I've got the cold start woes....

[Chris_Murder]

I figured I would post this here to see if anyone else had some ideas of what else to possibly look at or try. I've posted about this issue on TCCoA a few times in the past with no success. I'm trying to post as much helpful information I can to help in diagnostics. I'm at the point of trying another pcm . My 32v swapped bird completely fights to start in the cold.

This issue existed before I swapped in my 32v 4.6 dohc, it did the same non-sense with the old 16v 4.6 sohc. It also has done this with two engine wiring harnesses and one other chassis/dash harness.

Basically the vehicle in the cold (las vegas cold... 20~ degrees - 50~ degrees) will not start unless it's cranked repeatedly for a few cycles. Key on, key off, crank for 4-6 seconds, try again, try again, try again, try again, vrrroom... usually fires up anywhere from the 2nd to 6th key on, key off, repeat cycle.

In the warmth it will fire up immediately, heated garage over nigh starts up first key on and crank within 2-3 seconds, also once it warms up like it is about to it does the same thing.... starts right up.

I've installed a fuel pressure gauge at the rail thinking that it was a fuel pressure problem even after installing a new walbro 255lph pump. I have verified that I am getting good FP.

However it drops spark during this cold starting issue. It never drops spark running.

New CPS, new CKP, new CCRM/ICRM, replaced the wiring harness, measured resistance hot/cold and shook tested wiring harness from CKP and CPS sensor pin to bulk head pin, checked grounds, replaced crankshaft trigger wheel, measured air gap between trigger wheel and CKP, replaced front cover, machined front cover, new coolant temp sender and new sensor, new IAC, new TPS, new IAT, new IAC,... and yet it still completely fights to start below 60 degrees, which for me is every winter.

Drops spark during cold cranking only. It's like the opposite of people who can't get their car to start after it's hot.

Anyone else have any ideas? Finding a new or good used matching catch code PCM for this vehicle has been a complete p.i.t.a. I've been told the year and catch code must be the same in order to remove and reinstall my custom tune via xcal2.

I have also scoped various sensors from cold to hot to verify no "dead spots" with a snap on MODIS lab scope.

Any other ideas? Or is it time for a new PCM before winter rolls around again?

 

[zmt325]

coils?
is it cop or obd1?

 

[Chris_Murder]

coils?
is it cop or obd1?

2 motorcraft 4-tower coil packs and livewire plug wires with motorcraft plugs. Gen 1 mark style setup. 97 bird chassis fully obd2. With scan gauge 2 installed in the car. I hope to convert to COP next year.

 

[zmt325]

did you have these same coils on the 2v motor?

 

[Chris_Murder]

did you have these same coils on the 2v motor?

No these coils came off my mark VIII that I took the motor out of. My old coils are with my old motor. They are motorcraft units with about 15,000 miles on them.

 

[zmt325]

No these coils came off my mark VIII that I took the motor out of. My old coils are with my old motor. They are motorcraft units with about 15,000 miles on them.

it was a shot in the dark.

so you are loosing signal to the coils when cold? that is super strange, it is late and this may not make much sense. but if it was me i would start testing the signal and power going to the coils to narrow down the issue. then chase it back to the ecm.

 

[slowmkviii]

What has not changed from before and after the swap
And why can't your tuner work with different catch codes
my xcal does did a reputable shop say you can't move the tune
I would call sct and see what they say.

 

[SATURN5]

I'll shoot the dark and say bad engine ground.

 

[ford nut]

Is the PCM from the 32 v?

 

[Chris_Murder]

What has not changed from before and after the swap
And why can't your tuner work with different catch codes
my xcal does did a reputable shop say you can't move the tune
I would call sct and see what they say.

Not much hasn't been replaced lol. As far as I know I was just assuming, I'd imagine that custom tunes designed for certain catch codes wouldn't be fully compatible with different catch codes. I'm sure I could be mistaken. I just didn't want to mess anything up.

I'll shoot the dark and say bad engine ground.

4" thick braided strap from the block to the chassis on both sides. Also going to be doing the big 3 upgrade with 0-gauge wiring in the near future as well. Addition chassis to battery, chassis to block, and block to battery. Also going to upgrade to a fused 0-gauge wire for the alternator charging post.

Is the PCM from the 32 v?

Nope, the PCM is the original tbird unit reflashed with a custom tune for the 32v via xcal2.

 

[Chris_Murder]

it was a shot in the dark.

so you are loosing signal to the coils when cold? that is super strange, it is late and this may not make much sense. but if it was me i would start testing the signal and power going to the coils to narrow down the issue. then chase it back to the ecm.

Yes, exactly right, and it drives me bonkers.

 

[Lux]

Disregard

 

[zmt325]

Nope, the PCM is the original tbird unit reflashed with a custom tune for the 32v via xcal2.

then it is ether there or a bad ground going to the ecm. does the dohc engine harness just plug right into the chassis harness of the bird? i have a 2nd gen computer sitting right next to me. the catch code is mlxo shoot me an offer and it is yours.

temp change makes me think an expansion or retraction of something (hardware) not tune related.

pics of the bird would be cool, sounds like a bad as$ bird.

 

[ford nut]

Not much hasn't been replaced lol. As far as I know I was just assuming, I'd imagine that custom tunes designed for certain catch codes wouldn't be fully compatible with different catch codes. I'm sure I could be mistaken. I just didn't want to mess anything up.

I would think if you talked to sct they could unlock your hand held.
They might charge you, maybe not if you explained whats happening.

Nope, the PCM is the original tbird unit reflashed with a custom tune for the 32v via xcal2.

That is what I was thinking.

So your guess is something is wrong with your pcm which is continuing to be a issue?

Who did your tune?

Did they just modify the 16v tune that was on the pcm?
If that is true it might not be the pcm at all.

Maybe your tuner can compare your original 16 v tune to a known good 16 v tune that is known to not have this issue, before you hunt down a hard to find pcm.

Just throwing ideas up on the wall.

Must be frustrating as hell.
Put all this work into a car to have it do this would piss me off to no end.

 

[97MarkJA]

It doesn't take much to start a motor that is warm already. I would look at the grounds in the car, also check the ignition switch. Sounds simple but you should have one or two (can't remember) wires coming off the switch that are true ignition. Stay hot through crank, accy will drop out when turned to the start position.
If you have a bad chassis ground or a bad switch; under load your ignition through start could be dropping out.
It's a thought.?. I've seen it before.
Check at the switch and at the pcm (in on the pcm and out to the coils.)

 

[97MarkJA]

Let me know what you find.

 

[Chris_Murder]

I would think if you talked to sct they could unlock your hand held.
They might charge you, maybe not if you explained whats happening.


That is what I was thinking.

So your guess is something is wrong with your pcm which is continuing to be a issue?

Who did your tune?

Did they just modify the 16v tune that was on the pcm?
If that is true it might not be the pcm at all.

Maybe your tuner can compare your original 16 v tune to a known good 16 v tune that is known to not have this issue, before you hunt down a hard to find pcm.

Just throwing ideas up on the wall.

Must be frustrating as hell.
Put all this work into a car to have it do this would piss me off to no end.

My tuning was done by Don Lasota @lasota racing. I seriously doubt it is a tuning issue, I'm starting to believe it's a mechanical/electrical problem like a bad ground or bad pcm.

then it is ether there or a bad ground going to the ecm. does the dohc engine harness just plug right into the chassis harness of the bird? i have a 2nd gen computer sitting right next to me. the catch code is mlxo shoot me an offer and it is yours.

temp change makes me think an expansion or retraction of something (hardware) not tune related.

pics of the bird would be cool, sounds like a bad as$ bird.

No the mark harness doesn't plug right into anything. The 97 4.6 sohc thunderbird harness has to have 3 wires extended to reach their appropriate locations comfortably, however a stock harness thunderbird harness will physically fit unmodified, however it will look like crap and wiring will be strained.

Pics of the bird, no problem. LOL here's a 7 page progress build of it.
http://forums.tccoa.com/showthread.php?t=129485

It doesn't take much to start a motor that is warm already. I would look at the grounds in the car, also check the ignition switch. Sounds simple but you should have one or two (can't remember) wires coming off the switch that are true ignition. Stay hot through crank, accy will drop out when turned to the start position.
If you have a bad chassis ground or a bad switch; under load your ignition through start could be dropping out.
It's a thought.?. I've seen it before.
Check at the switch and at the pcm (in on the pcm and out to the coils.)

Your the second one to recommend looking at the ignition switch.... might have to bust out the fluke88 and take a look.

 

[97MarkJA]

I dont think its a tune issue, I would look at the switch first.

 

[ford nut]

My tuning was done by Don Lasota @lasota racing. I seriously doubt it is a tuning issue, I'm starting to believe it's a mechanical/electrical problem like a bad ground or bad pcm.

I would agree with you there.
Good tune I presume