88 GT wont idle.... help please

What did you get when you dumped the codes?

88mustang50 said:

i live in Austin Texas. and no one that i know of or have tried can get the codes for my car. they all say 96 or higher. i just fixed the exhaust leak so that was everything on that check list you sent me. all of it brand new (all OEM or motorcraft parts) or cleaned. do you know of a code reader i can buy for under $50 im tight on money now b/c of this car..... but i still love the car. its my first American car.

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Somehow I don't think you really read the Surging Idle Checklist very carefully. The very first item in the checklist is instructions on how to dump the codes with only a paperclip or jumper wire.

See the Surging Idle Checklist at http://forums.stangnet.com/showthread.php?t=698148 and start at the top and work your way to the bottom. If you really do check all the items, you will find and fix your problem.

Code 14 - Ignition pickup (PIP) was erratic – the hall effect sensor in the distributor is failing. Bad sensor, bad wiring, dirty contacts. You have to press the distributor gear off the shaft to replace the sensor. The pip signal is used for ignition timing and fuel injector timing.

Code 34 Or 334 - EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. If it leaks, there is carbon stuck on the pintle valve seat, replace the EGR valve ($85-$95).

If the blow by test passes, and you have replaced the sensor, then you have electrical ground problems. Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1.5 ohm. Next check the resistance between the black/white wire and the negative battery post. It should be less than 1.5 ohm.

Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

Let’s put on our Inspector Gadget propeller head beanies and think about how this works:
The EGR sensor is a variable resistor with ground on one leg and Vref (5 volts) on the other. Its’ resistance ranges from 4000 to 5500 Ohms measured between Vref & ground, depending on the sensor. The center connection of the variable resistor is the slider that moves in response to the amount of vacuum applied. The slider has some minimum value of resistance greater than 100 ohms so that the computer always sees a voltage present at its’ input. If the value was 0 ohms, there would be no voltage output. Then the computer would not be able to distinguish between a properly functioning sensor and one that had a broken wire or bad connection. The EGR I have in hand reads 700 Ohms between the slider (EPV) and ground (SIG RTN) at rest with no vacuum applied. The EGR valve or sensor may cause the voltage to be above closed limits due to the manufacturing tolerances that cause the EGR sensor to rest at a higher position than it should.

The following sensors are connected to the white 10 pin connector (salt & pepper engine harness connectors)


This will affect idle quality by diluting the intake air charge

88mustang50 said:

but now my fan went out.
it was ghetto wired to my fog lights. it blew a fuse and exploded the wire.
i was wondering what can i wire it to for it to work the best? (dont want it to be wired to the fogs again)
over heated bad today when it went out.

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What kind of fan?
Generally speaking, you will want a 75 amp relay to power the fan.

If you have a single fan with a 12" blade, you might want to toss it and get something better anyhow. If the summers in RR are anything like they are in Southern Arizona, you'll want a lot more fan anyhow.

A 75 amp relay is a safe bet for just about any fan out there. There are much better ways of controlling it however (a Dc Controller, etc).

Good luck.