Hiccup when idling and driving /video inside/

[mko]

Ok, I dont have Vr4, but its a 94 Galant ES-t. I hope someone can identify whats wrong

This is how it dips at idle. It does the same thing while driving for the same period of time

click

Got new spark plugs 1 step colder, gapped them to 0.3.
Changed both TB gaskets.
Changed the GM MAS.
Readjusted the TPS and cleaned the BISS.
Lowered fuel pressure to 45psi.
Pulled the charge pipe out right before the GM MAS, drove around same hiccup happens.


MOds: s16g, 2.5'' ICP, Evo3 Mani and O2 housing, 3'' core FMIC, 450cc, MAFT+SAFC, 1g BOV, FIAV block off plate, Aeromotive FPR at 48 psi, 6AN high flow fuel filter

 

[solidviper89]

Fuel filter?
Fuel leak?

 

[mko]

you think it sucks air in the system?

 

[mko]

OK, what we did today:

Swapped galants fuel pump with Evo one.
Blocked off the EGR.
Put injector cleaner in tank.
Readjusted all TB sensors and fuel pressure.
Bought a feeler gauge and the funny thing is that I set the gap of spark plugs to 0.3 with one of these coin gauges, well they suck. The feeler gauge says I had 0.8mm of gap...I was like WOW.....so i set it to 0.3mm for real this time
Bought new O2 sensor, havent installed it yet cuz I didnt have the socket.

Tomarrow I will :

Install the O2 sensor /hoping its the problem/
Install different distributor
and see if I can find another MPI relay

 

[mko]

no one whats to help?

 

[1990ggsxnj]

Viper isn't nobody and I'm sure people are waiting to see what happens with everything that you've done.
Quoting mko:


Tomarrow I will :

Install the O2 sensor /hoping its the problem/
Install different distributor
and see if I can find another MPI relay


You may have solved the issue without the need for other peoples' input. Have you tried running it after doing the last set of changes you described?

 

[mko]

I did compression test - 200psi across the board. It doesnt happen when car is warming up after first start, but when its in operational temperature. Ive noticed it does it even more often after Ive been hard on the pedal for some time, but never when its boosting and accelerating, only when cruising at light throttle. It started when weather got colder, I think.

So far Ive done:

Got new spark plugs 1 step colder, gapped them to 0.3.
Changed both TB gaskets.
Changed the GM MAS.
Readjusted the TPS and cleaned the BISS.
Lowered fuel pressure to 45psi from 48 /ECU wants 48-50, it was a n/a car, but still has stock ECU/
Swapped galants fuel pump with Evo one.
Blocked off the EGR.
Put injector cleaner in tank.
new O2 sensor
put a check valve after PCV

Still to check:

fuel system
ECU
MPI relay


I still havent got around playing with the fuel. Ive heard aeromotive FPRs sometimes have problems when cold. Also, IDK how good of a filter is that -6AN Summit Racing high flow filter, I think I will switch back to stock.

Also, I had similar problem when my EGR gasket was leaking. It would hiccup a lot worse and more often. Now, idle is at -24 and if I screw the BISS all the way in car dies. I think isnt a vac leak.

Check out the video and id appreciate any input that will direct me toward fixing the problem. Im lost and Im about to put my stock 275cc in and the stock MAS and just keep the waste gate wide open.

Thanks

Chris

 

[ApexHunter]

Boost leak test?

Was the gauge you were reading vacuum off of standard or metric? 24 inches of mercury would be plenty of vacuum (and probably rule out the boost/vacuum leak test), however 24 centimeters of mercury would be pretty bad (~9 in/merc), unless you have some insane cams or something.

 

[mko]

its 24 inches/hg of vacuum tho.

i pulled the charge pipe before the bov and drove like that, you know the maft translates with or w/o boost, and still does the hiccup.

 

[mko]

can someone chime in please? Its really annoying. I want to fix it.

 

[mko]

So, I did a few things today. I was trying to eliminate things one by one on top of what Ive done so far.

Switched back to my OEM fuel filter /brand new/ and filter to rail line, installed different TB and just in case I switched to 510cc. Well, the thrill of 510cc acceleration felt nice, but my hiccup problem still persist, and its driving me crazy.

Things Im doubting that might be the problem:

Aeromotive FPR, distributor and HG.

Here's a little picture of what is up:

 

[rgeier11]

BOOST LEAK TEST. This should have been the first thing you did. No more posts until you've performed this.

 

[toybreaker]

Check the distributor cap/rotor for carbon traces, and make sure the coil button in the cap is in good shape.

 

[mko]

SO SO SO, I got it fixed. OMG what a relief.

well the MAFT needs a RPM signal so u can tune with the knobs for low, mid and wot, but I dont use it since I have the SAFC do the fine tuning

Anyway, I had the wire tapped in the distributor for RPM signal, and soldered there. i was playing with it today and wiggled the 2-pin plug and it kind of did the hiccup, so I was like hmm and pulled that wire off and tada. so the MAFT was stealin the signal form the ECU to the distributor - making it weak enough to trip the power transistor shut meaning that the level of the incoming signal was so low that the power transistor wasnt able to open at times....doing the hiccup. Thats why it was quiet, and not like a misfire sound /pop/