Fuel injector leaking issues

cp2295 · Jul 21, 2014

Hi I have a 98 4.0 ohv, I found out a few months ago the #4 injector was leaking so I replaced it with a standard motor products injector. My issue was hard starting while hot. After putting in the new injector it still would have a hard time starting when hot, but I gave up and today I decided to investigate. I pulled all the plugs out and every cylinder was clean (no fuel in it) except the #4 again. I put it in clear flooded mode and had my dad look at 1 bank at a time, and sure enough #4 sprayed fuel out. Plus the plug was gunked up with carbon. All the other plugs are immaculate.

So I'm thinking now it could be a wiring issue or something, maybe it's being held open? Or maybe I got a defective part. Anyone got any ideas?

Dazzlin' Dave · Jul 26, 2014

Is it the same size injector? Might wanna check the lbs/hr rate, if it's a higher cap inj, it'll spray more fuel than the others.

cp2295 · Jul 26, 2014

I'm gonna run a couple tests but I'm thinking of throwing a motorcraft part in there to be sure

coopab · May 25, 2015

How hard is it to replace a single fuel injector 4.0 OHV

cp2295 said:
Hi I have a 98 4.0 ohv, I found out a few months ago the #4 injector was leaking so I replaced it with a standard motor products injector. My issue was hard starting while hot. After putting in the new injector it still would have a hard time starting when hot, but I gave up and today I decided to investigate. I pulled all the plugs out and every cylinder was clean (no fuel in it) except the #4 again. I put it in clear flooded mode and had my dad look at 1 bank at a time, and sure enough #4 sprayed fuel out. Plus the plug was gunked up with carbon. All the other plugs are immaculate.

So I'm thinking now it could be a wiring issue or something, maybe it's being held open? Or maybe I got a defective part. Anyone got any ideas?

Your thread kind of ended with issue unresolved so I hope that means you solved your leaky injector problem.
I've got a massive fuel leak on the passenger side of my 99 4.0 but can't tell for sure whether it's the #2 injector or something else. I got this quote from another old thread

RonD said:
Quick easy test for leaking injectors:
Turn key ON(RUN)
Press gas pedal to the floor and hold it there
Turn key to START
Engine should crank but not start or fire, fuel injectors are shut off
Release gas pedal at any time and engine should start normally, injectors back on

If engine fires with gas pedal to the floor then it is getting fuel from somewhere.

If you did a static fuel pressure test and pressure stayed up around 30psi, key off, and didn't continue to drop then there is no leak in the pressure side, i.e. injectors, FPR or fuel pump check valve.

But return lines can leak, no easy test for those, just visual inspection, and run your hand over the line where ever you can and then smell for gas, small leaks won't show on the ground easily but can lower that MPG alot.

I haven't tried these tests but within a couple of seconds after starting my engine there's a steady flow of dripping gas along the passenger side. It looks wet at the #2 injector but there's a flow of fuel at the back of the engine (gravity) There had been a gas smell for a little while before this massive leak developed. I'm probably lucky the thing didn't burst into flames the last time I drove it :stop:

Anyway, if I determine that the #2 injector is the culprit, will I be able to remove it and replace it without tearing the top of the engine off?

Fuel injector leaking issues

cp2295

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Dazzlin' Dave

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cp2295

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coopab

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