1986 Wont Start When Hot / Rich

gotcat85

New Member
Nov 28, 2018
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Bardstown
Got a 1986 mustang just done a mas air conversion. Had some problems getting it to run at first but finally got it to start run after swapping around a few A9Ls that I had. Since the swap the car seemed to be running correct. The mass air was installed due to a cam change. The car will start and run great when cold but will not start after it comes up to operating temp. Also the car smells like gas. Changed the coil and checked for fire at the plug. Getting fire!! Check timing and it's set at 13. The advanced timing seems to be working properly. Currently I'm running 93 gas. Currently the car is a fresh 306 with a 303 cam. The car is running on a stock A9L and has no current tunes.

Wont start when hot!
Smells rich
Getting Fire
New coil
New Plugs / Wires
12-13 volts on charging system
ideal is set around 900-1100 ( Car dose surge at low rpms when cold but stays smooth after warming up)
24 psi injectors
mass air flow for 24 psi injectors
Starter is new but original
bbk headers
new o2 on both sides of headers
new tps set at 1 volt
erg is hooked up
no vac leaks that I know of.
2.5 inch exhaust no cats with flow masters
new fuel pump (factory) car holds about 32 psi running or at ideal

What am I missing. Would a tune fix this? This car will flat out run cold or hot but will not start for several hours after hot and smells very rich at ideal!!! ??????
 
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I'm a beginner at these things but I run a Pro M ECU. I've had the same issues back then and thought it was my starter that was too hot. I replaced the old starter, problem didn't quite go away when hot.

I read through a forum two years ago and apparently if your Crank Lambda or something like that is too rich it may create an issue for a hot start. I leaned mine out a bit and the car starts no matter how hot or cold now. With an A9L, you may need a tuner?

Also, Chris from Pro M states that TPS voltage >0.90V is actually not a good thing. Ford Computers actually run better with 0.90V or less.
 
no a tune cannot fix mechanical issues

if the car is running rich then the o2 sensors need to be replaced

from what is described it sounds like either the tfi module or the pickup in the distributor is bad

a stock a9l ecu with only 24s and a calibrated maf should run fine. Thousands of people have done it over the years with no issues.

Chris has no idea what he is talking about. The stock ecu saves the lowest throttle voltage it see's since key on as a value known as RATCH.
actual throttle position is subtracted from ratch to give a relative throttle position.
Everything in the ecu is based on relative throttle.

The closed throttle voltage is absolutely useless on a ford so long as its not out of range to set a fault.
 
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no a tune cannot fix mechanical issues

if the car is running rich then the o2 sensors need to be replaced

from what is described it sounds like either the tfi module or the pickup in the distributor is bad

a stock a9l ecu with only 24s and a calibrated maf should run fine. Thousands of people have done it over the years with no issues.

Chris has no idea what he is talking about. The stock ecu saves the lowest throttle voltage it see's since key on as a value known as RATCH.
actual throttle position is subtracted from ratch to give a relative throttle position.
Everything in the ecu is based on relative throttle.

The closed throttle voltage is absolutely useless on a ford so long as its not out of range to set a fault.

Wow interesting! That's why I joined the forum and watches many of the threads closely! Learn something new every time!