Fighting a high idle...HO swap related Reply #15 – April 16, 2012, 09:55:41 PM I forget what the allowable pressure drop limit is. Anything over the limit would indicate either bad injector(s) or fuel pump check valve. Quote Selected
Fighting a high idle...HO swap related Reply #16 – April 16, 2012, 10:36:51 PM Don't worry about pressure fall off after shutdown unless it's almost instant...You need to be sure it's maintaining 39psi at WOT under load... This means you'll have to put a extension on your gauge so it can be seen while driving, or you'll have to convince a buddy to set on the fender while you make a WOT run up to 60-70MPH... Quote Selected
Fighting a high idle...HO swap related Reply #17 – April 16, 2012, 11:52:25 PM Fix your idle issue before worrying about fuel pressure, seriously.What codes do you have?Your tps should not read anywhere near 1.7v's. Its not even functioning if its above 1.18 or so when you turn the key on. Fix this first. Make sure your throttle cable has the full range of motion and that the throttle boddy is closed while pedal is off. Sometimes the throttle valce (or ghetto fixes) can bind and not allow the car to return back to idle specs. This will make the car hunt for idle. If you have no leaks, this *should* be a 5 minute base idle reset.Figure out why its reading so high and go from there, also check the ground cable that runs from battery, to fender, to the fuel injection harness. When this is fixxed, run codes. Its the easy button. Quote Selected
Fighting a high idle...HO swap related Reply #18 – April 17, 2012, 12:21:01 AM QuoteYour tps should not read anywhere near 1.7v's. Its not even functioning if its above 1.18 or so when you turn the key on. Fix this first.According to his first post, he did fix it.....QuoteI slotted both sides of the TPS and got it down to .97 with the key on and 1.17 when it's running. The idle is still high and still has the miss at idle.I'll agree and say reset your base idle first and go from there. Quote Selected
Fighting a high idle...HO swap related Reply #19 – April 17, 2012, 05:16:30 AM I had a bad IAC that was stuck and allowing air past so I couldn't idle down. I made a block off gasket to temporarily check it before I got a new one. Do get that TPS set right. Quote Selected
Fighting a high idle...HO swap related Reply #20 – April 17, 2012, 03:05:07 PM Every tps I have seen with a higher voltage at idle, the pots are worn out. That is what makes them read funky, and it causes the dead spots as you run through the throttle range. If the gas pedal even gets touched above his first reading while cranking, the tps will not function the entire time the car is running. In my opinion, adjusting it is just trying to temporary lengthen the time you can get by without replacing it.It should read around 1v at idle, max out about 2.5v above idle or higher with a smooth ramp up in voltage. This should be checked and fixed before anything except codes getting pulled. It is also possible the iac is frozen, but there's no point in throwing time and money into it before you know what the problem is.When I do a base idle reset, I pop the hood with the key on, check voltage on the tps. If it ramps up smooth and has good minimum and maximum, I start the car, unplug the iac, turn the throttle screw down until the ccar barely runs, plug in iac. Done, never screw with it again, unless you have some codes getting tripped, or have vacuum lines or gasket sealing issues.But I'm the one to talk, my crownvic shoots up really high and stays there, until it warms up, then it runs okay. Still haven't even pulled codes on it or anything. Quote Selected
Fighting a high idle...HO swap related Reply #21 – April 17, 2012, 03:30:43 PM QuoteEvery tps I have seen with a higher voltage at idle, the pots are worn outI'm wondering from his description on this how far the set screw has been turned on the TB.QuoteIt should read around 1v at idle, max out about 2.5v above idle or higher with a smooth ramp up in voltage. This should be checked and fixed before anything except codes getting pulled.From SBFtech:QuoteAdjusting the TPS......a case in MythologySummarized EEC-IV logic for the TPS......The following is a very short explanation of the EEC-IV Idle/TPS Strategy as contained in the EEC-IV Strategy Book - GUFB. Every time the Ign Switch is turned to the ON position.....the EEC-IV will do the following for the TPS signal: Minimum voltage at closed throttle over .49 vdc. , less than .49 and codes 23 and 63 will set as failures. SOS Urgent Max voltage closed throttle should not exceed 1.2 vdc, or codes 23 & 53 will set as failures. SOS Urgent TPS voltage between .5vdc and 1.19 = no codes, TPS ...then EEC-IV system is OK! (TPS wise)►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:QuoteThe variable RATCH is the output of a ratchet algorithm which continuously seeks the minimum throttle angle corresponding to a CLOSED THROTTLE position. This alleviates the necessity to set the throttle position sensor at an absolute position and compensates for system changes and differences between vehicles. The ratchet algorithm uses filtered throttle position for the determination of RATCH.► 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 Quote Selected
Fighting a high idle...HO swap related Reply #22 – April 17, 2012, 04:25:03 PM UPDATE....here's the latest.I pulled the TPS off of the TB but left it plugged in and then turned on the key. It reads .95v. So I bolted it back on and it read mid-.9v.So I set up to do the base idle reset. Had the battery and IAC unhooked for a while...at least an hour. Hook battery back up and try to start the car...would not run. I kept tweaking the TB adjustment until it would stay running. It idled right on 700...GREAT!!! Shut the car off, plug IAC back in and start it up....idle went right to 2,000 so I shut it off. Now, I did clean the IAC last week and the rod moved freely. Going to see if I have another to swap on and try.Your thoughts?? I really appreciate the help guys!! Quote Selected
Fighting a high idle...HO swap related Reply #23 – April 17, 2012, 07:16:56 PM When I swapped on a stang upper I used all the parts off of it, and had the time of my life getting it to work, same thing as you. The tps wasn't sitting right on the throttle shaft, giving me odd readings, the idle screw was set very high. After going over it again, swapped the tps and iac from the old one, plugged some vacuum lines, no more problems.If it doesn't calm down to idle after 30 seconds or so,see If you have aanother iac I would try that. If not, run codes and let us know. There are also some codes that will cause the computer to run in fail safe mode. This can cause the computer to ignore all kinds of sensors, and even run funny. Quote Selected
Fighting a high idle...HO swap related Reply #24 – April 17, 2012, 07:20:01 PM Also, the car will rev the engine up higher for about 30 seconds, then kick back down. Hop in the car and go for a drive. There is no reason to leave the car running before you try it. It should drive realatively normal quickly. If its set up properly, it shouldn't die or buck at all. Quote Selected
Fighting a high idle...HO swap related Reply #25 – April 17, 2012, 08:14:50 PM ANOTHER UPDATE:Swapped on another IAC. Idle with it unhooked is fine. Plug it in and the idle goes high, close to 2,000. So you are saying leave it run to see if the idle calms down??Also, I don't have a code scanner. Quote Selected
Fighting a high idle...HO swap related Reply #26 – April 17, 2012, 08:38:02 PM Probably not your problem, but the PO installed my IAC upside down, and it was causing it to idle too high. Quote Selected
Fighting a high idle...HO swap related Reply #27 – April 17, 2012, 09:54:39 PM If the idle is OK with IAC disconnected but too high with it connected, you likely have too high TPS voltage... IAC is only responding to info received... Quote Selected
Fighting a high idle...HO swap related Reply #28 – April 17, 2012, 10:00:19 PM Yes leave it running for a minute or two, see if it calms down. It should rev a bit high for a few seconds at the beginning of the startup. the iac is how the computer controls idle. It has to re-learn the idle, and it can take a minute or two. How does it act in drive, and is the tps voltage good through the whole sweep?Also, you can run cdes with a paperclip, ir your check engine light works from the drivers seat. If not, you can use a test light, a buttstuffog volt meter, I've even use a tail light with two wires soldered to it. All the fancy pants scanners do is beep. It beeps in stead of lighting up.Go to oldfuelinjection.com and read the how to run codes. It will literally take you two minutes, then we will know what's wrong instead of guessing. Quote Selected
Fighting a high idle...HO swap related Reply #29 – April 17, 2012, 10:03:13 PM http://sbftech.com/index.php/topic,2471.0.htmlHere you go, read though this. Shows you how to run codes, even has a video or two to show you what to look for. Quote Selected
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