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Fuel pressure loss.

atlantauto. They had no issues returning product but I noticed after i removed them the small black ring that sits just above the upper oring was cracked. Hard to explain but i didnt notice it when installing. They should not have sold them in that condition. Ill just get my money back and try again. Hopefully Ill have more luck next time. Im sure they send out working parts because they have high 90s rating. Maybe I just got unlucky. Oh well. Ive tried another seller and see how it goes.
 



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Good thoughts, mistakes happen, we just try to avoid the neglectful kind. That black ring piece I recall vaguely, I can't remember if it is part of the sealing of the injector though. I have good luck with two sets of rebuilt injectors I put in.

My 98 has a hard miss that my choices I'm down to are the injectors, or valve seats burned. I found rust in the fuel filter and the tank two years ago, so the miss has gone on a long time, the valve seats I hope it is not. I'll get rebuilt injectors most likely when I get back to that truck.
 






Good thoughts, mistakes happen, we just try to avoid the neglectful kind. That black ring piece I recall vaguely, I can't remember if it is part of the sealing of the injector though. I have good luck with two sets of rebuilt injectors I put in.

My 98 has a hard miss that my choices I'm down to are the injectors, or valve seats burned. I found rust in the fuel filter and the tank two years ago, so the miss has gone on a long time, the valve seats I hope it is not. I'll get rebuilt injectors most likely when I get back to that truck.
I took a peek into the intake ports with the lower intake off and mine dont look too bad. Ive maintained it well. Often using Techron in the gas. Theres of course a little carbon on them but not anything to make me concerned. I was wondering if since i have the intake off I could somehow get in there and scrub/spray/soak down the tops of the valves? Im assuming this is not practical?
 






I think simple fuel additives are the best treatment, add a bottle to the tank every month or two etc. Only the area very close to the valve seats matter typically, later direct injection engines are having growing pains with those issues.
 






I think simple fuel additives are the best treatment, add a bottle to the tank every month or two etc. Only the area very close to the valve seats matter typically, later direct injection engines are having growing pains with those issues.
Right. Having the injectors spray above the valves helps a bunch. Maybe why we dont hear of bad valves much in these motors. Especially when using additives. Seems the new injectors already shipped out. Wish me luck LOL!
 






I think simple fuel additives are the best treatment, add a bottle to the tank every month or two etc. Only the area very close to the valve seats matter typically, later direct injection engines are having growing pains with those issues.
Ok so the next set i put in i checked before installing and none of them were stuck open. I triple checked to make sure. All ohmed out evenly. I doubt they are bad.

Still smoking white smoke. Not the white smoke you get when its cold either. Thicker than that. I ran it for a few minutes and it seemed to get worse so i turned it off.

I then checked compression for the heck of it and all 6 are around 150psi. Im assuming if its head gasket related (burning coolant) or my rings are bad (burning oil) Id have low compression but I dont.

Im not sure whats going on because it didnt smoke like this before i changed injectors. The new ones are same bosch remanned ones. Look better with all new pintal caps.

I did notice 4 of 6 plugs were a little wet but I only ran the engine for maybe 3 minutes total at idle. Seems like either its perhaps flooding or its not getting enough spark.

Any ideas where to go from here? Would the fuel pressure regulator have anything to do with flooding? Im assuming the PCM controls the injector pulse when to release fuel? Not exactly sure what the regulator even does.
 






Did you disconnect the battery for a bit to reset the PCM?

Maybe the fuel trims are way ‘rich’ to compensate for the old plugged injectors and are now dumping way too much fuel in?
 






Is there any chance you got the wires mixed up? You can check your fuel rail pressure to try to rule out the regulator.

The regulator determines the fuel pressure. The pump produces more pressure than needed (not speed-variable), and assuming your '98 has the return fuel line back to the tank (attached to the regulator), excess pressure is bled off at the regulator, so pressure should be around 35PSI. You previously stated it was 30PSI which should be close enough to not cause this, if it's still 30PSI.

If you have a vehicle made after the changeover to returnless fuel system (otherwise '99 and newer) then the regulator is in the tank instead and what is sitting on the end of the fuel rail is just a dampener with no fuel line going back to the tank, should be around 62PSI, but since you previously had it running at 30PSI I doubt you have the returnless system.

Anyone know if it's possible to put the wrong injectors on (wrong parts sent)? There are at least 3 different injector part #s for 4.0L OHV, SOHC, and after the change to returnless fuel system.



 






All the 6 old injectors i pulled had exact same numbers on them. Mine is a '98 SOHC. It has a return line as theres two lines down where the filter is which i just changed last night. And I have the damper/regulator on the passenger side fuel rail towards the front. IT was not leaking when i checked it. Some have it located on the fuel rail on the drivers side near the firewall for some reason. Mine is definitely a return system so 32psi or so at idle is what i should have. And as I did more research I realized the damper/regulator will release excess pressure back to the tank so that is in line with what you said. Not to mention actually controlling how much pressure is being fed to the fuel rail.

The injectors were all MOTORCRAFT CM4832.

Im going to check pressure again and also remove entire rail with them still connected, turn the key on and see if one got stuck open again or is dripping. Its also possible I have a short in the harness somewhere that I caused when disassembling and its causing one to be stuck open as the PCM activates the injector by switching it to ground so if its shorted to ground itll always be on but I wont be able to tell doing that unless i run the engine. So a static pressure test on the rail might not show any signs of failure. Currently trying to see how I can rule out a shorted wire. I guess Id have a check engine light if that were the case??

I did notice the second I turned it on after this new set, it didnt smoke right away. Took maybe a minute then started smoking. So I shut it down because I didnt know what the issue was. Im now convinced it is either a bad wire or a failing injector again. The motor was never over heated and Ive maintained it very well. Never had this smoking issue. Just had a little miss at idle which I narrowed down to the injectors as Ive been chasing this miss for quite a while. Coil pack is good. New plugs, wires.

Ideally I would like to have it hooked up to a scan tool that shows which cylinder is missing but i just have a basic one that shows codes and ect temp and some other basic data. No live data like fuel trims and whatnot.
 






A shorted wire won't directly cause the check engine light on, but the resultant misfire should if happening often enough.

I'm hesitant to suggest running the engine much if dumping fuel down the exhaust (can ruin the cat) but one way to isolate an injector is unplug each injector connector one at a time. If it runs no worse, you found the problem injector, except that if it's happening consistently enough to make that easy to notice, you should be getting the check engine light on, and a scan tool that shows codes should show a P0300 series code for the cylinder (P0301 cyl 1 and so on) or just P0300 for random misfire.

I'd want to hook up a scan tool capable of live data, but I am starting to wonder if you are burning coolant. White smoke plus taking a minute (engine warming up), plus no misfires and not running very rough (not mentioned in last attempt) seems suspiciously not like fuel injectors. If you have a borescope it might be worth poking down in the cylinders to have a look, or re-examine the spark plugs. You wrote wet from a previous examination, but just gas wet?
 






Ok thanks JC. Yes spark plugs smelled like fuel. Im not losing coolant whatsoever. And if there is a coolant leak from head gasket it will not suck up coolant from the reservoir. So when I checked the coolant level by taking the cap off, the coolant was still at the top. The way it was smoking it would have to be a substantial leak and itd be obvious when checking coolant level in radiator. And if it was a bad enough leak my compression numbers would be low.

Edit: It does run rough. First thing I noticed when I installed them. Unusually rough. No vacuum leak either. Happened with the first replacement set. Then again with this set. Both remanned injectors.
 






Can you post any kind of video, I'm wondering if it's a cold start smoke or something not good? If it isn't obviously dumping fuel through the exhaust, I'd run it until it's warmed up fully. Checking the fuel pressure and/or unplugging the injectors one at a time are good steps if you think it's serious(the smoke).
 






Sounds like a good idea. The passenger side injectors are near impossible to get to with the upper intake on. And the connectors are a real pain to remove because they have clips on both sides. Not squeeze push ins. Ford really screwed us on the design of this engine I tell ya.
 






I assumed not cold start smoke because Las Vegas... fairly warm climate. Here on the other hand, some water vapor condensation "smoke" out the exhaust in the cold of a winter morning is normal, but not as much as you've described.
 






I just removed the fuel rail with injectors attached and powered up the pump, getting about 30psi and not a single injector is leaking.

It gets cold here but like 55F when I ran it yesterday. It smokes in the morning in the winter of course, but this was definitely thicker than Ive seen before.
 






"And the connectors are a real pain to remove because they have clips on both sides. Not squeeze push ins. Ford really screwed us on the design of this engine I tell ya."
A little late but for anyone else and for future reference.... Paint can openers ARE AWESOME FOR REMOVING FORD F. INJECTOR CLIPS....it's like they were made for this and paint cans secondary.....and Home Depot gives them out FREE... Just "start" loosen one side with this then go to other side of clip and it pops right off....perfect little hook to grab clip and lift off without breaking / tweaking anything....

OPENER.jpg
 






Great idea thanks I have a couple in the garage already.
 






The wires and the connectors are very fragile, avoid moving them at all.
 






The wires and the connectors are very fragile, avoid moving them at all.
Yes they are. I found a tiny knick on #1. Wrapped it up good and tight with electrical tape. I dont think this is my problem but I checked all of them after that and they all looked okay.

As far as testing without engine running. With Key ON, the power wires should all have 5v? And the control wires should not light up a test light when checking for ground? Since the pcm grounds that wire the test light should not illuminate with key on?
 



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Just because a car has a blown head gasket doesn’t mean it won’t pull from the reservoir.
 






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