[WhitePony93]

I pulled the intake tube and covered the idle air hole and it now idles. The throttle body itself seems a bit worn out, there's a lot of up and down play in the blade. Do you think the throttle blade is allowing too much air to pass, making it impossible to bring the idle down far enough with the screw?

[jrichker]

Originally Posted by WhitePony93

I pulled the intake tube and covered the idle air hole and it now idles. The throttle body itself seems a bit worn out, there's a lot of up and down play in the blade. Do you think the throttle blade is allowing too much air to pass, making it impossible to bring the idle down far enough with the screw?

That is a possiblity. Check the throttle butterfly for a hole drilled it it. Ford used the hole as a means to allow a calibrated airflow to control idle. They would insert a plastic plug to change the size of the hole if it was too big.

[Cougar5.O]

The TPS being below 1V makes no sense from the ECU point of view.

Any setting between 0.8 - 1.1V will be seen as "0" my the ECU.

I don't know where or how this rumor started, but it is not supported by the code in EEC-IV.

[Cougar5.O]

Originally Posted by jrichker

No.

...

Try this... Currently there is some dispute about setting it at .99 volts being worth the effort, but anything less is probably OK. All you need is less than 1.0 volt at idle ...

Sorry, it makes no difference if the TPS is above or below 1V at idle, so long as it is not below 0.5V or above 1.2V within the ECU. This means that a measurement of 0.8V - 1.1V will leave you WAY within the acceptable range. The ECU zeros to whatever voltage it sees at closed throttle, so it doesn't matter where it is. If it is outside of the range I mentioned, it will throw a code and behave badly.

[jrichker]

Originally Posted by Cougar5.O

Sorry, it makes no difference if the TPS is above or below 1V at idle, so long as it is not below 0.5V or above 1.2V within the ECU. This means that a measurement of 0.8V - 1.1V will leave you WAY within the acceptable range. The ECU zeros to whatever voltage it sees at closed throttle, so it doesn't matter where it is. If it is outside of the range I mentioned, it will throw a code and behave badly.

Site me a reliable source for the above information and I will gladly make changes.

My personal observation has been that the idle speed increases slighly as the base TPS voltage increases.

[WhitePony93]

I actually have that hole completely plugged now to give it an idle at or around 800 RPM'S . It's like too much air is able to squeeze around the T.B when it's closed. The blade actually slides up and down revealing a gap below or above it. A new throttle body seems to be in order, now the question is whether or not to get a 65mm from Ford Racing. Will I see any improvement with the minimal mod's I currently have, or will I be wasting my money and time? Keep in mind that I have no planned future modifications of the motor itself(H/C/I, Power adders, etc.)

[OonDeanisS]

When i turn my car on, it stalls once or twice and bounces from 1500 to as low as 200rpms before it gets warmed up then it stays at either 1000, or 1500 sometimes. Which of my many sensors do you guys think this is? I put on a new tps, but never calibrated it because i dont know how, but it did this before that anyway.

[joel5.0]

Originally Posted by jrichker

Site me a reliable source for the above information and I will gladly make changes.

My personal observation has been that the idle speed increases slighly as the base TPS voltage increases.

J.....this is from a write-up I did on the TPS adjusting myth, the quotes within the article are from the Ford GUFB Strategy document and has also been verified with "tests" I've done in SD and MA systems, including SN95's that allow the access to the parameters via the Datastream option......There are 3 parameters:

Throttle Pos ClsdVolt = used to id minimum TP value and is reset every time you turn ignition on
Throttle Pos Mode = CT for Closed Throttle, PT for Part Throttle and WOT
Throttle Pos Volt = real time value of TPS signal

Anytime the system detects an increase of .04vdc over the minimum TPS value recorded initially, the idle will increase because the system id's a part throttle condition and switches to a different IAC control strategy. Reason why you have to reset the system by turning the ignition off and recheck the setting when the throttle stop screw is used, as the base idle procedure calls for.

Summarized EEC-IV logic for the TPS......

The EEC-IV will check for the following:

- Minimum voltage at closed throttle over .49 vdc. , less than .49 and codes 23 and 63 will set as failures.

- Max voltage closed throttle should not exceeed 1.2 vdc, or codes 23 & 53 will set as failures.

- TPS voltage between .5vdc and 1.19 = no codes, TPS ...then

- Closed throttle TPS value is reset by the system to the lowest value read when ignition is turned on every time. Or as explained by the EEC-IV RATCH algorithm:

- A voltage increase of .04 vdc from the minimum registered will id part throttle status.
- Minimum WOT value of 3.21 vdc (.5 + 2.71) and not higher than actual Voltage REFerence (VREF) generated by the ECM to access WOT strategy.

FYI....This does not include the other registers and functions, the system uses to id acceleration, deceleration, cruise...etc, like:

APT = At Part Throttle flag

- OLDTP = Previous TP sensor value, counts.
- TAR = Throttle Angle Rate of change, deg/sec.
- TP = Throttle position sensor.
- FN331B = A multiplier as a function of the present throttle angle minus the lowest measured throttle angle (TP - RATCH)
- Etc, etc, etc

Adjusting the TPS is a myth....or more proof is needed?

In addition, if such a setting needs to be so precise, it would go against the benefits of having a computer controlling EFI.....or saying
"EFI is better over a carburetor setup because it provides the capability and flexibility to self adjust for changes in temperature, altitude, load, etc, etc......but the throttle position?" or......"they (Ford) provided an EEC system capable of dealing with everything but, the TPS variability normal, and expected, in any 3-wire variable resistor component?"......if that was the case.....what about the other sensors?....

Let us know.......

[jrichker]

Joel5.0: Your information on TPS settings has been incorporated into the main post, and I have given you credit as the authoritative source for the information.

Originally Posted by Joel5.0

In addition, if such a setting needs to be so precise, it would go against the benefits of having a computer controlling EFI.....or saying
"EFI is better over a carburetor setup because it provides the capability and flexibility to self adjust for changes in temperature, altitude, load, etc, etc......but the throttle position?" or......"they (Ford) provided an EEC system capable of dealing with everything but, the TPS variability normal, and expected, in any 3-wire variable resistor component?"......if that was the case.....what about the other sensors?....

I am not sure about the source of these comments, and I am also not sure about what you were trying to say. All the sensors have production tolerances and so does the computer and its input circuitry. Ford made a best case attempt to compensate for variables in sensor values and computer sensitivity. Most of the time, the variables fall within limits and everything works fine. Sometimes the shift of a sensor towards the limits upsets a computer whose hardware input sensitivities are also at or near the acceptable limits. The result is often a car that runs flaky one day and great the next.

[TENGRAM]

Originally Posted by jrichker

Site me a reliable source for the above information and I will gladly make changes.

My personal observation has been that the idle speed increases slighly as the base TPS voltage increases.

the idle speed is likely to raise when you raise TPS voltage with the engine running. this is because you have just shifted it into part-throttle mode. after turning the car off and restarting, the new "base" value for the TPS is recorded and the idle should be back to normal.

as evidence for the falsity of the TPS ".99999" myth, i offer this excerpt from an internal Ford document that was originally intended for their engineers:

[joel5.0]

Originally Posted by jrichker

Joel5.0: Your information on TPS settings has been incorporated into the main post, and I have given you credit as the authoritative source for the information.


I am not sure about the source of these comments, and I am also not sure about what you were trying to say. All the sensors have production tolerances and so does the computer and its input circuitry. Ford made a best case attempt to compensate for variables in sensor values and computer sensitivity. Most of the time, the variables fall within limits and everything works fine. Sometimes the shift of a sensor towards the limits upsets a computer whose hardware input sensitivities are also at or near the acceptable limits. The result is often a car that runs flaky one day and great the next.

And appreciated indeed.......the point I'm trying to make, and the source for the comments, is that the TPS is a non-adjustable device, it's a pass/fail, or G-NG (Go-NoGo) variable the system is capable to provide for w/out problems, as long as the operating window (no failure codes) is complied with otherwise, the problem usually lays elsewhere.

If you look at the strategy, the systems identifies TP state as -1, 0 or 1....-1 being the CT state (minimum reading within .5vdc to 1.19vdc) now, base idle could be set mechanically to 700 rpms and a TPS value of .7 vdc, which would be the same as 700 rpms and a TPS value of 1.09 vdc....anything less would make a carburetor setup gain the upper hand.

My apologies if it was interpreted negatively, that was not my intention...you have provided details regarding the EEC-IV system, and the proper procedure to eliminate the guesswork out of solving problems, that it should be duly acknowledged......I do.....

[vristang]

Man, these last couple of posts have been great!

I have seen my car run differently after setting the tps, but that was because the tps was originally out of range, over 1.2v



While the GUFB can be found on many tuning sites, I have posted it on my site to make it more accessible.
http://www.freewebs.com/vristang/GUFB.pdf

It is long, and can be a tough read sometimes...


jason

[leathernotch]

High Idle

After head install, of iron gt 40's. Car idles at 800 cold once she warms up the car doesn't go below 1400, revving causes the idle to stick and it takes awhile to come back down. Vacuum when the car is cold (800to1000) is about 10 or below. Went through top-end and replaced all gaskets. No change. Why would the car idle correctly when cold?

The car idled at 1400 before we went through and replaced all of the intake gaskets and adjusted valves when we finished she idled the same no change same rpm at 1400 when she is warm. So it has to be another issue

[jrichker]

You definitely have a vacuum leak with 10" of vacuum at idle. I have seen cases where the lower intake manifold gaskets have slipped out of place. This creates a vacuum leak in the lifter valley that is almost undetectable by most normal means.

Check up the fuel injector seals when you replace the gaskets. If the injector plastic pintle cap is missing, the O ring can slide down into the intake manifold.

My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.

When the surfaces are clean, use weather strip adhesive on the head to manifold surface, and on the side of the gasket that mates to the head. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.

Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.

Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. Yea! no leaks, and no gaskets that shifted out of place.

If you reuse the injectors from your old setup, a repair kit is available from most auto parts stores if needed. Coat the injector body "O" rings with oil before you use them and everything will slide back together. Take the other advice you got here and run with it.

Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $2.74 per kit. The following are listed at the Borg-Warner site ( http://www.borg-warner.com ) as being resellers of Borg-Warner parts:

http://www.partsplus.com/ or http://www.autovalue.com/ or http://www.pepboys.com/ or http://www.federatedautoparts.com/

Most of the links above have store locators for find a store in your area.

[leathernotch]

Tell me more about what the O-rings could be causeing. Could they cause the Vac leak w/ out a gas leak? Could I not see a rise in idle w/ the brake cleaner?

I also rechecked the F/P and it was at 50 w/ vac off so I broght it down to 40 and did not see any change. Is that odd.

Could this be the IAC causeing everyting. Because the idle does stick when reved for at least a few seconds at 2000 before droping down to 1400.

[leathernotch]

Unhooked IAC and the car revs and comes down in the Rs just fine but now idles at 1100.

So bad Iac????????????/

[jrichker]

Originally Posted by leathernotch

Tell me more about what the O-rings could be causeing. Could they cause the Vac leak w/ out a gas leak? Could I not see a rise in idle w/ the brake cleaner?

I also rechecked the F/P and it was at 50 w/ vac off so I broght it down to 40 and did not see any change. Is that odd.

Could this be the IAC causeing everyting. Because the idle does stick when reved for at least a few seconds at 2000 before droping down to 1400.

There is an O ring that seals the injector to manifold gap. If those O rings drop down into the manifold because the pintile cap that holds them in place is missing, you will get a vacuum leak.

Diagram courtesy of Tmoss & Stang&2birds
Notice the brown cap on the end of the 19# injector. That is the pintle cap that retains the O ring that is the injector body to manifold seal.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/


Go through the checklist on the first post, there are a number of checks to go through. There is a proceedure to test & set the base mechanical idle. If you cannot set the base mechanical idle on a warm engine, you definitely have a vacuum leak.

[leathernotch]

I am thinking multi problem could the iac be what is keeping the idle at 2k or higher when reved before comeing down, cause it isn't sticking when the iac is unpluged. So I am think O rings and the IAC I just bought and did the rebuild kit for the injectors on a friends car so I know where to get them just trying to figure out if it is causeing everything or maybe just the raised idle and not the sticking up high
'

[TENGRAM]

Originally Posted by leathernotch

I am thinking multi problem could the iac be what is keeping the idle at 2k or higher when reved before comeing down, cause it isn't sticking when the iac is unpluged. So I am think O rings and the IAC I just bought and did the rebuild kit for the injectors on a friends car so I know where to get them just trying to figure out if it is causeing everything or maybe just the raised idle and not the sticking up high
'

the hanging rpm you are experiencing is called "dashpot". its supposed to do that a little bit. once your idle is lowered to the appropriate rpm it will not be an issue. focus on the vacuum leak possibility and getting your idle right. my2cents

[Skoobie]

This isn't in responce to a particular post but I thought I would throw it in for users of the IAC adjustment plate. I've had a vac leak for a LONG time that i could not track down. When I got the car the previous owner had installed the adjuster plate. When I had a vac line fail (before I knew what was going on) I tried to compensate for the loss of idle control with the plate by opening the screw more. Well eventually I discovered the bad vac line and replaced it but I forgot about the plate I had adjusted. Well for months I delt with a crappy idle and MAJOR hesitation in the lower rpms. I was about to burn the whole car when my buddy made a comment about how loud my intake was. I had gotten so use to the noise I hadent thought about it until he started his car (same CAI) and he had next to no noise...so I worked my way up the intake path until I got to the plate. I started to tighten the adjustment screw and low and behold the noise went away and my idle started to stabilize....I was extatic and pissed all at once The plate had been opened so far it was creating a huge vacuum leak. Kind of like White Pony's problem with his throttle blade. So if you own one of those plates make sure you have it set right or they will do far more harm then good.

[leathernotch]

Check the TPS over and it was at 1.11 so I dialed it down to .90 then reset the battery. Now I have started her a few times and she is idleing at 1k and the vac is reading 13
Is that really low??
I have the B cam w/ 1.7s

[leathernotch]

I have the adj for the tps but what does the one for the iac look like?????

[leathernotch]

Replaced the IAC and she warmed up and Idled at 700, but the vac is reading 10. So........ vac leak wasn't idle issue?????

[Skoobie]

Originally Posted by leathernotch

Check the TPS over and it was at 1.11 so I dialed it down to .90 then reset the battery. Now I have started her a few times and she is idleing at 1k and the vac is reading 13
Is that really low??
I have the B cam w/ 1.7s

Thats about a normal hg for that cam. I run an E cam and have 12-13hg

[webslinger67]

i think i might have been incorrect, but, i want to clear the codes from my EECM , how do i do that? I have already read them, now i just wanna clear them..