Engine Starts then stalls Surging idle

Luisr010 said:

need help my mustang is stalling.
It’s a 1987 ttop Mustang GT.
It starts and surges high for a second then low rpm bouncing until it dies.
So far what I’ve done:
Fuel pump, Fuel pump relay, Fuel tank, fuel filter,
Fuel pressure regulator, tfi module, egr valve.

Took off my intake to and inspected all the hoses.
I get 30 psi at the rail at the front.
I spray starter fluid after the maf a little bit and it
Evens out and runs nice. Then it stumbles and stalls again.
I’m all out of idea I need HELP please.

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AeroCoupe said:

Define how you are checking the fuel pressure. Stock fuel pressure should be 38-39 psi with the vacuum line disconnected from the fuel pressure regulator (FPR) and the vacuum line plugged. With the vacuum line connected the pressure should be around 30 psi (+/- 1 psi). Checking the pressure with the vacuum line connected requires the car to be running. I think that is pretty obvious but wanted to point it out just in case.

Have you pulled the codes on the car yet? 1987 & 1988 cars do not have check engine lights (CEL) so you have no indication on the dash if codes are present.

Electrical - How To Pull Codes From EEC-IV In 86- 95 5.0 Mustangs

@Noobz347 - The code dump procedure isn't in the sticky - you may want to add it... Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on. Dumping the computer diagnostic codes on 86-95 Mustangs Revised 26-July-2011. Added need to make sure the clutch is...

stangnet.com

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AeroCoupe said:

Was the stall before or after the installation of the new pump?

Key On Engine Off (KOEO):
81 - Air Management 2 (AM2) circuit failure
82 - Air Management 1 (AM1) circuit failure
95 - Fuel pump secondary circuit failure
Key On Engine Running (KOER):
21 - ECT out of Self-Test Range
33 - EGR valve opening not detected
41 - HEGO sensor circuit indicates system lean (right HEGO)
91 - HEGO sensor circuit indicates system lean (left HEGO)
The codes are pointing that direction but you may have deleted a few things and/or the car is a 4 cylinder to V8 swap (code 95) and there are other issues due to a poor swap. 81 & 82 are the TAB solenoids related to the EGR so those combined with 33 leads me to believe all that has been deleted.

21 needs to be addressed as the ECU uses this info for trimming the fuel. 41 and 91 need to be addressed as well as these also contribute to how the ECU trims the fuel.

ECU could have an issue as is could be as old as 36 years if original and if a swap car then it could be a few years less. Several threads on here about the caps in the ECU's going bad and sending them off to ECU Exchange for repair. Cost is around $150.

Ford

Repair Service for Ford ECUs

www.theecuexchange.com

If you have access to another speed density (assuming the car is non-mass air) ECU try swapping them out and see if this clears up the problem. You need to be damn sure all the wiring it correct or you could damage another ECU.

Click to expand...

AeroCoupe said:

Was the stall before or after the installation of the new pump?

Key On Engine Off (KOEO):
81 - Air Management 2 (AM2) circuit failure
82 - Air Management 1 (AM1) circuit failure
95 - Fuel pump secondary circuit failure
Key On Engine Running (KOER):
21 - ECT out of Self-Test Range
33 - EGR valve opening not detected
41 - HEGO sensor circuit indicates system lean (right HEGO)
91 - HEGO sensor circuit indicates system lean (left HEGO)
The codes are pointing that direction but you may have deleted a few things and/or the car is a 4 cylinder to V8 swap (code 95) and there are other issues due to a poor swap. 81 & 82 are the TAB solenoids related to the EGR so those combined with 33 leads me to believe all that has been deleted.

21 needs to be addressed as the ECU uses this info for trimming the fuel. 41 and 91 need to be addressed as well as these also contribute to how the ECU trims the fuel.

ECU could have an issue as is could be as old as 36 years if original and if a swap car then it could be a few years less. Several threads on here about the caps in the ECU's going bad and sending them off to ECU Exchange for repair. Cost is around $150.

Ford

Repair Service for Ford ECUs

www.theecuexchange.com

If you have access to another speed density (assuming the car is non-mass air) ECU try swapping them out and see if this clears up the problem. You need to be damn sure all the wiring it correct or you could damage another ECU.

Click to expand...