I know a thing or two about that SEFI Ford stuff. Solving the hunting idle by adjusting the TPS , cept it's not made to be adjusted,,,,dremel to the rescue. Run about 15-16 base timing. Adjustable fuel pressure regulator to fine tune what pressure it likes. Block off that EGR and trick the sensor.
Okay, so the following issue is now resolved.
But here's the plea for help on the Bronco forum prior to resolving it.
Guys, I really need help with an incredibly stubborn Code 172 & 334.
I suspect the 172 is just a symptom of the code 334.
No mods that I know of.
Just bought it from a car lot a few weeks ago, issue has been present from day one.
Symptoms I get:
Runs smooth till it warms up.
Then when I stop at a light, the idle might suddenly drop from ~1k down to ~500 RPM and stumble.
Then pop back up to ~1k for a moment, then drop to ~500 again. And occasionally dies.
When this happens, sometimes the tranny will suddenly start shifting at really high RPM's with whiplash effect.
Things I've replaced in the last two weeks:
-EGR Vacuum Regulator Solenoid
-Coolant Temperature Sensor
-Idle Air Control Valve
-Throttle Position Sensor
-Fuel Pressure Regulator
-ACCEL Distributor Cap
-Ford Racing Spark Plug Set
-EGR Valve Position Sensor
-Replaced all vacuum hoses
-Cleaned PCV Valve
-Cleaned Throttle Body
Troubleshooting steps I've taken so far:
-Plugged Vacuum tester into EVR top line going to EGR and it held vacuum.
-Plugged Vacuum tester into EVR bottom line going to solenoids and it held vacuum.
-Applied vacuum to EGR while engine was running and the diaphragm moved and engine idle changed.
-EVR 12V pin shows -12V on my multimeter.
-Shorted EVR's pin 33 to ground while engine running and the engine died.
-Applied vacuum to vacuum canister AMP with MAN disconnected. It holds vacuum fine.
-When I do the KOER code test, the EGR does not move.
-Hooking a vacuum gauge inline with canister AMP shows "green" levels of vacuum (good).
-EVP shows 5v at pins VREF and SIG RTN.
-EVP shows ~3700 ohms at pins VREF and EVP and it goes down to ~350 when I apply 10hg vacuum to EGR.
-Disconnected IAC. Applied vacuum to EGR and engine RPM's stumbled as expected.
-Put Vacuum tester inline at EGR and raised engine RPM's, the vacuum does not register anything at all.
-I have yet to see the EGR move except for when I manually apply vacuum to it.
I'm sure I've forgotten a few things.
Any and all help would be appreciated!
If there are any sensors I should try replacing, then I can do that too.
And now for the fix. And yessir, I no longer pull ANY codes on my Bronco except for "111" which means "all is good, muthafucka".
A guy called out the EVP, saying the aftermarket stuff was rubbish.
I cannot believe it, but you were RIGHT.
That stupid freakin dorky tater tot silly EVP.
Both the old brand-new one AND the new-new one that I bought, were DEFECTIVE.
I shaved a tiny bit off the end of the pintle (thank you Bench Grinder).
Put it on the EGR.
Ran the OBD1 test.
Just 111 I loves you. 111 you are free. 111 **** the EGR. 111 time to move on now.
I put the spare old-new EVP on my bench grinder and took off as much metal as you can see in the pics below.
3rd pic is where it was before I touched it.
2nd pic is how much metal I removed from it.
And all is sooooo good.
I mean, pending drive test and all that.
But I'm going to buy the Motorcraft EVP anyways.
Should be here on Monday.
I was spending hours every night researching and trying different troubleshooting steps to resolve this bastard 334 code.
I actually did a dance when I found out it was fixed.
No video, you don't want to see me happy dance.
Nobody wants to see me happy dance.
So, uh... the EGR & 02 sensor codes appear gone for good.
But the same driveability issues continue.
Tranny gets warm and starts shifting above 2K instead of below.
Hard shifts that break your neck.
And random idle issues where it drops to ~500 and sometimes dies.
Next suggestion was to replace the Vehicle Speed Sensor, which I did yesterday with a Motorcraft part. No change in problem.
Next suggestion after that is to get your PSOM (programmable speed something something) replaced. The VSS sends its signal to the PSOM which is the electric board behind the speedo. Then the PSOM sends that signal to the PCM.
Lost my train of thought.
Next door neighboors who lost their son & daughter in the last five years and now take care of their grandkids, just brought over the one who turned four y/o today. I guess they went bowling for his bday.
He got puppy kisses from my dog Ghost and that made his day.
Well made him happy anyhow.
So while this section of dash is pulled out, I'll be replacing instrument cluster bulbs with LED's and doing some cleanup.
What's a good way to deep clean the a/c/heater ducting?
Not the vents, but the ducting. Some kinda brush with vacuum attachment?
Turn on the a/c full blast and use a drill attachment brush?