weird stuff happening? bad ecu?

[460beast]

first off this is my first post and i would like to say hello and this site rocks! it has helped me out greatly with my stang! thanks to all the mustang people:SNSign:
well i guess i should start from the begining, a couple months back i picked up an 88 coupe converted to mass air using an a9l cpu. the previous owner had taken off the egr. the car seemed to run fine for a week or so and then started running weird some days,random missing with a load at all speeds only when cruising. as soon as i would give it some gas it would stop. then some days it ran fine. i figured it was the egr so i put one back on. still doing the same thing. so i puled the codes and got a code 32 which is egr vacuum control selinoid not functioning. i checked the voltage at the seliniod and got nothing? i checked the wiring and everything looked fine. so i decided to disconect the battery and reset the cpu and check again. now i have 13 volts? well ran out of time had to go to work. so when i got home checked codes and a code 32 again.checked voltage and nothing again. is there suppose to be some kind of voltage all the time? i decided to check my tps and its at 3.98 volts? what happened to .98 volts i set it at before? cant adjust it? and when i go wot it goes down in voltage. is my computer bad? need some insight, thanks

 

[460beast]

bythe way, all the egr stuff is new including the vacuum lines. also i tried another tps and still the same thing. somebody help car is still having tha same problems

 

[vristang]

Welcome to stangnet

Are you saying you had the same voltage reversal with a new tps?
Or that the drivability problem was still there.

EGR can cause some minor issues, but you shouldn't see any major problems from that. (It would be nice to get it fixed though)

I would focus on the tps first.
A member here (jrichker) will probably know how to trouble shoot the voltage reversal problem. (JR always seems to show up when his name is mentioned in a thread; it's kinda spooky sometimes ).
If I had to guess at it I would say to start looking at the grounds, as you may have something shorting out.
If the vref is bad, then all kinds of sensor inputs will be completely hosed.

good luck,
jason

 

[jrichker]

The signal ground for the TPS is probably bad - it's the
black/white wire. Connect one ohmmeter lead to the
black/white wire on the TPS and one lead to the negative
post on the battery. You should see less than .5 ohm, more
than that indicates a problem. Always take resistance
measurements with the circuit powered off.

Clean the 10 pin salt & pepper shaker connectors.

.

See http://fordfuelinjection.com/index.php?p=85 for more help
See the following website for some help from Tmoss (diagram designer)
& Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine/

Diagram courtesy of Tmoss & Stang&2birds

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

CODE: 32 (KOEO) - EVP circuit below minimum voltage.
Vref missing or broken wire or bad contact in circuit. Check
for 5 volts on the orange/white wire. With the sensor
removed from the EGR and still connected, press the
plunger and watch the voltage change on the brown/lt
green wire. Check for the same results on pin 27 on the
computer. Check for continuity between the wiring at the
sensor and the computer. The brown/lt green wire on the
sensor & pin 27 should be less than 1 ohm. The
black/white wire on the sensor & pin 46 should be less
than 1 ohm. The orange/white wire on the sensor & pin 26
should be less than 1 ohm.

 

[vristang]

^^^See what I mean.


That is pretty spooky...


but in a cool way

 

[jrichker]

^^^See what I mean.


That is pretty spooky...


but in a cool way

I live here...sometimes it seems that way...

 

[460beast]

thanks for the info fellas. i'll check into it more when i find some time and let you know what i found.:SNSign:

 

[donsbad68]

nice j very nice