1990 full-size bronco problems!

[Cez97838]

I have a 1990 bronco with the 300 straight six motor and I have the e40d tranmission.

For a couple of months now it has been running rough. When I start her up any time of the day. She tries to die or does die. I will put her in reverse and she is fine. But when I put her in drive and I push on the gas peddle she acts like she isn't getting any fuel and tries to die but as soon as I let off the gas peddle she doesn't tri to die any more. She will do this for about 5 miles down the road. I have asked my husband to fix the issue but he doesn't know where to start.

 

[Rons beast]

Hey Cez, Welcome.

It sounds like a fuel delivery or mixture issue. Is the problem the same when the truck is cold as when it's been warmed up?

First do a visual check of the vacuum lines. Replace any that are cracked.

Has the fuel filter been replaced?  and is your truck fuel injection or carb?  How long since a "tune up".  What work has been done?

With a little more info you will get some great advice here. 

Good Luck

 

[miesk5]

yo CES,

WELCOME!

As RON advised!

&

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded

A helper is good to assist in reading Codes; best is to take a cell fone vid and replay it.

Some basics;

Visual Check

Battery is fully charged & clamps, wire strands and ground points are clean

Inspect the air filter and inlet ducting.

Check all engine AND HVAC (under hood & in /under dash) Vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc.

 

[Bully Bob]

Some good advice above..,

Something tells me that's a carburetor on that truck.

Stepping on the gas allows a large amount of air into carb throat. If this air isn't matched with a large squirt of fuel

via the accelerator pump.., the engine will run lean of fuel & stall.

Accelerator pumps are an easy fix.

However, this isn't the only issue that could cause problem.

 

[Cez97838]

Hello miesk5

I will check those things out.

Thank you

 

[miesk5]

yo Cez,

Bob asked if the 90 has a carb?

 

[Cez97838]

No I don't have a carburetor, she is fuel injected, we just did a partial tune up and 3 weeks ago, that consisted of, plugs and fuel filter. The vaccum lines have been replaced. After I start her up and diver her. When I put her in park and go to driver her later in the day most of the time she won't have the issue. The accelerator pump has been cleaned.

 

[miesk5]

yo Cez,

ok, ty!

Try the Self Test for Diagnostic Trouble Codes that I posted above.

Post Code(s) here by KOEO and KOER

Check 4.9L engine Firing order: 1-5-3-6-2-4 Distributor rotation: Clockwise

http://content.chiltonsonline.com/(S(1kx5y255ci5mz455ksj0i545))/content/images/8828/images/88282g02.pdf

 

[Bully Bob]

"...The accelerator pump has been cleaned"

There's no accellerator pump on fuel injection (that I'm aware of)

& these pumps are not really cleanable.., usually replaced. (cheap)

As M5 suggests.., auto parts can pull the codes for free.  OR do a self test as shown.

3 things needed; fuel air, & ignition to make an engine run. (& of course, several 'lil sensors)

One (or more) of these is your problem.

The codes will help you narrow the failure down.

If you get the code(s)  Fuel injection folks here can help you.

 

[Cez97838]

Oh! My husband said he cleaned the accelerator pump. Maybe he is thinking of something else? Could it be the egr valve?

 

[Cez97838]

Oh and my bronco isn't throwing out any codes

 

[Bully Bob]

"Oh and my bronco isn't throwing out any codes"

You would know this how...? 

1) There's no "check engine-or-service engine soon" light lit on the dash..?

2) You already had the auto parts store scan for codes..?

If it's the former, the light could be burnt out.  Does the "check engine light" flash when key is turned to "on" ..?

 

[Cez97838]

No I haven't had them scan for codes. I was just assuming because there isn't check engine light on. The check engine light does turn on when I turn the key over. I will check to see if it flashes.

 

[Bully Bob]

It doesn't flash.., (bad choice of words by me)

I just meant does it light up.... & you said it does. (with key on)

(goes off when running)

Still.., wouldn't hurt to have the auto parts do a read-out..., it's free.

 

[Cez97838]

Okay thank you. I will take it down there and see if it picks up anything.

 

[Bully Bob]

Another thought is the modulator on the transmission.

It could be bad.., or leaking fluid or leaking air. That's an easy fix.

It's not exactly easy to diagnose via a keyboard..,

But don't get discouraged.., we'll figure this out. Keep us posted/updated.

 

[miesk5]

...I was just assuming because there isn't check engine light on. The check engine light does turn on when I turn the key over. I will check to see if it flashes.

Yo,

Don’t worry if the Check Engine Light is not on, the computer will store lesser important codes without flashing lights in your face.

by Ryan M @ http://web.archive.org/web/20101130223010/http://fordfuelinjection.com/?p=13

If the shop can't scan for Codes; find another shop that will scan using just a paper clip or as Ryan describes

http://web.archive.org/web/20101130223010/http://fordfuelinjection.com/?p=13