ok, so mare car almost died and the check engine light came on while i was accelerating, so i get home and pull the code. code 34. my GM service manual does not list a 2.8L(MPFI) engine in the diagnostic section, it lists 2.5L(tbi) and 5.0L 5.7L (PORT)

the PORT (5.0 & 5.7) says MAF sensor (signal voltage low) i have replaced the MAF about a month ago (because i got the same code and figured it was probably the original factory one and "needed fixin anyway")

the (TBI 2.5L) says MAP sensor voltage low.

do i have a map sensor. wich one of thses aplies to my 1986 MPFI/TPI 2.8L v6?

what is wrong with my car? please help me.

 

From my Helms manual for 2.8

034 = MAF sensor, low

MAF sensor disconnected, faulty relay, or signal circuit shorted to ground.

Also says a loose or damaged air duct can cause this code.

 

thankyou. i have a custom intake made of pvc that has a tendancy to disconect every once in a while. i should glue it together to solve that problem.

but if i have a MAF do i have a MAP too? i thought it was one or the other...

 

No.
MAP = manifold air pressure sensor used on the 4cly eng. GM calls it a Barometric pressure sensor.
Our engines use MAF = mass air flow sensor

 

i thought so. also, since my MAF is new i think it is the wiring. how much is involved in replacing the wiring to the MAF. do i haveto replace the entire wiring harness?

 

i had to replace the wiring to my tps, i just followed where it connected to the wires it branched off from. then went to the wrecker and cut it off a car with low miles and a good looking harness. then souldered it in by heating up the wires and touching solder to the wires, not just melting the solder onto it like wax.

it fixed my problems.

 

cool, how hard would it be to replace the COMPLETE wiring harness? i have thought about buying an all new one. that way i know that my wiring is good. the current harness is 19 years old, thats old wiring, and it has been exposed to alot of heat. i think it would be a big step toward returning my car to showroom glory.

but would this be a huge pain in the *** or what? under the hood would not be so dificult, but does it just go through the firewall to the ECU or does it connect to a bunch of crap behind the dash i would have to trace as well? anyone done this before?

 

Haven't priced wiring harnesses lately have you?
To extreme a move to solve your problem.
Wires die from age (like on 1953-1982 Corvetes!!!!).
Your car is so young!
PLUS you live by the ocean? I thought not!
IF ya need to patch in the wires and be done. Use shrink wrap over connections soldered. And it could also be a bad replacment sensor. It's happened to me. I bought a replacment & it was bad. Swapped for another no problem. AND since warrantied, easy low cost solution/fix.

 

keep an eye out for Jerriko on e-bay (yeah, same dude who welded the 2.8/3.1 rubbers on a tpi mid section intake). He parts out the firebirds and usually has the complete harness for sale.

 

yah jerriko is awesome

 

well they are discontinued anyway...... so shrinkwrap huh. cool, i will get some in red to match my sparkplug wires. thanks all for the advice.

 

Check around this Forum, we were talking about this few months around. Otherwise let me know so I'll post a 34 CODE diagrams. I had have the same problem too, it was not the MAF sensor itself, they were the fuses at the engine bay and and fuse cluster.

 

for 1985. 1986 might be similar:

http://memimage.cardomain.net/member...40_95_full.jpg




http://memimage.cardomain.net/member...40_96_full.jpg

 

Check the connections at the MAF and at the relay. I had a code 34 because the connections at the MAF relay were gummed up with dirty dielectric grease (or something of that nature).

 

project, thanks, i have that book (1986 version) but those pics will be helpfull to anyone who looks at this later.

i will definatly check the wires carefully before i go cutting a soldering. however i do have a theory. my dad was talking about being "bit" by spark plug wires while the engine is running, he says that they carry enough current to give you a good zap even through the insulation. this got me to thinking, when i re did my plug wires i did not run them in the stock location, i ran them around the outside of the exhaust and away from the engine block. the passanger side set runs right along the wiring harness for about six inches. could this be interfearing with the signal going to my ECM ?

 

good call

relocate the spark plug wires and you tell us!

 

I wouldn't rule out interference for sure. You'd be surprised what the causes of problems are sometimes.

 

yes, I was intamtely introduced to the wonders of an HEI ignition on my 77T/A while adjusting timing. Needless to say,
I've not grabbed teh distributor cap barehanded ever again while the engien is running

 

well i gave it a good reving up and let it idle for about 3 minutes. light never came in and the car never died. i think i fixed it. i will no for sure once i actually drive somewhere.

also, it was not ONE of my wires being close to the harness. it was all six of them for a total af about 3 inches of overlap. thats alot of interferance.

that brings me to another question, how come the wires don't interfear with each other?

 

they can, thats why you have wire seperators.... right?

 

.....right, that is why i just ordered some . they are red!

 

well, problem not solved. still dies. i am not going to get time to work on it till friday, i just have to drive it like this....

 

you dont have a washable air filter such as a k&n filter do you?

mine got oil all over the maf and ruined it. had to even clean my spare with compressed air after i thought about it and figured out what was doing it.


my mechanic unplugs the wire and twists it clockwise when he thikns the wiring it bad, the wires inside will tighten up and if the problem goes away you know to replace the wires.

i would do a tuneup on your car, plugs, clean the cap and rotor, clean the iac, everything that can be done cheap.

check the tps with an analog multi meter

then disconnect the + batt cable to reset the comp

and drive for a bit.

 

yes i do. how do i prevent my MAF from getting ruined?

also, i am in the process of a full tuneup. i have replaced the plug wires and have a new cap and rotor and new plugs, just waiting for good weather.

 

IS YOUR COIL ORIGINAL?

 

you gotta clean your current maf with compressed air and put in paper air filters. no real way around it.

it may be your pickup coil? or your ignition coil as well like ked sugests. i had a problem with the pickup coil years ago

 

The clue to me was the inclement weather mentioned problem.
When it's wet a flaky coil, ON IT'S LAST LEGS!!!!, SEEMS to really die more.
Go score another coil to test & see if that's the real problem.
It may well so be.
ESPECIALLY IF ya still using the original coil.

 

go brab 2 or 3 coils from the junk yard. just to test and see if it is.

 

Let me also toss this out.
A K & N Filter in the air can of a FIREBIRD can't/SHOULDN'T BE DOING ANY DAMAGE.
IF ya soaked your K & N Filter SO MUCH that excess oily fluid getting to MAF you have a problem!
A Camaro air fliter wet with K & N fluid oversoaking a MAF, SURE that's "easy to do". A Firebird with that K & F Filter in there? Nearly next to impossible.
I know. I've got a K & N in my Firerbird & NO problem whatsoever. I do also run mine really "dry" very little lubricant on the filter.
I think your problem is LOW VOLTAGE to the MAF assembly which in return gives/sends out a "problem signal".
Low voltage signal is caused by engine electricals not up to par.
Causes of that is a worn down alternator & poor condition coil, causing poor engine idle/dying. And yep, that can also include a worn down internals on distributor shaft (pick up coil).
I'd start with a few more basics before ya say your MAF is the problem (unless ya get other to test for free due to warranty). AND have ya cleared out the previous trouble codes yet?

 

ok i forgot to mention i also purchased a new HYPERTECH 55,000 volt coil; to replace whatever piece of crap is in there now. just waiting on the weather

as for a "pickup coil" i have never heard of this.

and as far as the intake is concerned it's not in a can. click the "custom cold air intake" link on my sig or click HERE to see what my intake looks like. actually screw that. i'll attach a bigger picture here.

as for the oil thing i just used the stock ammount of oil that was on it. tommorow, when i work on the car and install all this stuff (knock on wood for the weather) i will wash it in the dishwasher (needs a cleaning annyway, no longer makes that badass hissing sound). also, is it ok to leave them oil-less?

 

I use mine both ways. Current one in the Firebird air can is oil-less.
Forgot about the air intake set up.
No on dishwasher.
Keep the fabric intact longer if ya do it by hand/low water flow method.
Try the coil & I'll bet you may solve it that way.
Pick up coil is the circle item on base of distributor which is only replaced by unit outta car pulling apart the whole distributor. Your car could be at the point of the ignition system rebuild. Seek out the distributor rebuild tech thread somewhere in past.

 

so i DID have a stock coil. i had to remove the entire bracket to put it in a vice and drill those damn rivits. what a PITA.

also i found and fixed a small vacuume leak. and caused another.

i am going to need to buy some new vacuume line and re run some stuff. i might just re-do all the vacuume lines under the hood. only thing i worry about is all the hard lines, where do you get that stuff. i am just so tired of breaking them every time i touch them. it is so frustrating.

also, new plugs, new coil and new cap did not fix code (yes i cleared them) so i will need to re-wire that MAF wire. but the weather has gotten a bit icky today, perhaps tomorrow before work i can hit that up.

i'll keep everyone posted as to progress and try to get a picture of my vaccume line misfortune. that way if it's a useless one you all can tell me to just cap it off.

 

5/16" windshield wiper hose is your best friend as is 1/4' windshield wiper hose.
To test new coil do as I did, just click/clip it in and see if car runs better. I'm sure it will. Then remote mount coil as I did and be done. Leave old one there as a "just in case"!

 

well i allready bolted it all back up. but the next time i replace my cap/coil. (every 30k right?) i will go to the coil-in-cap style.

vaccume line: thanks for the sizes, but what about the hard line? how do i replace those?

 

You don't replace hard lines.
You just patch & be done. 5/16" windshield wiper hose & spit to lube ends to slip together.
The coil in cap is the 70's GM V8 set up not this ride of ours.
Replace cap when necessary.
Replace coil when necessay. Your last coil ran for how many years?
Below is a picture of a 1985 stand alone one year vacuum hose set up. Your ride is based upon this hose routing, yet different.
Fixing vacuum leaks is oneof the best things one can do to these V6 engines.

 

there is no better picture of that anywhere is there?

 

SO FAR Nope!
You can work forward from this
Just work with all the known connections and work backwards to the varibles.
When I did my initial swap boogie I had NO MAP to work with and it only took me a whole day of taking my time.
Unless someone else can volunteer one, this may be it for ya!
Unless ya want smog routing map for a 2.8 carb'd F body or 2.8 S-series. Those I do have!
Actually that may help ya due to the 2.8 carbd has the AIR pump & those damn tubes on the maifolds.
But connections to AIR smog pump is easy to hook up, those hoses fall into place, also.

 

If you still need a better pic in a couple days, I can try to take one from my car on Tuesday.

 

YES. if not for me for those who follow. think of the children..... the children!!!!

 

How about a stickie of the smog routing maps?
I'd contribute ones I have.
And VOLUNTEER SOMEONE ELSES! that I often use!

 

ok, i went to do my pre-work survay of the situation. i start looking at the wires around the MAF. since i am going to re-do them. there are three wires going to it. an orange w/blk stripe that goes from MAF to some box. (pictured) and a thin black W/grey stripe that goes away along the harness (presumably to the ECM and thus the signal wire) and a third black wire that goes to the box as well. does anyone know what this box is (looks like a relay but for what?) and could it be the cause of my problem?



and for all of you that are just iching to see what my plug wires look like with there spiffy new sepperators, well i snapped a pic of them as well.



they look pretty swell yeah. i got the v8 set specifically so i would have an extra loop to use with zip ties.

 

IF I am right that is a junction box of power.
IF I am right I had a crossed wire there that kept car running even after I turned off key.

 

junction box of power, is that anything like the ORB OF POWER :HAIL:

 

It's one of the junction of power hot spots that a lots of power from car runs thru.

 

That's just the MAF relay.

 

On Firebird Front passenger corner by rad on the rad support is a juntion block. That was why I mentioned my choice of what it is.

 

I won't argue cause I don't have a bird, but maybe we can consult a bird Haynes manual or a bird Helms manual. I know the exact same box on the Camaro is called the MAF relay (cause I had problems with it) and in fact I think it's the same relay as the fuel pump. Although I'm still kinda foggy on the reason for having a relay for the MAF...

edit: KED, the block with all of the red wires is a junction block. The box that is shown in the second picture with the two plastic clips on top is the MAF relay. I'm not sure if I'm making much sense at this point as I've just celebrated "School's out forever" with some beer and wine.

 

id also drill and tap a hole in that pvc pipe for the IAT sensor you have ziptied to the fender

 

ok i replaced the wire from the connector all the way to where the harness enters the fenterwell. (about 2.5 feet.)
i am still getting a code. should i re-do the wire all the way to the ECU or replace the MAF sensor.

also, i was looking for my recipt and i can't find it. the people at knechts (kreger/checker) said that i need to talk to the manager about a replacement. that sucks cause he will probably say no dice. i might have to spend another 60 bux.

 

have you tried blowing some compressed air over the contacts and internals of the maf sensor?

that worked for me... i still think theres K&N oil on the electronics in there.

air is free

do it