rough idle and engine light flashes

[d.GATOR.b]

i checked the codes and they all say the TPS isnt reading right. i just replaced it to months ago and it has a lifetime warranty so i will be getting a new one from autozone tomorrow.

 

[1989LongbedGT]

Ok. So unplug the TP Sensor and start the truck up and see how it runs. It will set a code but it may clear it up since the ECM will now have to look at the Map sensor, IAC and engine RPM to calculate the amount the throtle is opened instead of reading it from the TP Sensor.

If it runs fine after unplugging it than you have most likely found the problem.

Matt

 

[d.GATOR.b]

She purrs like a kitten with it off!! Il be glad to replace it. She can be my daily driver again. I will update y'all tomorrow if she runs this good with a new TPS.

 

[1989LongbedGT]

When you replace the sensor im pretty sure there is a procedure you need to do with the TPS sensor to adjust it so it reads the proper voltage at closed throttle position and at WOT

The reason for this is the ECM uses the reference voltage sent back from the TPS to figure out throtle position in order to adjust IAC and Proper fuel.

Try to look up the specs for setting the Min voltage at closed throtle and Max Voltage for WOT. Sounds like a pain in the ass but will deff help with the truck running properly instead of just throwing a sensor in.

TPS are usually on a 1 to 5 volt range but in some cases min voltage would be .489 or .500 and max would be 4.89 instead of right on 1 and 5 volts.

You will need a Volt meter to set the proper voltage, Positive lead for reference voltage and just put your black lead to battery ground or a good engine ground. Sensor plugged in. Key to on position and back probe the reference wire at the connector. DONT shove the voltmeter lead through the insulator on the wire, this will cause corrosion down the road or maybe even splitting a wire. put it in the back of the connector until you get a reading.

0 volts would mean your on ground wire
5 volts is ECM Power supply wire
and if everything is ok you should see .4 to 1 volt on the reference wire then adjust it accordingly.

Hope it helps!

Matt

 

[d.GATOR.b]

What on the sensor do you adjust? I don't see anything adjustable.

 

[d.GATOR.b]

Just got it replaced and she is fixed. Thanks for all the help!

 

[1989LongbedGT]

the adjustment was on some ford models. I had a look at the throtle body I have at work off my 2.9 while im doing the P & P to the intake manifolds and the only adjustment there is the large screw that moves the linkage to adjust the butterfly.

Glad its fixed!

Matt

 

[d.GATOR.b]

Yea I read in another thread that you have to do it with a voltage meter and I don't have one. The truck ran fine for a bit. I guess I have to adjust that. Does anyone know the correct voltage for closed. And wide open throttle?

 

[1989LongbedGT]

Search engine is your friend.

http://www.therangerstation.com/forums/showthread.php?t=66515

You can pick up a Dvm for about 10 15 bucks

 

[d.GATOR.b]

I'm having this same problem again. I got a digital multimeter and adjusted the TPS to .94(closed) and 4.64(WOT). The engine light no longer comes on but I'm still having problems with the idle. It sounds like the IAC valve is closing in the middle of idle then it dies. I've used the "search" but can't find how to test it or if you can test it. Any ideas?

 

[PGHFord]

Trying cleaning the IAC, I posted some pics of mine in my album, on my old IAC you could remove the screws and the solenoid comes off from the valve body part if you wanted to soak it in cleaner, but even after cleaning mine still didnt fix problem, went out and got a new IAC and MAP sensor and fixed idle problem in park and neutral so far. worth a shot to clean it first and try it again.

 

[d.GATOR.b]

It's spotless. I just put a new one on about 2 months ago.

 

[PGHFord]

Have you ever cleaned your EGR valve pintle? or checked the passage into the intake plenum? for carbon build up?

 

[PGHFord]

being you said it was TPS related, you switched it out, then said the problem is back, did you try resetting the plug on it, by taking it off and then putting it back on? if it acts fine again after doing this but then acts up again, maybe the plug is bad? or maybe as someone suggested after my issue which is always true after adjustments or sensor replacement remove negative battery cable for 20 or 30 minutes and let the computer reset itself.

 

[PGHFord]

Another idea, is there carbon buildup around the TBI plate/flap that opens and closes, maybe carbon is built up and keeping it open, even if you adjust the voltage on the tps, it still doesnt mean the plate is closing all the way inside alowing more air than is necessary to go through it rather than going into the IAC and allowing the IAC to control air flow. Just another idea. Standard makes a TBI gasket kit I think part number 2011, napa and other stores should carry it it has a new IAC, EGR, and TBI gasket it, think it works on all 2.9L TBI and IAC, EGR.