Engine starts but stops immediately

CISCO123

MEMBER
1987 FORD BRONCO
2.6L
V6
4WD
AUTOMATIC
200,000 MILES

My engine starts but stops immediately, after revving the engine for a bit, then the engine starts idling okay, but seems a little rough. We just changed the spark plugs, spark plug wires distributor cap and rotor. Don't know what to look for next.

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,269 POSTS

Welcome to 2CarPros.

This can be caused by a few things. First, take a look at this link:

https://www.2carpros.com/articles/engine-vibration-at-idle

Next, I would suggest checking for engine vacuum leaks. A leak can do this too. Here is a video that shows how it is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, a fuel pressure regulator can cause too much fuel to enter the engine which can do this too. You may want to test fuel pressure and the regulator. Here is a link that shows how it is done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Here are the fuel pressure specifications for your vehicle:

Key On Engine Off 35 - 45 psi
Key On Engine Running 27-37 psi
Engine Running Vacuum Hose Disconnected From Pressure Regulator 40 - 45 psi

Start with that and let me know what you find. Let me know if you have other questions or need help.

Take care,
Joe

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Tuesday, March 26th, 2019 AT 6:48 PM

CISCO123

MEMBER
2 POSTS
1987 FORD BRONCO
2.9L
V6
4WD
AUTOMATIC
200,000 MILES

Hi, emailed you a couple of weeks ago, thank you. My problem is my vehicle listed above ll model, when I first start it, it shuts off off, then I start it again and just rev the gas pedal for a bit maybe two minutes, then it starts to idle and run fine. It is just the initial first start up. I was thinking we may need to change the vacuum lines but can't seem to get a good diagram online. My manual says to check the vacuum hose near the intake manifold. Is there any way you could guide me on this and help me get a good diagram, on the vacuum hoses for my vehicle? Thank you

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Sunday, April 7th, 2019 AT 11:22 AM (Merged)

SEVAG P

MECHANIC
405 POSTS

Hello thanks for using 2CarPros.

Hello it seems your idle control is not working properly. check attached files for complete trouble shooting.(fig 1,2,3) and fig 4 for vacuum diagram.

Check our guide for engine stalling:
https://www.2carpros.com/articles/stall-at-idle
https://www.2carpros.com/articles/throttle-actuator-service
https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Let us know what happens with you.

Thank you.

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