stevex

ok. I have maxima '91 SE VG30E, M/T.
here is problem:
cold start - idling unstable (1500 rpm then 500 rpm then 1500 rpm, 500, 1500...)
when worm - form 700-800 rpm to 1100-1200 rpm
starting is no problem
while engine running - whole car (engine) vibrating
while accelerating - in first 2-3 sec no enough power and after 2-3 sec power back

I do trouble diagnoses and:
mode I - OK
mode II - OK
mode III - code 55
mode V - more then 5 min inspection lamps are not flashing (seems OK)

seems to be all OK but...

I suspect for bad fuel and change supplier, but problem stays

what can be???
p.s. sorry for bad english

richard_85zxt

ok, step one is check the distributor to see if it's lined up properly, should help with the shaking of the car, the jumping up to 1500 is the ECU telling your car to idle up to get rid of excess fuel, AKA usually running rich. Could be a faulty MAF telling your car to run rich intermittently. Bad fuel as you stated could also have similar effects as running rich because more fuel getting dumped than can be burned off since it doesn't burn well. If you suspect bad fuel start there, it's cheaper than everything else, run high octane fuel, some seafoam and maybe an octane booster depending how much fuel you have in the tank before you add more.

YearOfTheGus

iTrader: (2)

Test the injectors. http://forums.maxima.org/3rd-generat...ctor-test.html

stevex

could it be bad battery?
I bought it in august 2003!!!

theallpowerfulme

I chased this problem for quite a while on my 91 max. I replaced injectors 3 times, plugs, wires, intake gasket (3x again), and it never changed. I hope one of these things fixes your problem.

richard_85zxt

Not likely, the car more or less runs off the alt once it's running the batt is for starting and running electrical components while the car is not running. should not affect the way your car idles at all. MAF can do this and is common to go bad on VG's, also common on VG's is the CHTS which can cause the change from cold to hot, but the acceleration thing combined in there makes me suspect fuel or air, check the MAF

Matt93SE

iTrader: (44)

Sounds like a vacuum leak or un-metered air getting past the MAF.

often this is caused by failed o-rings around the injectors or broken air hoses around the intakes.

The injector o-rings are the largest opening on the intake manifold subject to vacuum that doesn't have metal and a thin gasket (i.e. it's a 1/8" gap filled with rubber), so they're the most likely sources for a major vacuum leak.

broken connections or hoses from the idle air valve or whatnot can allow unmetered air into the engine since they enter the intake stream behind the MAF. if the engine is getting too much air from some place like that, it will act like this as well.

Take a can of starting fluid and open the hood. carefully look over all of the intake and vacuum hoses and whatnot looking for cracks or broken parts with the engine running. (listen for sucking sounds mainly, then try to trace it to the source.)

If you suspect a spot, spray some starting fluid on it and see if the engine rpm changes. it'll usually happen almost instantly when you find the source of the air leak.

hope that helps.

theallpowerfulme

This sounds good, but I would use 3m throttle plate cleaner instead of super-flammable starting fluid. If you hit a hot manifold with ether, you could easily have a fire on your hands.

Matt93SE

iTrader: (44)

The locations you're going to be spraying are nowhere near the exhaust manifolds.

Besides, it's ether. it'll burn up in a half a second and the problem is gone.

it doesn't burn hot enough to do anything but sear the hair off your arms and eyebrows and it's gone. amhik

stevex

OK. I checked distributor cap and found this:


So, I replaced it, but problem stays.

I replace MAF, but problem stays

I measure resistance of all 6 injectors and it's between 13,00 ohms to 13,75 ohms

I disconnect each spark plug cable when engine running, and notice when I disconnect cyl No 3 and No 5, engine running (sound) doesn't change

So, I checked spark plugs 3 and 5 but its working and it's dry (not wet by fuel).

Finally I checked spark plug cables and it's OK.

Is, maybe, injector block by dirt?

Matt93SE
I didn't find any broken air hoses

Probably I must replace/clean injector(s). But first I must find (order) gaskets (here, in Europe it's not easy, especially for Max).

BenStoked

iTrader: (7)

first, how did you check resistance, through the harness?
double check the injector connectors for corrosion.
check the harness for signal with a noid light

you may try PM-ing interneautomar, here, see if you can talk him into an international ship.
if that is a no-go, try emailing the people at courtesyparts.com

richard_85zxt

also check the MAF harness with electrical tester, an FSM should have proper testing methods. The MAF is just a common issue on most VG's and cause that idle issue you talked about if there's a short either in the harness or in the MAF. Being intermittent and the ECU not registering I'm gonna go with short or poor connection, which thankfully narrows down a bit since it's for the fuel or air delivery system. Like Ben said check the connections for the injectors, check MAF harness, if all connections seem good, I'm assuming you already checked for air leaks in vacuum lines, next will be testing contact for conductivity to narrow down an electrical short.

stevex

VERY STRANGE!!!???

yesterday I checked engine (electric, corrosion, connections...) and back original MAF. After that when I start the engine it runs like a tractor. DISASTER!
no power, vibrating, bad sound... I drove 10-15 km and back home.

BUT...

this morning when I start engine EVERYTHING seems to be OK?????
Idle - OK
running - OK (no vibration, no bad sound)
power - back

definitive, I'm but

richard_85zxt

time to find a short

BenStoked

iTrader: (7)

or a bad injector.