1UZFE runs great without AFM

[extractors]

Does anyone know how much timing advance is pulled when the IAT reads too high etc, say 35 degrees plus ? The LS1-LS2 engines pull a fair amount of timing with heat soaked MAF sensors, and rising intake temps, and hence the popularity of the OTRCAI. I just did a 450 km round trip in my soarer V8, and I'm still blown away with how that thing pulls on the open road, and around town for an essentially stock car, so I know how these lexus V8's should go

I really think this is the issue, Ive checked and replaced just about everything.
And the car really does motor when cold. I'm going to try a nice cold air intake, as it is only getting hot air at present. Failing that I'm going to clamp the IAT sensor at around 2.5k ohm, atleast for testing purposes.

 

[gloverman]

When I have had stock management 1uz's on the dyno the I expect the timing to be at 17-20 at idle (diagnostic connector not bridged) then around 40-48 on light load , 28-35 around 3K and it drops back to around 19-22 at full load. I had one which had issues which the timing was fine until about 4k when it when to 10-15ATDC. It had wiring issues. Another was dropping back to TDC and it had a stuffed alternator and it was sending a strange ripple through the knock sensor circuit. One way to check knock sensors is to pop the pins out of the ECU. With a bit of thinking it would be possible to set up comparison temp reading between you two vehicles. Also have you wired a diagnostic connector and got some live data yet? I think there is live data for air temp. Doing one today so I will check. Its also going onto the dyno too. Cheers

 

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Hello Gloverman,

It doesn't have the diagnostics port wired in. Ive got all the wiring diagrams for the car, so I'm sure I could put one in if needed.

Can the knock sensors really kill performance through the entire rev range ? I always thought you had that scoop out of the graph up top in the rev range, when the knock sensors were causing issues. The car just loses power through the whole rev range, Ive had it on the dyno in the early days for a AFR check, was well into the 11's, nice smooth graph, nice sign of knocking then. The power was about 121 rwkw, for with shocking crown headers, actually modified and more restrictive than stock crown headers. The dyno operator did say his dyno consistently reads 10 % lower than others, so seemed to think that was a reasonable figure. The car now has custom headers.

Do you notice a huge change in the character and response of the engine when disconnecting the AFM ? When mine is dead cold, there really isn't any difference, but once she gets hot, theres a huge power hike when disconnecting it, heaps more low down torque.

The v8 soarer runs fine with or without the AFM, but if she gets really hot I guess power does drop off a bit, and running with the afm disconnected does sharpen it up somewhat.

Does anything else pull timing, other than the IAT and coolant temp sensor ? Ive replaced the latter, and assuming everything is ok there. The only thing I was thinking was changing the thermo fan to come in earlier, I have a davies craig 16 inch, and have it set at the highest temperature. I think its a 40-100 c thermo switch. But what never makes sense to me is according to my gauges the car is only just over 80 c when the fan kicks in, so might have to double check all of this.

 

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Haven't got much done on this lately, just been doing some driving and planning a few bits and bobs, oh and trying to get the a/c cooler than present.

One thing I noted when replacing the ac compressor was the crappy looking ground wire. It doesn't look heavy gauged enough, and secondly is just held to chassis with a self tapping screw. I actually attempted to start the engine with that one disconnected, an nothing at all, would not rotate let alone start. The engine does have a second ground, but that obviously is not sufficient to start the engine. So essentially the engine is running on one, semi ordinary ground.

Whats peoples thoughts on this, do you think it could effect the performance significantly, I was thinking my ignition system may be struggling at current.

I'm going to replace both grounds, any tips on type and gauge of wire needed ?

Cheers,

Brett.

 

[MinaT]

hate to bring up a old post but was this ever solved am having the same issue:

car runs great when cold, feels sluggish when warmed up.

new plugs and new coolent temp sensors also good afm and 02 sensor were changed no codes stock, 1uzfe from a 94 sc400 in a mkiii supra

 

[4U2QUIK]

it's actually the 94.5 engine. the 1uz swap in your car originally came from me.
A matter of fact cory still owes me 800$ for that car...... I'm starting to get a little pissed because he said he'd give me the money when he sold that car and I have yet to hear from him. Obviously not your problem, and I'm glad you have the car.....

 

[MinaT]

^ Im see sorry to hear that man, i appropriate you saying that about me am just very picky about things like this am leaning more toward the tps i tried every thing but the weird thing is that there is no codes at all, after the car is done getting painted it off to bossting it i need every thing damn near perfect

 

[MinaT]

Thing I might of solved the issue dialed in the TPS.. feels like a diffrent car..

 

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Just looking around the net for IAT relocation on 1U's and came across my old thread.

Anyway, solved this, basically put the biggest radiator in I could find, fit. Was a custom 350 chev, all alloy. Has transformed the car, The car was just simply getting to hot before, from my guess over 100 deg, not sure how much over. My gauge was accurate at idle temps, but seemed way off when car got hot. So keeping these 1uz's cool, really helps performance. Explains the elaborate length toyota/lexus went to with the hydraulic fan setup.

Now I'm still running the IAT clamped with a 2.5kohm resistor. I really want to run a IAT relocation now. Can anyone point me in the right direction for a IAT sensor that would work for mounting somewhere else, and not in the heatsoaker AFM.

 

[Zuffen]

Recently I was playing around with my IAT sensor and I discovered the water temp sensor used the same resistance curve as the IAT.

On that basis you should be able to swap a standard 1UZ water temp sensor into the intake air stream and get the correct reading.

To me it makes sense that Toyota would use a similar curve on all their temp sensors.

 

[extractors]

Thanks heaps Zuffen,

Makes a lot of sense when you think of it. The 1jzgte uses a IAT that looks looks almost the same as the coolant temp sensor, so I suppose it runs the same setup, curves, resistance etc. Will definitely give that a try. Did you manage to log some data with the standard AFM/IAT to see what the readings were, any heat soak etc ?

 

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Looks like it, makes it too easy great.

 

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Last link was for IAT, this one is ECT sensor.

 

[sideshow]

the only prob u might run into is most air temp senders are plastic around a metal sensor

coolant temp senders are brass so they very slowly change resistance

air temp senders change quick due to air temps variations
I have seen in the early days bosch air temp senders that were brass
but they might have been to prehistoric efi system
u don't see many brass air temp senders these days mainly in euro crap cars

 

[sideshow]

what I found after abit of testing was engine drove better when cold
well this is normal with most enignes
but once my 1uz got hot and I used full throttle it went worse than half throttle

u should really put an air fuel sensor a proper accurate one
not a gay ass fking autometer crap one

u will find on std ecus they run lean to ok mixtures on light and medium throttle
I found once my scanner live data said throttle was over 85 or 90% the mixtures on air feul sensor went down to 10
most of these senders stop at 10 so I would hate to imagine how low they went in mixtures

90% of 1uzs with aftermarket ecus make power but leaning the engine off when compared to std ecu

interesting thing I found with live data and my engine use to get hot like 110 120 degrees
was that when cruising timing was 50 to 55 degrees
that's a lot of timing and that's y mine used to ping
best thing to do if u can is piss of electric fans unless u can fit the big holden or ford twin fans and fit a clutch or the best is a hydro fan

ive also measured live data on a 1uz std soarer
and engine temps went up to 108 degrees on a normal day
no wonder soarer looms are the worst out of any 1uz ive seen
engine bay temps are ridiculous and they even run a hydro fan
so make sure u have scoops to get air out of engine bay not in

 

[stevieg]

First thing that popped into my head is green coolant temp sensor, disconnecting the afm puts it into open loop, a bad coolant temp sensor could be demanding much more or less fuel than needed and making it run like crap while not necessarily giving you a fault code

 

[extractors]

Stevieg, ECT sensor was replaced, genuine Toyota one from memory. Green and grey one. Getting the thing running cooler was the key to helping performance, factory setups run too hot for performance, but better for emissions, not much else I would believe.

Sideshow, I think those temps are pretty ludicrous, The radiator I end up putting in is about twice the size of the original and the original was off a 4.5 mercedes V8. Has helped a lot, but yes still needs plenty of airflow, I run two electrics. Std hydraulic would be the go, but it would make a real mess of the install.

Factory tuning on the 1UZ is pretty ordinary, would love to do a standalone, but hard to justify the $$$, and despite that, you would still have little issues that need sorting like above.

I would be really interested to see if you have any logging on IAT temps, I think heat soaked IAT, and 100 deg C + coolant temps could be the curse of many a sluggish 1UZ.

 

[gloverman]

Oz sucks when it comes to keeping engines cool. And you guys often seem to want a/c. Over here I try to keep the 1uz's under 100c. We have a few around 95c but often manage to get them into the mid 80s.

I also think moving the air temp on some might net some improvements. Especially those with long 4x4 style intakes. I'm thinking the little factory denso push in units that is used in many other Toyotas may work. I use them in many of my aftermarket ecu installs and they configure the same as some bosch IAT sensors.

 

[sideshow]

90% of conversions are on hiluxs and its very hard to fit a decent radiator without removing the hilux cab and removing the hilux chassis and fitting an f100 chassis and f100 body hehehe

anyway I found improvements could be done with playing with the tps settings
so u get full throttle opening but not full throttle voltage
just never bothered because I hardly touch 1uzs anymore
and I don't own one anymore
lsx engines are the engine of choice this decade
last decade was 1uz

std ecu tune is shitloads better than any aftermarket tune as an overall
if a sensor fails in an aftermarket ecu its doesn't have as many fail safes as std ecu

the main problem with std ecus is the manufacturers don't want u blowing up their engines and coming back for warranty
so they run the engines lean for fuel economy and rich at full noise so u don't blow them up
so all u do to gain power is run them lean up high or full noise
I bet u will gain way more by driving the car at half throttle than playing with air temps
go buy yourself an air fuel meter as this is proper way to tune a car and u will see the mixtures are perfect until full throttle and that is any load and revs, as soon as tps goes to 100% mixtures go full rich, that was an a crown ecu so not sure if others do the same

I just learnt to drive mine using half to 3/4 throttle off the mark as I had a hilux and I knew it was too hard to keep temps below 90 so I just didnt care about that side of things

but to test things properly and know these little changes work u realy need a scanner to read live data and u need an air fuel meter to see mixtures otherwise your just guessing

 

[extractors]

Gloverman, I would be really interested to see if there was another Toyota part that could be used. Hopefully an open element sensor, keen to do this on a1jzgte also. I recently relocated an IAT on a l98 chev, makes the car a lot more stable when it comes to power / performance, old sensor used to see 60 + degrees and now it sits 1-2 deg above ambient.

Sideshow I'm pleased to here that you like the std tunes, although conservative. I've often pursued piggybacks for this reason. But do like the idea of a standalone if done correctly.

Emanage ultimate will run the 1UZ in mafless mode, tps verse rpm. However as always it's finding some one able and willing to tune it. Road tuning is always an option but introduces obvious concerns.

Interested in your TPS voltage adjustments too, I recall when the car was running really rough at idle, went like the clappers, just idles like it had a huge cam. Turns out TPS was setup wrong, but the thing went better under load, WOT. Might be something in this. Possibly running a voltage clamp ?