alright got an 88 bronco 4x4 with the 300 5 spd. when i take off in it it will start off and roll a little bit then when i give it more gas it boggs down, pump the pedal to keep it running and it will run for about 4 seconds then dies, hit the key starts right back up but does the same thing. will the egr being unhooked have anything to do with htis? havent had any time to mess with it so figured i would start here first

 

big78f150,

Just a couple of thoughts to let you know people are reading and thinking. Having a 5 speed, indicates some changes have been made by someone. Is everything [hoses, sensors, etc.] still hooked up? Have you pulled the codes to see if any information is stored in the computor?

 

All of its hooked up. Broncos didn't come with 5spd? I ain't had much time to look at it yet going to after work today. To me it seems like its not getting enough fuel or the timing is off but I'm not sure

 

My mistake [senior moment?]. They DO come with a 5 speed... my son has a 1984 and I drive a 1986, both with 4 speed O.D., so I was thinking 4 speeds.

Has the check engine light come on? Does it light up momentarily when starting the engine?

 

Yea this ones 4sp overdrive. I ain't even picked it up yet, litterally just got it lol. He said he's checked codes twice 1st time it was map censor 2nd time it was fuel pump. Is it normal for them to change like that?

 

I am not as familiar with fuel injected systems, but it is not unusual for there to be more than 1 code stored in memory.

If the fuel pump is faulty, it would help explain why your truck starts and dies after a few seconds. When you first turn the key to the "run" position, prior to twisting the key to the "start" position, do you hear the fuel pump running? It should be a rather high pitched whine.

 

it will start and run fine it only dies when you take off then give it gas to speed up. Yea you can hear the pump its got a decent whine to it

 

At this point, I am stretching my ability to help, due to lack of experience, but there is a fuel pressure regulator which controls the pressure going to the injectors. Somewhere on the fuel rail, there is a port where a pressure gauge can be attached to measure the fuel pressure. Someone else can provide the correct pressure, but I believe it is around 45-50 psi. Perhaps there is enough pressure to be able to idle, but insufficient for greater demands, as when trying to drive off?

Has the fuel filter been changed? If not, maybe enough fuel can pass at lower RPMs, but not at higher RPMs?

 

I was going to do a pressure test. And fuel filter was my first guess too. Just don't have the money to start tearing into it yet

 

Messed around with it today. Fuel filter was sludged up bad, put new one on didn't fix it. Put a known good map sensor off my car on it, exact same sensor same part number and everything, still didn't work. Question there was a plug on the end of the egr that's no longer hooked up because egr has been removed. I'm gettin fed up with it

 

check the fuel pressure at the rail. I susspect your high pressure pump is bad. It won't run on the lift pump alone. You have 2 pumps in your truck. 1 in the tank to lift the fuel, other is in the frame rail up by the front body mount on the driver's side. That pump is the high pressure pump. It sells for about $100, so check the fuel pressure 1st, it should be about 60 lbs