Fuel Pump/Tank: Update post 40 February 27, 2010, 07:56:54 PM Brought home an 87 today, 5.0, 121k.Trailered it from San Antonio. Car is a little hard to start, but once it starts, it idles pretty well. The very second you put a load on it, it stumbles and dies. Sometimes you can get it in drive, but if you breathe on the gas pedal, it dies. You can rev it a little in park, or nuetral, but not under a load.The car sat for awhile, per the previous owner, couple years. He claims he started it a couple times a month, but who knows. Im thinking fuel filter, or some other obstruction? Starting and idling seems to tell me the spark is there, but the second you need more than that, no can do.Good reasoning???Ideas?Thanks in advance.yeah I know, pics. Pretty cool, the guy was in the military, and bought this thing in puppiesan, previous owner is listed in puppiesan, and the car has puppiesanese inspection and emission stickers. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #1 – February 27, 2010, 08:15:41 PM My 5.0 Bird did that.....it had a dying fuel pump. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #2 – February 27, 2010, 08:24:40 PM hahahahahpulled codes.23 TPS sensor. I look over, touched it. IT FELL OFF. The screws were still on it, but it was completely backed off..98v key on engine off right? Quote Selected
Fuel Pump/Tank: Update post 40 Reply #3 – February 27, 2010, 08:43:45 PM Yeah .98, but the TPS is self adjusting via the PCM. Is your fuel pump loud? My bet is on the filter, but be prepared to do a pump in the future. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #4 – February 27, 2010, 08:49:44 PM Quote from: jandmmustangs;311840Yeah .98, but the TPS is self adjusting via the PCM. .cite your proof on that one,,,,no the tps is not self adjusting, perhaps in limp mode yes as the chart built into the firmware will at some defective point take over.use a rat tail file to oblong the mounting holes so when you install the TPS, you can rotate the sucker ccw or cw to obtain the .6 to .9vdc on the green wire to chassis or black wire. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #5 – February 27, 2010, 09:07:23 PM I was using a very basic term (self adjusting)The computer in your car only looks for a reasonable range of TPS voltages at idle. That voltage range is .6 volts to 1.1 volts. If idle throttle voltage is outside that range you should get a check engine warning light.The next significant engine trigger is WOT, which is about 2.71 volts above the idle voltage. If the car idles at .8 volts, the computer thinks anything over 3.51 is wide open throttle. All of this is measured between the green and black wires on the TPS, NOT between the block or chassis and the green wire.If it is between .6 to 1.1 volts nothing will change with an adjustment.If it makes **you** or the tuner "feel good" (it won't affect the tune one bit if the TPS is anywhere in range) you can hog out the holes a little and adjust the TPS for middle range at idle. But you should also check the voltage over the range of the accelerator and be sure it smoothly increases to some voltage well beyond base idle voltage plus 2.71. Otherwise the computer won't go into WOT open loop mode.Another example, if it idles at 1 volt the EEC will learn that is idle, and then it will consider 1+2.71=3.71 or higher as a WOT call. WOT is always 2.71 more than idle. Be sure it does that, and be sure it is between .6 and 1.1 volts at idleMost of the time an idle problem is in the IAC, or someone has used the throttle stop as a idle set screw. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #6 – February 27, 2010, 09:10:25 PM Got the tps adjusted, but I did it to ground, ill have to check vs black in the morning.It runs a tad better, but still dies after about 30 seconds, or as soon as you look at the gas pedal.Going to check fuel pressure in the morning. Probably do a filter either way, but still check before and after.Thanks again, ill post updates, and pics tomm. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #7 – February 27, 2010, 09:13:05 PM Also this. Im by no means the be all end all of Ford EEC info but ive never touched my TPS on any of my carsA Ford TPS on a Ford TB with the idle screw set properly is plug and play. There is no adjustment at all for the TPS. The TPS is non-adjustable. It never has been, and never will be. :) People will adapt the TPS when they use a non-Ford TB or they adjust the idle screw up high. You can't adjust a non-adjustable part. :) Basic grade school grammar tells us that. :) No Stang TPS has ever been adjustable! People adapt the TPS by elongating the holes so that the TPS is between ~0.6v an ~1.2V at startup. All Stang EEC (86+) "Zero-out" the TPS at startup. They also look for "invalid start-up voltages" for the TPS. That's why it has to be between ~0.6v an ~1.1V. So, ~1v is easy to remember. However, as long as the TPS is between ~0.6v an ~1.1V, it won't make any difference at all. So, if you have a Ford TPS, a Ford TB, and the idle screw is set properly, Vref to the TPS is ~5V, then the TPS should be under ~1.1v at idle. If it is not, then you have a bad TPS. Get a new Ford TPS. Don't waste your time or money on a non-Ford TPS - they're all junk. For all Mustangs with EFI from the factory, the TPS is zeroed out at start up. That *includes* the SD EEC-IV's. Most Stang EEC's set WOT at ~2.7 volts over the turn-on voltage of the TPS. The main purpose of the TPS, in normal driving, is to add "accelerator pump" or the dash-pot function when there is a "quick" change in the throttle. The MAF (vacuum for SD) is slow to respond, and the O2's are super slow. So, the EEC uses the rate of change of the TPS along with the RPM to "estimate" the proper amount of additional/reduced fuel for the desired A/F ratio. When the MAF (vacuum for SD) catches up, the EEC can "better estimate" the desired injector pulse width for the desired A/F. However, it's really the O2's that determine a ton of stuff. At WOT, the EEC uses the trim, the MAF output (vacuum & RPM for SD), and special WOT tables to calculate the fuel. Of course, those tables are often set to be on the rich side in order to prevent pre-detonation. But, being too rich does cost HP. So, some tuners can adjust those WOT tables for a specific engine and set up and get you "a few more HP". The sensors run off of ~5v from the EEC (Vref). Vref to the sensors can vary by ~+/- 5%. So, you can't set the TPS at the "max spec" that Ford allows, because Vref varies over temperature, load, battery/alternator load, etc. The TPS resistance and the tang on the throttle vary over temperature and age. The EEC ADC (buttstuffog to Digital Converter) has a couple of "counts" of noise and is accurate to only a few "counts". Then, there are many more real-life issues that go into doing a full buttstuffysis. For something like the TPS, it would take about total of man month of time (from all of the different departments) to do a full and accurate buttstuffysis. Most big companies take that time. Some companies will do a "quick estimate" and make sure they leave plenty of room for error. You can't set your TPS to 1.20 volts at idle and just see if the EEC doesn't give an error code. Over time, temperature, age, and battery voltage, that setting will vary. There is also the consideration of how accurate your meter is and how accurately you get a reading (by measuring the TPS output and TPS ground wire directly). So, that's why it's suggested to make sure your TPS is between ~0.6V and ~1.1V at idle. But, saying ~1V is easy to remember. So, that's where that "magic" value came from. :) See pages 88 & 89 in Probst. All of the rotary TPS (sensors) with an EEC IV/V have had the EEC zero out the TPS. That includes all stang EFIs. So, from 86+, all stang EEC's have had the EEC zero out the TPS. The 94/95 EEC's add in more error checking on the TPS. They had bigger proms. So, the algorithms, and diags are much more complete/ involved/ robust/ complicated. With 94/95's, you can also read the sensor and trim values with a scanner via the EEC extended diag protocol. BTW: The quote from Probst: Recent Ford systems, all EEC since 1988, use a Rotary TP. The potentiometer increases resistance as the throttle shaft rotates. It is not adjustable, but the control-module programming compensates for the differences in sensors, readjusting to a base voltage when the throttle is closed. See the book by Probst. The TPS does basically Four things: o Tells the EEC the engine is at idle. Compares start-up voltage with current voltage and the rate of change of change of the TPS. o Determines WOT (Wide Open Throttle - open loop - "Max HP" no emissions needed). For most EEC's it's ~2.7v over the start-up voltage of the EEC. So, if your TPS was 0.8V at start-up, WOT is at 3.5v. If your TPS was 1.0V at start-up, WOT is at 3.7v. o Tells the EEC that the driver wants to accelerate. The MAF, and RPMs lag. The TPS is the first indication. The EEC will add fuel (accel pump) depending on rate of change, RPM, etc for a Short time until the MAF catches up to the new air flow. o Tells the EEC that the driver wants to decelerate. Similar to above. Except, that the EEC adds "dashpot" to the fuel calculation for a smooth transition. What is does not do: o No Stang TPS sets the idle speed or mixture. o It does not effect the A/F (rich/lean) mixture in any way other than for the accel/decel conditions that I described above. o It does not matter at all what the TPS voltage is set at as long as it's always between ~0.6v and ~1.1v at idle. The +5V Vref can vary by ~5%. So, when the FORD TPS is adapted to a Non-Ford TB, it's "suggested" that you set the TPS to below 1v. =============================== There are absolutely no slots in TPS for a Stang (type D/RD). :) One hole is a very slightly larger than the screw. The other is "oblong" to help in mounting. Some people mistake that "oblong hole" for a "slot". That's fair. The difference could be considered "semantics". But, for a technical answer/ paper/ article semantics are critical! The same is true of the terms adjusting and adapting. If I say that something is a circle and someone else calls it a square, then there's a misunderstanding somewhere. There are tolerances in the plastic of the TPS and the screw holes in the TB. The oblong hole is there on the TPS to allow for looser tolerances on those parts. Therefore, they are cheaper to make. However, regardless of how you put a Ford TPS on a Ford TB, it's always plug and play. That's part of the job of the EEC-IV & EEC-V. Having the "computer/ software/ firmware/ ASIC/ FPGA" zero out sensors is a very common practice in hardware. You will never ever find or see anything from Ford that even remotely hints at adjusting that type of TPS. Ford did have an older style TPS (Level C) that was used mostly with the POS EEC-III's computers. Those "Level C" TPS units had to be adjusted. The EEC-III was such a POS if the temp sensor went bad, or if the wire to the temp sensor broke, then the engine would die. Today, if Ford or another car company had a ECM that did that, they would be sued out of business. When Ford switched to the EEC-IV's they still left the old TB's on some models for a while until the next update of the engine components. Also, until ~1989, Ford had problems making the D/RD TPS units with a proper seal from water. So, they kept using the Level C units until they where sure they could make the new TPS units reliable and also update the all of the needed TB's. From a Ford dealer Service manual: Quote Selected
Fuel Pump/Tank: Update post 40 Reply #8 – February 27, 2010, 09:23:35 PM Quote from: mtgmike;311852Got the tps adjusted, but I did it to ground, ill have to check vs black in the morning.It runs a tad better, but still dies after about 30 seconds, or as soon as you look at the gas pedal.Going to check fuel pressure in the morning. Probably do a filter either way, but still check before and after.Thanks again, ill post updates, and pics tomm.you can groung the tan/light green wire at the self test conn to make the pump run full time with the key on so you can get a decent fuel pres reading. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #9 – February 27, 2010, 09:27:06 PM Quote from: jandmmustangs;311855A Ford TPS on a Ford TB with the idle screw set properly is plug and play. There is no adjustment at all for the TPS. The TPS is non-adjustable. :nice but i will call the bluff on the above. years ago the mounting holes on the tps were both oblong. now they are not.anyone know why they were oblong?I do not know if i have an older tps in the garage or not, ive mentioned this a lot but no one picks up on it. in various JY runs, I will try and find an older car with the mounting holes oblong.actually, now that i think about it, in the late 90's one hole on the tps was oblong and the other round, nowadays they both are round. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #10 – February 27, 2010, 09:29:47 PM Let's agree to disagree, and not hijack the OP's thread. If it makes you feel better to adjust the TPS go for it. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #11 – February 27, 2010, 09:39:05 PM i guess my point is that you can line up a dozen tps's (off brand or motor craft and arrive at different resistivity at the same rotation in degrees, as well- arrive at total resistance from yellow to black being different as well.without books,, i sat there at my work bench and did this. It occured to me that there must be some huge tolerance here , perhaps thats what I am seeing as i tie it to your info above.what i do know is that its harder to get a tps to tune in at .9vdc with a max resistance of 4.4k than it is for a tps with a max resistance of 4.8k or better. Now that makes perfect sense to me. when I buy one, i judge them by thier capability to divide voltage,,ie- the greater max resistance, the more accuratly they can divide voltage. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #12 – February 27, 2010, 09:42:41 PM Quote from: jandmmustangs;311861Let's agree to disagree, and not hijack the OP's thread. If it makes you feel better to adjust the TPS go for it.point taken but you have to understand that good info is more imporatant, you have to ask yourself why myself and everyone else make it a habbit to tune the tps and have been doing so for years.the problems were the direct mounting of a tps out of the box 50% of the time yielded a high idle condition.the rememedy was obvious, tune the tps.we dont disagree, we share info but its gotta be the best info with no reguard to anything other than experience first and foremost. Quote Selected
Fuel Pump/Tank: Update post 40 Reply #13 – February 28, 2010, 09:47:36 AM Key on, engine off, fuel pressure blipped a hair when the pump tunrned on, but went back to 0. At idle, vacumm off, FP was 32 psi. Went straight to 0 went the car shut off. Tells me the regulator is definitely bleeding down, but pressure was ok while it was running...Previous owner just told me he replaced the filter, regulator, and ign module trying to trace this down, so Im back scratching my head? Quote Selected
Fuel Pump/Tank: Update post 40 Reply #14 – February 28, 2010, 10:57:15 AM Checked timing, dist was loose. Set it and car picked up, but still dies after about 30 seconds. Pulled codes again, 14-pip sensor. Its Sunday, so I guess im going to have to roll a parts store distributor for awhile. Quote Selected
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