FlipSquad

Ok so I just spent the last hour looking for something similar to what happened to me this morning and I could not find anything matching my situation...soo here goes. Any help is greatly appreciated!

Ok, normal routine began today. Warmed the car up, drove it to work, everything was fine. Lunch time, got in the car to get some chow, and I noticed that when im at or around 25% throttle in any gear cruising, the car feel like it loses a little power for about 2 seconds then goes back to the normal feeling when driving.

I managed to get on a road and cruise at about 40mph in 4th gear, and I have the gas pedal held in one position, and every couple of seconds the power decreases and then increases.

Car idles ok, under about 50% throttle car drives normal up to about 3000rpm and the throttle closes and the bov releases, but I am still inputting the same amount of throttle.

I only tried once giving it a little more than 50% throttle, and the car shuts either fuel or ignition off for a second or two and then it comes back on if I let off a little.


Spent my lunch poking around, and I noticed a leak from the smaller of the two fuel lines. Very minor, but none the less there was a leak due to the crappy stock squeeze clamp. I also noticed debris around the #3 injector. Looks like its been that way for awhile. Bad 0-ring? Fuel pump relay??

Pulled the plugs and the tips look a little dark, but the porcelain is still all white...dont have another set of ILKR8E6 to try, I have some other NGKs that were in the car before, but theyre wrong....

Would the o-ring cause the hesitations during driving?...it really feel like the car is loading up on fuel when the power decreases. AFR's fluctuate from 14-16 when cruising along with the rpms bounce up and down about 500rpm.


BTW, Mod list: AMS downpipe, AMS 4" Intercooler, AMS test pipe, ETS Extreme catback, E-tuned on COBB AP by RRE, Turbosmart dual port, Grimmspeed EBCS, ETS charge pipes, AMS intake, AEM UEGO, stock everything else engine wise.

HELP

static_set

When this happened you're sure the car was warmed up completely? Mine does the same thing under the same conditions until it's up to temp. Just a very small hardly noticeable blip in the power for a couple seconds here and there.

Sounds like you're checking all the right stuff but possibly chasing a ghost.
-asher

LetsGetThisDone

iTrader: (1)

The smaller fuel line is just the return line. Get a new OEM clamp on it.


Do a boost leak test, fix any leaks, and put new plugs in.

4G63_EVO

iTrader: (4)

What is it that causes this? Across all the evos ive been in ive never seen this happen, But it could possible explain a problem im having while cruising for long periods of time

FlipSquad

Thanks for all the input guys.


UPDATE: switched out the plugs for known good ones but they werent brand new and fixed the return fuel line. Same symptoms. I noticed that if I apply more than 50% throttle between shifts 2nd and on, car feels normal and AFRs look normal in the 11s/12s. Then after, if I cruise in 4th it runs fine......seems something related to TPS or MAF sensors maybe? This ****s killing me. I love this car but too much elecrtonics haha.

I do believe he O ring on one of the injectors is bad/leaking slightly...possibly dead at this point....making the car lean out?

FlipSquad

Sometimes when the power decreases, the throttle even closes because the bov releases with a little flutter.

I wish I could just yell at it and it would fix itself hahah

FlipSquad

UPDATE: Changed out the injectors for known good stockers. Still same symptoms. Also, replaced the pump relay with Mitsu blue. cleaned the MAF, cleaned the TPS, and nothing.

My next plan is to replace the fuel filter....fuel pump, then idk. I checked all the fuses, salt shaker test on all relays, chased all vac lines and plugs and wires and FML cant figure this out and I have that feeling in my stomach that its something stupid.

P.S. I did change out my Prosport gauges (Boost and Wideband) for a Depo Volt gauge and AEM UEGO. But I cant imagine any of the wires I played with would cause the issues im having, because the car ran fine for a day after I did the install....I did unplug the G sensor under the center console,,,but the car ran fine afterwards..

There is also an existing C161E code but thats been on and off for a few months.....PLEASE HELP

LetsGetThisDone

iTrader: (1)

You need to datalog the event. See if the ecu loses signal from the TPPS (throttle PEDAL position sensor). Or if something else weird is going on.

static_set

Sorry for the delay - just saw this. I can only speculate since this is my first Evo, but my particular instance probably has to do with the combination of throttle and cam timing while the engine is below optimal temps.


Doesn't really affect driving at all - but it's there.



Here's a little troubleshooting guide from AllData that might help you the next time that code pops up:

DIAGNOSTIC PROCEDURE

STEP 1. Check whether the diagnostic trouble code is reset.
As for vehicles under low temperature condition, carry out the contents of the precautions, and then check the diagnostic trouble code again.
Q: Is diagnosis code No.C161E set?
YES: Go to Step 2.
NO: This diagnosis is complete.

STEP 2. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.
Q: Is the check result normal?
YES: Go to Step 4.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 3.

STEP 3. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES: Go to Step 4.
NO: This diagnosis is complete.

STEP 4. Fluid check
Check that the fluid level is adequate. (See: Transmission and Drivetrain\Differential Assembly\Service and Repair\Procedures\Rear Axle\Fluid Level Check)
Q: Is the check result normal?
YES: Go to Step 5.
NO: Add the fluid. Then go to Step 15.

STEP 5. Scan tool diagnostic trouble code
Check if the AWC diagnostic trouble code No. C1611, C1612, C1625, or C161D is set.(See: Diagnostic Trouble Code Descriptions\S-AWC)
Q: Is the DTC set?
YES: Perform the relevant troubleshooting.
NO: Go to Step 6.

STEP 6. Scan tool actuator test
OK: Operating sound of the electric pump can be heard.
Q: Is the check result normal?
YES: Go to Step 14.
NO: Go to Step 7.

STEP 7. Electric pump relay single unit check
Check the electric pump relay. (See: Transmission and Drivetrain\Transfer Case\Service and Repair\Procedures\Sensor, Switch and Relay)
Q: Is the check result normal?
YES: Go to Step 8.
NO: Replace the electric pump relay. Then go to Step 15.

STEP 8. Electric pump relay connector check: A-26X
Q: Is the check result normal?
YES: Go to Step 9.
NO: Repair the defective connector. Then go to Step 15.

STEP 9. Check the wiring harness between A-26X electric pump relay connector terminal No. 2 and fusible link (35).
Check the power supply line for short or open circuit.
Q: Is the check result normal?
YES: Go to Step 10.
NO: Repair the wiring harness. Then go to Step 15.

STEP 10. Electric pump connector check: F-14
Q: Is the check result normal?
YES: Go to Step 11.
NO: Repair the defective connector. Then go to Step 15.

STEP 11. Check the wiring harness between A-26X electric pump relay connector terminal No. 4 and F-14 electric pump connector terminal No. 2.
Check the power supply line for short or open circuit.
Q: Is the check result normal?
YES: Go to Step 12.
NO: Check C-21 and D-12 intermediate connectors. When no problem is found, repair the wiring harness. Then go to Step 15.

STEP 12. Check the wiring harness between F-14 electric pump connector terminal No. 1 and body ground.
Check the ground line for open circuit.
Q: Is the check result normal?
YES: Go to Step 13.
NO: Repair the wiring harness. Then go to Step 15.

STEP 13. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES: Replace the hydraulic unit. Then go to Step 14.
NO: Intermittent malfunction.

STEP 14. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES: Replace the AWC-ECU. Then go to Step 15.
NO: This diagnosis is complete.

STEP 15. Check whether the DTC is reset.
Q: Is DTC No. C161E set?
YES: Return to Step 2.
NO: This diagnosis is complete.


-ash

bolothedv

It's probably due to heat and humidity in Guam....Just kidding. not providing any useful information. Just saw a fellow Chamorro. Keep us posted though.