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87 B2 wont start when cold outside.


89Bronco2Micheal

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My 87 b2 with 2.9 wont start if outside temperatures are cold but will start around 12 noon when the sun has warmed it up. My mechanics are stumped and so am I. This has been going on now for two years. Todays temps where the low was 46F and highs where 82F. It wont start in the morning but when outside temps get high enough it will start first time no hesitations.
 


Uncle Gump

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Well my first question is... will it properly crank the engine over? If it doesn't crank it's mostly likely the battery. if it does crank properly...

First thing I would do is check the fuel pressure. Cold engines require richer fuel mixtures. If the pressure is low... it's not getting all the fuel the cold engine requires.
 

89Bronco2Micheal

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Well my first question is... will it properly crank the engine over? If it doesn't crank it's mostly likely the battery. if it does crank properly...

First thing I would do is check the fuel pressure. Cold engines require richer fuel mixtures. If the pressure is low... it's not getting all the fuel the cold engine requires.
The battery is good strong, yesterday I put in a new intake air temperature sensor tried to start it this morning still wont start just turns over, outside temperature is 52F. It will crank on first try when outside temps are over 60F. I will check fuel pressure today and give an update tomorrow.
 

tw205

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The battery is good strong, yesterday I put in a new intake air temperature sensor tried to start it this morning still wont start just turns over, outside temperature is 52F. It will crank on first try when outside temps are over 60F. I will check fuel pressure today and give an update tomorrow.
Next time no start condition rears it’s head, along with fuel pressure check for spark. Three things needed. Air, fuel, and spark.
 

89Bronco2Micheal

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Well my first question is... will it properly crank the engine over? If it doesn't crank it's mostly likely the battery. if it does crank properly...

First thing I would do is check the fuel pressure. Cold engines require richer fuel mixtures. If the pressure is low... it's not getting all the fuel the cold engine requires.
I found the problem the TFI module on the distributor was loose the two screws that hold the TFI on were about two turns loose and the dielectric grease was about dried up, I cleaned the back of the distributor and TFI with rubbing alcohol applied new grease put the TFI back on and it started first time and now starts on cold mornings no problems. I hope this could help someone with similar problem with no start. I still haven't figured out why it would start if outside temps where above 60F.
 

tw205

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I found the problem the TFI module on the distributor was loose the two screws that hold the TFI on were about two turns loose and the dielectric grease was about dried up, I cleaned the back of the distributor and TFI with rubbing alcohol applied new grease put the TFI back on and it started first time and now starts on cold mornings no problems. I hope this could help someone with similar problem with no start. I still haven't figured out why it would start if outside temps where above 60F.
Nice find. Heat expanding and cold contracting is likely why there were temp related issues. Thanks for updating us on your success. Too often a tread just dies without the resolution included. Good work. 👍🏼
 

89Bronco2Micheal

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Update on my B2. Don't use dielectric grease between TFI module and distributor use a heat sink paste instead. I had the no start issue this morning again I had a friend try starting it while I wiggled the TFI it would start up while I held the TFI tighter against the distributor but would shut off when I let go of the TFI. We did same thing this time I let the engine warm up a minute then shut it off, tried starting it without wiggling TFI it started up fine I turned the motor off tried starting again and it started up again no problems. I'm think when the engine warms up the TFI it will start. So this time I removed the TFI cleaned all the dielectric grease of it and distributor applied a heat sink paste compound put TFI back on and now it cranks, I'm not a pro mechanic just learning from my mistakes, Thanks again for your help hope what I said makes since.
 

Uncle Gump

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Yes heat is the number one reason of TFI module failure. The heat sink paste ensures that the module makes full contact with the distributor housing for heat transfer. More is not always better. A thin even layer is all that's needed. Just try to ensure there is no voids in your layer... that will cause a hot spot.

I'm not sure how heat sink paste alone could fix your condition... but you will know first hand if it doesn't. The TFI module gets it ground through the distributor via the fasteners. So it has to be secured well to create the ground connection.

I
 

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