mis-firing and bucking

[Blackened302]

thanks for the heads up, JT. do you happen to have the correct firing order?

cleaning the sensors (iac, tps, maf) didn't help much (although the maf was pretty dirty). cel hasn't come on since last night, though the code could still be there.

at my mind's end.

 

[Blackened302]

just put in a new ect sensor and the fan seems to be behaving a little better. i would've liked to check the voltage as you mentioned, JT, but i honestly don't have the patience for that right now.

i suppose it would be a good idea to mention that i hear air blowing or maybe even a vacuum somewhere behind the dash. at first i thought it was my a/c on, but it was off. i've heard it a few times these past couple days, but i don't remember whether it's constantly on or sporadic. thought it may be the pcv, but that's on there and connected. Nacho suggested it may be some holes behind the heads for the egr, but i'm not sure if the gt40p heads have that.

thoughts?

 

[Blackened302]

could the PIP have anything to do with this?

 

[HISSIN50]

thanks for the heads up, JT. do you happen to have the correct firing order?

See the bottom of the page.


I think if it was the PIP, it would get worse. Stranger things have happened though.

If you have a vac gauge, toss it on the intake. With a stockish cam, you should see more than 15" hg of vac at idle. Now if you turn on something like the vent or AC, if the reading drops, there might be a leakie inside the car. I'd wanna track this down a bit myself...........

Good luck Paul.

 

[Blackened302]

just verified the firing order and it is correct according to the link you provided, JT.

i can't think of anything else to check externally. guess we'll have to pull the heads off and check to see that any pushrods aren't bent.

 

[HISSIN50]

just verified the firing order and it is correct according to the link you provided, JT.

i can't think of anything else to check externally. guess we'll have to pull the heads off and check to see that any pushrods aren't bent.

Hold up brah. I'm not sure that I'd go crazy like that yet. What Grady said earlier was what I was thinkin too - this kinda sounds like something non-hard-part related. Otherwise the issues would would not be ephemeral. That's just my keyboarded read on things.

Can you datalog stuff to see if something looks quacky?

 

[Blackened302]

unfortunately, no data-logging--i have the base version of the tweecer. i'm definately going to send it in as soon as i can to get it upgraded to the r/t version.

my brother-in-law (who helpe me w/ the engine swap--and by "help" i mean he did like 90% of the work, hehe) thought the bucking & mis-firing may be because of valves not opening and what not. trust me, i'd really like to not have to tear into the engine again--i wanna drive this thing!!

you bring up a good point, though. the few and ephemeral times that the car runs well and hauls @$$ seems to be some proof that it isn't hard-part related. that is, unfortunately, only about 30% of the time it's on.

aside from pulling the codes again, i can't really think of anything else to check/fix other than replacing sensors one by one, and i don't think that's the smartest and most cost-effective thing to do. hell, even if it doesn't perform, i'd just like it to drive/run well like it should.

 

[HISSIN50]

Paul, If you or your BIL know someone with a scanner (like an Autoxray scanner), that might be an option. You can view PIDs and drive the car. When it acts up, you can datalog a little bit.

Otherwise, I cant think of anything specific to check out.

Good luck brah.

 

[Blackened302]

my buddy owns a diagnostics place, so i'll stop by with him asap. he wanted to give me some $ for the explorer wiring harness and coil packs i didn't use, but i'll just ask if he'll help me out instead.

thanks agian, JT.

 

[final5-0]

Well Paul

As for the valves not being set correctly

Yes ... many times we've seen peeps have them too tight
but
When that is the case ... you got the prob all the time
not
Some of the time

btw ... A compression check will confirm that prob

as for the bent pr's

only the vc need to be removed
and
the heads can stay put

I've seen a coil cause those symptoms. It can be OK
at times and partially break down enough to cause
probs at other times.

Grady

 

[Blackened302]

ah, the coil! hadn't thought of that one (even after replacing the cap, rotor, and wires today). i dind't wanna buy stuff hoping to fix it, but i figure i replaced all that, might as well go get the coil right now--it'll cost me $12.


also got the codes scanned again:
511--PCM ROM circuit malfunction
173--H02S, system rich, bank 1
327--EGR below min voltage

egr i turned off w/ the tweecer, and it probably came on because i was running it on the stock setting today. the o2 sensor code i had gotten before the engine swap.

the one that worries me is the first one--could that be because of the tweecer?

could a bad o2 sensor cause all this mis-firing and bucking?

 

[Blackened302]

just put the new coil in and it helped a little, i would say, but not completely.


still wondering if the o2 sensor (or pcm trouble code) has anything to do with this...

how 'bout any other sensors that i haven't checked? tps? iac? i cleaned them, but they could be faulty from the inside.

 

[HISSIN50]

TPS in theory could cause a chop chop but it's not real likely and it would probably be at the same pedal depression (TPS reading) everytime. Multiple dead spots are uncommon.

IAC = big neg IMHO.

Did you try douching the PIP is electrical contact cleaner? If that helps for awhile, that can be real telling. It only takes a minute to douche it, so it's not a difficult thing.

Good luck.

 

[final5-0]

also got the codes scanned again:
511--PCM ROM circuit malfunction
173--H02S, system rich, bank 1
327--EGR below min voltage

egr i turned off w/ the tweecer, and it probably came on because i was running it on the stock setting today. the o2 sensor code i had gotten before the engine swap.

the one that worries me is the first one--could that be because of the tweecer?

could a bad o2 sensor cause all this mis-firing and bucking?

I can help with the 511 code

Thats usually bad connections on the service port/Tweecer interface

http://eectuning.org/forums/viewtopic.php?t=6831&highlight=511

Now for the 173 code

I ain't up on the pcm codes near as much as JT
so if I get this wrong
JT ... Please clean up my mess here

It would seem you got the rich code cause the adaptive is
pegged due to a lean condition.

I CAN say this for certain ... Your K's will tell you for sure

K's < 1.00 means adaptive is pulling fuel cause you're fat
K's > 1.00 would be the opposite

Maybe you got a small exhaust leak sucking in air which would
drive the reading more lean

Grady

 

[final5-0]

Forgot your last Q about a bad O2

After you get your head together about how to use K values

Here is a simple little test that costs nothing but ......
a bit of labor on your part

All you gotta do is switch sides with the O2's
and see if the readings switch as well

Grady

 

[Blackened302]

thanks, JT and Grady.

cleaning the PIP seems like a quick/easy thing to do, so i will do that in a while. can you tell me exactly where it is, though, please? i've douched everything else (iac, tps, maf, connection to coil, etc) in some pretty good electrical cleaner, and i still have a bit left for the PIP.

my buddy just got a new msd dizzy, so we're gonna try it out on my car to see if that could be it--just to cross that out if it isn't.

thanks for the info on the 511, Grady. i'll clean up the connection today w/ a qtip + electrical cleaner and try to get it to go away.

there is, in fact, a small exhaust leak coming from the headers. i'm giving the copper gasket time to get settled, tightening the header bolts every other day. it's gotten significantly less worse w/ each tightening, so i figure it'll clear up after the next couple.

the K values you're referring to, though: do those show up w/ the tweecer? once i know where to check those, i'll switch sides w/ the o2's and see if the readings switch, too.

thanks, gentlemen.

 

[HISSIN50]

Paul, Swapping the dizzies will be more reliable than douching the PIP. However, the PIP is inside the dizzy bowl. I remove the cap and rotor and start hosing the guts down. If you see (or pickup, with a magnet) any ferrous metal, that's a sign the PIP is worn (often from a bad dizzy bushing).

I very very well could be wrong (I need to wake up and check) but I think 173 is one of them more obscure goofy codes that is what it means - simply system rich. I very well might be thinkin of something else but this is what my gut's teling me.


Good luck.

 

[final5-0]

thanks, JT and Grady.

thanks for the info on the 511, Grady. i'll clean up the connection today w/ a qtip + electrical cleaner and try to get it to go away.

You need to look and see if the Tweecer interface has a clear coating on the
contacts. If so you may need to use something like a pencil eraser to gently
remove the coating while not doing damage to the pcb.

there is, in fact, a small exhaust leak coming from the headers. i'm giving the copper gasket time to get settled, tightening the header bolts every other day. it's gotten significantly less worse w/ each tightening, so i figure it'll clear up after the next couple.

You just can't tolerate things such as this
or
Your tuning efforts will be inconsistent

the K values you're referring to, though: do those show up w/ the tweecer? once i know where to check those, i'll switch sides w/ the o2's and see if the readings switch, too.

thanks, gentlemen.

When you get a chance Paul ........
Look at the info on my site for details and pics

Don't worry

The focus of the info is simple and basic
but
I do think it could help you

Grady

 

[Blackened302]

will do those things, grady--thanks, bud.

 

[Blackened302]

words to live by: CHANGE YOUR PCV when you do an engine swap!

we had bought a pcv but it didn't fit, so we used the stocker thinking it was still good. big mistake. the valve was stuck so it was causing a vacuum leak (so was the #7 header and throttle body gasket) which was tricking the ecu into thinking it was running lean, hence the rich o2 on the #2 bank. we didn't realize this until after doing a vacuum leak test, fuel pressure test, compression test (thankfully wasn't any sticking valves!!) and a diagnostics scan w/ my buddy's $300 tool (he owns a diagnostics shop and definately knows his stuff). the little things, man...

a new pcv, o2 sesnor, and throttle body gaskets seem to have cured the problem. no more mis-firing and bucking, i'm happy to report!! in fact, i even got to enjoy a little track time tonight, but that's for another thread.

still need to take care of cleaning the tweecer connection, but thanks Grady and JT! you guys hit the nail on the head, as always!