I have an '86 berlinetta with a 2.8L V6. This car has no "get-up & go" at all, My little 4 cyl. Mustang will run off & leave this car. Is this engine this sluggish, or do I have a problem? The "check engine" light comes on sometimes, and when I did a code scan, I retrieved a code 34 ( MAP sensor or Mass airflow sensor). The counterperson at Advance auto parts advised me not to buy any sensors until I sprayed WD40 all over the intake & vacuum lines to check for leaks. I sprayed the WD40 and it made no difference. Will a MAP or Mass Airflow sensor make the enging run better, or do I have other problems? I appreciate any suggestions..Please help...

 

If you are throwing codes you have a problem...

 

Are you handy with a voltmeter and test light? If so, here's two bits of information. First is <a href="https://www.thirdgen.org/techbb2/showthread.php?s=&threadid=162251" target="newwin">a link to my major tuneup message</a>, that should cure any power problems you're having.

Second is the "code 34 chart". I typed this up a long time ago for someone, it's straight from my <a href="http://www.helminc.com" target="newwin">GM Service Manual</a> for my '86 Firebird. Also if you go to the V6 forum and search for "MAF", you'll find we have a ton of messages up about that sensor. (Click the <a href="search.php?s="><img src="images/top_search.gif" alt="Search" border="0"></a> button, and be sure to choose the V6 forum from the drop-down box. We have a different sensor than the v8's sensor... v8's use a Bosch "hot wire" MAF, v6's use an AC/delco "frequency film" MAF. Most messages on thirdgen.org that talk about MAF's are talking about the v8 style one.)

Here's the chart:
-----------------------------------------------
DIAGNOSTIC CHART FOR CODE 34 (2.8L MPFI ENGINE)
---------------------------typed by Tom P------

First off, they want you to check out the air intake duct for being loose or
damaged.

Since you are getting the code 34, and no other error codes, we can kind of jump into
the middle of the chart:

1. Ignition off. Disconnect the MAF sensor wire. Connect a voltmeter between the
____harness pin "B" (center) and ground.
_______Less than 1 volt? Go down to "1A"
_______Over 4 volts? Go down to "2"

____1A: Disconnect ECM A-B connector. Check circuit 528 (brown/white, on connector
_________"B", terminal #6) for an open or short to ground. If it's not open/shorted,
_________it's faulty ECM connector terminal B6 or a bad ECM. By the way, this is the
_________MAF's "signal" wire.



2. Connect a test light between MAF harness pins "A" & "C".
_______Light on? Go down to "2A"
_______Light off? Go down to "3"

___2A: Faulty MAF sensor connection or sensor. So since you've tried two sensors,
________I'd imagine the connector's at fault. Try checking for corrosion on the
________connector's pins- I had that happen once. Also, try wiggling the connector,
________and seeing if you get a SES light. If I wiggle my current one, I can make
________a code 34 set, and the car almost stalls. I've gotta get another connector
________from a junkyard... Pep Boys sells new ones, but for an outrageous price.
---------update 10/2000: I replaced the connector (actually, the whole MAF harness!)
---------with one from a junkyard car. No more connector problems!



3. Connect a test light between MAF harness pin "A" and ground.
_______Light off? Go down to "4"
_______Light on? Go down to "3A"

___3A: The ground wire for your MAF, which is MAF harness pin "C", is open. Fix
________the problem with the black ground wire, either it's bad or burnt thru or
________it broke at the passenger-side-upper-frame-rail grounding point (a ring
________terminal on a screw).



4. Disconnect MAF relay, ignition "on" (not "start"). Connect a test light (at the
____relay connector) between CKT 840 (brown) and ground, and CKT 39 (black/pink) and
____ground.

____Okay, now, the MAF relay is located between your air filter box & radiator, on the
____radiator support, I believe. It should have one long black connector to the harness,
____NOT two connectors (one black and one gray)- that ones for your flip up headlights.
---------update 7/2001: For Camaros, you guys have a different location for your airbox.
---------But, the MAF relay's in the same spot, at the passenger side of the radiator, on
---------the radiator support. I believe it's the only relay you Camaro guys have down
---------there; just check the relay for the wire colors I mentioned for CKTs 840 & 39.


____The test on CKT 840 checks to see if voltage is getting from your MAF fuse to the
____MAF relay.

____As for CKT 39, that's controlled by your GAGE fuse. (So that's what it does! Cool.)
____It comes on with the car's ignition- that's why you need the ignition "on". When this
____black/pink wire gets power, it flips the MAF relay's magnet ON, which basically switches
____the MAF on- that's how power gets from CKT 840 to the MAF.

_______Only one light? "repair the open circuit".
__________No light on CKT 840? See "4A"
__________No light on CKT 39? See "4B"
_______Both circuits are fine? Go see "5"

___4A: If no light on CKT 840, find the MAF fuse- it's under your hood, screwed down
________to the upper-frame-rail on the passenger side of the car, closest to the
________headlights. You'll see two little black boxes, each with two wires coming out
________of them, screwed down to the upper frame rail by one screw each. One of them
________has a red wire and a BROWN wire coming out of it- that's your MAF fuse holder.
________Pop the top off to see the MAF fuse. (The holder with red & orange wires is for
________your computer and fuel pump.)

________If the fuse looks fine, try replacing it anyway... I've had that happen to me-
________the fuse looks fine but's really shot. Perform test #4 again. Still no light?
________Probe the MAF fuse holder's RED wire with a test light to ground. This checks
________the MAF fuse holder's connection to the positive-junction-block, located on the
________passenger side of your radiator support. If it's bad, follow the red wire to
________the junction block & fix it. Do test #4 again- still no light? Check
________for corrosion on the MAF fuse holder's contacts. You should get a light by now-
________unless your test light's shot!

___4B: If no light on CKT 39, check the GAGE fuse in the fusebox. As I said up in "3A",
________if the fuse looks fine, try replacing it anyway. Do test #4 again. If you've
________got no light, you get to trace CKT 39 thru the firewall, so hopefully you get
________a light on this one. This one would be a bitch to fix. All I could tell ya is
________that the black/pink wire goes to the GAGE fuse, and the GAGE fuse gets turned
________on when your ignition switch gets turned to "on".



5: Connect a test light between circuit 840 and CKT 450 (black ground wire from the
____relay connector).
_______Light off? See "5A"
_______Light on? See "6"

___5A: Fix the bad ground wire (open on CKT 450) from the relay to the chassis.
---------update 10/2000: This is buried! It follows the wiring harness along the
---------passenger side lower frame rail. You'll have to trace it the whole way. It
---------joins with 5 or 6 other ground wires at one point. Then, after that junction,
---------one wire goes to a ring terminal on the rear driver's side head.



6. Check out the condition of the orange/black wire that goes from pin "A" of the MAF
____connector to terminal "E" of the relay. If this wire is fine (not shorted or open),
____then your relay's bad... you could get a junkyard one but I think a new one is only
____$10 or so from GM.

 

Tom P..you are the Man!!!!:hail: :hail:

 

well i dont no if u know this yet, but in general they are slow engines, so that could be it for get up and go area.

 

2.8's aint that bad of an engine good runners for thier displacment. Tom, time to cut and paste the list for making the 90* scream

 

I agree with ssc..before I did my swap, The 2.8 could smoke the tires, from a roll in a turn, with an auto. I just didnt have much top end power. At 120,000 mi I had to rebuild the distributor, Made a heck of a difference!

 

LOL, not really, just a guy who can type reallly fast, and helped someone out many years ago with that. Thank GM/Helms and their Service Manual!

Pretty much any motor can follow my major tuneup guide; the differences are minor, most of them would have to do with the style of induction (port fuel injection, carburated, throttle body injection) and the # of spark plugs needed.

I just found out after rebuilding my suspension (front = 100% changed for new, rear = still need to install my LCA and track bar poly bushings) that I can chirp my rear tires on a WOT 1-2 upshift. I could never do that before! Not bad for 253,000 miles! (It's all about the yearly major tuneup, baby! Yeah!)

 

I TIP MY HAT AND THANK YOU!! IF I CAN'T MAKE THIS 2.8 RUN BETTER WITH THIS INFO. I SHOULDN'T BE WORKING ON IT ANYWAY. THIS STUFF IS PRICELESS. I'LL LET YOU KNOW THE OUTCOME.