loads up and stalls

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Feb 18, 2002 | 07:49 PM

stractor

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Elder User

Joined: Feb 2002

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From: Saddle Brook United State

loads up and stalls

Hello, I hope some on can help before I spend the rent money. I have a 90 F-150 with a 4.9L six. The truck nas 87000 miles and I use it mostly on weekends.Recently it has developed a problem. When you take off in first the engine will start to miss and try to stall. It feels like a carburated engine running out of gas. If you play with the throttle it will take off and run. I have been able to reproduce the problem sitting still. It seems to occur at low RPM's while running the engine through a varied range of throttle settings. If you hold the throttle still while this , the problem, is happening the engine will stall. I noticed while this is happening the exaust is black and the engine feels and acts like it is being flooded. If you play with the gas it will start to run correctly. I can't always duplicate the problem. The ignition system, except for the module, is new. It will do it on either fuel tank as I was able to switch tanks while it was happening. There are no codes generated. I am leaning towards a bad pressure regulator, but have no gauge to test it with ( looks like a good excuse to buy more TOOLS).Any help will be appreciated.

Thanks
Bob M

Feb 18, 2002 | 09:10 PM

wtroger

Cargo Master

Joined: May 2001

Posts: 3,208

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loads up and stalls

Either fuel pressure regulator or a map sensor.

Feb 18, 2002 | 10:34 PM

Billmack

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Joined: Feb 2002

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From: Coupeville WA

loads up and stalls

How can you tell if it's the MAP sensor gone bad or something else causing the MAP sensor to send a bogus signal to the computer so that the engine floods?

Feb 19, 2002 | 12:35 AM

PAUL_2

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Joined: Jul 1999

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loads up and stalls

You should be able to rent a Fuel Psi Gauge @ a local auto parts store , Get a reading on it before you go any further . Also check the vacuum hose to the regulator , Red Vacuum Line , to make sure its connected to both the intake & the regulator & it isnt damaged . KOEO Psi should be 40 to 60 Psi , KOER it should be about 50 Psi .

Feb 20, 2002 | 09:12 PM

kspilkinton

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Joined: Jul 2001

Posts: 4,038

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From: South Kitsap County, WA

loads up and stalls

[updated:LAST EDITED ON 20-Feb-02 AT 10:15 PM (EST)]If it is the MAP sensor you should be getting a code/ check engine light. You can disconnect sensors (the computer will see the missing input and put a failsafe code in its place) and see if the problem clears up. I had to do this with a '93 Escort. I disconnected one sensor at a time, ran the vehicle to get the same condition. When the problem cleared I had found the Mass Air Flow sensor was the problem. The computer codes were telling me my injector pulse width was to long, nothing about the MAF. The problem was fixed and the car ran great.

Also with a vehicle that only gets driven sparingly you may have a carbon build up or plugged injectors. You may need these cleaned out.

-Kerry

Feb 20, 2002 | 10:26 PM

stractor

Thread Starter

Elder User

Joined: Feb 2002

Posts: 504

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From: Saddle Brook United State

loads up and stalls

Guys, thanks for the replys.The engine runs fine 90% of the time and then will start to load up and stall, usually after a standing start in first. Then it will clean itself out and run OK. Sort of rules out clooged injectors or carboned up ones. I suspect the pressure regulator ( wishful thinking ). Went out and bought a pressure tester so I will be able to check that when I get a chance ( I have no garage ).

Feb 21, 2002 | 11:31 PM

Dumbtruck

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Joined: Jan 2002

Posts: 42

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From: Gladstone

loads up and stalls

[updated:LAST EDITED ON 22-Feb-02 AT 00:36 AM (EST)]This probably won't fix your problem, but try replacing the fuel filter. Sometimes they will 'clog', or just get old, and can limit the amount of fuel going through. If it works, then you spent $5. If it doesn't, well you got a new filter at least.

Brian