NOrmal Idle, but it fast idles when cruising

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

Any help will be appreciated.

Sounds as if a coil of your idle air speed motor has gone...
The stepper motor has two coils, one for stepping out and one for stepping in...
http://www.scribd.com/doc/4570538/Mi...63-4G64-Engine

On side 11 F-59 you´ll find a way to measure if it´s working....

I dont have these. Ive installed a block off plate

What type/number off engine you have?

4g64 w/ 1g 60mm TB

So, I ve been 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 due to a misfire that can not be detected since I have the OBD1 codes. And then I remembered 4GRim had that kind of problem. Ill take a look at them tomorrow since its getting dark already

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.

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

http://www.youtube.com/watch?v=HQhlSFufjeU

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.

isc, iac, plugs and maybe wires.

No ISC or FIAV
Changed plugs today
Wires are 6 months old

Seems to be idling just a bit to high... can you set your idle lower thru your maft gen maybe?

Could your distibutor be going bad?

Quote:

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Originally Posted by phizzalot

Seems to be idling just a bit to high... can you set your idle lower thru your maft gen maybe?

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Ive set it a little higher, cuz its winter and I dont have the bottom part of my TB, so its easier to start in the morning.

Quote:

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Originally Posted by Shadow19

Could your distibutor be going bad?

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Its 2 year old, but it could be. I have to go to Skrap's, he has a brand new one.

id try that.. im trying to wrap my brain around this... maybe its an intermittent crank sensor issue?

I wouldnt worry about the idle. Does it affect driving when cruising? Since it happens in closed loop only, I would look at replacing your o2 sensor.

all the time Seth, just randomly, not in pattern or anything

Try swapping out the o2 sensor first.

Quote:

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Originally Posted by seth98esT

Try swapping out the o2 sensor first.

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exactly what I was going to say! remember from my thread dude.

I dont think its the distributer becasue It was happening to me for 3 or 4 months before my distributer went... I am telling you it has to do with your TPS... It did it to me right after i messed with mine.... I would also chec k the o2 sensor also... But I highly doubt its your disrtiobuter. If it was an crank sensor would a cel throw??? I'm really not sure.. MKO if you want to come down today I can throw that new distributer in and try it out but you cant keep it lol. Im going to be needing soon considering that I am going to be running soon!!!!!! Text me... I get out of work today at 1:00pm

Quote:

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Originally Posted by skrap

I dont think its the distributer becasue It was happening to me for 3 or 4 months before my distributer went... I am telling you it has to do with your TPS... It did it to me right after i messed with mine.... I would also chec k the o2 sensor also... But I highly doubt its your disrtiobuter. If it was an crank sensor would a cel throw??? I'm really not sure.. MKO if you want to come down today I can throw that new distributer in and try it out but you cant keep it lol. Im going to be needing soon considering that I am going to be running soon!!!!!! Text me... I get out of work today at 1:00pm

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LOL the possibilities. My distributor went bad when i first got my car and it was a fucking nightmare. Drove it around the block and home from the place i bought it and nothing wrong. But as soon as i put insurance on the bitch 2 hours later after it sat the problems began. No CEL. My car would just shut off on me at stop lights and take off. Took it to my friend and we spent WEEKS trying to figure it out and we couldnt. Took it to the dealership and they couldnt figure it out so on a last limb i replaced the distributor and that was the problem then 2 weeks later the bitch started doing the similar things so with the assumption that the distributor couldnt have gone bad since it was brand new we started the whole process all over gain......... Anyways there is my story about distributors and how bad i fucking hate them. On the contrary i really hope you get this worked out man. I know what its like to chase problems with no lead and it sucks very bad.

dude, its either the iac or tps thats it.........................

Dude i dont have an IAC.

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 /if someone has a spare one, gimme a holla/ 94 MPI relay is a single piece with 8 pins.

So nothing, New O2 sensor and still nothing. Im thinking the worst - bad HG

Still havent got around changing the MPI relay, Distributor or ECU.

And on top of all this, my windshield cracked.

Im tired of this car

One more thing. can the lower thermostat cause this, I mean switching back and forth the low and mid trims. I still got the 170 deg thermostat in

i think if it were the bad head gasketunder boost would be shitty too.. it goes rich so maybe a leak behind the MAS idk its weird chris wish i could help you more

if it were a head gasket there would be a hell of a lot more issues than idle. did you reset the ecu after the o2 sensor? that is vital. compression test homie. report back.

Dont have a compression test tool.

anyway, I was outside and retarded timing a bit and now it does it less, but still does it. IDK

Well did a compression test - 200 across the board. Not bad when having 230k on the clock.

So its either fuel issue or more likely a spark issue - dizzy is going bad

So, I think Ive found what is causing this. Ill post later when i fix it.

Coolant temp switch????

ok, a little update.

So, I zeroed out the SAFC and reset the ECU. It idles like it used to before I installed the SAFC, around 18-19, but I has no hiccup anymore. I drove around and it behaves ok. IDK if its the wet/humid weather, but it acts like i dont have a MAFT - when I shift AFRs go straight down to 11.0 for a second and then recover back to normal. It didnt do that in the summer tho. Im confused. I may switch to draw thru setup instead of blow thru sometime this winter.

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?

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.

so, I put new coolant temp sensor and switched back to my stock fpr, and guess what, its still doing the hiccup. So most likely i have an ignition problem. The distributor is probably going.

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/