3sgte hesitation Options

[rjbibeau]

i'm working with a 2nd gen 3sgte in an mr2 and when it's below 32 degrees outside or so when started it has a wierd hesitation when you open the throttle alittle bit almost like a rev limiter. but when i unhook the tps the hesitation goes away but soon as the engine is warmed up and the tps is connected again it runs perfectly fine. although when we first started the car up the tach was registering but not the right rpm it was under of what it was supposed to be. for example at like 4 grand it would read maybe 2. the car drives perfectly fine after being warmed up. i remember seeing something about the adjustment screw on the afm and it controls how much air is bypassed. would adjusting this screw fix the problem with the hesitation. any ideas?

This post has been edited by rjbibeau: Feb 14, 2008 - 2:08 PM

[lagos]

Start out by checking the ecu for codes.

[rjbibeau]

i didn't see a check engine light? would some codes not trip the light?

[presure2]

art, dont the 3s ecu have a thing with it being above freezing, and coolant temp above what is it 160* before it allows full boost or somthing?

[lagos]

i didn't see a check engine light? would some codes not trip the light?

Most codes will NOT trip the light. You need to bridge te and e1 in the diagnostic box and see if there is anything stored. Do this first!

[lagos]

art, dont the 3s ecu have a thing with it being above freezing, and coolant temp above what is it 160* before it allows full boost or somthing?

Yes.
But since he is having issues with the tach, there is a good chance its an igniter issue or something along those lines.

Ive actually been planning to do a big 3sgte hesitation faq, since its such a common problem.

[rjbibeau]

thanks guys I'll check for the codes asap and repost my findings. that tach is really wierd after the car has been warmed up a bit it has little more movement but not to the full extent that it reached redline even though the engine is at redline it's not showing up.

This post has been edited by rjbibeau: Feb 14, 2008 - 8:41 PM

[lagos]

Are there any white glow gauges installed on the tach?

[rjbibeau]

ya there is actually....totally forgot that it could be sticking. thanks lagos i'll check that out.

[rjbibeau]

just checked the codes and came up with none. i also checked the bezel from sticking and didn't find anything.

[GriffGirl]

This might sound really weird and simplistic, but what about the engine temperature sensor? If it's failing, wouldn't the engine rev differently until the sensor communicates that the engine is warm? And in that case, especially when it's particularly cold out?

[lagos]

Ok, since you have glow gauges, and are not having any codes, then the tach problem IS because of the gauges. Sometimes they might seem like they are fine, but will start to stick anyway. You need to remove them, or glue them down to solve that problem.

Here are 2 things you should try:
1. Calibrate the tps. Youll need a feeler gauge and a multimeter. The bgb on ctech will tell you exactly what to do.
2. Adjust the afm. Read this entire thread....
http://mr2oc.com/showthread.php?t=285098

[3SGTE]

When i first start the gt-four up, you must let it warm up before you put the foot down, it does have a secondary rev limiter which comes into play when the engine is cold, obviously to stop the engine from being ruined.... just a standard feature i guess..

[lagos]

When i first start the gt-four up, you must let it warm up before you put the foot down, it does have a secondary rev limiter which comes into play when the engine is cold, obviously to stop the engine from being ruined.... just a standard feature i guess..

This is very true. You should never try to boost 3s before its warmed up.
However the 2nd gen 3sgte has some terrible cold weather hesitation issues just when you are trying to drive it normally. After much research, trail, and error, I found found a simple fix that can be done by adjusting the afm that cures it (assuming this is what is causing his problem).

[rjbibeau]

thanks guys i will remove the gauges to see if the tach is sticking and then i will see if the tps is calibrated correctly and if all else fails i will try to adjust it.

[rjbibeau]

alright i talked about it a little more with my gf and she said at cold engine when the temp is around 32 degrees it starts up fine but soon as you tap the gas just a little bit like as sliver and hold it steady it does a weird rev. i have a video that she can post a here later today. even when the car is still warmed up when she gets near that point of weird reving on acceleration just a little but it still does it. when she is decelerating to that point it does the same thing. i'm thinking this is a tps related issue. it's kinda hard to tell what rpm it is considering we have no tach.



This post has been edited by rjbibeau: Feb 15, 2008 - 3:22 PM

[malecrod]

Now, I see exactly what you are saying after watching the video. The problem appears different from the general cold motor hesitation issue. Hmm, could it be your TPS not functioning right? Just a sugestion, if you can find a spare TPS to swap to see.
G/L

[lagos]

Its the TPS then.
You need to remove the whole throttle body and adjust it with feeling gauges and a multimeter. Look at page 5 of this pdf.
http://www.celicatech.com/93rmsour/1993/93...ca/fi/throt.pdf

Skip the part where it says to apply vacuum to the throttle opener, and follow the rest of the directions.

[rjbibeau]

what does you have yo turn the tps until it deflect...does that mean read 0.00

[mr2nerkitty]

Yea he really didnt explain it that well. It doesnt hesitate just when its cold and its not when boosting its just when giving it very little throttle, as you saw in the video. It happends under 1k, i have no tach so its all by sound and feel. I figured it was a tps problem. We put it on without even calibrating it. So im sure thats the problem, just didnt know that it was that important. The hesitation isnt all that bad either, it doesnt dramatically affect the performance of the car, or at least none that i can tell. I dont even notice it when accelerating because i rarely give it so little pressure. I only notice it when i am coasting and let off the gas or when i am turning a corner and apply little gas. God its so hard to explain but its gotta be the TPS. I guess when we find time or another decently mild winter day we will fix it.

LAGOS you are a freaking genius....lol you help alot on MR2oc too. Thank you

This post has been edited by mr2nerkitty: Feb 15, 2008 - 5:54 PM