It's not necessary to adjust the TPS. It is reference by the EEC at startup and scaled.
Might [might] be necessary with a new TPS is a Base Idle Reset.
Might [might] be necessary with a new TPS is a Base Idle Reset.
Vacuum line help
- Thread starter Artyom
- Start date
-
- Tags
- 95 5.0 hesitation vacuum line
-
Sponsors (?)
I think it’s safe to say the computer has been reset many times. It may be dumb to think, but is it trying to relearn?
I’m not sure why, but the car has recently now developed a struggle to start and stay alive? I have to give it rpms to keep it from stalling, but keeping the rpms at a stable 500-600 it will stay running. This makes it a slight issue to pull codes for KOER.
I’m not sure why, but the car has recently now developed a struggle to start and stay alive? I have to give it rpms to keep it from stalling, but keeping the rpms at a stable 500-600 it will stay running. This makes it a slight issue to pull codes for KOER.
Courtesy LMR:
Please Note: These steps MUST be performed in sequence.
1986-1995 Mustang Idle Setting Procedure
Please Note: These steps MUST be performed in sequence.
- Get engine to operating temperature.
- Disconnect IAC (Idle Air Control) Solenoid. If the engine stalls, turn the throttle-stop screw in one full turn and restart. Repeat as necessary until the engine will idle with IAC unplugged.
- Set idle using throttle stop. Idle speed will vary depending upon modifications made to the engine. Set to where you are comfortable with idle speed.
- Set TPS (Throttle Position Sensor) anywhere from .96 to .98 volts. This is done by loosening the mounting screws and lightly rotating TPS. If you cannot obtain the desired range, you may need to make the mounting holes slightly larger. This can be done by drilling them.
- TPS wire colors to be probed are generally BLACK and GREEN wire or the GRAY/RED and GRAY/WHITE, depending on your vehicle.
- Stop engine. Disconnect negative terminal battery cable for 15-20 minutes. You may wish to tap the brakes or turn the headlights on and off a few times as this will help to ensure that you have purged any remaining electrical current from the vehicle.
- Reconnect IAC Solenoid
- Reconnect battery cable to the negative terminal
- Restart engine.
- If problem persists, inspect for mass air meter problems and possible vacuum leaks.
89ripper
Founding Member
Its not "relearning" to stay running. By resetting ecu its wiped of the dtcs that were set in the memory, it has cold start files and when it reaches operating temp it monitors data from the various sensors to determine where the issues are you need to fix. What was the reason for all the various vacuum line fittings again? It really sounds like vacuum leaks still...
Ah ok, good to know! Sorry for the confusion there.
The vacuum line fittings where the main vac is plumbed into is to try and replicate the little metal vacuum tree that screws onto the lower part of the upper intake. I could try to reroute some stuff and see if it changes anything.
Could vacuum issues be the reason my car is running pretty rich? It seems like on the forums it’s divided. Either it causes it to run rich or lean.
The vacuum line fittings where the main vac is plumbed into is to try and replicate the little metal vacuum tree that screws onto the lower part of the upper intake. I could try to reroute some stuff and see if it changes anything.
Could vacuum issues be the reason my car is running pretty rich? It seems like on the forums it’s divided. Either it causes it to run rich or lean.
Jeeze, you're jumping around, do the 'surging idle checklist '
www.stangnet.com
Do it step by step.
If you keep changing things and try'n stuff you could be making things worse and confusing everybody trying to help.,
Take notes and ask any questions in this thread.
Did you buy this car running poorly?
Help me create the "Surging Idle Checklist"
Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank...
www.stangnet.com
If you keep changing things and try'n stuff you could be making things worse and confusing everybody trying to help.,
Take notes and ask any questions in this thread.
Did you buy this car running poorly?
Wow... There are [so] many things that can effect the answer to this question.
If you have a vacuum leak then you are introducing unmetered air into the system. Your O2 sensors will detect this lean condition and [try] to compensate for it. The location of the leak will vary the effects of a malfunction. If it's just one bank then one side will try and richen up but can still run [lean].
If you have a cylinder misfiring then it pumps unspent O2 to the O2 sensor along with unspent fuel. This particular condition snowballs as the additional oxygen makes the o2 sensors thing that the system is [lean] and again, try to compensate.
Too many people conflate the EEC's ability to "adapt" to some ability to make up for mechanical discrepancies. This is just not true.
As your vacuum system. I would begin by removing all the BS to extra gauges you might have. Get rid of it all and get down to the bare bones vacuum lines that you need to operate. Make sure the system is sealed. I've seen more Vac/boost gauge installations cause issues than any other single item aside from "modified"
throttle bodies.Are you running any vented valve cover caps or anything like that? Catch cans? Oil separators? Get rid of it all.
What vacuum source is running the PCV and Brake Booster? If it's the same source, that's not going work. Too much volume from a single source.
Once you get to the basics you can consider what you want to add back in.
All Vac lines are stock, I have no aftermarket gauges. Along with no catch cans or any of that.
I’ll attach a reference image on how I have my vac lines hooked up to my trick flow intake. So the main vac comes in on one side, that feeds the FPR and the EVR. The port right across from that has the PCV hose.
I’ll pull codes again soon, if the car can hold idle or run even.
Right now the codes I’ve been getting since owning the car has been 121, and codes for both O2 sensors returning a rich code. I did try to pull codes a few weeks ago but I just get a code for the car not being able to control rpms or something during KOER.
I’ll attach a reference image on how I have my vac lines hooked up to my trick flow intake. So the main vac comes in on one side, that feeds the FPR and the EVR. The port right across from that has the PCV hose.
I’ll pull codes again soon, if the car can hold idle or run even.
Right now the codes I’ve been getting since owning the car has been 121, and codes for both O2 sensors returning a rich code. I did try to pull codes a few weeks ago but I just get a code for the car not being able to control rpms or something during KOER.
I found that the TPS has 0 volts probing the gray/white wire to the black/white wire (in my case for whatever reason the black/white wire is red/white). Probing each wire to a good ground the brown/white wire has around 5 volts, white/gray wire has around 1.3 volts, and the white/red wire has .02 volts. I’m not sure if I’m probing the TPS wires correctly. They were exposing a little bit of copper at the connector so I used electrical tape to make sure they weren’t shorting to each other (yes I have a new pigtail I will solder in later). The car would finally start up without having to keep pumping the gas.
I do have to keep RPMs stable until it can idle on its own. After it slowly warmed up it would hold idle just fine, no surging. But giving it gas and letting off can cause it to stall/have poor idle again.
The timing seems ok? Not sure if it’s the spark or just a bad timing gun but sometimes the light will not flash consistently? Causing readings to be confusing but I think I can be confident the timing is still at 10 degrees. I’m still also noticing a slight knock/tick coming from the passenger side of the engine ever since it’s ran poorly.
I do have to keep RPMs stable until it can idle on its own. After it slowly warmed up it would hold idle just fine, no surging. But giving it gas and letting off can cause it to stall/have poor idle again.
The timing seems ok? Not sure if it’s the spark or just a bad timing gun but sometimes the light will not flash consistently? Causing readings to be confusing but I think I can be confident the timing is still at 10 degrees. I’m still also noticing a slight knock/tick coming from the passenger side of the engine ever since it’s ran poorly.
Last edited:
89ripper
Founding Member
Sounds like you have some wiring issue on your tps if you cant get a correct reading. The tps is important for the ecu to be able to have a reference for idling, which is probably why you have to keep rpms stable.
I had a code for my tps out of range and had some of the symptoms you have. Make sure you have a good timing light and the marks are clear on your balancer. Also something to consider balancers do go bad overtime so make sure nothing "walked" down there
I had a code for my tps out of range and had some of the symptoms you have. Make sure you have a good timing light and the marks are clear on your balancer. Also something to consider balancers do go bad overtime so make sure nothing "walked" down there
hmmm ok. I’ll get that new pigtail connector wired in as soon as I can hopefully it will make a difference. I still have a few things to test from the surging idle list.
Looks like a previous owner had done it right and have 10 degrees marked in red, then a white mark a few degrees out on both sides of the red mark. How do you check if the balancer is spun or “walked”? Is it just turning it to TDC and checking the #1 cylinder is at TDC?
When I had the spout pulled and checked the timing with the gun at 10 degrees, the red mark would line up with the timing mark. Originally I thought my engine was way out of time because I had accidentally left the spout in and that made my readings very off.
Looks like a previous owner had done it right and have 10 degrees marked in red, then a white mark a few degrees out on both sides of the red mark. How do you check if the balancer is spun or “walked”? Is it just turning it to TDC and checking the #1 cylinder is at TDC?
When I had the spout pulled and checked the timing with the gun at 10 degrees, the red mark would line up with the timing mark. Originally I thought my engine was way out of time because I had accidentally left the spout in and that made my readings very off.
89ripper
Founding Member
Im sure your balancer is fine, just was something to consider if you werent able to check your timing. Are you confident you are at 10 deg? Get that tps situated and next work on the base idle reset/surging idle
I’m still new to the whole timing thing, only thing that confuses me is the inconsistent flashes from the timing gun at times. I was thinking maybe that is a sign of something wrong with the ignition system or the gun itself. But that’s a whole other thing. Just going to focus on replacing this wire.
I also tested the IAC at idle and I’m getting 13-14 volts. The trouble shooting forum mentions measuring between both wires you should get .5-12 volts. I get 13-14 volts still. So maybe there is still a problem with that wire as well?
I also tested the IAC at idle and I’m getting 13-14 volts. The trouble shooting forum mentions measuring between both wires you should get .5-12 volts. I get 13-14 volts still. So maybe there is still a problem with that wire as well?
89ripper
Founding Member
Think so? The 20 volt DCV.
Also I found something concerning I think. Had to take off all the intake stuff again to comfortably get at the wires I need to replace. I also need to retap the holes that bolt the upper intake to the lower because a few screws don't tighten properly. I’m finding someone used helicoils everywhere!!
I noticed the upper intake reeked of the pcv smell, if you get what I’m saying? The middle most runner was also wet? Like condensation, and you could see it on the gasket too. Is this a sign that my pcv hoses aren’t hooked up right or the system is not working properly? Or something worse?
89ripper
Founding Member
As long as the pcv valve "clicks" and is not gummed up i wouldnt worry about it. Is the gasket wet too or what is that on there that im looking at? Looks like sealant...get a new gasket and clean that up..
Similar threads
