TCCoA Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
119 Posts
Discussion Starter · #1 ·
Went racing Friday night.

Got real annoyed that the off-idle stumble that I've experienced since day one (in February) was forcing me up to the second light on the tree.

Jump on this pig, and it THINKS about it before it decides to explode with wonderful, set-you-back-in-the-seat-type, acceleration. Also, it "chokes up" when simply revving it from the engine compartment.

Spent Saturday night playing with the car and a code reader.

No codes were read initially. In order to "test" the reader (and teach myself about code readers, as well), I finally decided to MAKE the car set some codes by pulling some connectors. Since OBD-II didn't come on cars twenty years ago, I learned a bunch.

Pulled the MAF connector. No code was set -- but the stumble was completely eliminated. I mean, throttle response was RIGHT NOW, like I would have expected from an injected car.

A short test drive (with MAF disconnected) revealed that throttle response was perfect under driving conditions. However, even with the instantaneous response, the car didn't "pull" as hard as when the MAF is connected.

Return to garage -- still no code.

Yanked the TPS connector. FINALLY, the 'Bird throws two codes on restart. I got the "Low Voltage" error on both the MAF and TPS circuits. A trip around the block show the car runs like crap, "searches" for an idle speed (down to 400 RPM!), and almost stalls off-idle.

Return to garage, reconnected the sensors, and cleared the codes exactly as instructed.

Now the questions:

How can the car bog that badly, and think everything is "okay?" (Suspect it's within factory correct "range"...)

How come the car runs fine (if not as strong) with no MAF? (I suspect a default value is being subtituted...)

How come the disconnected MAF never set a code?

How come no codes were set until I pulled BOTH the MAF AND the TPS?

Does anyone have experience with correcting an off-idle stumble by cleaning the MAF? (Don't really wanna screw up an expensive part by accident if I don't have to.)

I'm not trying to modify the intake tract right now, although I do believe the silencer is about to hit retirement age. I simply want to optimize what's there, because I think it should be better.

Thanks for reading all this -- and hope to learn quite a bit more from all who respond!


Blindly stumbling through the basics of computer cars,
 

·
Registered
Joined
·
261 Posts
Definitely clean your MAF. Don't be afraid about messing it up. I was the same way after reading the tech articles. I thought for sure I was going to break the wires. But, when you pull it out of there, it's not as fragile as some say. You can take a Q-tip to it, no problem. Just don't drop it, or take a jack-hammer to it, and you'll be all right.
 

·
Registered
Joined
·
1,431 Posts
After you clean your MAF wires...

with windex and a Q-tip...I'd make sure to clear your computer
so that it relearns from the, once again, correct MAF signals...
 

·
Registered
Joined
·
130 Posts
MAF Cleaning

Periodic cleaning the MAF is a good thing. If you're using a K&N air filter, some people believe that the blended mineral oils cause the MAF to get dirty sooner, as compared to an untreated paper filter. I haven't performed any tests, but I do clean my MAF every 20K or so.

I prefer NOT TO USE Windex, just beacuse it can leave residues. I use a cholrinated solvent (then again, I have access to a chemistry lab so it's readily available to me :D ).

But a good substitute is acetone (fingernail polish remover; also sold by the quart in hardware stoers). It doesn't cost much and is very effective at removing the grime from the wires. I do not recommend using solvents like turpentine or paint thinner since they may cause any grime on the wire to gum, rather than dissolve it.
 

·
Automatic Weapon
Joined
·
1,219 Posts
Wait a minute, Steve. You are running 16.9 in the quarter? I realize you do not have all the mods in the world done yet, but 16.9....what elevation are you at?
The Mid-America Raceway is at 500 ft above sea level, that should be near you, is that the one you raced at?
 

·
Registered
Joined
·
1,431 Posts
That's why I wipe down the wires with

birdofprey said:
Periodic cleaning the MAF is a good thing. If you're using a K&N air filter, some people believe that the blended mineral oils cause the MAF to get dirty sooner, as compared to an untreated paper filter. I haven't performed any tests, but I do clean my MAF every 20K or so.

I prefer NOT TO USE Windex, just beacuse it can leave residues. I use a cholrinated solvent (then again, I have access to a chemistry lab so it's readily available to me :D ).

But a good substitute is acetone (fingernail polish remover; also sold by the quart in hardware stoers). It doesn't cost much and is very effective at removing the grime from the wires. I do not recommend using solvents like turpentine or paint thinner since they may cause any grime on the wire to gum, rather than dissolve it.
a dry Q-tip after cleaning with windex even though any possible
deposits would be minimal. Also, not knowing how acetone will react with a given plastic or surrounding materials I would not use it.
Same goes for brake or carb cleaners. The wires clean easily,
strong chemicals aren't necessary in my experience - so far my
MAFS have all performed properly after cleaning.

Hope this helps,
 

·
Registered
Joined
·
119 Posts
Discussion Starter · #7 ·
CHA-CHING! (long, but necessary)

I KNEW YOU ALL WOULD RUSH IN TO HELP!

THANK YOU! I'm tearing my hair out!

First -- Big Al -- Yes sir, my best ET/MPH is shown at the bottom as part of my signature. A coupla quick details: It's been over two years since my last "trip down the strip", and I will admit that I sucked at the start (plus frigged up my own head by running through the staging lights -- at least I figured this out before anyone had to knock on my window!).

I went for "Test-and-Tune" at Gateway International on Friday night (only to be told they do this on Fridays anymore) so I was really racing. I made five runs (and got through the first three (out of five) rounds of eliminations, before being taken out by "Mr. Dirt", who eventually won the night -- AND who apparently TEACHES poeple how to drag race, and who also apparently writes for two drag racing periodicals).

Runs went like this (in order):
17.064 @ 83.01 (1.622 R/T -- sheee-yut, I suck!)
17.021 @ 82.54 (.972 R/T -- I STILL suck!)
16.955 @ 82.88 (.855 R/T -- still bad, but I can PICK a dial-in: 16.95!!! Win!!!)
16.959 @ 83.00 (.926 R/T -- wrong direction, but dial-in was 16.92. Win!!!)
16.922 @ 82.95 (.752 R/T -- hey! better! dial-in STILL 16.92. LOSE -- "Mr. Dirt" R/T .543)

One thing's for sure -- I put a dial-in on the window, and then I RUN IT!

Maybe I oughta soap up 12.00 on the window...LOL

Also, in the whining column, it was 85 degrees (and didn't cool off much) and it was probably the same number in percentage humidity. And the car is flat-out STOCK, except for the tranny, which I did simply because I have enough experience to know that the 4R70W won't like being hammered without "THE" mod.

However, I'd also EMPTIED the car (except for my small fire extiguisher, goes everywhere), and even removed the spare tire and stuff outta the trunk.

So -- have I been TOO honest? I mean, these figures are REAL.

Should I learn how to lie (like in the "Kills" forum, lol)

Or -- do I just suck, and should stick to brackets?

Or -- should I call "Mr. Dirt" and sell him my car?

I dunno, I cut my reaction time by more than half (not real tough, I admit), but the car was SUPER-consistent, leading me to believe that I have gone as quick as this car will go.

And, it ain't near fast enough for me.

WHICH BRINGS ME TO THE TOPIC OF THE POST -- THE HELLISH STUMBLE BOG,

Thanks again to all who responded!

I did do a search on cleaning the MAF wires prior to this post -- and heard that carb cleaners and solvents weren't recommended, and that cleaner residue is a concern. My concern was specifically about the "reward' for mixing it up with my MAF.

MagerThom -- I'm gonna keep your Windex idea "in reserve" -- but I WILL definitely clear the computer after I clean them. You've been a ton of help in the past, and will continue to look forward to your posts!

Birdofprey -- since I don't work in a chem lab, and since I use brake cleaner for everything (no residue, nice evaporation, no clean-up) -- I thought about Brakeleen. But then I thought again, and ran down to Radio Shack and picked up a can of TV tuner cleaner. Whattaya think? Time to hose 'em down?

How 'bout you, About2beBAD? How often do you clean 'em up? And, what is your chemistry of choice?

And -- any guesses on the lack of codes would STILL be hugely appreciated!


(groan) I'll probably STILL be slow even after I hang the AED 'charger (next year?),
 

·
Registered
Joined
·
25 Posts
Cleaning MAF Sensor

Everyone should clean the MAF Sensor on some sort of regular basis. Check out the tech articles but I would also suggest getting a jeweler's loop or good magnifying glass to inspect it. 10x magnification works OK but 15x or 20x would be better. Inspect it under really good light, sun light works best. Also, with the spray contact cleaner from Radio Shack works pretty well but you will have to apply it several times if it is really dirty. Use Q-Tips very gently. Once you see the wire under magnification, you will know when it is clean.
 

·
Moderator
Joined
·
8,239 Posts
Fellas,

I've used windex and qtip. It works, but some electronics cleaner is better. Just spray it on, and the gunk practically melts away. Most of the time, you don't have to wipe it with the qtip, because the cleaner evaporates quickly, leaving no residue. If you insist on the qtip, be careful not to break the maf wire, or you will be buying yourself a new maf.

ALso, nobody mentioned to reset the EEC after you do this. This will clear the trouble codes. If they come back, see what they are, and go from there.

BTW- I had MAF low voltage error code once. It turns out the maf plug had came partially unplugged. Plugging it in fixed that problem right away.

JH
 

·
Registered
Joined
·
803 Posts
Have you checked to make sure the octane plug jumper is in place?
there should be two jumpers near the EDIS box by the Aircleaner box. One is the SPOUT ,the other OCTANE adjust. Make sure both are in place.

Can you monitor TPS voltage? You may have a weird dirty signal coming from the TPS and it is affecting your tip-in responsiveness.

Those times suck. You definitely have a problem somewhere. My '95 , basically like yours, in totally stock condition at 6000 feet above sea level ran 17.20s.
After all the normal easy mods, intake, exhaust, J-tune, MAF and Mustang TC, I was able to get down to 16.46.
Best it ran at near sea level , Ennis TX, in that setup was a 15.18.
 

·
Astrophysicist / PostWhore
Joined
·
2,028 Posts
EEC/computer reset

JustinH said:
Fellas,

I've used windex and qtip. It works, but some electronics cleaner is better. Just spray it on, and the gunk practically melts away. Most of the time, you don't have to wipe it with the qtip, because the cleaner evaporates quickly, leaving no residue. If you insist on the qtip, be careful not to break the maf wire, or you will be buying yourself a new maf.

ALso, nobody mentioned to reset the EEC after you do this. This will clear the trouble codes. If they come back, see what they are, and go from there.

BTW- I had MAF low voltage error code once. It turns out the maf plug had came partially unplugged. Plugging it in fixed that problem right away.

JH

quick (and dumb, almost newbified in nature) question:
how do i reset the computer? I have a lot of cleaning and things to do with my car this weekend, so i figure i'll clean my K&N filter and my MAF. I will need to go and get some contact cleaner...any suggestion on the best kind, or just go to radio shack and ask for contact cleaner? once i do that, how do i reset the computer so that it gets 'clean' readings?


throw me a fricken bone here
lol...sorry...too much austin powers...

any help is appreciated.
 

·
Registered
Joined
·
119 Posts
Discussion Starter · #12 ·
Clearing the 'puter...

...is real simple.

Just disconnect the negative battery cable for, like, five minutes. Not one do do anything half-hog (except drag racing, apparently), I left it off overnight.

Seems like everyone has their own chemistry of choice -- I used Radio Shack TV tuner cleaner. And the black stuff that came off those wires was amazing.

SPOUT and OCTANE adjust are in place, and tight. I do (did) have the ability to check the TPS voltage (borrowed scanner), I just can't remember what those readings were. Moreover, I wasn't sure of what they were SUPPOSED to be -- I was just trying to learn HOW to use the darned thing before I lay down big cash to get one of my own. Decision made, saving up now.

With the tip of a weird, dirty signal, I got something to "go after" this weekend, when I can re-unite car and borrowed scanner.

It is agreed, my times suck. I'm hoping for a "Most Improved" award some day. :D


Can't do anything but get better from here,
 

·
Astrophysicist / PostWhore
Joined
·
2,028 Posts
Re: Clearing the 'puter...

Chlngr said:
...is real simple.

Just disconnect the negative battery cable for, like, five minutes. Not one do do anything half-hog (except drag racing, apparently), I left it off overnight.

Seems like everyone has their own chemistry of choice -- I used Radio Shack TV tuner cleaner. And the black stuff that came off those wires was amazing.

SPOUT and OCTANE adjust are in place, and tight. I do (did) have the ability to check the TPS voltage (borrowed scanner), I just can't remember what those readings were. Moreover, I wasn't sure of what they were SUPPOSED to be -- I was just trying to learn HOW to use the darned thing before I lay down big cash to get one of my own. Decision made, saving up now.

With the tip of a weird, dirty signal, I got something to "go after" this weekend, when I can re-unite car and borrowed scanner.

It is agreed, my times suck. I'm hoping for a "Most Improved" award some day. :D


Can't do anything but get better from here,
ok...now i feel stupid.....that easy eh...
i thought i'd have to dig out the computer from the kick panel and stuff...

argh.
im an idiot.
lol

thanks for your help!
 

·
Registered
Joined
·
803 Posts
Good luck on your hunt.
Another thing that I think you might want to check, and can possibly clean.
IN the throttle body throat there is a port that bypasses air around the butterfly for idle control. There is a needle valve to adjust this flow rate. If the needle vavle is clogged then the IAC valve has to do all the work and it may be responding negatively to opening of the throttle. Spray cleaner might get the crap out if it is in there. I have found that once it is clean, if you disconnect the IAC valve, start the car and just get the car to idle at about 500 rpm without anything else on, then when you hook up the IAC it works more precisely.

As for resetting the EEC. Take out fuse 15 from the underhood fuse block, KAM fuse, (keep alive memory) , crank the motor for a second or two and then reinstall the fuse. Memory is cleared.

rm
 

·
Registered
Joined
·
267 Posts
i try to do it a couple times a year. you'll need a T-20 tamp proof torx bit. dont lose the oring when you pull the sensor out and try not to let the oxidized aluminum get into the intake. suck it up with a vac. acetone works the best (hardware store), just try to minimize the amount you get on the black plastic. use a cotton rag and just let the weight of the cloth do the work. make sure everything is clean b4 it goes back together. make sure both screws are snug before you torque them down and dont go too tight. just pull fuse 15 under the hood, plug it back in and your good to go. just let it idle for a few minutes, then do some normal city and highway driving so it relearns properly. make sure plugs and plug wires are good. fuel & air filters and timing, that sorta thing. clean injectors by putting some cleaner in the tank. you should run mid 15's if all is well.
 
1 - 15 of 15 Posts
Top