it hasn't ran right in over 2 months. It's idling high, bad MPG, hesitates. I have tested for boost leaks... none that are audible, replaced a bad intake gasket, swapped ECU, swapped ISCV, no CEL. Engine is in time, I ran new wires for he RSO(ISCV Open) and RSC(ISCV Close) the B+(Positive) has 12v with the Key on. If I hook up both the RSO and RSC with B+ to there respective places, it runs aweful. If you unplug RSO it idles normally but still has a hesitation from running rich... Especially when cold starting. Anyone familiar with the 3S-GTE? Also I have cleaned the ISCV, Spec'd Plug Wires, Recent Cap/Rotor/Plug/Wire replacementso I'm reasonably certain its an electrical short. Input?
To me that all sounds like unmetered or not properly metered air getting into the intake, somewhere.
Lots of fun acronyms!
Coolant VSV? Vacuum/boost leak? Those cars hate both of those.
Actually... those cars are just never happy on stock electronics.
Coolant VSV??? I replaced the sensor shortly after getting the car, could it be bad? I'd like to find and swap engine the engine harness.
Here's a long shot but it sounds electrical to me. I had a Jeep that ran like that, stumbled , bad mpg etc. Turned out one of the battery cables had chafed through and was shorting out against the fender. You couldn't even see it , just one little wire poked through was all. Tried everything and finally found it. After that it ran fine but still had bad mpg. Well it's a Jeep. Told you it was a long shot.
Megasquirt coming with Tax Refund;-)
I'm gonna run a new wire from B+ as well to rule out it being shorted to RSO & RSC
Sourced a good used engine harness, hopefully this will resolve the issue!
Issue remains.... :-( going to look into engine grounds this evening....
What do the plugs look like? Are they all black from running rich or just some? Have you checked compression?
http://www.diyautotune.com/catalog/megasquirtpnp-g2-ts9092-for-the-9092-toyota-mr2-celica-3sgte-p-518.html
That or Apexi Power FC. I had the same issues with my 350Z btw and I was never able to figure it out. Except on the Nissan it was going into limp mode and giving CELs on occasion as well.
I'm betting that megasquirt isn't going to fix your problem here if a ECU swap was already done.
How is the ECU? I know other Toyotas/Lexii from that era used a capacitor that leaks out as they age and cause all kinds of gremlins. If you have access to a reader that can interface with the ECU or a decent multimeter you may be able to diagnose that way.
http://www.clublexus.com/forums/ls400/715345-how-to-check-your-ecu-without-removing-it-from-car-by-yamae.html
(for an LS400 but same principles should apply)
or you can pop it open and see if there are any leaky caps or damaged traces due to leaky cap guts.
So far here's what I've done in order...1.boost leak test (found leaking intake manifold to head gasket... replaced with Toyota part
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Replaced rubber intercooler hoses with Silicone (rubber hot pipe to intercooler hose had a split)
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Cleaned idle Control Valve
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Swapped Spark Plugs (Black from tunning rich, one plug wasn't shine on the sides... arcing to head???). New OEM Toyota Wires were installed 6-9 months ago
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Swapped ISCV
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Swapped ECU
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Swapped engine harness (I did have to change the Dizzy connector as the wiring was cut for it.
Tomorrow I can do a compression test & going to boost leak test it again, as well as check the engine grounds. Its killing me in gas as I drive it 80 miles a day to work....:-( open to any input.
Are there no codes from the ECU? Not a CEL, but a code?
What does "one plug wasn't shine on the sides." mean?
A long shot but have you checked the air filter? Is there a rubber tube that can collapse under boost?
Baseline the engine. Compression/ leakdown. Fresh plugs, wires, distributor, rotor, fuel filter. Then retrace the AFM or use a known good unit if you have a buddy. (If you cut the sealant and remove the plastic cover, you can very slightly bend the afm arm such that it travels a new path across the resistor plane.) Also, make sure the flapper door moves smoothly.
Could be a leaking cold start injector, also. Warm it up and pull it out (duct tape the hole) and see if the injector is dripping.
It almost sounds like the engine thinks it's cold (warm up enrichment/idle). Coolant temp sensor of some sort ?
http://www.mr2oc.com/showthread.php?p=5743450
already had it posted... not much of a response :-/
I replaced the Coolant Temp Sensor a year or so ago.... Just as a last resort I unplugged the CTS while it was running... It immediately goes into a smooth 850rpm idle and all the issues of hesitating disappear... ironically when I removed the connector the CEL comes on. It must be reading the engine is cold constantly and dumping extra fuel in. Ordering new CTS tomorrow
