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New to the forum/engine loping/trouble codes

markmnotdead

New Member
Joined
April 21, 2016
Messages
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City, State
New Orleans
Year, Model & Trim Level
1994 Ford Explorer EB
Hi, my name is Mark and I'm located outside of new orleans in louisiana.

I recently picked up a 94 explorer eddie bauer edition for $300 bucks. the truck had misfires real bad when i got it, turned out the guy that changed the plugs and wires before me didn't have his wires going to the correct cylinders, LOL! anyways i straightened that up quick and the truck ram pretty good for the most part, kinda sluggish. i changed the plugs and wires and it ran alright for a day then it just started running horribly. the rpms were way down to almost 500 and it would lope like someone put a performance cam in the engine. the engine would rock back and forth while doing so. i did some looking around and i found some vacuum hoses disconnected and i repaired them. still having the same issue.

if you keep the truck idling at 1000 rpm it runs good, anything below it lopes and struggles until you get it moving above 30 mph. i talked to multiple people and every said it sounds like a vacuum leak. i plan on replacing all the original vacuum lines with new lines. i replaced the MAF sensor with a new one because if i unplugged my old one the truck would run the same plugged or unplugged. i also replaced the ECT sensor because my coolant gauge never moves further than right before the N on NORMAL. new sensor still doing the same thing, maybe its faulty? I'm not sure. i do have a check engine light on and i read it with an obd and it came up with the codes:
O-327:EGR valve position circuit below minimum voltage/EVP-EPT circuit below minimum voltage
O-539: A/C on/defrost on during KOEO
O-565: Canister purge solenoid circuit fault
C-327:

The canister purge solenoid is plugged in but there are no vacuum lines running to it because the barbs on the bottom have been broken off..

anyone ever ran into these codes before? any idea if 327 would cause the engine to lope??

I plan on replacing the TPS sensor and the IAC sensor too…
 



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EGR can really mess with an engine's performance, especially at idle.

There's 2 coolant sensors. The ECT is a 2-wire unit right below the throttle body. There's another, just a couple inches towards the passenger side that's got a single wire on it, that one is for your gauge. The 2-wire ECT goes to your computer. Good to replace it, they go bad commonly.
 






Make sure that all the plug wires are securely snapped onto the plugs. While doing that make sure that the plugs are actually tight and not the plug socket binding when the plugs are installed, it can fool you.

Re-install the plug wires into the coil pack. Keep spreading the ends of the brass barbs slightly until you feel them slide into the coil pack sockets. You don't want an air gap here since the system is a ' Wasted Spark ' type and the plugs and wires work twice as hard. Check for corrosion in the coil pack sockets as well.

The purge valve pulls vacuum from the bottom of the throttle body, fix or plug to stop leaks.

Good Luck
 






i started replacing vacuum lines today and i also pulled out all my plugs and wires. checked the gaps and made sure they went in nice and tight. made sure all the plug wires were secure to the plugs and coil. still running bad.

its loping in drive while at idle, when you press the gas to drive it lacks power. also my volt meter starts acting wacky in idle while in drive. I'm not too sure what to think. ill continue replacing the vacuum lines and replace the
EGR along with the DPFE sensor, the fuel pressure regulator and the TPS sensor.. maybe these things will help with how its running..

my mind is completely boggled by this truck
 






Get the Wells/Airtech DPFE sensor from Autozone, the one from O'Reillys is junk and fails in two weeks.

http://www.troublecodes.net/ford/

Our 94 Explorers have a sequential fire injector system unlike the earlier batch fire system. This gets a signal from the Cam Position Sensor behind/under the intake. It sends a signal to the ECU that controls the injectors. The CPS will show a code if it is failing but it can make a squeal like a slipping belt. we also have the better 4-hole injectors.

Check the electrical connectors on the injectors, they get brittle and can loose their locking tabs.
Check the Crankshaft Position Sensor, it signals ignition timing.
Check the metal EGR pipe coming up from the exhaust, it can crack or rust out. I likes to crack where it is accordioned to make it flexable

The loping has to be caused by something affecting a single or a couple of cylinders. That means Fuel or Spark/Timing. Electrical is the easiest to cause a sudden change like you had.

Good Luck
 






Easy way to test vacuum leaks is to get a cigar and blow smoke into the brake booster line. I don't smoke, and never have, so I don't enjoy doing it, but it works. You can pull the vacuum line off the egr valve and plug the line with a screw. This will trip a code for the EGR, but it will effectively delete the EGR for testing.
 






Get the Wells/Airtech DPFE sensor from Autozone, the one from O'Reillys is junk and fails in two weeks.

http://www.troublecodes.net/ford/

Our 94 Explorers have a sequential fire injector system unlike the earlier batch fire system. This gets a signal from the Cam Position Sensor behind/under the intake. It sends a signal to the ECU that controls the injectors. The CPS will show a code if it is failing but it can make a squeal like a slipping belt. we also have the better 4-hole injectors.

Check the electrical connectors on the injectors, they get brittle and can loose their locking tabs.
Check the Crankshaft Position Sensor, it signals ignition timing.
Check the metal EGR pipe coming up from the exhaust, it can crack or rust out. I likes to crack where it is accordioned to make it flexable

The loping has to be caused by something affecting a single or a couple of cylinders. That means Fuel or Spark/Timing. Electrical is the easiest to cause a sudden change like you had.

Good Luck

I have been notcing a squeal every now and then similar to a belt squeal... Maybe I should hust change the crank sensor, the truck has over 200,000 miles... For me to check that sensor I would use the OBD1 with the engine running right?
 






It's a simple Hall effect sensor, mine was worn and it left KOEO codes. It's expensive and hard to get to so I would only replace it if you HAD to. There is a sticky for it so read up on what is required.

All your codes seem EGR related so repair that and the purge system, clear your codes and then warm up and re-test is my best advice.


Good Luck
 






The crank sensor is cheap and easy to replace. It wouldn't squeak either. You are thinking of the cam sensor.
 






Right there with ya! Except mine has rebuilt heads with maybe1000 miles on them. Seemed to run pretty well for a bit, and now after any moderate period of driving it starts the "knocking under load" deal. Pretty bad. 5-6 oil changes, 12 spark plugs(last 6 pulled were white and blistering already-cylinder 1&6 kind of oily threads), new 02 sensor (snow white), new cats, cleaned MAF, new fuel pump relay, new fuel filter. Doesn't use up coolant. Would closing the gaps on the plugs possibly help them burn more efficiently or not get so hot? I couldn't imagine there would be much carbon in the cylinders this soon-enough to cause such a disturbing load knock.
I'm almost over it..
 






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