Recently finished the HO conversion on my 1988 T-bird Sport Coupe. I put in a '88 Mustang GT motor, Explorer upper/lower intake, 70mm BBK TB/EGR, under drive pulleys, 1-5/8" shorties, 2.5" BBK offroad H, Flowmaster lers. Also used stock HO injectors (orange top) and a BBK FPR w/ gauge. The car also still runs SD w/ a DA9 computer and T5, I did not do the MAF conversion.
Here's the problems.
First....high idle. It hold steady at 1200rpm. Friday I tore the intake off to search for vacspooge leaks and found none....all the lines are either hooked up or plugged if not used. Also cleaned the TB, IAC and blocked off the EGR (it was in the way of the FP gauge). I adjusted the throttle screw and it did not help.
Second...it's got a sputter. When setting still at idle (1200rpm) it sounds like it has a miss. The FP is steady at 39#, drops to mid 30's when floored. When adding fuel and setting still (under no load) the sputter is mid-RPM (2500-ish) but floor it then it rips to 6K. The other sputter is driving....when accelerating smooth it goes along good. Floor it and the car goes flat, not fall on its face flat, but just does not go any faster. Back off the pedal a little bit and it picks up smooth.
I also tried to check the TPS voltage today. It was reading 1.7-1.9. I 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. It was raining so I did not take it for a ride, hopefully Sunday I can take it out.
When stopped on the road I can rev it up to 4K and side step the clutch...it will hone the tires and rev to 6K nicely till I lift or the car catches up to the tires. Occassionally when I do this and lift, it will pop back through the TB.
I think that is about all and I'm not leaving anything out.
Any ideas??? Looking for help here......want to get this thing going.
How old are your plugs, wires and fuel filter? Plugs gapped correctly? No plugwires crossing or touching each other? I would think a 70mm throttle body would be pushing it on an SD setup. Any codes or CEL? Maybe you have a dirty injector?
The TB size aint an issue. I'm of the opinion that you need to reset your base idle.
http://sbftech.com/index.php/topic,1031.0.html
X2, also the voltage for your tps shouldn't change if the car is on or off.
Do a idle reset, run codes, check grounds, and work from there.
If you can disconnect the IAC and set base idle to 600 RPM, you don't have a vac leak problem...
As mentioned, the voltage should not change with the engine running, if there isn't a wiring issue you may have a bad ECM... Anything over 1.1v(maybe even a little less) will cause a high/hanging idle, I like to see voltage around .85 to .90v max(forget the set to .99999 , it's BS)... You can reinstall the orig ECM long enough to verify voltage is or isn't correct with it...
Once the base idle is correct, then set TPS voltage...
Fuel pressure should hold 39psi at WOT, if not you have a restriction(maybe clogged fuel filter) or weak pump...
How are you measuring/checking the pressure?
Fuel pressure should not drop off at WOT. Change your filter. If that doesnt help, put in a bigger pump. The stock pumps are only good for 75 lph and probably less if its old. You might be able to improve the idle by adjusting the tps. I would check the timing also.
A brand new stock pump runs around 35psi under loaded wot, tested off the fuel shcrader. Could be my harbor freight guage too. As long as its 30-40psi, it has nothing to do with your idle.
Replace your tps. It should read below 1.2 volts at idle, but more importantly, it should not have any dead spots while throttle goes up. With key off, run the throttle up. Any dead spots, and its garbage. Fix this very first. I would also worry about the lower intake sealing well, which can cause a leak.
Check the ground wire for the ecm, its right next to the battery. You voltage might flucuate some if you have a bad ground.
I have a guage right on the BBK regulator.
Are you checking with the vacuum line on or off?
FP? With vac line on.
Also swapped the TPS for another one I had. Still reading way high.....1.7. Should I slot the holes on this one?
Check the voltage with the TPS removed from the TB, if it's still high you have a bad TPS, wiring or ECM issue...
In park this is actually normal for the pressure to drop a little when you check with the vacuum line in place.
Read the following thread: http://www.foxtbirdcougarforums.com/showthread.php?18145-Vacuum-increase-at-part-throttle-!!-Apparently-It-s-OK-in-park....-Solved!&highlight=
I saw a little tidbit in that thread about fuel pressure drop after shut off. I noticed that mine drops down to the mid 20's soon after shut off. You saw something about dropping to 30 a certain period of time after shut off being acceptable. If mine is dropping so fast and lower than 30#, does that indicate something??
I forget what the allowable pressure drop limit is. Anything over the limit would indicate either bad injector(s) or fuel pump check valve.
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...
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.
According to his first post, he did fix it.....
I'll agree and say reset your base idle first and go from there.
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.
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.
I'm wondering from his description on this how far the set screw has been turned on the TB.
From SBFtech:
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!!
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.
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.
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.
Probably not your problem, but the PO installed my IAC upside down, and it was causing it to idle too high.
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...
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.
http://sbftech.com/index.php/topic,2471.0.html
Here you go, read though this. Shows you how to run codes, even has a video or two to show you what to look for.
I swapped it to a stick......T5 baby! Sweep...I'll check it out. Bolted down and car running the TPS reads .95v.
Last night my wife told me to sell it and get a new 5.0 Mustang.
I know what I'm doing tonight..............
It really shouldn't be that hard to figure out.
Did you hook up the nss?
Which computer did you use? Is it a 5 speed computer or auto?
Ssorry, I keep forgetting you have the 5 speed.
Let us know your codes.
Didn't do the codes...spent the night cutting firewood. Will try to run the codes on Thursday. I used a SD, 5 speed computer.
Cutting wood???? Is it still cold up there?
I'm cutting for next year. Always get my firewood done during March, April and May so I'm not sweating my nuts off in the summer!!
BTW....it was in the 30's last night.
Still didn't pull codes.....got tied up selling my motorcycle . If I don't get this think fixed soon I'm gonna be a very unhappy fella.
Just ran codes.......nada. I used a jumper wire from the SIGRTN port to the STI and got nothing. CEL works, it lights up when you roll the key forward to start the car but it did not blink any codes.
Also ran a sweep of the TPS...no zero's popped up. At idle position it sets at .95 and it maxed out at 6.0v.
A code 11 is a OK system pass, if you didn't get that you either didn't perform the test correctly or have wiring/ECM issues...
Also,try a test light or a jumper.
Check the black wire behind your battery on the fender that connects to your fuel injjection harness. That is a ground for the ecm. Also you wouldn't get a good reading on the tps if that wire was broken.
6.0v's is also a very high number for the tps. I have hardly ever gotten one above 5.0v's. Usually topping off in the gigh 4.9's.
Ignition in RUN without starting, does the fuel pump run continuously instead of just 'priming' for a second? If it does, the EEC is in LOS (limp home) mode.
Try grounding the STI to run codes. If that works, the SIGRTN land in the EEC is probably blown.
Fuel pump....YES!!! It does run constantly.
Will ground the STI today and see what happens. From the diagrams I look at telling how to set up to run codes, I don't see one that lays out grounding the STI. More info please??
Thanks!
BTW......folks......so far we are up to 6" of snow overnight with another foot coming before the end of the day.
Ummm about a 100 posts ago I recommended trying your original ECM to see if it corrected the TPS voltage problem, would also address the fuel pump running issue as well...
Is your tps signal voltage different when tested with ground at the battery instead of black wire (strtn ground)? This should tell you if. The computer is getting grounded properly. Also, your map sensor and other sensors will read high.
It is possible that the ground behind your battery that runs to the fuel injection harness could also be bad. It shouod be black with a white stripe. Take a test light or volt meter and test for connection. Testligght, hook it up to power and probe the wire. With the volt meter, test for resistance.
This caused my buddy a no start.
Read post #6 on that small block ford tech I linked you to on how to run codes. It shows you how to check for a ecm and body ground. You also need to try to run codes with a test light or volt meter. When my buddies car had a bad ground to the ecm, couldn't pull codes with a test light, but we could with a digital volt meter.
EEC in LOS(Limited Output Strategy) mode means that the software in the EEC is not running. The EEC hardware keeps the fuel pump relay picked and generates fixed length injector pulses from the TFI PIP pulses. All sensor inputs are ignored and no codes can be generated.
However sometimes people haywire the fuel pump relay because the EEC relay driver circuit is blown and that would make the pump run continuously.
Jumpering STI to SIGRTN is the correct way to pull codes. SIGRTN is the EEC's logic ground. So grounding STI will not hurt anything and will help confirm that the EEC is the problem.
Did you check the EEC ground wire that Haystack suggested? The little pigtail wire on the negative battery cable should go directly to the cable harness wire or to the same chassis grounding point.
Can you install the original EEC and see if the pump primes and you can pull codes?
I didn't forget that buddy....been looking for it. Not sure that I have it anymore.
I swapped ECMs this afternoon. Pump primed and shut off. Car started and idled at 800 but FP is really low...thinking pump is bad.
But.....I ran codes via the CEL. It displayed four codes..........23.....54.....31.....85.
23 is the TPS out of test range. I need to adjust it or swap on another that I have...forgot the adjust it before running codes.
54 is the ACT Signal too high. Not sure what this is...but searching.
31 is the EGR valve position sensor. Not a suprise since I have it removed to fit on my fuel pressure gauge.
85 is the canister purge selonoid circuit failure. Is this coming up since I removed the air pump plumbing?? From a little web searching it sounds like I may need to hook this back up or is there a way to trick this circuit?
As this is posted I'm looking for solutions to my problems............but post info if you have it. Thanks!!
I could be wrong, but I think the ACT is a sensor mounted on the upper intake. I had to install one when I upgraded my turbo 2.3 to '87-'88 specs. It may stand for air charge temp sender.
Again, I could be wrong on that one.
The code 85 shouldn't affect engine idle and/or performance. Try swapping the TPS or performing the full-sweep test.
Full sweep was good. Maxed out at 6.0v with no flat spots...someone here said 6.0 is way too high. Need to reset base TPS voltage with ECM swap and retest to see if that changes anything.
Tps, act and egr codes all effect idle.
Tps should read above .5v's and under 1.19. Should read 2.71vks or higher above idle value.
Act is a 5 minute job. In the lower intake right near the fuel injectors. Has a single wire on it. I remember it being a pink stripped wire.you should run codes at operating temps.
Without checking for ground on pins 20,40,60 on the old ecm, you will not know if it is burned up or not.
Your tps is bad. Has to be. You need to check you signal return wire(ground to ecm) to make sure it isn't open then if it is still good, you need to replace tps. Act should run under 20 dollars.
Don't expect the engine to run anywhere near correctly on the orig ECM, as firing order and injector size are incorrect... I only suggested swapping as a quick and dirty check...
You still have TPS or wiring issue... Voltage should never read over 5v as that's supplied by a regulated supply inside the ECM that is limited to only 5v(you sure your meter is correct?)... Max at WOT is usually around 4.5v to 4.7v...
I didn't even think about it being a 5v power supply...
My buddies read 12v's at idle or wot. The problem was a bad ground. Found by accident because we could get codes with a digital volt meter, but not a test light. I had the set ligt grounded to the block and accidently stuck it in the sigrtn wire and the car started acting normal. This is why I asked if you did it with a test light or volt meter. The volt meter supplies its own power and gives no load to the circuit. However, my harbor freight $2.99 meter would not update the display fast enough to read codes. I couldnkt get codes with a test light because it would blow the ground.
If I had followed procedure and checked the ecm ground, or resistance from ground to sigrtn, problem would have been fixed in 5 mins.
I painted the engine bay while everything was apart. Maybe I'm not getting a good ground through the battery pigtail and back to the ECM? I'll look into that today.
How do I do this??
Yes, but I was referencing his code for the evap canister - code 85.
Yup, not singling anyone out. That was just how I read the posts.
For now I guess only worry about 23 and 54.do the trouble shooting steps here. http://sbftech.com/index.php/board,98.0.html
Pins 20 40 and 60 are all grounds for the computer. Check the with a volt eter against a power wire to make sure you have good continuity. Then check for resistance on the sigrtn, and those pins to make sure everything is flowing right. Should be less then 5k. The sigrtn is not only the main ground for the computer(meaning the car will not fuction, at all with it broken), but it also splices into every sensor. Including the map, tps, act and other major sensors that will throw your car into limp mode.
Basically, plug h.o. computer in, replace act, probe pins 20,40, and 60 for resistance, and finally, and one of the first things mentioned, check that stupid ecm ground. Check resistance between your tps and battery. Follow procedure on sbftech, check and clean you salt and pepper shakers, install new tps, go do burn outs depending on what you find.
There really isn't too much to go wrong, and it isn't that hard to find out. We still don't even know if your computer is fried, which takes all of 5 mins to find out.
I had a high idle after swapping my HO for a GT40, and I tracked it down to a too small EGR plate gasket allowing EGR to flow into the intake unchecked. After that I still had a slightly high idle, and it was running really rich. I traced that to a bad HEGO on the right bank. swapped them both out, now I'm golden. You should borrow a 60-pin breakout box and check what your o2's are reading.
Kinda been ignoring the T-bird for a little bit until my fuel pump comes in. Got my TC hood and some spots that needed attention on the wife's stang'vert in primer this evening.
This has turned out to be more work than expected since I HATE wiring problems!!! Did I mentioned that I really, rally HATE wiring problems!!!!
Just thought of this......since I had help reassembling everything the o2's may have been installed into the wrong sides...I'm guessing the O2's are side specific, right?What are the wire colors for each side??
Maybe my mom installed them incorrectly.............DOH!!! ;)
Yes the O2's are side specific.
From the 88 EVTM: Right= DG/P wire. Left= DB/LG wire.
You should figure out why you are seeing 6v on the TPS sense wire. If this is not a false reading by the meter, it is the first thing you have to fix. No error codes should be considered valid.
Check with a different meter.
Check a 1.5 volt flashlight battery and see what the meter reads.
The O/W wire on the EGR position sensor, Map and TPS is the 5v reference voltage from the EEC. Check it to ground, then check it to the SIG RTN pin in the self test connector. Are they the same?
Will check the O2's when I have the car lifted for the puel pump swap.
Checked TPS voltage this AM with the stock ECM in place and using a new volt meter.....it read way low (.5v). Of course, it was set from the DA9 ECM. So I reset the TPS to .9v. Ran a full sweep and it went smooth, maxed out at 4.5v. Also checked the pigtail ground with a volt meter. It was grounding through the wires but not through the eyelet against the body so I cleaned that up and reconnected.
Reinstalled the DA9 ECM, TPS read way high and fuel pump ran constantly. Stuck the stocker back in and TPS was fine and fuel pump cycled properly.
I also found a single orange wire sticking out of a wrapped harness around the rear of the intake in the area of the EGR. It looked cut off. Any clues??
I reread the entire thread this AM and still have one or two things to check out but thinking it's an ECM issue since things are reading fine with the stock one.
It might be the ecm if it reads fine with the old one, however, if you haven't checked ground on pins 20,40,60 and sigrtn, you don't know if its ungrounded because of a wiring problem, or an internal issue.a wiring problem (like the ecm ground near the battery, check resistance and connection here!) Which could burn up the computer. It can also cause problems with turning the fp relay on and off.
Good luck, but I don't think. There is anything else I can tell you.
How do I check ground on the pins??
The orange wire is likely the o2 ground wire which should be on one of the intake bolts. I would say the DA9 PCM is bad or not correct for the wire harness,
I have that orange wire also, and like you, it is connected to nothing. On 88, as far as I can tell from the EVTM, it's not used on 5.0. It seems a little late to ask, but how high is your idle? I just found out that while I thought my idle was high, it wasn't, my digital tach was just wrong. I figure it's because the stock 5.0 had a different firing order, but that's just a wild guess.
It's around 1200rpm. With the IAC unplugged it will settle right at 800 and with the stock computer I can get it right also. But plug the IAC in with the DA9 and it goes high. Right now I have several items going on and I'm tired of it. I need to replace the fuel pump and check the DA9 to see if it is toast or not. There's a local guy that's a wiring whiz and rates are very reasonable. I'm going to try a few more things on my own, if nothing is fixed after that; it's going to him.
Read the following thread concerning your o2 sensor harness and whether or not it's reading the wrong banks. http://www.foxtbirdcougarforums.com/showthread.php?21560-White-10-pin-connector...
As far as the orange wire, it's been pretty much determined that they are redundant in the Cougar/Tbird wire harness and therefore not needed (or even hooked up from the factory) due to the o2 sensor harness in these cars having the grounds built in. There were apparently different engine harnesses and HEGO harnesses in the Stangs.
Check the following post for the pictures that were removed from the thread I linked to.