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Discussion Starter #1
Car info:
91 mustang Gt.
New remanufactured A9L computer installed
Stock MAF and injectors, both very clean
Stock cam
Stock rebuilt 302 standard bore with trickflow heads and 1.72 rockers, explorer intake
New started solenoid
New battery
Dist at 10 degrees with spout unplugged
Computer is grounded near computer and near battery.
TPS voltage around 1.0 volt
MAF has .4 volts between pins c & d per a checklist I read thru.

Symptom:
Car starts cold fine but dies instantly with all sensors plugged in.
If I unplug IAC, MAF or dist plug, or just IAC the car will idle very low at about 550 rpm and sounds like it has a cam.
Eventually the car dies.

Been doing a lot of reading but don’t know what else to do at this point. I’m at my wits end.

Any ideas anyone?

I would be very greatful for any assistance or expertise.

Thanks.
 

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so the symptom is

It starts, runs then stalls?, all sensors plugged in?
 

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Discussion Starter #5
Yes sir that is correct. I just started the car after letting it sit all night, all sensors plugged in.

Starts fine, upon start idle immediately goes to about 1500rpm, then comes down to about 500rpm. Within 2-3 seconds. Will bounce between 5-600rpm, sounds really choppy. Idle seems to go lower within the first minute until it just craps out after about 1-2 minutes. Seems the idle gets lower and lower as it warms up.

Ground strap is tight between head and firewall as well as orange ground from 10 pin harness connector.

Have cleaned with electric contact cleaner pretty much most harness connectors.

Checked the solenoid and all wiring appears to be correct from diagrams I’ve seen.
 

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Discussion Starter #6
It also seems to be making a pop noise via the air box every 10 seconds or so. Stock Maf inlet tube with a stock air box, paper filter.
 

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Discussion Starter #7
Has a 130 amp alternator with wiring kit that’s only about 2 years old.

Original distributor with newer replaced cap and plug wires.
 

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sounds like a fuel delivery issue

connect a fuel pressure gauge on the rail and verify near 40psig without the vac line on the reg.

this is just a start
 

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Discussion Starter #10
Was able to run to oreillys and rent a fuel pressure test kit.

Hooked it up to the Schraeder valve. Made sure it was tightened.

Remover vacuum line from my regulator (replaced last year).

With key on and engine off, fuel pump kicks on for a half sec then stops. pressure gauge shows 0.
When I crank it, it cranks and dies instantly. Pressure gauge shows 0 during that time.

If I remove the tester and press the shrader valve fuel squirts out.

Don’t know why it’s saying 0.

Car has gas.
 

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Discussion Starter #11
Car has a Walbro 190lph pump in it, I put it in about 5 years ago.

But if I unplug the IAC and spout the car will have a lumpy idle around 550 rpm and die after about 30 sec.

Any attempt to give it gas is met with a sputter or pop noise coming from the intake tract.
 

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Discussion Starter #14
Question, the rubber fuel hoses between the body fuel lines and fuel rail were replaced. Wanna make sure the supply is hooked up to the supply and same thing for returns.

On the body by the sway bar and k member, is the larger line the supply or return?

On the engine, the line with the shrader is the supply correct?
 

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Discussion Starter #16
Fuel hoses are connected correctly between body lines and rails.

Gonna order a fuel pressure gauge that screws into the shrader valve to try to confirm fuel pressure.

I can’t get the gauge I rented to budge off 0 during key on car off and when cranking it.
 

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ensure the depressor on the gauge is screwed out, so it can depress the the depressor
 

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Discussion Starter #18
Aero motive gauge and adapter came in today. Installed and confirmed 32psig fuel pressure with key on engine off, vac line unplugged.

Car won’t run long enough to get reading while running with all sensors plugged in.

Unplugged spout, MAF, and iac. Car started and idled very very choppy at 500rpm for about 10 sec, just long enough for me to verify 40psi fuel pressure before it died.

I’m at a total loss, any next steps that could be offered would be hugely appreciated!
 

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reconnect all the sensors, then unplug the act, probe the connector key in run

what are the voltages on the two pins?
 
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