I bought some 5 liter Ford fuel injectors to replace the 131k mile injectors in my 4.9. I have some questions though! The Ford injectors have a different tip on them, which lengthens the total length of the injector. This tip doesn't affect performance since it goes into the intake manifold more, does it?
Also, the injectors don't fit as tight into the fuel rail as the stock ones do. The o-rings that came with the Ford injectors are slightly smaller than the 4.9 injector o-rings, so I re-used the 4.9 o-rings. The injectors fit tighter, but not as tight as the stock 4.9 injectors did. I don't assume this will be a problem, right?
I'd like to hear from others who've done this swap! :thumbsup:

I believe the most common swap is for the 4.6L ford ones from crown vic, towncar, etc. I did that, and they worked better than stock ones. I initially considered the 5.0 ford ones, but nobody had done it, so I went with 4.6er's.

Don't know if anybody has done 5.0 before.

I thought both the 4.6 and 5 engines used the same injectors...not completely positive... Anyway, I swapped some Bosch from the yard (some off a Crown Vic, some off a Town Car), and my mileage and gas gauge discrepancy is even worse now... So I've just ordered new ones from Five-O-Motorsports. I'll post the results (which had better be good...ouch $) when they get here.

I'm really not sure which engine they are from. They are the 19# injectors that most here are using.
Tailfin: Did you have any problems with your replacement injectors fitting a bit loose? Also did they have different nozzles on them that are longer?

Well, I'm not entirely sure lol. They may have not been quite as tight, but they weren't loose to the point I noticed or was concerned. I sprayed carb cleaner around them and didn't notice anything suspicious (though I was in a hurry at the time). Yeah, they are 19#, I think they're the same. Someone stop me if I'm wrong though.

As for the nozzles, I noticed the different design, but I didn't put one up to one of my old injectors to compare the length. I wouldn't worry about that issue in particular though. The spray pattern of the Bosch injectors is different anyway. I'm not positive of the exact shaping of things in there, but I doubt it's something of much consequence. I'll have a peek at the length all the same when I change them.

The stock injectors are a two-pattern spray, with only 2 little holes that essentially...shoot fuel.

The 19# Ford 4.6L injectors are a four-pattern, which is more efficient at dispersing fuel with air.

OK, thanks! Hopefully everything will work fine! I just have to get everything all back together now. I decided to replace the valve cover gasket since the PS pump is off, and since that is off, I replaced the PS pump because it's whiney. So it'll be like a new Caddy, well almost.

I've had the orange Bosch Ford 4.6 injectors in my 4.9 for quite some time now. the Factory Nependenso are rated at 18#, the Bosch are rated at 19.4lbs, but Ford runs ~38psi fuel pressure while GM runs ~43psi, which means those Bosch injectors are really pushing about 23lbs/hr.

They have a much better spray pattern too. Direct replacement, either the upper, or lower o-rings (don't remember) were switched from the old injectors for a better seal.

Direct replacement, either the upper, or lower o-rings (don't remember) were switched from the old injectors for a better seal.

It must be the upper o-rings. The Ford ones seemed too loose, but the Cadillac o-rings made the injectors fit into the fuel rail a bit tighter.

yeah, it probably was them.... I would reccomend swapping them tho, seals better.

Also after they are in, when it is running, spray some carb cleaner around each injector, make sure none are sucking it in.

Yeah, I planned to check for leaks when it's all done! Now I just need some decent weather to put it all back together! 46 degrees with wind and rain is no fun!!!!

Yeah, I planned to check for leaks when it's all done! Now I just need some decent weather to put it all back together! 46 degrees with wind and rain is no fun!!!!

Don't be a wuss!

http://myspace-985.vo.llnwd.net/00072/58/91/72411985_l.jpg

^ Changing the water pump and doing an oil change in the middle of a snow storm.

I also have pictures of when I replaced the rear drums and shoes on the Olds, in the iced-over, snowy driveway... tho it wasn't snowing that day....

its fun.

meh , you havent lived till you work with a broken water pipe that on one end has 1500 gallons waiting for you when its 70-80 below ...so cold that duct tape doesnt stick ....but stilll makes good rope ended up wrapping the break with latex gloves and useing the duct tape rope to wrap it up and tie it off

tho 120 above in dress clothes fixing a firetruck on the tarmac with a plane full of marines waiting for you to get it fixed so "we can go" isnt much fun either

maybe it was times like that that i dont turn wrenches for a living ....

Yeah, I've been there, done that when it comes to cold weather repairs where you can't feel your hands!

Now, I'll just wait until the weather gets a bit better! I DO have three Cadillacs! I'll just drive another for a while! :)

Well I got my injectors all in, and everything all back together. I put on a freshly painted front valve cover, since the gasket was leaking anyways. And I installed a rebuilt power steering pump. It fired right up, so that was a good start! But the power steering pump began to make some noise because it was low on fluid, and I'm out!
But at least the engine ran good for the one minute I had it running! :)

Mine should be in the mail soon. Let us know if that stupid gas gauge discrepancy goes away! :stirpot:

Will do. I'm also hopeing that since these injectors have a better spray pattern, that my gas mileage increases! Or am I asking for too much???

Mine should be in the mail soon. Let us know if that stupid gas gauge discrepancy goes away! :stirpot:

It wont.

Will do. I'm also hopeing that since these injectors have a better spray pattern, that my gas mileage increases! Or am I asking for too much???

Should increase a little, all things considered.

I took the Deville out for a test drive, (after adding power steering fluid) and it runs great! I'll have to see if my gas mileage increases.

Ok just got mine done and test driven... Damn it Night Wolf, you were right that it didn't fix the fuel gauge discrepancy... But fortunately, it did fix the actual problem as I suspected... No more surges, rough idle, and the actual mileage now averages out to 25 on a little drive I took which was roughly 85% highway driving.... Of course the fuel data center is now telling me I'm getting 30 :bigroll:. I've seen in more than one place that this discrepancy is either FPR or injectors...now both on my car are brand new...so there's something else. I'm gonna poke around for engine grounds and reference voltages to the damn thing, but after that, I'm gonna start thinking it was there to make you think it was more impressive than it is lol.

Oh well, at least it's finally acting like it should...now for my suspension...:hide:

Ok just got mine done and test driven... Damn it Night Wolf, you were right that it didn't fix the fuel gauge discrepancy... But fortunately, it did fix the actual problem as I suspected... No more surges, rough idle, and the actual mileage now averages out to 25 on a little drive I took which was roughly 85% highway driving.... Of course the fuel data center is now telling me I'm getting 30 :bigroll:. I've seen in more than one place that this discrepancy is either FPR or injectors...now both on my care are brand new...so there's something else. I'm gonna poke around for engine grounds and reference voltages to the damn thing, but after that, I'm gonna start thinking it was there to make you think it was more impressive than it is lol.

Oh well, at least it's finally acting like it should...now for my suspension...:hide:
Good job! Did you by chance measure the resistance of your original injectors? What was the problem?

Nah, I didn't, but I think the problem was just the injectors themselves. Ever since I got the car, the mileage wasn't quite up to snuff. I actually suspected the injectors a while back, but I had to blow my money on every other part of the fuel system first before I'd cough up for them lol.

I originally tried to cheap out and get the Ford injectors from the salvage yard...off 2 different cars even....but got burned there, the mileage and discrepancy was actually worse after that... But hey, at least it taught me I was sort of on the right track as for the actual issue. I guess the fact of the matter is, injectors of this era just won't last 16 years without cutting into the performanc/economy a little.... Either that, or there have been things in the fuel bashing them, or I'm just very unlucky...which...is also true :stirpot:.

I don't know if this was wise or not, but I figure while on the subject, I'll share... When I had the fuel rail off, I noticed I could see some sludge on the valves through the injector holes...I didn't like that... Probably not enough to affect anything much but...I didn't like that... And it's just too cramped to get anything effective in there, even a toothbrush, so I sprayed some Engine Brite in the holes... Hey, it's combustible, right? I'll never know just how much was dissolved, but it did the typical GM TEC smoke for a few moments with a little chugging. Just in case anyone wants to try it, nothing explodes...

Ok just got mine done and test driven... Damn it Night Wolf, you were right that it didn't fix the fuel gauge discrepancy... But fortunately, it did fix the actual problem as I suspected... No more surges, rough idle, and the actual mileage now averages out to 25 on a little drive I took which was roughly 85% highway driving.... Of course the fuel data center is now telling me I'm getting 30 :bigroll:. I've seen in more than one place that this discrepancy is either FPR or injectors...now both on my car are brand new...so there's something else. I'm gonna poke around for engine grounds and reference voltages to the damn thing, but after that, I'm gonna start thinking it was there to make you think it was more impressive than it is lol.

Oh well, at least it's finally acting like it should...now for my suspension...:hide:

Yeah, the Bosch injectors really smoothed out the idle and off-idle hesitation, actually, its gone. Mileage went up a hair too.

You will never fix the fuel discrepency, just live with it. My avg MPG is off by about .5-1mpg (reads higher) and my fuel used is off by .5-1 gallon (reads lower) the computer thinks it used less fuel, thereofre there is a higher MPG... makes sense... tho the last 3 fill ups the fuel used has been accurate, as well as the MPG, I was surprised.

A couple hints, stop filling the tank on the first "click" of the pump (when it automatically stops) me... I will keep going until it starts to leak out.

The system measures injector pulse width, so in theory, it should be 100% accurate, but.... its not, oh well.

About the suspension, just go to Advance and get a set of Monroe Sensatrac struts, about $80 each, and you keep the rear air level system.

Nah, I didn't, but I think the problem was just the injectors themselves. Ever since I got the car, the mileage wasn't quite up to snuff. I actually suspected the injectors a while back, but I had to blow my money on every other part of the fuel system first before I'd cough up for them lol.

I originally tried to cheap out and get the Ford injectors from the salvage yard...off 2 different cars even....but got burned there, the mileage and discrepancy was actually worse after that... But hey, at least it taught me I was sort of on the right track as for the actual issue. I guess the fact of the matter is, injectors of this era just won't last 16 years without cutting into the performanc/economy a little.... Either that, or there have been things in the fuel bashing them, or I'm just very unlucky...which...is also true :stirpot:.

I don't know if this was wise or not, but I figure while on the subject, I'll share... When I had the fuel rail off, I noticed I could see some sludge on the valves through the injector holes...I didn't like that... Probably not enough to affect anything much but...I didn't like that... And it's just too cramped to get anything effective in there, even a toothbrush, so I sprayed some Engine Brite in the holes... Hey, it's combustible, right? I'll never know just how much was dissolved, but it did the typical GM TEC smoke for a few moments with a little chugging. Just in case anyone wants to try it, nothing explodes...

Engine brite? the stuff used to degrease the engine? IE... spray it on the (outside) of the engine and pressure wash it off?!?

ummm... well..... nevermind.

Get Seafoam and run that thru it, it will clean all the stuff out, and is made for that.

Yes, that Engine Brite lol. I've already used Seafoam and GM TEC. Seafoam doesn't do much, and TEC, when poured in through the throttle body will clean that area of the intake manifold on its way to the chambers pretty well, but as I said, the evidence showed that it didn't get the valves that great. I figured hey, if I had my engine apart, I doubt spraying this stuff on it would etch the metal down or wreck it or something, so I went ahead and put a little in each injector hole, hoping it would clean off some of the sludge. The other reason for using it was that it could be sprayed in... Seafoam or GM TEC, I can't seem to find in aeresol around here, so pouring it in wouldn't have gotten on all the parts I was after. I was actually thinking if it was possible to rig some sort of flexible spray shaft with a siphon going into a can of the stuff to hook up to an air compressor...but that's another story...

I don't overflow my tank usually lol... But I know, due to my 85, that these things are capable of reporting the fuel more accurately. On a full tank, mine's like 2-3 gallons off on the fuel used. It's probably an electrical inconsistency. But I'm not really worried about it...things are running fine now, so I'll probably just let it lie to me for a bit.

As for the suspension, I was doing just that and pricing those Monroe struts... I was expecting to give up the air-leveling system though, because I thought you had to get OEM to keep that working. The Monroe struts are compatible and will still work with that?

Anyhoo, not going to do that right away. My car is a boat around turns, and I want to redo the whole thing, springs and struts all around, and I don't quite have $400+ to just dump in now... I mean I do, but I like to have a financial cushion... I also need to get a spring/strut compressor. Do you have to have a specific one, or more than one to work on all the struts AND springs?