more idle/rev problems... im stumped..

Idealsupra

Supramania Contributor
Mar 31, 2005
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well i posted a day or so ago about my problems after pulling my dash...

i have yet to figure out wtf is going on...

basic story is i pulled my dash to change the color...did so...put it back in...and all hell broke loose...

i turned the car on and it was at a VERY low idle...around 400-500rpm... and then it surges from around 300-600rpm...gets steady for two seconds...then surges again...

now i started with codes...there are none....great...lol....i thought maybe TPS anyways...so swapped it out with two other ones i have...no change...

actually to begin with it was just the idle and i could rev fine....now i cant rev at all...it breaks up and i can hear slight knocks sometimes when i try to rev it...so its gotten worse somehow with all my fiddling lol...

i changed the iacv with another one i have....didnt change anything...however i didnt really look at the one that came off...but even if it was dirty etc that wouldnt cause me not to be able to rev cleanly now would it?

ugh im just out of ideas...it has to be something stupid...i know it...but im usually the one who finds the impossible stuff and overlooks the stupid shit....

anyone with any help would appreciated....
 

Idealsupra

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Mar 31, 2005
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sooo yeah i worked on this all day... im almost positive its something completely stupid...

its NOT the tps...its perfectly adjusted and in spec...its NOT timing...its dead on... its NOT the afm...working perfectly and reading perfectly...

sooooo im stumped and im about to light the bitch on fire...
 

GrimJack

Administrator
Dec 31, 1969
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Well, this is the obvious bits, because it's been well documented for a long time... :)
Reg Reimer said:
Section 1 ~7M-GE & GTE Engines 1.0: Idling problems

On a warm day, when restarting the engine, as when leaving a gas station or coffee shop after a short visit, the 7M-GE and 7M-GTE engines may exhibit weak idling, hard starting and putting around at 500 rpm for a short period. If this happens only very occasionally it is perfectly normal and is caused by a condition called HEAT SOAK, which happens, after shutting off the engine. After shutdown the water pump and fan are no longer cooling the engine so the heat from inside the engine comes out into to engine bay cooking everything in its way, EFI sensors say "Wako sure is hot in here," gasoline in the fuel rail on the intake manifold is boiled {not to mention a host of other thermodynamic conditions that occur after shutdown}. All Engineering levels are taxed.

To combat this inherit EFI {Electronic Fuel Injection} problem a number factory installed electronic and mechanical engine control systems are used, but under certain conditions they fail to correct the problem completely. For the most part EFI is a wonderful system allowing great fuel economy and silky smooth drive ability so a small bug like HEAT SOAK is still a more livable end than going back to carbs. If this rough idling symptom is happening more often than seems normal there may be a problem with one or more of the following: Cold start injector time switch, Bad Fuel, Throttle position sensor, Plugged or restricted fuel filter or gas cap, Idle speed solenoid air valve (ISC Valve), Fuel pressure, 2 speed fuel pump system, Head Gasket, Air intake leaks, Engine mechanical, Fuel pressure up VSV {vacuum switching valve}.

Other points to remember about the idle speed control valve (ISC valve) are: After shutting of the engine you should here a faint clicking sound for a short time after the engine is killed, this is normal operation.

Unplug the wire at the ISC valve after the valve makes its normal clicking noise after engine is shut off, will cause the engine to run in high idle when the engine is restarted. This is a good sign that the ISC valve is working correctly.

When E1 & T1 in the check connector (Diag Block) are shorted, this will cause the valve to go to a standard closed position. This is the first step in setting the curb idle and ignition timing.

Failure of the ISC valve is not a common problem, what should be checked is the seat section of the valve that sits in the intake manifold. When the ISC valve is removed, this seat will remain in the hole in the intake manifold. This seat valve will get sticky and not work smoothly due to excess carbon and deposits in the intake manifold.

The Bardal Super Tune kit comes with a can of gunk for the fuel tank and a can of gunk to be slowly sucked into the intake manifold while the engine is running at high idle. This gunk stuff works great. Also included in the Bardal super tune kit is a can of gunk that is sprayed into the intake plumbing, and throttle body. Spray this gunk into the airline going into the idle speed control valve. Presto changeo the valve will most often work fine again. Wins also makes a good fuel injection cleaning kit that works wonders as well. The Wynns kit does not have the can of gunk spray, but it does a great job on the injectors and intake manifold.

When the VSV for fuel pressure up is working correctly it allows the fuel pressure regulator to receive atmospheric air pressure to its vacuum port when the engine is hot. To test this VSV you can unplug the vacuum line from the fuel pressure regulator and start the car to see if the vehicle starts normally. If it does the fuel pressure up VSV is the problem.
 

Maroon88

I collect BHG's
May 3, 2005
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Since it didn't start hapening til you removed the dash then the problem is probably in the dash. Something probably worked loose or an electrical connection was missed so you will probably have to pull the dash again. Make sure every connector is tight and check those in the driverside kickpanel as well along with the fuses.
 

Idealsupra

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GrimJack said:
Well, this is the obvious bits, because it's been well documented for a long time... :)

heh...well its NOT heat soak..im sure of it..ive NEVER had problems like this before...heat soak or not...

i dont have the fuel VSV...havent for over a year and never had a problem...the iscv is fine..tested fine...the tps is fine tested fine and in alignment..fuel filter...possible but doubtful...i do have a new one here ive been meaning to change in anyways... but i still doubt thats the problem...

the cold start injector switch...havent checked that..BUT wouldnt that go away after the car warmed up if that was the problem?? how do i go about checking that?

this is retarded lol
 
J

JerzeySlowpra

Guest
everytime i reset my ecu my car acts liek that until i drive it for a couple mins, struggles with idle drives kinda shitty then its fine after a few mins though