I know there are a lot of these idle surging posts on here already. After searching for 2 hours I cannot find someone with exactly the same symptoms as me.

I have a 93 E150 4.9L with 189K that has driveability issues. The van will cold start just fine, but once you start driving and give it a normal amount of throttle from a stop it almost dies. The other issue is that after driving around it will not restart until it cools down.

Thing I've done:
Replaced the IAC
Replaced the TPS
Verified that the FPR isnt bad by applying vaccum.
Van has spark when it won't restart (doesnt mean the PIP isnt bad)
Fuel pressure=Key on engine off 55-60 psi, Key on engine on 50-55psi
Coolant temp sensor appears to be working as the gauge needle does move.

I havnt taken the throttle body off yet to clean it but being a van that is a chore and a half. This happened overnight so I'm inclined to believe it fuel related, but the fuel pressure seems to be within spec.

If anyone has any ideas I'd appreciate it.

 

the gauge is a different sending unit than the one thats on the thermostat housing. the one on the housing could theoretically say its -40 all the time and the dash could be fine. the one on the dash is taken off one on the rear part of the motor. is your ignition module OEM?

And what brands did you replace the IAC and TPS with?

 

I believe the ignition module is original.

IAC and TPS are both standard brand. I kept the originals just in case.

 

She is 100% right the computer gets its cold / hot information from the sensor at the stat housing not the same one the gauge uses.

I would say before throwing more parts at it pull the codes and write them down so you have them.
I think I would then clear all the codes and drive it a bit so it can reload codes and see what they are.
Are any of them the same as before clearing them?

With the new codes you repair from the first to the last as you may do the first say 2 code repairs and the rest may clear.
Let us know what the codes are before and after clearing.
Dave ----

 

So after letting it warm up I pulled the KOEO codes.

Active:
116: engine coolant temp sensor incorrect signal
636: Transmission fluid TFT signal highlow

History: 118: Engine coolant temp sensor above maximum value

It would seem to me that the temp sensor in thermostat housing is bad. Out of curiosity do you know where the gauge temp sensor is located?

TY

 

You shouldnt be getting those 3 digit codes, how are you checking codes. Counting flashes, using an analog DVOM? I ask because on a 1991 ranger I had tried counting flashes but I wasnt doing it right, so Instead I went online (but you can get one off the shelf from autozone!) a

Actron



Inova

The innova is nice because it gives you a digital readout of the codes despite the source being an analog signal.

 

These are the only codes I can pull up for a 1993 E150 with a 4.9

 

You may be able to access the gauge sender from your doghouse in an E150 (god I would hope so) but that doesnt seem to be an issue on your van.

 

Reading up it looks like they used 2 digit codes up to/through 91 and then switched to 3 digit codes.

 

"Bronco 5.0L, "F" Series 5.0L and all 7.3L diesel models use 2-digit codes. All other models use 3-digit codes. When CIRCUIT TEST procedures apply to both 2-digit codes and 3-digit codes, the applicable codes will be separated by a diagonal mark (example: Code 31/327)."

 

So looking at it, your 116 and 118 could be explained by a bad ECT easily. Can you send a picture of your ECT? To my understanding ford replaced the connector design and you may not have the ability to find an ECT With the same connector as your van has.

since coolant temp sensors DO go bad with age and yours is likely OE, I Think a new one is in order. They are cheap and yours is very accessible especially for a part on a van.

 

I did find the temp gauge sensor (first picture) The other three are the other sensor in the thermostat housing. Im almost positive that the T stat sensor is bad because it measures open with a Ohm meter.

 

time for a replacement, make sure to get one with a pigtail. hopefully you can reach the oem wires well enough to splice in a new connector?
That should fix a majority of your issues. Once you do that you can turn your attention to the transmission temp sensor

 

Figured I owe you an update. Got the new sensor wired in and it runs much better and restarts when warm. Crazy how many systems that one sensor was hosing up.

Appreciate all your help.

 

Awesome, glad to hear you got it!