Time To Ask For Help

[TheDHndrsn]

I've run a '00 Mustang GT 4.6 convertible since driving it off of the showroom floor with 33 miles. A few years back I discovered the hard way that not all transmission service joints can be trusted. During a rather routine pan drop, filter swap and fluid top the idiots not only didn't use Marcon V, they didn't even use a synthetic. Needless to say within a few months I started having issues but it was already too late. I figured out what had happened when I returned to the shop 6 months later and the price for the same service was 2x the original price.
I decided to rebuild the original 4R70W and drop it back in at some point (or sell it... maybe). To carry me over I picked up another 4R70W from an '01 Crown Vic. I did the swap with only a few issues that went beyond the normal stuff (top starter bolt, top trans bolts, header bolts, top bracket reinstall, LOL). These issues were ...

1. Swapped out the CV shift lever and replaced with the GT shift lever
2. Swapped out a two pronged CV sensor that did not mate up with the harness for the equivalent GT sensor
3. Removed the speed sensor from the tail of the CV trans and replaced it with the plastic cover from the GT trans
4. Swapped the GT shift sensor as the CV shift lever was a few mics larger diameter, a few millimeters longer, and extensions on the CV shift sensor meant no room to fit on the GT

I bolted it up, by the book, made the usual adjustments to the shift cable, and it ran great out of the gate. At least, the first time started. Later that day and the next few days have been pure Hell.

• Once back to the garage after an initial test run, it refused to start. I adjusted the shift cable and that appeared to solve the problem.
• The next morning my wife drove the car and it let her sit by refusing to start for the return home. This time, a shift console jiggle between P and R was all it took to get it going.
• Once home, I re-adjusted the shift cable using N as the reference point (just like before). Good to go. It started right up.
• Next day, the GT starts up but again leaves me sitting, this time in front of a Lowes. About 3 hours later (just as my neighbor with tow was a half mile away) it starts. I returned to the garage.
• That was the last time it started. It will not start. Period.

I worried the shift sensor harness was not securely attached (I remember it being snug). I removed the sensor and found the cable loose but attached. Snapping it on tight (notable click) I reattached the sensor, readjusted the linkage and expected things to start.
Nothing. At this point I am thinking starter solenoid, so I did some testing.
I checked the starter and starter solenoid using a multi meter. I saw 12v + change to the starter but nothing, absolutely nothing, to the solenoid at start. I tried adjusting the shift linkage / shift / combination of two until exhausted. The car simply is not sending juice to the solenoid at start. Period.
I do not believe the problem to be either the starter or starter solenoid.
I pulled and checked fuses. All good. At the turn of the key. I hear a click from within the engine compartment.I have proved the click is not coming from the starter so assume it to be the relay. That said, I am at a loss to diagnose the problem.
I have read that the pin out on a Crown Vic trans and GT were significantly different in the mid-late '90s but was assured these issues did not exist with an '01 CV to '00 GT swap. Both are running the 4R70W.
Up until it stopped starting, it ran great with the CV transmission. It shifted smoothly and performed nicely on the highway. Absolutely no complaints other than maybe a slight loss in kick when I punched it down at speed.
What am I missing?
I am not knowledgeable about transmissions. Just lucky with a wrench.
Seriously. HELP!
Dave

 

[wmburns]

First. I'm going to assume this is a "no crank" problem instead of a "no start" problem.

If the pin out of the DTR sensor were the problem, then it would NEVER crank. Since it does crank sometimes and not others, IMO this points to an DTR being out of alignment.

For proof jump the DTR pin #10 (RD/LB) and #12 (WH/PK). This will bypass the neutral safeties. Be sure to set the parking brake and BLOCK the wheels. Why is this important? Because IF the DTR is out of adjustment, disabling the NSS could allow the motor to start with the transmission in gear.

 

[TheDHndrsn]

A few developments since first post.

The starter was determined to be by shorting it to start. I had starter spin but no engage. I replaced the starter.

The no crank problem persisted. It will not turn over using the ignition key. I took the following actions:

1. Replaced the starter relay >> No Change
2. Evaluated and Tested all related fuses >> All Good, No Change
3. Rigged a Remote Start and attempted to Crank the Engine with key in and ignition set to run >> Success!!

With the new starter the engine will start and the vehicle drive but cannot be started using the key. I tried my second key. Same problem.

I suspect the computer because of the transmission swap. PAT related (possibly).

I am rigging a remote start switch for the driver compartment. If it doesn't want to start the way it is supped to, it can operate the old fashioned way.

In parallel I am looking at swapping out the GT computer for one from an '01 Crown Victoria. Will see if that makes a difference.
Dave

 

[Noobz347]

If you have not performed the steps outlined by wmburns above, I would encourage you to do so.

You should then post whatever results you observe whether they are good or bad.

Please do not start jurry rigging. Real life malfunctions require real life troubleshooting and faulty component replacement.

You are dealing with a computer controlled vehicle that includes a system of sensors that expect answers within a predetermined tolerance. It's probably not the best practice to hold a blow-torch to the intake and yell, "CLEAR PROP" as you try the spin the thing over with a pull rope and dump gas through the plenum.

Just thinking out loud... I'm kinda new at this.

 

[TheDHndrsn]

First. I'm going to assume this is a "no crank" problem instead of a "no start" problem.

If the pin out of the DTR sensor were the problem, then it would NEVER crank. Since it does crank sometimes and not others, IMO this points to an DTR being out of alignment.

For proof jump the DTR pin #10 (RD/LB) and #12 (WH/PK). This will bypass the neutral safeties. Be sure to set the parking brake and BLOCK the wheels. Why is this important? Because IF the DTR is out of adjustment, disabling the NSS could allow the motor to start with the transmission in gear.

The "sometimes start" issue was determined to be a starter. Using a remote start the replacement starter turns the engine over and it runs fine.

I added a 50A momentary contact switch to the dash (marine use switch). I can now start the car (being cautious it is in P) and it drives A-OK.

One of the testing procedures included separately plugging two different DTR sensors into the harness with the vehicle raised and the shift linkage detached from the trans. At no time, in no position with either sensor, would the car crank. Because I did the test using two separate DTR sensors for the same transmission (4R70W) I concluded the DTR Is not the bad guy here. I could be wrong. It is possible to have two faulty sensors however unlikely.

I have been reading in other threads / forums comments about folks who have swapped 4.6L engines from Crown Vic to Mustang and run into similar issue b/c of the Mustang computer and the anti theft logic. The solution offered was to drop a Crown Vic computer into the Mustang.

At this point, the vehicle is operable but certainly not in the condition I would like it to be. I remain in the dark as to the root issue on this problem.
Dave

 

[84Ttop]

It's probably not the best practice to hold a blow-torch to the intake and yell, "CLEAR PROP" as you try the spin the thing over with a pull rope and dump gas through the plenum.

Just thinking out loud... I'm kinda new at this.

you have it all wrong... ^^ That sounds like a good time, we never had to use a rope though. Maybe because the Cub is a whopping 35 Hp

Sorry for the derail, carry on

OP: It's always better to diagnose the problem rather than put parts in a cannon and shoot them at the car. Have you bypassed the NSS as outlined above?

 

[wmburns]

This is not a PATS related issue. PATS does not disable the starter. PATS works by with holding fuel injector pulse. The symptom of a PATS issue is crank with no start.

The automatic transmission neutral safety circuit (NSS) is a simple circuit that closes the starter pilot duty circuit only when the DTR is in Park or neutral. The circuit is open in any other position.

note the DTR sensor is actually several switches all aligned together. That's why the alignment between the shifter and the DTR range selector is so important. So if the NSS are out of alignment it seems reasonable to me that the other gangs of the DTR could also be out of sync.

Or the problem could be inside the DTR wiring harness. I compared the DTR pin outs between the 2000 Mustang and the 2001 CV/GM and the NSS circuit is in the same pins (10 & 12) with the same wiring colors. So this tells me that it's not a problem caused by the swap itself. If asking for a WAG, how about a bent or pushed pin the DTR body connector?

If this were my car I would test DTR pin # 12 (WH/BK) for 12 volts with the key in start.

IF no voltage, the problem is actually upstream. Fuse, missing manual transmission jumper, ignition switch. Also test CJB Fuse F2.6 and confirm voltage in/out with the key in start. If no voltage, the problem is either a blown fuse, bad ignition switch, or body harness wiring fault.

IF voltage, then confirm there is voltage at DTR pin #10 (should be a closed circuit between pins 10/12 when DTR is in park or neutral). IF voltage, then the problem is downstream Towards the Starter relay.

Finally, I would check the white/pink wire near the battery. It's a larger wire that's part of the starter system. I could easily see a case where this wire became disconnected during major repairs.

I'm going to drop off of this tread as clearly my input is not really helping to fix the problem.

 

[TheDHndrsn]

This is not a PATS related issue. PATS does not disable the starter. PATS works by with holding fuel injector pulse. The symptom of a PATS issue is crank with no start.

I'm going to drop off of this tread as clearly my input is not really helping to fix the problem.

Oh my no. The comments above are the best information received to date on this issue. I am not ignoring input in the least. The is good stuff and I greatly appreciate it. Understand, I need an operable vehicle. Seriously, I'm not a bone head here. I am just a guy making decisions based on priorities. If I may comment to a few things from your last post [Also ... I am a retired biochemist, not a tech. I do not know / understand the same language the rest of you take for granted nor do I posses the same skill set].

note the DTR sensor is actually several switches all aligned together. That's why the alignment between the shifter and the DTR range selector is so important. So if the NSS are out of alignment it seems reasonable to me that the other gangs of the DTR could also be out of sync.

I understand this. I attempted in my own way to determine if this was a DTR sensor issue by detaching the original DTR and manually rotating the sensor ring with the trans shift set to P and the console shift set to P. No start either way. I did this with 2 different DTR assemblies (one from the original GT trans and one from the CV trans). I completed this test BEFORE your comments, however which is why it appears I ignored your recommendation.

Or the problem could be inside the DTR wiring harness. I compared the DTR pin outs between the 2000 Mustang and the 2001 CV/GM and the NSS circuit is in the same pins (10 & 12) with the same wiring colors. So this tells me that it's not a problem caused by the swap itself. If asking for a WAG, how about a bent or pushed pin the DTR body connector?

If this were my car I would test DTR pin # 12 (WH/BK) for 12 volts with the key in start.

I will complete this test. A start bypass allowed me to get the vehicle running. It took very little time to rig it up. And ... it is a temporary fix to be disconnected once the true issue is identified. I cannot complete the pin #12 test until I can a half day with the car. That may be a couple days.

IF no voltage, the problem is actually upstream. Fuse, missing manual transmission jumper, ignition switch. Also test CJB Fuse F2.6 and confirm voltage in/out with the key in start. If no voltage, the problem is either a blown fuse, bad ignition switch, or body harness wiring fault.

IF voltage, then confirm there is voltage at DTR pin #10 (should be a closed circuit between pins 10/12 when DTR is in park or neutral). IF voltage, then the problem is downstream Towards the Starter relay.

Unsure what CJB fuse F2.6 designates but will Google. What complicates this one is that the starter solenoid was bad, apparently going at about the same time the swap completed. That may have contributed to the "crank when cold / sit when hot" syndrome. It will be good to understand if this is an upstream issue. I have already replaced the starter and starter relay assuming that to be the problem with the starter refused to work. That said, when the voltmeter was applied to the starter I saw +12 and change into the starter and nothing into the solenoid. That condition has not changed when I checked it after a new starter and starter relay. I will report back here on what I learn by testing DTR voltages at pins 12 & 10.

Finally, I would check the white/pink wire near the battery. It's a larger wire that's part of the starter system. I could easily see a case where this wire became disconnected during major repairs.

This is an intriguing comment. Happenstance has it that when I completed install of the start bypass switch the starter refused to turn over. I ultimately discovered this was from an improperly tightened negative at the battery. I will take a look for the white/pink wire.

Remember, this vehicle ran perfectly after an initial adjust to the DTR following the trans swap. It did not fail until (I assume) the start solenoid began acting up. Then, once the starter was swapped out, it failed completely. The starter swap involved disconnecting the positive battery terminal. I would not at all be surprised to find that the white/pink wire is somehow compromised.

Again, I appreciate the input.
Dave

 

[TheDHndrsn]

UPDATE: Before I even have time to test the things described by wmburns above, the root issue raises it's nasty head. Have been driving the vehicle for a few days now using the start bypass switch I wired into the white / pink wire running to the starter solenoid. No troubles. Today I was waiting for my wife in front of a shop and turned the ignition to the ACC position. Nothing. No windows, no radio, and no gauges. Fearing the obvious I turned to off pulled the key. Several seconds later? That lovely smell of shorted electrical circuit. I suspect it is a matter of time until the entire ignition switch goes. Time to start saving money for dealer involvement.

Thanks for all of your help, folks. Light at the end of the tunnel!!
Dave