ok i know the whole throttle surge thing has been asked over and over so im not going to ask. im still trying to track it down. I see some engines that are somewhat different but same models. Ok everything in green is brand new from the store. The Blue one is the butterfly supposed to be open all the way? and the red theres some i guess vaccume lines capped off i do not see where they go to but i seen them on other ls400's Is there a certain way to test or a write up for the Electronic Fuel Injection sensor? thanks again and sorry if some of these have been covered.

 

I'm sorry this isn't the place to ask questions for your 1965 Lincoln.


Model + year in title post please....
a more detailed description of exactly what's going wrong wouldn't hurt either.

 

hilarious guy ok if you cant tell by the GIANT "L". For other helpful people Ii got the 94 LS400 4.0 it surges when RPM's hit little over 2k, wondering about the butterfly valve for the Electronic Fuel Injection sensor should be sitting horizontal is there a way to test this one like the TPS sensor? and 2nd thing is theres 3 vaccum lines on top there 2 are plugged i seen on others all 3 run. If need a better pic just let me know and ill take it

 

Electronic Fuel Injection sensor??

I have been working on fuel injected vehicles since 1976 and I don't know what an Electronic Fuel Injection sensor is! -- your Electronic Fuel Injection system in your Lexus has dozens of sensors!! - which one are you referring to, and what makes you think it is causing your issue?

PS - the TPS in your pic doesn't look like the genuine Toyota (NipponDenso or Aisin) part.
and when you installed the TPS, did you follow the adjustment procedure in the factory service manual?

 

You can get faulty parts you know. Test the TPS, and MAF. Also, did you clean the IACV?

 

the Idle Air Control Valve (IACV) or the electrolytic capacitors inside your ECM (ECU) are the most likely culprits, assuming you have all of your vacuum lines routed where they are supposed to go.

the service manual has a procedure for testing the IACV - mine was bad, as were my ECM capacitors

also, you have two TPS's in your pic, one for the EFI and one from TRAC system, which one did you replace?

 

I replaced the TPS (grey) one yes i did and it is functioning like it should, dad is a proffesional electrician. And the other one next to it is I believe the Electronic Fuel Injection sensor because 1 theres only 2 i can buy and it tells you the difference on them before you buy them. I buy from oreillyauto.com anyways is the 1st butterfly valve supposed to be wide open? LScowboyLS i will check the (IACV) at this point ill check everything to get it sorted out.

and here is the TPS for the electronic fuel injection part number Part Number: EC3101
http://www.oreillyauto.com/site/c/de...2207&ppt=C0024

 

Yes that first butterfly valve was open when mine was not running, if I remember correctly.

I remember looking in there when I did the timing belt and I could see the second one behind it and remember thinking about how clean it was in there.

The throttle position sensor by the OBD2 codes on my 1996 LS says it is a Sub-Throttle Position Sensor.

I remember this, because I forgot to plug it in after the T belt change and I got a p01400 and a p01401 code

.I wrote this down when it happened.

When you say the engine surges at 2000 rpm does the rpms increase or decrease? Surge to me means increase but....... maybe a conversation will get going and you might get some useful info.

I'm no expert on these, But....... ( like LsCowboy said it looks like part of the TRAC system ).......the lexus description of that sensor is ( part number 8945250020 ) THROTTLE POSITION SENSOR .

It appears to operate in conjunction with the TRAC throttle body control motor that is on the opposite side of it.

http://lexus.sewellparts.com/oem-cat...S400-1996.html This for my 1996 though.

Only trying to help.

 

there are 2 Throttle Position sensors (TPS) on cars with TRAC, one for the main EFI (at small green arrow) and one for the TRAC system (at blue arrow) -- it would appear that you replaced the main one and replaced it with some aftermarket crap rather than the correct NipponDenso made Toyota part. Your large green arrow appears to be pointing at the Mass Air Flow (MAF) sensor, which could likely stand a proper cleaning with MAF sensor cleaning solvent (I like the CRC brand) - be careful and don't actually touch the MAF sensor with anything!

what you are calling the "Electronic Fuel Injection sensor" is actually the TPS for the TRAC system. - You need to get your nomenclature correct so we can better help you, well at least you have photos with colored arrows!

You can actually find the brand new NipponDenso real Lexus TPS on ebay for half the price of the aftermarket part, once you realize that sometimes they are found in a Delphi box!

I somewhat doubt that either TPS was a problem, these are pretty reliable, actually. Regardless of whether your Dad is a "professional electrician", you still need to calibrate the TPS properly, which involves following the steps in the service manual.

The most important thing a Lexus LS400 owner should do, to solve driveability problems, first and foremost is replace the ECM capacitors (your electrician father will be perfect for this). This is a known issue, and even if it turns out not to be the culprit in this case, it will likely give you fits soon, so get 'er done!

 

the MAF is brand new. I did get a random numbers with the old TPS when testing it, the readings where all over the place. Now its a steady Reading and it is better now with that one and it is calibrated correctly. I am going to do the ECU when I do the Dash cluster but i want to get a "how to" with pics for the ECU haha.

As in Surging i mean either you slam on the gas and it hits 2k and looses power but trys to regain it over and over untill you slightly press the gas in and it slowly gets up to speed. I tried multiple gears O/D on/off trac on/off um shifts fine. but im going with the ECU first

 

Did you shift the TPS around to find the "softspot" when the idle was running nicely or did you just put the TPS in?

 

we put it on and followed the directions and also unplugged while reading the numbers with engine on so im 100% positive it is done correct and its not an issue i believe it sits at 8.7 ad idle on the voltmeter

 

what does factory spec call for?

 

the tps sensor is fine now the old one is/was bad doesnt matter now its the ecu i posted pics of the Capasitors for 94 and actually a bad spot on mine.
https://www.clublexus.com/forums/ls4...-solved-3.html