3.8 CFI questions July 19, 2009, 12:53:39 AM Hey folks I'm doing a 3.8L CFI swap onto a 2.8L V6 Ford Ranger I have. The Ranger currently has an Offenhauser 4bbl intake, and header back dual exhaust. 1) Since I can't use the EGR system will this cause a problem? What can I do to make the computer play nice without the EGR?2) I will not be installing an air pump for the emission system on this engine, once again will this cause a problem? If so what can I do to work around it?3) From what I saw in wiring diagrams it appears that this system uses O2 sensors. The left and right bank exhaust are completely separated. Can I get away with just one 02 sensor or is there a way I can set it up for an O2 sensor in each header. I have though about installing an X-pipe since I have to replace a ler and re-route the system a little, if I install the X-pipe could i just put the single sensor in there?Since I know someone will ask "Why not just put a carb on it?" There's one on it now, a 390cfm Holley 4160, before that there was a 390cfm Holley Double Pumper on it. Well the reason I want this CFI system is because I'm no good at tuning a carb, and after having more knowledgeable people tune on it the mileage is still terrible (averaging 10mpg on a good day). I know of people getting twice the mileage after doing this CFI swap. I want the gas mileage, and since I'll never be able to match it with a carb, I am going to perform this swap as soon as I can source the components needed.Any help that you can give me will be appreaciated. Any tips, tricks, or mods that can be done to this setup will also be welcome.Thanks,-Josh Quote Selected
3.8 CFI questions Reply #1 – July 19, 2009, 09:26:45 AM Block off the EGR and throw the pump in the trash, the puter won't care, will set a code but it will run fine... You sure about the dual O2 sensor on CFI?? Thought that was a SEFI thing...That said, I'd just about as soon pour boiling water on my feet as even look at a 3.8... They are basically a POS that eats head gaskets... 10mpg is piss poor no doubt, what jets you running it that Holley(also what are stock)??? It should get decent mileage if tuned with economy in mind... Jetting needs to be at stoich(14.7:1 A/F ratio) at cruising speeds, currently probably is far too rich... Tuning ain't no big deal, just set the float correctly, reduce jet size 2-3 numbers and try it a few days to see how it does... Can also install a power valve that opens later... Not sure what's avail, but should be able to get one that doesn't open till vacuum is less than 5 inches... May make it feel a bit lazy at part throttle, but should still go when opened more than 1/3 way...Could also install a A/F ratio meter would aid greatly in tuning... Quote Selected
3.8 CFI questions Reply #2 – July 19, 2009, 12:40:30 PM Quote from: TurboCoupe50;282781Block off the EGR and throw the pump in the trash, the puter won't care, will set a code but it will run fine... You sure about the dual O2 sensor on CFI?? Thought that was a SEFI thing...3.8 CFI's have two O2's, 5.0 CFI has one. Quote Selected
3.8 CFI questions Reply #3 – July 19, 2009, 02:30:14 PM TurboCoupe50: I wouldn't fool with the 2.8 or the 3.8 CFI system if the engine wasn't a fresh rebuild. Hell if I had realized how much the rebuild was going to cost I would have done a 5.0 swap instead. It's done now and having just bought a house I can't justify spending the money on a V8 swap without at least trying to break this engine. As for the carb, as I said I can't tune one for ****. Besides it will probably cost me less to do this CFI swap that it will to buy all of the parts and an AFR meter to tune this Holley. I'd end up with a better running engine, better gas mileage, and not have to tune it again.Softtouch: I can put one in each header, and be good to go. That's good to hear! Quote Selected
3.8 CFI questions Reply #4 – July 20, 2009, 09:12:24 PM Direct swap any 5.0 CFI (early CFI LTD and the like) onto your 3.8 but use the green top injectors you have. That will open up some of the bottle neck at the lower half of the CFI on the 3.8's. while you have the injectors out, start a screw in the top of each one and pull the screen out with pliers. thats what a primary and secondary fuel filter is for,, never liked the idea of an injector having a nice little tiny screen filter but it is what it is.Some 5.0 CFI have a choke pull off assembly which can be cut off and you groom your existing hardware / linkages onto the 5.0.pop the center cover off the CFI fuel pres regulator and turn it on time cw,, that will add in approx 3psi of fuel presure if your interested in adding a little more fuel on off roading. back it off for normal everyday driving.make sure the green wire on the tps to ground is less than a volt and if not,, use a chaninsaw file to oblong the holes so you can adjust the tps ccw or cw to dial in the voltage.Take out the air charge temp sensor and clean that bugger offtake out the coolant temp sensor and clean that bugger offrun a 1993 supercoupe 3.8L fuel pump in the tank as it provides 90+ liters per hours fuel.I suppose you have a mechnical pump on your old engine or your setup with mechanical. If thats the case, id visit getting an electric pump in the tank or an external mounted somehwhere safe.take the cfi off the base plate, chip away at any carbon build up along the bottome. Do the same to the spacer plate which probably has the egr mounted to it off to the left side. You can plate block the egr and keep the EVP sensor just hangin in the wind so to speak for computer purposes. A few little things can be done but the runners in the 3.8 just limit the hell out of you. The biggest bottle neck I know of is the lower half of the CFI 3.8L is much smaller than the 5.0 CFI lower half. Quote Selected
3.8 CFI questions Reply #5 – July 20, 2009, 11:01:10 PM Thanks for the tips! Mind if I copy this onto another forum for others who may do this swap.Quick question, I know that the 3.8CFI is supposed to flow about equivalent to a 350 cfm carb, how about the 5.0 unit? Currently I'm running a 390cfm 4bbl on this motor, so I think that I'll be fine with the 3.8 unit for a while. If the 5.0 unit isn't to large I may keep my eyes open for one. Keep in mind that the motor I'm putting this on is one liter smaller than the 3.8L.Yes I am currently running a mechanical fuel pump, but I was planning to remove it in favor of an electric pump. I have to check into what will work best for my swap, it will be either a 2.9L in tank pump which is a bolt on swap, or an inline pump. I'm leaning towards the latter since I plan to install a 20 gallon fuel cell in the future.I'm installing this setup on a Ford 2.8L V6 which currently has a Offenhauser dual plane 4bbl intake installed. There will be no EGR port to block off. The only spacer will be a 2bbl to 4bbl adapter. This intake is the very reason I believe that I may decide to upgrade to the 5.0CFI in the future. Simply put it can flow a lot, probably a lot more than my heads can. Quote Selected
3.8 CFI questions Reply #6 – July 22, 2009, 12:25:04 AM Quote from: Josht;283025 If the 5.0 unit isn't to large I may keep my eyes open for one. .why would you "if" this? it will work. Its a direct exact replica of the 3.8 cfi. If there were other differences, id tell ya. the flow (air) is the increase. bigger butter flies .... just install your green top injectors and lay the 5.0 blue tops to the side.THere aint no "if" around here on CFI's,, not to much to discuss,, simple sweet and to the point, they are all about the same.Now you talking about not using CFI spacer,, ok,, sure. Make it work. Not sure why you would delete it. top pic.....View of regular 3.8 cfi and the red line shows where a hone would do some good.middle and bottom pic....the middle lower CFI shows a regular 3.8 lower half butter fly.the right shows a 5.0 cfi (much larger butterflies.just hone the upper half of the cfi after you split it open to increase air. Quote Selected
3.8 CFI questions Reply #7 – July 22, 2009, 12:51:29 AM Quote from: jcassity;283216why would you "if" this? it will work. Its a direct exact replica of the 3.8 cfi. If there were other differences, id tell ya. the flow (air) is the increase. bigger butter flies .... just install your green top injectors and lay the 5.0 blue tops to the side. THere aint no "if" around here on CFI's,, not to much to discuss,, simple sweet and to the point, they are all about the same. Now you talking about not using CFI spacer,, ok,, sure. Make it work. Not sure why you would delete it. top pic.....View of regular 3.8 cfi and the red line shows where a hone would do some good. middle and bottom pic....the middle lower CFI shows a regular 3.8 lower half butter fly.the right shows a 5.0 cfi (much larger butterflies. just hone the upper half of the cfi after you split it open to increase air. Somehow, I just KNEW you'd have a peg board with all the spots marked for each tool. I may go junkin again and find a CFI for a 5.0 now. I may wind up with another '86 with a 3.8 in it after this weekend. Now that I've actually seen the difference in the venturis .... Quote Selected
3.8 CFI questions Reply #8 – July 22, 2009, 01:35:04 AM Big difference there on the venturis. I'll be on the look out for the 5.0 CFI, then when/IF I find one I'll put it on. To start with I'm mostly interested in getting the system and getting it installed. if that means the 3.8 CFI then so be it. From the sound of things the CFI out is easy enough that doing it later won't be a problem.Quote from: jcassity;283216Now you talking about not using CFI spacer,, ok,, sure. Make it work. Not sure why you would delete it. I don't understand the reason to use the CFI spacer unless it will bolt directly onto an intake designed for a holley 4bbl square bore. Let me say this again. The 3.8L CFI system is being swaped onto a 2.8L V6 that has an aftermarket Offenhauser 4bbl intake installed. Part of installing that intake was deleting all of the truck's factory emissions system, including EGR, as such the spacer's EGR port is useless to me and leaves an extra hole I've got to block off. If it won't bolt onto my intake I might as well pick up a an adapter to mount a holley 2bbl onto a 4bbl intake manifold. If there's something special about this spacer that I'm missing please fill me in. Quote Selected
3.8 CFI questions Reply #9 – July 24, 2009, 07:18:09 PM I take it you're calling the EGR Plate a spacer. In fact, the spacer sits on top of the EGR. The way it was explained to me, that spacer is to isolate heat from the throttle body. The EGR plate draws the gasses from the original intake manifold, which has ports running down to #2 and #5 cylinders. The Offy you have won't have those ports, obviously. You would at least need a valve on the end of that EGR plate to prevent it from sucking air, yes, or some other means of blocking off the gaping hole which opens up right at the hole in the intake. Plan B, take some JB Weld, fill the hole and the notch between the venturis, then finish it down to make it smooth again. The gasket that goes between the TB and the EGR plate is really thick, and is actually the spacer. It's little more than a heat insulator. The inherent problem with the EGR plate is that the PCV inlet also comes in right next to the EGR inlet. This cooks the oily gasses, and plugs up the EGR, BIG TIME. Probably one of the most common driveability issues with the 3.8. What the EGR basically does for you is enhance fuel mileage and keep the engine running cooler at cruising speeds by displacing some of the A/F mix with non-combustible exhaust. Believe it or not, it does make a big difference in fuel mileage. Without the exhaust being mixed with intake gasses, you have to fill every cylinder every intake stroke with fresh Air / Fuel mix. This burns hotter than the diluted mix, AND, obviously requires more fuel to keep the same mixture. You said you were hunting mileage. Just thought I'd throw that bit of info in for you. Despite the claims of some, EGR affects performance a LOT LESS than it affects fuel mileage. There is a mild HP loss at steady RPM, but anytime you throttle hard or chop throttle, the EGR closes. It's closed at idle and at WOT with the EEC-4, and is otherwise modulated based on ECT and EGO feedback to optimize fuel consumption and reduce emissions by reducing combustion temperatures and fuel consumption. While the engine is cold, the EGR is closed to help bring the engine up to operating temperature quicker. You're certainly not going to feel an EGR delete in the seat, especially on a V-6. Quote Selected
3.8 CFI questions Reply #10 – July 24, 2009, 08:58:31 PM Quote from: Josht;283226Big difference there on the venturis. I'll be on the look out for the 5.0 CFI, then when/IF I find one I'll put it on. Bigger doesn't necessary mean better... You run a 5.0 CFI with the larger injectors and a 3.8 EEC('puter)and it's going to be rich at cruse... Period... Yes it may have a little more power at WOT, but cruse will be rich(wave bye bye to your MPG)...The engine uses a certain amount of air & fuel at a given RPM, increasing the TB cfm and injector size only gives more fuel at that RPMs(cause the 'puter is programed for smaller injectors)... Possibly the EEC could dial the fuel back enough to compensate(doubtful), but it will undoubtedly have some drivaibility issues... Quote Selected
3.8 CFI questions Reply #11 – July 24, 2009, 10:03:34 PM Quote from: Old_Paint;283667I take it you're calling the EGR Plate a spacer. In fact, the spacer sits on top of the EGR. The way it was explained to me, that spacer is to isolate heat from the throttle body.Thanks for clearing that up. I did not realize that there was a spacer between the "EGR plate" and the CFI unit. In that case, if possible I will use the spacer, but since my intake has no provisions for EGR I will not be using the EGR plate.Quote from: Old_Paint;283667What the EGR basically does for you is enhance fuel mileage and keep the engine running cooler at cruising speeds by displacing some of the A/F mix with non-combustible exhaust. Believe it or not, it does make a big difference in fuel mileage. Without the exhaust being mixed with intake gasses, you have to fill every cylinder every intake stroke with fresh Air / Fuel mix. This burns hotter than the diluted mix, AND, obviously requires more fuel to keep the same mixture. You said you were hunting mileage. Just thought I'd throw that bit of info in for you. Despite the claims of some, EGR affects performance a LOT LESS than it affects fuel mileage. There is a mild HP loss at steady RPM, but anytime you throttle hard or chop throttle, the EGR closes. It's closed at idle and at WOT with the EEC-4, and is otherwise modulated based on ECT and EGO feedback to optimize fuel consumption and reduce emissions by reducing combustion temperatures and fuel consumption. While the engine is cold, the EGR is closed to help bring the engine up to operating temperature quicker. You're certainly not going to feel an EGR delete in the seat, especially on a V-6.Interesting concept there, I'll have to study it more sometime. On this set up those exhaust gasses will not be helping to cool the engine. This intake manifold has no provisions for an EGR set-up and I'm not going to try to jury rig one onto it. If that means I don't quite see the full potential in MPG then so be it, it'll still be better than with the carb. Quote Selected
3.8 CFI questions Reply #12 – July 25, 2009, 03:00:02 PM nevermind all that EGR plate stuff, everyones got it mixed up.Im talking about the aluminum plate that sits below the CFI and off to the left the actual EGR bolts to it.,,,, The only reason I thought it would be a good thing is because it raises the height of your cfi as to not conflict linkages and such. The CFI isnt really a direct bolt on to a aftermarket 4bbl intake but i guess you could make something work. Some sort of square adaptor with a cut out in the middle with studs ready to accept your CFI.TomI was saying that he would need to swap his 3.8 injectors into the 5.0 throttle body. That will cure the EEC conflict as nothing changed, just a little bit more air.Your right as always,, the car wont run worth a at idle or even at upper r's with 5.0 blue top injectors. Too rich,,too much unburnt fuel, = washing the engine bearings from all the gas in the oil. Quote Selected
3.8 CFI questions Reply #13 – July 25, 2009, 04:29:52 PM No it won't bolt directly onto a 4bbl intake, but it does match Holley's 2bbl carb bolt pattern from what I understand. I should be able to use a 2bbl carb to 4bbl intake adapter and be fine, the adapter would probably also be thick enough to that it would do what you are saying to do with the EGR plate. Quote Selected
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