3r3r

lastly, have a look at this -

Idle Speed Control Valve (ISCV)
Cars affected: 1800 RS/GSR, Evo 1-7
Symptom: Unstable idle and possible stalling or higher than normal idle speed
especially when the engine loading changes (e.g. when fans or A/C comes on).
Problem and cure: Unstable idle is possibly due to deteroriation of the Idle Speed
Control Valve stepper motor. The motor controls a valve that allows air around the
throttle butterfly to maintain a steady engine speed at idle, if the motor does not work
correctly then the idle speed cannot be maintained.
Note that if unstable idle occurs and the car has been fitted with a vent to air blow off
valve then this is the likely to be the problem.
There a few checks you can make before condemning the ISCV (the checks below
apply to all car models mentioned). The ISCV is situated underneath the throttle body
(see figure 1) with an electrical connector on the right hand side.
Check to make sure the connection to the ISCV is secure. Remove the connector
and with the ignition on measure the voltage between pin 2 (top centre) and earth on
the harness side of the connector. Do the same with with pin 5 (bottom centre). Both
these pins should be at system voltage. If they are not then there is a problem with
the harness between the connector and the Engine Control Relay. If system voltage
is present then the next step is to check the ISCV stepper motor coils. Measure the
resistance between pins 1&2, 2&3, 4&5 and 5&6 on the ISCV body connector (see
figure 2).
All these should measure between 28 and 33 Ohms, if any of the coils do not fall
between these values then the ISCV needs to be replaced.
Approximate cost of repair: New ISCV for E4-7 = £210 + VAT & fitting. New ISCV for
1800GSR & E1-E3 = £164 + VAT & fitting. Second hand or reconditioned ISCV’s are
also available.

pwrofturbo

iTrader: (2)

I want wideband AFR when it happens and I want you to do a boost leak test.

S0rc3r3r

I 2nd this if you have not done so already; very important this one check.

djikonatx

iTrader: (33)

^^^ holly moly that's a lot if reading...but anyways i also have a evo 4 engine/tranny etc in my evo 8 and had a very similar problemabout a week ago.the problem i found that was causing this was a couple of leaks.so if i were you if start there.my car would feal like it hit fuel cut at higher boost.gl

Kid

sorry, I haven't been keeping up but just to let you knwo I found the problem. It was the cam sensor. I replaced it adn the problem is fixed. Now I have a new problem. My car won't stop boost at 1.4. it goes all the way to 1.5 even to 1.6 sometimes. It just sounds like I need to replace the actuator. Any thoughts?

Kid

Thanks for all you help by the way.

chrisnicole88

hello. my evo 4 dose this kind of thing also has a bump in idle. and i can also here a hissing sound from somewhere around the cams power steering pump

Tatmonster45

iTrader: (1)

Do a boost leak check also