Normal Idle, but drives shitty /now with video/

[okm12346]

Im lost. So I got all AFR dialed in, and my idle is now steady /no fast idling/ at 14.7. If I hold the gas pedal at 2k the RPMs will start going up and down, same thing at 3k and 4k.

When I cruise, Ill get that hick up for a moment at around 10% throttle or mild acceleration just like the throttle position switch gets closed and cuts off the fuel to the engine.

My first guess was the TPS, so I found all tutorials about adjusting the TPS and followed step by step. Now the voltage of TPS is 0.65V.

Also I iadjusted the SAS bolt to spec according to tutorial.

After all that It will still do that hick up at some point. I noticed that when it does it my AFR jumps 3.0 numbers to the rich side /lets say 15 at cruise and it jumps to 12 for a moment/ and it will recover to normal again. Also noticed that when I let off the gas it takes some time for the AFR to go in the lean side /20/. It takes a 3-5 sec to do that.

First thing tomarrow is to get new TB gaskets. i went thru 3 TPS so far and same thing happens. TB was rebuild 3 months ago. Its a 1g TB with 2g 4-pin TPS

Any help will be appreciated.

MOds: s16g, 2.5'' ICP, Evo3 Mani and O2 housing, 3'' core FMIC, 450cc, MAFT+SAFC, 1g BOV, FIAV block off plate
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[Backinajiffy12]

What do your plugs look like? Could be a boost leak. and are you throwing any codes?

 

[okm12346]

This was exactly what i was thinking. I gaped the spark plugs, but I never put the new turbo ones. And maybe thats why my AFRs go to rich, because it sees the unburned fuel. No no codes at all, and no boost leaks. I think OBD1 doesnt have misfire code, so no, no codes

 

[Backinajiffy12]

Ok what kind of plugs are you running?

 

[okm12346]

ngk bkr5e stock galant plugs

 

[Backinajiffy12]

With the upgrades on your car I would upgrade your plugs to either ngk bkr6e's or ngk bkr7e's the 7's might be a bit much.

 

[okm12346]

I still have them in the car, but never got around changing them. Will do tomarrow

YouTube - Bogging at 0:32

You can hear it bog for a moment at 0:32 and the AFR drops and then recovers. It usually happens when cruising. under acceleration it goes smoothly.

All my efforts to change the spark plugs were unsuccessful. The new bkr7e were bigger for my spark plug socket, so i went i got 13/16 from pepboys. Well now the new socket doesnt fit the spark plug tubes.

 

[Shadow21]

It could be your plugs or a boost leak as well. Or maybe your SAFC could be going bad?

 

[Backinajiffy12]

All my efforts to change the spark plugs were unsuccessful. The new bkr7e were bigger for my spark plug socket, so i went i got 13/16 from pepboys. Well now the new socket doesnt fit the spark plug tubes.

If they dont fit then they are the wrong ones. just go with 6's instead of 7's

 

[okm12346]

Someone please say something!

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

YouTube - bogging 4g64

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.

 

[Shadow21]

Ok man.. Just doing some thinking check your EGR valve.. Ive had problems with mine that were similar before.

 

[okm12346]

I'm open to suggestions

 

[Backinajiffy12]

Do you have a GM MAF trans

 

[okm12346]

^Yes I put it in Mods list in first post.

Vacuum looks healthy at 24


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 ### 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

 

[->PrOjEcTGS<-]

It seems like everytime it "hiccups" your vacuum goes down. This is a missfire of course. And it's an ignition misfire and not a fuel missfire. This is because if it was a fuel missfire then your AFR would go lean and not rich. This is indicating that it's not firing on that cylinder and the fuel is getting expelled without combusting causing your WBO2 to read the extra fuel for that cycle. If it was a fuel missfire the cylinder would missfire due to a lack of fuel and the WBO2 would read lean because the fuel was not present and did not burn = lean.

So, this points to an ignition problem. Random missfire.

 

[okm12346]

I like your answer. Thank you! Finally someone is giving me an answer with some meaning

 

[Shadow21]

Any update man? Ive been trying to think and im drawing a blank.

 

[okm12346]

So, I think i've found what's causing my problem. I used to have the same symptoms when I had a leaky EGR gasket, same hiccup, but a lot worse and often since car was still n/A. It's post MAS leak related.

Found this post:

I asked this same question awhile back. First off adding a MAFT in a blow-thru set-up will create a major boost leak in non-boost conditions. The reason for this is that during these conditions, the PCV valve is open and is pulling fresh air from the VC port. When using a stock MAS, the VC port is routed back after the MAS, which would make it a closed system. After moving you MAS to the UICP, the system is no longer closed and the air that it pulls in from the intake will now be unmetered making it a boost leak. The way I solved this problem was putting a straight barb fitting on the VC instead ot a PVC (or drilling it out), and routing both lines to a catch can. I went one step further added another line from the catch can into the intake so the the vapors could be sucked back into the combusion. You can add larger ports to the VC if you are still having high crank pressure.

The factory setup is ideal. It pulls the crankcase pressure out under vacuum and under boost, and doesn't rely on the pressure finding a way out.

I will do that tomorrow and post again.

 

[mko]

any updates? I'm getting the same thing

 

[okm12346]

Can we get wisemen on this matter please? This thing is annoying. Ive been talking to mko and since he lives close we met and his car does the same thing.

So far, i Havent messed with fuel system only. Upgrades i have done to it:

Aeromotive FPR, Evo9 pump /not rewired/, braided lines,summit racing high flow fuel filter, earl's 6an fittings, fuel rail fittings.

I replaced the main ground wire today, and still does it.

i was told it could be clogged cat. I have 3'' high flow magnaflow cat and 3'' cat back. still have the silencer.

It really weird. i dont hear any popping or misfire. its very quiet and muffled like its a post MAS leak. It usually does it at 10% throttle and when i keep my foot steady. If I accelerate its fine. Its random, not it pattern. It happens more often after its been in boost. Idle is at 22hg/inch. I removed the charge pipe before the GM MAS and still does it. I was having problem with one of the TB nipples, it was clogged, but I fixed it. The only other thing i can think of is bad TB.

Could it be some kind of pre-ignition?

 

[mko]

yes, can a wiseman help with this issue? Thanks

 

[okm12346]

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.


C'mon guys, help a brother out! Its like Im answering my own questions. It's no fun

 

[okm12346]

SO SO SO, I got it fixed. 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/