fuel or electrical

tht077 · Oct 1, 2014

I've got an 86 ranger that runs rough and severely floods. I have changed plug wires, distributor cap, rotor bug, and fuel pressure regulator. The fuel pressure checks at 44#'s. The truck starts and runs rough and is flooding terribly, but if I unhook the fuel pump the truck levels off and starts to run lean. I tried to check the codes with a test light but it just lights up and never shows any codes. Any help would be appreciated.

adsm08 · Oct 1, 2014

Pull the vac line off the fuel pressure regulator and check for fuel in the line, it's probably ruptured. 44 PSI is almost the max the system will make, which means the regulator isn't holding vacuum. If the diaphragm ruptured it will go to full fuel pressure and start sucking fuel into the intake through the rupture.

If you find that is the problem you also need to check your brake booster. It can fill with fuel, which will damage it. The rubber on that diaphragm isn't rated for fuel exposure.

RonD · Oct 1, 2014

What engine??

Assuming 44lbs of pressure I would guess fuel injection

What happens to fuel pressure when engine is shut off?
Does it slowly drop to............0 or ??

May be a leaking fuel injector if fuel pressure regulator was replaced already.

Try this test:
Turn key ON(RUN)
Press gas pedal to the floor and hold it there
Turn key to START(crank engine)
Engine should NOT start, just crank, the fuel injectors are shut off

If engine fires and starts or tries to start you have fuel leaking into the intake.

If you release the gas pedal, fuel injectors will start up and engine will start.

tht077 · Oct 1, 2014

The engine is a 2.9. The pressure drops to 0 after about 5min. I did change the regulator off of a wrecked truck. I may get a new regulator in the morning. Thanks for the advice.

tht077 · Oct 20, 2014

Just an update. I changed the fpr and it ran the same. I found the in tank pump wasn't working and the tank was all rusty. I cleaned and coated the tank and changed the pump, ran the same. I changed the computer out with an 88 model and it ran the same. I pulled the plugs and burnt off the build-up and gas and put them back in and it ran the same. I then started it and run the rpm's up some and tried to hold it at a constant rpm and it started to level out and run right. It now will idle roughly but seems to rev good. I haven't drove it much,I'm having tranny problems now.Thanks

fuel or electrical

tht077

New Member

adsm08

Senior Master Grease Monkey

RonD

Official TRS AI

tht077

New Member

tht077

New Member

Sponsored Ad

Sponsored Ad

Staff online

Members online

Member & Vendor Upgrades

Latest posts

Truck of The Month

Recently Featured

Follow TRS On Instagram

Latest Album Photos

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals