🔧 BUILD Eagle's 92 Fox 5.0 5spd resto

[1quick]

Ok, so I've got some kinda gremlin going on.

New injectors, wires, plugs, fuel pump and filter. Replaced the old rails and engine lines with clean stockers, including an adjustable FPR and gauge. PSI at idle is set to 39psi. Base timing is set a bit strong at 16*. New 95amp alternator is also in, voltage is strong, even at idle now.

The engine, when started cold surges and will often stall out. Once it runs for about a minute, it seems to run better, but still idles rough. With the hood open, it shakes quite a bit just sitting at idle. RPM @ idle once warm, hangs out at ~800.

WTF am I missing? Do I need to do a base idle relearn maybe? I've not probed the TPS wires for voltage, wasn't sure the best place to do that on this car.

Finally... I almost need someone to come tell me if this thing is putting out the power that it should. It feels pretty damn sluggish to me. I know I know, 200hp isn't all that... but it feels "soft" - not sure how else to put it.

You can probe the tps right at the sensor plug, I used the pointed probs and just pushed the tips through the insulator of the wire right at the connector, I believe the tps is adjustable if it’s like mine you can move it slightly and have to set the base voltage by doing that, also if you haven’t check replace or clean the iac

 

[Eagle]

A few pics of the upgrades.

 

[Eagle]

Going to follow this for base idle reset:

How to do a base idle reset and how to check and set...

www.allfordmustangs.com

Ok so, if your having idle issues and you have ruled out everything else to include your tps voltage, vacuum leaks...etc, follow this step by step.

1. Disconnect your negative on your battery to clear/reset your computers memory. caution when ever you disconnect your battery remove the negative first then positive, reconnect in the reverse order, if you dont you can possibly cause a battery explosion or destroy your computer. Leave your battery disconnected for at least 30 mins to let the capacitors in the ECM to discharge fully.

2. Disconnect the IAC connector.

3. Reconnect your battery.

4. Start the motor, with the IAC plug disconnected.

5. Set your idle, via the stop plate screw on the throttle body, between 650-850 rpms, it is best to set it at the lowest setting to prevent idle problems, such as surging, rolling etc.

6. Turn the motor off and reconnect the plug on the IAC.

7. Start the motor at let it run for 2-4 mins at idle with all accessories off, if the motor stalls out or the idle drops to low repeat steps 4-6.

8. Once your idle is good, turn the motor off and wait 2 mins, then start it back up and run for another 2 mins with all accessories on.

9. Check your TPS voltage. It should be at .98v if not refer below on how to set it.

10. If your idle and TPS are good, allow 10-20 mins to let the computer "relearn" under normal driving conditions.

How to check and set your TPS
Note to check and set your TPS the key must be turned on without the motor running, this also may require a second person.

To do this you will need to set your voltmeter to 20 volts dc, then take your negative lead on the voltmeter and pierce the coating on the black wire(SIGRTN) and with the positive lead pierce the green wire coating (TPS signal) side note the orange wire is VREF. The voltage between black and green wires should be .98v if not you will have to adjust it to .98v.

To do this if you dont have an adjustable TPS. Loosen the 2 philips head screws on the tps and play with it to avoid unnecessary drilling, if you cannot get it to .98v without drilling, drill out on hole on the TPS (when i did this i drilled the hole closest to the front of the car not the one closest to the firewall), NOT your throttle body, just enough to move it to .98v.

Once your TPS is at .98 carefully tighten the screw down that you didnt drill, then recheck the black and green wires for .98v, then tighten down the screw that you did drill, tighten down both screws, check the black and green wires for .98v if its at .98v still you are good.

 

[boostedguy05]

I'll come race you with the impala. They should be close if you are putting down the right power.

 

[Nate]

Eagle you need two t-pins and a dvom.
KOEO backprobe the tps wires (green and black)

adjust the tps voltage to .92-.98

this is MOST LIKELY your issue

 

[DEEZUZ]

So nate is like the deezuz of the foxbody/sn...


Anytime someone gets dick deep in shit they don't know they hit him up....

 

[DEEZUZ]

Just remember this brother

 

[Eagle]

Eagle you need two t-pins and a dvom.
KOEO backprobe the tps wires (green and black)

adjust the tps voltage to .92-.98

this is MOST LIKELY your issue

Ok excellent. I'll be certain to get this checked/corrected today.

 

[Shawn1112]

Just remember this brother
View attachment 59627

Thats awesome, lol

 

[Nate]

Ok excellent. I'll be certain to get this checked/corrected today.

It should help with your power as well. If it doesn’t swing by and I’ll check it out. And if everything is ok let’s put a gear in it LOL

 

[Great White Drake]

Clean the iac?

 

[LikeABauce302]

If it isn't the TPS voltage being off, make sure the MAF is clean. Also check the MAF connector and wiring harness. I've seen them get burned on the header from not being properly routed if the car has been apart before.

Otherwise keep it simple and check for vacuum leaks. These cars will run like absolute garbage with the smallest of vacuum leaks.

It's probably not down on power. They are painfully slow compared to anything modern. My 88 GT is all stock besides 3.73s, exhaust, and intake manifold. My '17 Escape would put a bus length on it. With stock heads and intake, they run out of steam over 5,000 RPM.

 

[Gav'sPurpleZ]

Just remember this brother
View attachment 59627

Thats awesome, lol

can also be used for detailing.........................

 

[DEEZUZ]

can also be used for detailing.........................

 

[The Beast]

If it isn't the TPS voltage being off, make sure the MAF is clean. Also check the MAF connector and wiring harness. I've seen them get burned on the header from not being properly routed if the car has been apart before.

Otherwise keep it simple and check for vacuum leaks. These cars will run like absolute garbage with the smallest of vacuum leaks.

It's probably not down on power. They are painfully slow compared to anything modern. My 88 GT is all stock besides 3.73s, exhaust, and intake manifold. My '17 Escape would put a bus length on it. With stock heads and intake, they run out of steam over 5,000 RPM.

I’ve owned some slow foxbodys and I’ve owned some factory freaks with stock intake and heads. Well they felt like factory freaks in my seat. Eagle u bumped the timing to 16 degrees did that make a difference in power compared to stock? That usually wakes them up. Did you replace the cats not sure if I saw that. Like ^ he said vacuum leaks makes a difference.

 

[Eagle]

Eagle you need two t-pins and a dvom.
KOEO backprobe the tps wires (green and black)

adjust the tps voltage to .92-.98

this is MOST LIKELY your issue

Well... Darn. Looks fine.

 

[Eagle]

MAF has been cleaned multiple times. Furthermore, the engine responds when running if I spray MAF cleaner on the sensor, so I somewhat doubt there is a harness/wiring issue. Mind you, the only codes I have are 81 and 11.

Timing did make a difference, but it still feels lame... Maybe that's because it's <200hp?

I just really do not feel like it's running as smooth as it should. The exhaust note sounds right, but there is what I would consider a significant shake when the engine is running - significant enough to shake the shifter, the hood when propped up, and the entire engine in general.

I think I need to run a base idle relearn process to fix the cold start stalling /surging. But at least I know the TPS voltage is correct.

 

[Nate]

I spy a EGR valve. Which may be sticking. I have one here if u want to play the swap parts game

 

[DEEZUZ]

Old license plates make great block off plates lol

 

[FESTER665]

Shouldve bought my 427, wouldve solved all these issues.

 

[Eagle]

I spy a EGR valve. Which may be sticking. I have one here if u want to play the swap parts game

That might not be q bad idea. I appreciate he offer. How might I take you up on it?

 

[Nate]

That might not be q bad idea. I appreciate he offer. How might I take you up on it?

Dan just shoot me a PM and come on by if you don’t mind the 2min drive

 

[Eagle]

I'll try to make some time tonight to swing by... need to put the new calipers on the front, as the driver's side was hanging up a bit. Then I can drive it over without too much issue if you'd like to lay eye's on it Nate.

 

[Nate]

I'll try to make some time tonight to swing by... need to put the new calipers on the front, as the driver's side was hanging up a bit. Then I can drive it over without too much issue if you'd like to lay eye's on it Nate.

Sounds good. I’ll be out there after 8 tonight

 

[Eagle]

So I did the base idle relearn process and did have to adjust the idle screw a bit, but my TPS voltage was still in spec at .971v.

Car seems to start from cold a bit better, but it STILL feels like its missing a cyl. I'm going to do a cap and rotor... my neighbor who used to work on marine stuff says he can't count the number of times he's seen a cap/rotor that can pass visual inspection as seemingly fine and without corrosion cause issues like this. I'll give it a shot.

Wife got a job offer today, so we're going to dinner here shortly. I'll swap calipers when I get home and see if I'm still up for swinging by tonight Nate, otherwise, hopefully you're around this weekend too.