Ignition timing all over the place

[Spencerider]

Hey y'all. I have a 1995 GT 5.0 that pings really bad. It has 170,000 miles and I bought it last week for a steal knowing that it had an issue with the PIP. I've done all of the basic SN95 stuff like cleaning the MAF, new fuel filter and all that. I also put in a new distributor and set the baseline ignition timing at 10 degrees btdc with the little plug pulled out. So, after putting the new distributor in and setting the baseline timing, I put the little plug back in. Upon starting I noticed that it would idle normally at about 800 rpm but would slowly drop down to about 500 and it idles a little bit rough. (Also idles the same way with the little plug pulled out) So I take it for a spin. If I go anywhere above half throttle, it starts to ping. I took it back to the house and looked at the timing again with the little plug in and I saw the timing not only jumping all over the place, but it seems to be at 25 to 30 degrees btdc while at idle, if I rev it up it jumps around even more and goes more advanced. If I pull the plug back out, it goes back to 10 degrees and doesn't ping at any throttle amount whether it's parked or driving. To fix this, I went to O'reilly's and tried a new ignition module with no luck. Does anyone have any idea what could be causing my ignition timing to go crazy? Any insight will be greatly appreciated.

 

[Frank.JD.Perez]

jeez that sounds like a nightmare... ttocs, [MENTION=20210]lwarrior1016[/MENTION] any idea?

 

[lwarrior1016]

This one will take more expertise than mine, I haven't messed with a distributor in a few years. How does the spout connect to the distributor? Have youe tried to warranty the distributor and put a different one in there?

 

[Spencerider]

This one will take more expertise than mine, I haven't messed with a distributor in a few years. How does the spout connect to the distributor? Have youe tried to warranty the distributor and put a different one in there?

I don't know how the spout connector is connected to the distributor if it is at all. All I know about it is that it allows power to go to something that is connected to the wiring harness up or down stream from the spout connector. And I didn't try to warranty the distributor and get a different one. If I knew what was in charge of increasing the ignition advance as the engine rpm increases, I could probably figure it out.

 

[SlowRider]

Its an old thread but how did you fix the timing issue?

 

[RAU03MACH]

Its an old thread but how did you fix the timing issue?

if your having the same issue , check your computer and all grounds

 

[SlowRider]

Are you suggesting checking grounds at the computer?

 

[RAU03MACH]

yes

 

[96blak54]

Im simply a firm believer that the factory distributor has a time limit and needs replacing. Through the course of years for Ford that same distributor design was in multiple platforms including 6 and 4 cylinder cars/trucks/vans which turns out to be a faulty pip pickup within the distributor or fuel control module.

 

[SlowRider]

if your having the same issue , check your computer and all grounds

It idles perfectly with the spout connector out at ~700RPM but lacks power during driving due to lack of time advance from computer. I believe this won't be the case with faulty distributor/pip pickup or ICM and coil pack. I have new HB and I will check the distributor orientation anyways. Checking the computer ground connection makes sense. Do you have any idea what the two wires that the spout connector/jumper connects go to?

 

[lwarrior1016]

It idles perfectly with the spout connector out at ~700RPM but lacks power during driving due to lack of time advance from computer. I believe this won't be the case with faulty distributor/pip pickup or ICM and coil pack. I have new HB and I will check the distributor orientation anyways. Checking the computer ground connection makes sense. Do you have any idea what the two wires that the spout connector/jumper connects go to?

Have you checked timing with the spout out? And have you verified tdc marking on the balancer is correct?

 

[RAU03MACH]

It idles perfectly with the spout connector out at ~700RPM but lacks power during driving due to lack of time advance from computer. I believe this won't be the case with faulty distributor/pip pickup or ICM and coil pack. I have new HB and I will check the distributor orientation anyways. Checking the computer ground connection makes sense. Do you have any idea what the two wires that the spout connector/jumper connects go to?

right back to the computer

 

[SlowRider]

Have you checked timing with the spout out? And have you verified tdc marking on the balancer is correct?

With spout out and warmed up engine the timing is at 12* BTDC and stable. With the spout in the timing at idle is erratic from 10* to 30* with rough idle. I changed the harmonic balancer recently, so no slipped balancer. I have not checked the #1 cylinder TDC with HB. Since the HB is keyed to the crank shaft and running smooth with spout out I believe the TDC marking is correct. I am planning on checking the TDC with the #1 spark plug out just for completeness.

 

[SlowRider]

right back to the computer

I looked up the PCM to ICM connection and it seems that the ICM is grounded through PCM. Also it seems the spout directly connects the PCM pin#36 to ICM pin#2. The car is almost 3 decades old with only 24k miles on it. It mostly sat in garages. There is a high chance of corroded/rusted terminals. It seems to me the PCM control signal is somehow misinterpreted by the ICM.

 

[RAU03MACH]

Dirty corrosion connector
Corrosion on pins on harness loose connections
There are a few things that will cause stuff like that

I did have a problem in the computer that caused the problems your having
It was a lot of corrosion on the board of the computer
And some soldered welds were barely connected
Sometimes you have to pull stuff apart and look at it
And make sure its good

 

[RAU03MACH]

Had another car like that
Come to find out the car was in a flood zone
Water had gotten into the computer
It took me a while to figure that shit out

 

[95opal]

I don't know how the spout connector is connected to the distributor if it is at all. All I know about it is that it allows power to go to something that is connected to the wiring harness up or down stream from the spout connector. And I didn't try to warranty the distributor and get a different one. If I knew what was in charge of increasing the ignition advance as the engine rpm increases, I could probably figure it out.

With spout out and warmed up engine the timing is at 12* BTDC and stable. With the spout in the timing at idle is erratic from 10* to 30* with rough idle. I changed the harmonic balancer recently, so no slipped balancer. I have not checked the #1 cylinder TDC with HB. Since the HB is keyed to the crank shaft and running smooth with spout out I believe the TDC marking is correct. I am planning on checking the TDC with the #1 spark plug out just for completeness.

Your timing with the spout in jumps around because that lets the pcm make timing adjustments just as an old vacuum advance dizzy used to. With the spout out your timing is locked and the pcm cant make adjustments. Your rough idle is a separate issue

 

[SlowRider]

Your timing with the spout in jumps around because that lets the pcm make timing adjustments just as an old vacuum advance dizzy used to. With the spout out your timing is locked and the pcm cant make adjustments. Your rough idle is a separate issue

Well, with the spout connector in the PCM should not advance ignition time when the engine is at normal operating temperature and idling. But that is not what is happening with this vehicle.The timing should be just the timing I set at the distributor. instead its jumping around like crazy which is causing the engine to shake while idling. Today I checked the #1 cylinder TDC with HB and distributor alignment as they should be according to the guideline. Actually even with the spout connector out, #1 cylinder spark timing is off sometimes but it is mostly stable at the set timing. In fact it is more stable with some dielectric grease on the distributor cap and rotor connectors. This makes me wonder if the it is because the cap and rotor is not making good contact sometimes and the PCM is trying to correct it making it have even more unstable timing. I checked and the ICM ground is good. I am planning on checking the connections at PCM end as well. Meanwhile I will order new cap and rotor.

 

[lwarrior1016]

Well, with the spout connector in the PCM should not advance ignition time when the engine is at normal operating temperature and idling. But that is not what is happening with this vehicle.The timing should be just the timing I set at the distributor. instead its jumping around like crazy which is causing the engine to shake while idling. Today I checked the #1 cylinder TDC with HB and distributor alignment as they should be according to the guideline. Actually even with the spout connector out, #1 cylinder spark timing is off sometimes but it is mostly stable at the set timing. In fact it is more stable with some dielectric grease on the distributor cap and rotor connectors. This makes me wonder if the it is because the cap and rotor is not making good contact sometimes and the PCM is trying to correct it making it have even more unstable timing. I checked and the ICM ground is good. I am planning on checking the connections at PCM end as well. Meanwhile I will order new cap and rotor.

Watch out with the dielectric grease. It is not conductive and over time will get hard and cause issues. When I ran the Allison transmission dealership, I can’t tell you how many times a truck came in with strange problems and when I sprayed all the dielectric grease out of the connector and computer, the problem went away.

 

[Michael Plummer]

Q. Well, with the spout connector in the PCM should not advance ignition time when the engine is at normal operating temperature and idling.
A. Removing the spout connector creates an open circuit, and reinstalling it completes/closes the circuit. With the spout connector plugged in, it completes the circuit and gives the Engine Control Module or Engine Control Unit (ECM/ECU) the ability to advance the timing per RPM. The ECM uses timing to control idle. So I expect the timing to be moving a little with the spout re-connected.

Q. But that is not what is happening with this vehicle.The timing should be just the timing I set at the distributor. instead its jumping around like crazy which is causing the engine to shake while idling.
A. When you remove the spout connector you have disabled the ECM-controlled timing advance so that you can correctly reset your base timing with a timing light. Under this situation, the timing should be stable. With the spout connector reinstalled the circuit is complete to the distributor and the ECM takes control of the timing.

Your pinging or detonation problem could be other factors but ignition advance and total timing along with octane play a major role here. You don't have the ability to see what your total timing is at WOT so I can't say this is an issue without further troubleshooting. Try running the highest gasoline octane you can along with 32 ounces of Boostane Professional and see if you can get your vehicle from detonating.

I hope this helps
Michael Plummer