Hi, help needed with my 1993 351w 5.8 efi.

She starts first time and runs for about 10 seconds but then cuts out. She is then really difficult to re-start and when is running runs lumpy and changes gear harshly.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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I pulled the codes<o></o>
122, Throttle position sensor below minimum voltage.<o></o>
334, EGR valve position sensor voltage above closed limit.<o></o>
631, Transmission control indicator lamp (TCIL) circuit failure KOEO.<o></o>
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I don't really understand what these mean.<o></o>
Any explanation or info to get me back on the road would be very much appreciated.<o></o>
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Best regards<o></o>
Allan<o></o>

 

Your TPS is out of range, you can confirm this with a multimeter and the info in this link.. Ford Fuel Injection Throttle Position Sensor (TPS) The TPS is located on the bottom of the throttlebody so if you need to replace it you will have a much easier time if you just remove the complete throttlebody first.

EGR position sensor(EVP) is located right on top of the valve just behind the throttlebody and it can be tested with a multimeter and this info. Ford Fuel Injection EGR Valve Position sensor (EVP). Note that if there is a buildup of carbon on the EGR valve itself that may prevent the valve from fully closing and produce this code.

I don't think the other code would affect engine operation so you can ignore it for now, maybe clear the codes after fixing the other two issues and wait to see if it comes back. Sometimes engine sensor problems will cause ***** transmission response and trigger additional codes that aren't really problems.

 

Thank Conanski, I have replaced the throttle control position sensor, still same code. when probing for voltage reading there is no signal, do you know where there voltage is sent from?
I ran out of time so never got to the egr but will be able to work on her again on monday so if anyone can give me something to think on until then I would be very grateful.
Best regards
Allan

 

the TPS requires some adjustment to work properly. go to that website and follow the proper install procedure for the TPS.

 

Hi, I have no voltage at the TPS, I have checked all three wires.
Best regards
Allan

 

that was with key on?

 

Yes with key on. I need to check the reading from the ecu. Gotta find it first, will have a go on Monday.
Best regards
Allan

 

ecu should be behind the driver side kick panel. you may need to remove the E brake bracket to really get to it.

 

Thanks my friend, will check on Monday and let you know.
Best regards
Allan

 

Put 5 hours in and still none the wiser.

The actual TPS is fine, took it off and ran tests on it, works fine.

Of the 3 wires going into it the voltage readings are as follows
vref-5.00v.
sig rtn-0.04v.
tps-0.04v.
If i move the thottle the readings do not change. I followed the sig rtn and tps wires back to the computer and took readings from there and they were the same. As a matter of interest I took readings from the egr valve and they were the same as the readings on the TPS sensor.

Should one of the wires be to earth, I don't understand this at all and really need some help. Please give me any suggestions that you can think of that might help (already thought of the box of matches but I love her to much).

Best regards
Allan

 

Sig return should be ground I believe with Vref = 5.0. If the sensor voltage isn't changing then it's possible the EEC has lost it's main ground.. since it generates both the refernece voltages and provides the ground reference. Check out www.fordfuelinjection.com for wiring diagrams and EEC pinouts.

 

Thanks Conanski, have checked on there, I will check the earthing for that circuit, do you think that the tps and the sig ret could be touching somewhere or earthing out somewhere?
Best regards
Allan