94 mustang 5.0 idles as if it has big cam after warmed up and dies. Anyone ran into this?

[jpgearhead]

Okay did some reading on other forms but didnt come up with much. So thought be faster just to ask.
So little info on it it runs great start and runs great intell its warmed up. Then it will start to idle up and down not like its missing but sounds like it has a cam i can give it some gas and it will run fine. and still runs good but will die from time too time when stopping. It has always started right back up after dieing but once and turn over as if it was not firring. So went too parts house got new coil and tune up why i was at it. When i got back i put the coil on fired right so i thought hell yea. But when it warmed up started doin it agian but would start back. so just too check plug the old coil in and fired right up. has always started back up but that once. Anyone think maybe it could be the pick up in the ditributer? any ideals just want too check before i throw parts at it. car has new tune up new intake gaskets and all new vac lines .

 

[stdyhand]

I would look at the pip. I'd also clean the IAC, EGR, and MAF while I was at it.

Have you had the codes ran yet?

 

[Three50won]

jpgearhead...to me it sounds like a vacuum leak. That is why it idles better when giving it gas...because at that point the leak is being masked since there is more air entering the engine. But at idle it is more sensitive to the leak because there is not as much air entering in. It sounds like it has a cam because the ECU is trying to compensate to prevent the engine from stalling out. Check all your vacuum lines, check all the hoses, make sure everything is connected and has no cracks. Listen for the leak and spray the intake down with engine start while it is running. If the RPM's rise then you def have a leak so trace it. Or run a vacuum gauge on it. At idle in park and in drive you should have between -10 and -15 on the vacuum side...if more than -10 (more in negatives is numerically lower so more would be -9, -8, etc) then you have a leak.

And +1 on stdyhands suggestions...you might as well do all that while you're at it...

 

[2vNotch]

Vacuum leak, TPS OR IAC

 

[jrichker]

See the "Surging Idle Checklist” for help with all your idle/stall problems. You can guess at the problem and throw parts at it, or you can use the checklist to help you find the problem quickly and inexpensively.

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the fixes & updates. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[jpgearhead]

I had cleaned all the sensors and such with no luck and was for sure there was no vac leaks. As that was what my first thought was thats why. I put new intake gaskets and all new vac lines on. We had a slow day at work yesterday at the garage i work at. So i drove it to work and i got lucky and it died and wouldnt start back. Checked for spark and had none and put a ditributer in it seems too be fixed i know it needed one i could grab the button and it had 1/4 inch play in the shaft Can someone tell me why i couldnt find this post in the fourms.I looked the next day after posting and couldnt find it and thought id posted it wrong and it got delete. But checked my email and found a link too it sorry if thats dumd new to this site. Thanks

 

[VibrantRedGT]

We have a 94-95 Specific section on Stangnet. Next time post in there, you'll get a bit more replies.

 

[jrichker]

See the last paragraph of this tech note. You'll find a link to an incident that mirrors your experience...

PIP Sensor functionality, testing and replacement:
The PIP is a Hall Effect magnetic sensor that triggers the TFI and injectors. There is a shutter wheel alternately covers and uncovers a fixed magnet as it rotates. The change in the magnetic field triggers the sensor. A failing PIP sensor will often set code 14 in the computer. They are often heat sensitive, increasing the failure rate as the temperature increases.

Some simple checks to do before replacing the PIP sensor or distributor:
You will need a Multimeter or DVM with good batteries: test or replace them before you get started.. You may also need some extra 16-18 gauge wire to extend the length of the meter’s test leads.
Visual check first: look for chaffed or damaged wiring and loose connector pins in the TFI harness connector.
Check the IDM wiring – dark green/yellow wire from the TFI module to pin 4 on the computer. There is a 22K Ohm resistor in the wiring between the TFI and the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 22,000 ohms +/- 10%.
Check the PIP wiring - dark blue from the TFI module to pin 56 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the SPOUT wiring – yellow/lt green from the TFI module to pin 36 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the black/orange wire from the TFI module to pin 16 on the computer. Use an ohmmeter to measure the wire resistance from the TFI to the computer. You should see 0.2-1.5 ohms.
Check the red/green wire; it should have a steady 12-13 volts with the ignition switch on and the engine not running.
Check the red/blue wire; it should have a steady 12-13 volts with the ignition switch in Start and the engine not running. Watch out for the fan blades when you do this test, since the engine will be cranking.
If you do not find any chaffed or broken wires, high resistance connections or loose pins in the wiring harness, replace the PIP sensor or the distributor.

The PIP sensor is mounted in the bottom of the distributor under the shutter wheel. In stock Ford distributors, you have to press the gear off the distributor shaft to get access to it to replace it.

To remove the gear, first you drive out the roll pin that secures the gear to the shaft. Then you get to press the gear off with a hydraulic press or puller. When you go to press the gear back on, it has to be perfectly lined up with the hole in the gear and shaft. I have been told that the hole for the pin is offset slightly from center and may require some extra examination to get it lined up correctly.

Most guys just end up replacing the distributor with a remanufactured unit for about $75 exchange

PIP problems & diagnostic info
Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse. You will need an oscilloscope or graphing DVM to measure the output voltage since it is not a straight DC voltage.

See http://www.wellsmfgcorp.com/pdf/counterp_v8_i2_2004.pdf and http://www.wellsmfgcorp.com/pdf/counterp_v8_i3_2004.pdf for verification of this little detail from Wells, a manufacturer of TFI modules and ignition system products.