new to me 1996 explorer from grandma ignition issues , many parts changed

[eric mentzer]

Another question, fuel pressure running and at higher rpms is 28 psi. If I take vacuum line off pressure reg (which I can feel vacuum) fuel pressure jumps back up to 40 and stays there. I thought vac increases pressure?

 

[96eb96]

Another question, fuel pressure running and at higher rpms is 28 psi. If I take vacuum line off pressure reg (which I can feel vacuum) fuel pressure jumps back up to 40 and stays there. I thought vac increases pressure?

The FPR is a diaphragm type spring loaded valve that opens with vacuum. Maybe similar to the EGR.
No vacuum makes it more restrictive.
Higher vacuum (idle) makes it less restrictive and more fuel is returned to the tank. Don't need too much fuel at idle or high vacuum.
At WOT vacuum is very low (like pulling off the line) so you get max pressure to the injectors. Less gas returned to the tank.

 

[eric mentzer]

Took out and got her hot after changing remaining 02 sensors (because I like wasting money lol) but then can at least rule it out. Failure to start hot resumed. Wouldn’t fire several try’s, sprayed starting fluid in intake and ran till fluid burned off 2 times. Third time stayed running and rough idle resumed. Think I should pull rail and injectors? Fuel was steady at 38 psi entire time.

 

[Centaurus5.0]

When an ECT goes bad, it can cause hot start issues. It tells the computer the motor is way cooler than it actually is and in turn sends way more fuel that it actually needs essentially flooding the engine out.

Pretty cheap to replace.

 

[eric mentzer]

I changed air temp sensor and engine temp charge sensor recently. Both at same ambient temp new and used were within a decent ohm range, maybe 1000 ohm or so off if i recall

 

[Centaurus5.0]

Those measure the air temperature. The ECT measures the coolant temperature.

 

[eric mentzer]

Replaced ect previously. Update got rail and intake off. Pulled injectors. Getting cleaned and rebuilt. All ohmed around 16 . Anything else i should do with it this apart? No rush shes sitting in the garage. Inside of all intake channels nasty and black buildup. Any suggestions welcome.

 

[Centaurus5.0]

Any suggestions welcome.

If that don't work, and if all else fails...

 

[96eb96]

So what is the symptom? runs like crap when started hot?

Replaced ect previously. Update got rail and intake off. Pulled injectors. Getting cleaned and rebuilt. All ohmed around 16 . Anything else i should do with it this apart? No rush shes sitting in the garage. Inside of all intake channels nasty and black buildup. Any suggestions welcome.

Maybe lower intake manifold gaskets if you are that far in? They do fail eventually.

Could be carbon buildup on the valve from short trips. That can cause crappy running.

 

[Centaurus5.0]

You say it had a code for o2, side 1, bank 1 at first? Do you remember what code it was? Lean? Rich?

When you get those codes, it doesn't necessarily mean the o2 itself is bad and needs to be replaced but that something is wrong with the combustion/timing on that side (bank) of the engine unless there is coolant or excess oil leaking into the exhaust fouling out the sensor and causing it to read poorly. In any case, that should narrow down the problem.

These Ford dealer mechanics are getting more and more lazy or incompetent of performing a proper diagnosis.

"Could be the torque convertor making it not start... on second thought put some new wires on it and pay us and get the hell out of here"

 

[eric mentzer]

Alot of carbon buildup visible through empty injector holes in motor. Def encroaching from the sides creeping over. How do i clean intake valves if neccesary? Will try and scope them to look. Was bank 1 sensor 1. Dont remember code. Replaced sensor and it went away.

 

[Centaurus5.0]

Heavy deposits in the intake and on the valves would make it run bad or at least less that optimal, but I don't see how that could cause it to not start sometimes and start just fine other times.

Do you still have the old o2's? Did it look like it was coated with something? White/ gray ash?

At this point clean it up as best you can and see what it does after you put it back together.

 

[96eb96]

Heavy deposits in the intake and on the valves would make it run bad or at least less that optimal, but I don't see how that could cause it to not start sometimes and start just fine other times.

Do you still have the old o2's? Did it look like it was coated with something? White/ gray ash?

At this point clean it up as best you can and see what it does after you put it back together.

They could act like sponges at certain temps, drinking up the gas. If his grandma used it for a 2 mile drive to church or shopping, that could certainly cause it. There are products made to clean GDI engines which have this problem, can also be used for regular engines too.

 

[eric mentzer]

Some white deposit on old 02. Injectors are nasty looking with black buildup all over pindle caps. Bottom of o ring i can see was allowing engine dirt to get sucked in on several injectors. Waiting on gasket to reassemble.

 

[Centaurus5.0]

Could you take some pics of inside the intake eric?

 

[eric mentzer]

yea i will, need to upgrade to post pics i believe. i got borescope down in intake below fuel rail. all the black and brown gunk on sidewalls stops and disappears before the valve. i guess its backside of the valve but it looks clean as far as i can tell with my crappy chinese cell phone scope lol. was reading about injector heat soak with short drive cycles. trying to clean oem injectors. energizing in pulses with cleaner. one def was plugged. also read if one is plugged engine reads lean and trys to overcompensate with other working injectors?

 

[eric mentzer]

Below fuel rail pics are after spraying the crap out of it

 

[1998Exp]

I seriously doubt your buddy's theory about the air temp and coolant sensors. A bad coolant temp sensor will cause trouble starting, but will definitely throw a code. Intake air temp sensor is not that critical, and I have driven for months with a problem there with nothing but the CEL occasionally turning on. I am with Koda on fuel delivery - for which the '96 has no sensor. By the way, the best part of this story is the dealer's service writer telling you to replace tire pressure sensors -- there was no such thing until model year 2002 or so, not to mention that it has no relation to starting problems!

 

[Centaurus5.0]

I seriously doubt your buddy's theory about the air temp and coolant sensors. A bad coolant temp sensor will cause trouble starting, but will definitely throw a code. Intake air temp sensor is not that critical, and I have driven for months with a problem there with nothing but the CEL occasionally turning on. I am with Koda on fuel delivery - for which the '96 has no sensor. By the way, the best part of this story is the dealer's service writer telling you to replace tire pressure sensors -- there was no such thing until model year 2002 or so, not to mention that it has no relation to starting problems!

And I serious doubt you actually read what I wrote..

-A bad ECT will not always throw a code based on my experience and can cause the issues he is having. I figure it was worth bringing up considering this thread was on the 3rd page and hadn't been mentioned yet.

-Yes, the Air Temp Sensor is not that critical as to cause the problems he is having and didn't consider it to be.

-"Fuel Delivery" does have a sensor... the O2's.. which he confirmed did throw a code for one bank.. which would go back to Koda's assessment about it being a possible fuel issue.

-There was mention of using a Tire Pressure Gauge in place of a Fuel Pressure Gauge but... dealer and sensors?

-Tire pressure doesn't have anything to do with starting problems?? Yeah, you did get that right.

 

[1998Exp]

And I serious doubt you actually read what I wrote..
-A bad ECT will not always throw a code based on my experience and can cause the issues he is having. I figure it was worth bringing up considering this thread was on the 3rd page and hadn't been mentioned yet.
...

Thank you for your observation. I apologize; it's a long thread, and I missed some responses. Indeed, the ECT can read the wrong temperature and still be within acceptable voltage range, which will not set a trouble code. More often the problem is not the sensor itself but an intermittent connection or an intermittent short to ground, which will set a code.