Bad idle when cold

fastazzsupra

New Member
Mar 23, 2006
46
0
0
South Carolina
I've heard a couple of different ways to set the tps adjustment, but what is the best way per you jdub? I am a little new to this forum and supras in general, but that doesn't mean I'm unhelpable. You need to learn some pactience with people. Just because some aren't as knowledgable as you, doesn't mean they're stupid. I need help not critics.
 

Halsupramk3

Member
Apr 4, 2005
444
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16
Mississippi
jdub;1393833 said:
The hot start FP up VSV is only active when coolant temp is above a certain level (i.e. HOT START)...no effect at all on a cold start. The only possible issue is if the vac line is disconnected allowing an increase in FP at all times. Plus, it's the VSV that is forward on the intake manifold, not the rear. The EGR VSV is the one at the rear of the manifold. Per this diagram:


The CSI is only active when when the starter is engaged (it's call a Cold Start Injector for a reason). It has absolutely no effect on idle or warm-up whatsoever. Once the car is started, the CSI shuts off...it is not possible for it to function without STA active at the ECU.

Basically this post is just full of bullshit Hal. You obviously do not know what you are talking about and are leading this guy on a wild goose chase. Do not post in the tech section again unless you are 100% sure of what you say. This is your one and only warning.


Well, jdub, you called me on the vsv and csi info. i have not had any of these on my car since i installed the aem ecu on my car a few years back (all by my ignorant self) : ) My half truths do not help solve this mans idle problem. i made the mistake of not researching a little to analyze my initial thoughts just because it was past my bedtime. I hope others see here to put more fore thought into posting.

i did forget about the fp up vsv being for hot starts and its location. the csi can stay on longer than it should as i have read posts to that effect but i have not ever had that problem.

I have had TBody gasket or intake gaskets leak and idle up but then when heated up they seal off. but these leaks did not do so precisely or timely as this leak sounds. this leak from what he said makes me think it is a control device turning on then off.

Any of the vsv, csi, idle up on the power sterring pump, missing vsv for the egr and other egr parts all could be the source for his idle problem. trail and error elemination of any air source to the intake as shown in the pic Jdub posted could contribute to his idle problem.

Doesnt the csi get a ground from the ecu to turn on and also have a temperature switch in the Tstat housing or is that switch control something else. the large switch on top right of the Tstat housing with the square plug. if so it would be my guess that the temperature switch there turns the csi off when the engine is warm and not needed to start the car.

The overall knowledge that jdub and a few others have on these cars is not common. Keeping threads on track and factual is an endless task that is taxing on our often underappreciated moderators. i do not post very often as my post count shows. And i would never say i am a master of Supra knowledge just because i have kept my 90T on the road for the past 19 years. (More years than the age of what 30% of this forums members). But I would also prefer not to be addressed as if i am some newb.

Hal
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
Hal - I was not addressing you like a Newb...I was addressing you in a way that was appropriate to what you posted.
The reason is it would have distracted him from what is really going on...I hope you learned something.

A couple of things as to be absolutely clear:
- You pointed at the VSV's, not the vac lines leading to them. It is correct that a vac line leak can cause idle problems, but that is not what you said previously. Any type of air leak in the manifold area can cause problems.
- Regardless of what you read, it is impossible for the CSI to remain on once the starter is disengaged...the way it is wired requires the STA power from the ignition to complete the circuit at the time switch. The time switch is a ground that does 2 things: 1) Allows the CSI to function for set time while the starter is engaged based on coolant temperature...time decreases as coolant temp increases. 2) Disables CSI function above ~22 deg C.
- The only way the CSI can affect a running motor is if it leaks...a mechanical problem with the injector itself.
- I didn't say you you can't work on these cars...I said you don't know what you are talking about when it comes to the Hot Start FP up VSV and the CSI circuit. You having a standalone EMS explains why ;)
- I have to deal with a wide variety of misinfo posted on here on a daily basis...it gets old. Posting experience is one thing, but when it is just flat wrong leaves me little choice. We can't tolerate "guesses", "hearsay" and/or other postulations other than the facts.
- I can pretty much promise I'm older than you...LOL...I'm also from the state next to yours on the east side.
 

fastazzsupra

New Member
Mar 23, 2006
46
0
0
South Carolina
Sorry JDUB, I didin't mean you. You have been very informative and patient. I just don't appreciate it when others chime in with sarcasm instead of advice. I will try recalibrating my tbody this weekend. I only have a digital meter and I have a coworker who has an anilog meter. Thanks for the link as well.
 

fastazzsupra

New Member
Mar 23, 2006
46
0
0
South Carolina
Sorry about the slow response, my computer decided to take a dump. Alright, here is an update on my car. Recalibrated the tps, installed new denso o2, and reinstalled emissions parts. The car runs great. Idles a little high still(750rpm), but response is quicker and idle is steady. I still have a code 52 coming on shortly after going down the road. I checked the knock sensor wiring to see if this guy had ever done the rewire previously. I'm going to try that first and see if it fixes the code from coming back. Thanks guys for all your info and help.