Loss of power?

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Jul 4, 2011
OK, I don't have time to do an in-depth search, so off the top of the head things to look at would be appreciated.

1997 LX 450 Supercharged, Running a Landtank MAF housing, not sure exactly which MAF is in there, Probably whatever LT suggested to the PO?

It used to feel really good, Pulled like a non lifted, non 6500# vehicle, I washed the motor cause I lost the oil filler cap, and made a huge mess, but caught it pretty quick so no major low oil situation. Ran like crap for a day after washing, Normal, Wouldn't shift right for a week, (downshift while going up hill), but then got back to normal. Just noticed today that I have very little power above 60mph. It down shifts to 2 or 3rd? motor revs like i should be flying, but it has trouble going the speed limit 70 mph. Before it would pull hard to around 90 now it flattens out around 45-50 and has trouble making and holding 70. The boost gauge reads 6psi, so it seems like the SC is working properly? One thing i did notice is when going up the hill to my house, before I could floor it and it would accelerate to the top, 70+mph, now it revs like before, but looses speed? and there is significant black smoke out of the tailpipe? May of done that before, I never noticed?
Everything Vacc hoses wiring connectors ect. seems to be in order in the engine bay, nothing melted resting on EGR, loose vac lines ect? NO odd noises, Nothing feels clunky(tranny has a bit of a clunk going from R to D but nothing bad?) No drivetrain noises that are out of the ordinary? All seems fine Just no power. Als, seemed to burn a lot more fuel than normal, but that could be from me flogging it up the hill trying to figure out what wasn't right?

Any thoughts? Is this some simple common issue that I am just missing? pOssible MAF sensor taking a dump? Some other sensor involved with the SC not letting it work right?

thats the 2nd generation MAF

When you washed the engine, did you cover the distributor and Maf harness with a towel? Both those places are suceptible to problems from water on any vehicle.

I'd take of the distributor cap and clean it and wipe it down, make sure its dry. Make sure the wires are connected well

Remove the MAF sensor and clean it with MAF Sensor cleaner. It could be water damage in the harness as well. See how well you can inspect the harness
BTW- black smoke indicates poor fuel mixture, which suggests to me the MAF is more likely. Might also check the vacuum hookup to the fuel pump. Could also be a vacuum leak with the hoses

Black smoke indicates excess fuel in the mixture
I was thinking the fuel mix was off too, but it only smokes at WOT, so in the lower power bands I guess it could be mixing wrong as well, just not as evident? Seems normally strong up through 1st and 2nd, to about 45 MPH, then it is like driving through Jello? It goes Just not well.
Seems like it could be MAF, makes sense? It's the 2nd gen housing but the actual MAF sensor is a Part # from some other toyota, maybe a Celica? Supra? The harness doesn't clip to the sensor, doesn't have the lock tab.
I didn't cover anything. Not a very good idea, but I thought about it after it was too late. I have washed other motors a bunch with absolutely ZERO negative issues, so I thought this one would be no different, especially as it is equipped for water crossings. My mistake.

I ll try cleaning the dizzy, Cleaning and DE grease all the electrical fittings, and try cleaning the MAF sensor. and look for any obvious van lines loose or leaking?

It's weird though, seems like all those "Fixes" are for things that would cause it to run crappy all the time, not just at higher speeds, and it downshifting going up hill, which is normally to get the lower gear power band, instead of gaining power/speed, it just looses speed? It sounds like it used to when it downshifted and where it used to take off, it just has no go? Like the boost is Gating out, Does it even have a waste gate? , but the gauge is consistent at 6 psi? So I assume that is controlled somewhere? Humm....
Need to read up on how the fuel is regulated in relation to boost pressure, and how the boost itself is regulated? Maybe that got out of whack somehow? Or if the timing is vacc adjusted as the SC creates more Pressure? I guests a leak in the Vacc lines could cause an issue only at WOT?
Ok so I was wrong. The maf sensor has the tab, it's the harness side connection thats broken.
So it's prob the oe sensor. Going to clean and grease the fitting and see what happens?

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The maf sensor has the tab, it's the harness side connection thats broken.

I missed what was broken on the harness side. Is there a pulled wire, loose pin, etc??
The actual harness side plug has the locking mechanism, that interfaces with the tab on the sensor. That locking mechanism is broken off.
All pins/ wires are good and it still plugs in fine.

I cleaned the sensor, DE greased the plug. Popped the distributor all was fine in there. DE greased the connector on top of the distributor. Checked for loose vacc lines, none I could see.

Driving it around in 1st and 2nd it is good. Torquey, feels great. When it gets in third it starts to Peter out. And 4th is just gutless. Going up a hill, it down shifts to 3 rd but total loss of torque. No advantage from downshifting. Before it would DS and you could feel it pull and accelerate?

Could it be a torque converter issue? Valve body in the trans gummed up? Or maybe trans filter clogging and not letting 3rd and 4th do their thing?

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Zach, just want to make sure I am clear on the timing

This all happened immediatly after you washed it? None of these issues happened before?

If it's tied to that event, I don't see the torque converter getting impacted. If its tied to that event, then more likely a connector, control signal or other that impacts the fuel trim (e.g Black smoke)

Also, from your last post - si there any change based on cleaning the MAF or is unchanged

Is the small hose between the SC and the FPR on the drivers side near the back still connected? Is that hose on tight?

Do you have an OBD II reader to see if any codes are set that don't set the engine light?
Yes Ken, It all seems to have gone south after I washed it. I am hoping I am just overlooking some loose vacuum line or something. I will look it over more in a few weeks when I have time to get back to it. It would be a little too much of a coincidence if the transmission or torque converter just decided to give up right after washing?

When I was driving into town today after cleaning the MAF it seemed to be the same, Although I was towing a trailer, small utility trailer with a dead washing machine on it. coming back home it seemed a little better, Unloaded trailer. it still seemed like it was trying hard to maintain speed though, and downshifting a lot. I need to drop the trailer and try it again. it has to be a loose/fouled connection. Just have to find it.

Maybe after disconnecting the MAF after washing a few weeks ago, It is taking a little while to "Learn" it again?
Thats a thgought. Maybe you should disconnect the battery for 15 minutes to let the ECU reset. It's an easy thing to do.
Pulled po110 and po100 both maf related
May of been from Pulling the maf plug while trying to diagnose my after wash running like crap day. Cleared them and will drive it more when I get back from NZ in a few weeks, And see how it does?

Thanks ,as always, for the help Ken!

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Still seems a little weak, but a not as bad.
I adjusted the kick down cable, changed the oil and air filter, just regular maintenance.
As soon as I get time I'm going to do the plugs and maybe go to a larger Bosch fuel pump?
Been also considering trying WRX blue injectors?
But that is just an idea at this point. It's running fine for me right now, my other vehicles are getting all the attention.

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