GA16I Bogs unless DISTRIBUTOR FULL-LOCK!

B12_GA16I · May 19th, 2006, 02:01 PM

I have a 90 B12 w/ the GA16i TBI engine.
Engine gradually seemed to need more and more retarded timing
to have any power (or even just to idle smoothly).
To the point now that it is only drivable with the distributor
clocked at FULL RETARD! Balks and Bogs at anything less.

ALL cylinders are bogging at once.
Fuel Pressure before and after the regulator is good.
ECU never shows any codes!!! - Arrg.
And no, the distributor itself IS correctly timed.
(does not even start in the other dist gear positions).

Parts already replaced/excluded:
New O2 Sensor.
New Injector.
All-New Plug Wires & Plugs.
ALL-New Distributor assembly (including crank-angle sensor).
Even tried a different ECU/ECC computer, Same result.

Remaining suspects NOT replaced:
Throttle switch/Sensor.
Mass-air Sensor.

Any ideas? I've heard this problem mentioned before,

bob89sentra · May 24th, 2006, 12:54 PM

Probbaly not the TPS (throttle posistion sensor) the TPS only effects throttle response
I would look into the MAF (AFM) for the problem first, because the MAF can give you some big running problems
Also Take the Dist. cap off, and check the rotor, I was a dumb A$$ and didn't tighten the screw all the way, resulting in a similar problem when the screw came out.
Since you don't have a timing belt, but a chain I don't think it is in valve timing. The dist. cannot go on in more than one posistion, because it has an ofset key. If you got the cap on upside down, or got the plug wires on wrong it could do that. Since you said it did it over time, and not after you replaced or changed something I would think MAF or loose rotor in the dist.
Let me know what you find, and I will give you some more ideas.
Bob

B12_GA16I · Jun 6th, 2006, 04:41 PM

I have looked all over the net for Non-OEM / aftermarket sources for
the 1990 GA16i 1.6L engine. I checked NAPA/Rockauto, etc.
Lots of them out there for the 1.8, but not the 1.6.
So what gives? do I HAVE to buy this particular MAF from the dealer? - Ouch.

The Mass Air Flow Meter seems to be the only suspect left I have not replaced already.
I will try unplugging it tonight to see if the ECU has a 'limp mode' that
allows it to run any better than it is. If it runs better I'll know for sure.
BTW, the MAF's connector pins were corroded (green).
Curiously they were the only corroded connector pins on the car.
The boot was fine/selaed, so my theory is there is actually electrolysis
in the meter due to static charges generated in the MAF wires??????

Cleaning the contacts did not do a thing, so I'm looking at the
meter itself and bet it is corroded internally too, for the same reason.
The pins are probably just external evidence of internal corrosion.
Like I said all other connectors on the TBI are fine.

Right now with the timing correctly set it will stall upon full-thottle,
even if I'm already rolling down the road!
With the dist at full-lock, it runs decently but wont pass smog because
the rpms are too high at idle and of course there is no dedicated
idle adjusatnment on these dam'n things... Arrg.

modenaf1 · Jun 6th, 2006, 09:38 PM

My GA16i would bog, miss, sputter, and buck like a pissed off bronco when I had the timing set correctly. I cranked the distributor a little more to advance the timing even further and it runs smooth as silk, quieter too (really noticeable with my blown out muffler). I think it is running a wee bit lean though, my exhaust smells like sulfur.

I don't think it is your throttle position sensor, in mine when I disconnect the TPS to set the ignition timing, I can floor board it and it sputters and pops, almost dies, then revs up and I smell a lot of icky fumes in the exhaust.

bob89sentra · Jun 7th, 2006, 08:09 AM

Quote:

Originally Posted by B12_GA16I

The Mass Air Flow Meter seems to be the only suspect left I have not replaced already.
Cleaning the contacts did not do a thing, so I'm looking at the
meter itself and bet it is corroded internally too, for the same reason.
The pins are probably just external evidence of internal corrosion.
Like I said all other connectors on the TBI are fine.

Right now with the timing correctly set it will stall upon full-thottle,
even if I'm already rolling down the road!
With the dist at full-lock, it runs decently but wont pass smog because
the rpms are too high at idle and of course there is no dedicated
idle adjusatnment on these dam'n things... Arrg.

I have a good used one (MAF) you can have for the price of shipping.... PM me if interested
The Idle speed is adjustable, it is quite hard to get to though. On the TBI it is on the driver side, and you will need to use a screw driver coming from between the fire wall and the TBI. If you have a vaccume gauge, hook it to the manifold vacuume, and see what it is doing. Is it fluctuating, or low, bouncing? There is a section in my chiltons that helps diagnose using a vaccume gauge.
Bob