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sprinkles08
sprinkles08, ASE Certified Technician
Category: Ford
Satisfied Customers: 22813
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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1994 ford ranger 2.3l manual engine has 40 psi on the rail

Customer Question

1994 ford ranger 2.3l manual engine has 40 psi on the rail when key on
I have replaced the fuel pump modual fuel filter, gas , clean injectors, starts right up then slows and dies cannot add accelerator or it wil die,runs rough at idle. But when I disconnect the air intake hose from the air filter it runs perfect, I took top of air filter housing all looks good , when truck is running , I go and put air hose on filter housing top and I dies, and it's not even mounted to the lower half of the housing , grey motor craft box on air filter housing , I don't know what it is or does , but my problem might be there. Please help
Submitted: 1 year ago.
Category: Ford
Expert:  cloe0626 replied 1 year ago.

its your mass air flow sensor

Customer: replied 1 year ago.
On another note I can completely over the air horn at the manifold and truck stays running , telling me the idle air sevo is working! Ok I'll buy a mass air flow sensor
Expert:  cloe0626 replied 1 year ago.

you need anything else let me know please be sure to rate my service when you get the chance

Customer: replied 1 year ago.
I replaced the mass air flw sensor, and no change does the same thing starts and then dies, I have replaced the pump,filter,and cleaned the injectors, has 40 psi on the rail replaced mass air flow sensor,has good spark on all 8 only runs when you remove the air horn hose and keep it from sucking from the MAFS.
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

The first step in diagnosing the problem accurately is to check for fault codes.

Do you know if any codes are setting?

Are you able to monitor data?

Does the exhaust smell as if it's running rich or lean?

Customer: replied 1 year ago.
No codes , cannot, monitor
Customer: replied 1 year ago.
Exaust is prob lean
Expert:  sprinkles08 replied 1 year ago.

How did you determine no codes are setting?

Customer: replied 1 year ago.
No check engine light
Expert:  sprinkles08 replied 1 year ago.

You didn't actually check for codes then, correct?

Customer: replied 1 year ago.
Koeo code 111 is what I get obd1.
Expert:  sprinkles08 replied 1 year ago.

You mentioned covering something and the truck stayed running. Was it the throttle body you covered?

Customer: replied 1 year ago.
I took off the air hose to air cleaner from the manifold truck runs , I can completely cover the air intake at the manifold and it still runs ,hook the hose up to the MAFS and it dies
Expert:  sprinkles08 replied 1 year ago.

If you can cover the throttle body and the engine doesn't die then you have a vacuum leak, it's running on air that isn't coming through the throttle body.

Customer: replied 1 year ago.
Is it not going through the idle air servo?
Customer: replied 1 year ago.
Has mass suction cannot hear a vac leak I thought that it was sucking the air through the servo?
Expert:  sprinkles08 replied 1 year ago.

All air entering the engine comes through the throttle body including the IAC's supply. If you cover the throttle body and the engine still runs then you have a vacuum leak.

Customer: replied 1 year ago.
Ok , so if I cover the air intake at the throttle body with my hand the engine will still run but if I also plug the PVC hose also it will die and I hear no vac leaks.
Expert:  sprinkles08 replied 1 year ago.

I'm a full time tech and at work this afternoon, I'll get back to you as quickly as I can!

Expert:  sprinkles08 replied 1 year ago.

Is your oil cap or the PCV makeup air hose to the valve cover off?

Customer: replied 1 year ago.
Do you have face time ?
Expert:  sprinkles08 replied 1 year ago.

I do not.

Customer: replied 1 year ago.
There is a Motorola dis box bolted to manifold injector harness goes through it,not sure what it does .im lost don't know what it could be ?
Expert:  sprinkles08 replied 1 year ago.

If you can upload a picture of what you're questioning I can hopefully identify it.