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Topic: Fighting a high idle...HO swap related (Read 8578 times) previous topic - next topic

Fighting a high idle...HO swap related

Reply #45 –
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.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fighting a high idle...HO swap related

Reply #46 –
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?

Fighting a high idle...HO swap related

Reply #47 –
Quote from: TurboCoupe50;387574
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...

I didn't forget that buddy....been looking for it.  Not sure that I have it anymore.
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Fighting a high idle...HO swap related

Reply #48 –
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!!
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Fighting a high idle...HO swap related

Reply #49 –
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.
[SIGPIC][/SIGPIC]

Fighting a high idle...HO swap related

Reply #50 –
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.
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Fighting a high idle...HO swap related

Reply #51 –
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.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fighting a high idle...HO swap related

Reply #52 –
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...

Fighting a high idle...HO swap related

Reply #53 –
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.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fighting a high idle...HO swap related

Reply #54 –
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.

Quote from: Haystack;387600
Without checking for ground on pins 20,40,60 on the old ecm, you will not know if it is burned up or not.

How do I do this??
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.

Fighting a high idle...HO swap related

Reply #55 –
Quote from: Haystack;387600
Tps, act and egr codes all effect idle.


Yes, but I was referencing his code for the evap canister - code 85.
[SIGPIC][/SIGPIC]

Fighting a high idle...HO swap related

Reply #56 –
Yup, not singling anyone out. That was just how I read the posts.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fighting a high idle...HO swap related

Reply #57 –
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.
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Fighting a high idle...HO swap related

Reply #58 –
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.

Fighting a high idle...HO swap related

Reply #59 –
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!!!!
1988 T-Bird Sport Coupe--5.0 HO, MAF swap, 1-5/8" shorties, BBK/Flowmaster exhaust, Explorer intake, 70mm Edelbrock TB, T5, B&M short throw, Centerforce clutch and PP, disc brake TC rear w/ 3.55's, TC front brakes, '98 Cobra springs, DIY SFC's, other misc .  14.05 @ 98mph with launching too low and shifting too high.