Ford Mustang Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
54 Posts
Discussion Starter · #1 ·
well first off I have a 66 mustang with a fuel injected 302 the motor is a stock 96 short block from an explorer I recently added afr 165 heads and a trickflow street intake 65mm t body k&n air filter headers the car has killer low end torque it just runs out of steam as the revs climbs (yeah I know the cam is choking those afr's). My problem is I thought I could get away with the stock injectors (they are the newer style Hi flow 19# injectors that is what ford says anyway) I have my fuel pressure cranked to about 70 psi vaccum disconected I know that is way too high but the plugs are still just as white as can be way too lean for my taste I thought 19# injectors could support 330 hp is this motor making that much already with no cam swap I know I will have to step up to 24# injectors but what do you guys think about the power of the motor
 

·
Registered
Joined
·
35,904 Posts
Is it just the plug color that makes you think you are lean? Get some a/f ratio data along with some dyno info - that's a much better source of info to act on than your musings about plug color and power guesses. For about $50 you'll have the data you need to make educated decisions about your injector size. Have you considered that the adaptive learning strategies of your computer have probably taken most of your "fuel pressure" richening out by reducing the pulsewidth? A 19# injector at 70psi is capable of flowing a bit more than a 24# injector; so if you truly are too lean, theoretically, moving up to 24's at stock pressure isn't going to change anything. I don't think you're that much too lean with that set up.

I'd pull the diagnostic codes to see what's happening - perhaps you have other issues that are impacting air/fuel ratio. Once you've done that and have it working right - throw it on the dyno with wide band a/f ratio data. Then you'll have a/f ratios and power levels that'll tell you what to do regarding injectors. The Explorer cam is EXTREMELY mild - I doubt it's running out of fuel with that cam in it.
 

·
Registered
Joined
·
207 Posts
I dont understand why people even bother paying for 24s. If you need to step up, most people dont realize that a 19 can do all a 24 can. Go with a 30s or more, and you wont ever have to worry about it again. If you are looking for a more temporary fix, put colder plugs in it. To read a plug correctly you need to make a full throttle run, shut the motor off , and then pull them out and look. Most people make a runs at the strip, then drive 50 miles back home and say, well this is what I got! Thats not good science.

I doubt you are making over 300 hp. Hell you probably just have a better breathing 265 hp engine, your cam probably has 30+ hp couped up! Best of luck.
 

·
Registered
Joined
·
54 Posts
Discussion Starter · #4 ·
first of all have any of you ever actually worked on a car or do you just read magazine cause I for one cant afford to go to a dyno every day or even spend a whole day there at $100.00 bucks an hour so maybe you guys should learn some good ol fashion engine tuning tech. and where do you get off saying I only have 265 hp did you not read AFR heads trickflow intake etc.etc. maybe if I had my old combo of gt40 heads and intake but not with this stuff I try to be conservative on my guesses to but I do think I have right at or more than 300 at the crank I am relly not trying to be rude but I was asking for help and you guys want to critisize me I have already had a bad day my car isnt running the way I want it to and one of my custom wheels has a crack in it now so can we keep the amateurs away and get some people in here that know something about cars. And yes I know i sound like an ******* but I do know a little about what I am doing but I dont know everything and I do appreciate all the help the people here give. and yes michael I see what you are saying about the injector pulse width that is a good idea but I cant go any lower than 55 psi or it will start poping through the intake when you rev it up just like a severe lean condition any ideas
 

·
Registered
Joined
·
1,978 Posts
Agreed on skipping the 24s and going straight to 30s.

Sounds like you have some sort of other problem. What MAF are you running? What computer? Try a stock MAF. It will be a bottleneck but at least it will tell you if the MAF you have is [email protected]
Another thing is perhaps your timing is up too high. I've seen some cars that run fine with 14, some won't go past 12. I had a Vortech car I could put up to 16 with no problem. Every engine is different.
 

·
Registered
Joined
·
167 Posts
He is running a 96 motor with no distribitor and it is running stock timing(what ever that is) but it would not be enough to cause concern. And he is running a stock MAF.I think he does need to go up in injector size but he needs to change his computer first. He has an explorer set up for now.
 

·
Registered
Joined
·
54 Posts
Discussion Starter · #7 ·
yes thank you! there is intelegant life on this planet haha!

yes I am running stock 10 timing with the stock maf and explorer computer I am going to switch to a 96 4.6 mustang computer and buy 24# injectors and matching maf for the 4.6 computer that way I can retain my DIS ignition. the only aftermarket maf I know about that will work with the explorer computer and can be calibrated for 24# injectors is from pro m and its $300 does anyone have a set of injectors and a maf for a 96 mustang they want to sell
 

·
Registered
Joined
·
35,904 Posts
Perhaps we should've asked which computer you were running. There are very few people on the 5.0 tech site running the Explorer computer or asking questions about it. I've got an acquaintance or two who have tried mods with that computer, and apparently it's not nearly as tolerant of mods as something like the A9L is. However, different cams seem to give it the most problems; it should run ok with heads/intake mods. Do a search for BrianB31 - he's running a modded Explorer motor in his Ranger - he knows a bit about the Explorer computer.

I mentioned it before - have you pulled the diagnostic codes? You could go on 'guessing' for quite sometime without finding the problem. Let the computer help you with it - see what it's saying about the problem.

As for the rest of your comments about whether we've worked on cars before or not -- uh, yeah, I've worked on a few, maybe for a few years. One of the things I've learned is to get solid data during the diagnosis phase. In my neck of the woods you can get 3 pulls with the wide band for about $50-$70 bucks. That will tell you what your a/f ratio is doing, and it will tell you how much power you've got and where it's occurring. Pulling the codes is usually free - any Autozone or PepBoys will usually do it for you. Post the codes here and people will usually tell you what they are if you don't have the resources to look them up. Investing in getting some good data will save you money in the long run -- the kind of money people spend guessing on the solution, and then changing parts hoping they've found it. Attitude is everything - not sure why you responded so defensively; but one thing's for sure. If assistance on the forums is what you're after, responding the way you did will pretty well assure you of no help. Heck, if you'd just chill a little, we'd even over look your lack of punctuation. :) Given that you're talking about the Explorer computer, and 96 mod/4.6 parts, you might get more assistance by posting in those forums.
 

·
Registered
Joined
·
1,042 Posts
You havn't said what fuel pump or fuel system your running.
If an 88l/hr pump, at 70 psi the pump can't supply any more volume no matter what injectors you have.
I run 19s with a K.B.blower and FMU at 8 lbs boost making about 320 hp and this is the limit.
The pump won't do any more than 78 psi and who knows what the volume is.
I'm just lucky to get by with no problems.
Just bringing up a point and not trying to challange your position.
 

·
Registered
Joined
·
618 Posts
gap the plugs to 55-60 the dis can handle it.i had the 24's before blower plugs run clean.lean in a n/a setup is good to a point not like blower apps.what is you fp while running? did you mod the tank for intank pump? or sump and external?.using stock tank and external with siphon feed to pump will cause starviation.the explorer comp just needs a chip or reflash to work well.
 

·
Registered
Joined
·
207 Posts
Woah, I wasnt trying to be an ass or offend you in any way. I was just trying to say that HP doesnt come cheap, and most people tend to overestimate their it. I dont measure my HP at the crank, so that is another reason why we arent in agreement, I was meaning RWHP. To me, its how much you get to the tires that makes the car go, so if you lose 20%, thats a bad thing, not a good thing that your engine makes more power than you put down. I agree with Mike, if it costs you 100 bux to put on the dyno for a few pulls, I would do it, you are going to spend more than 100 bux on any part that you swap out, and I bet you dont find the right one on the first try (from experience). Best of luck let us know what you find.
 

·
Registered
Joined
·
167 Posts
Im sure he wasnt trying offend anyone with his reply. He is a good guy who is just very fed up with all the trouble he is having. You guys are great to help. Now can you tell me how to remove a rear seat in a vert(89)? As for pumps he is running a 90lph with a Vortec T-rex. He is currently trying to get a 96 gt computer and mass air ti swap out. And I may have netted him some 30lbs injectors.That will give hime pleny of fuel at stock pressure. Leaving room for mild boost and a FMU.
 

·
Registered
Joined
·
207 Posts
Is a rear seat in a vert any diff than one with a roof? I would guess it would be the same, just pull up on the back so it tilts forward, then wrestle with it some, and it should pop out. (push the seat belts through seat before pulling).
 

·
Registered
Joined
·
167 Posts
i NEED TO GET THE BACK REST OUT I HAVE NO PROBLEM WITH THE SEAT YOU SIT ON. BUT THANKS FOR THE ADVICE (DAMN CAP LOCK)
 

·
Registered
Joined
·
891 Posts
I think Micheal was on to something here. Having delt with carbs most on most of my vehicles I have found that a lot of EFI only guys like to skip some very basic trains of thought when trouble shooting.

IMO the car should be running well at 55lbs of pressure, not popping, having to run 70lbs and still have white plugs doens't mean much to me. I was recently informed by a street outlaw racer that reading the tips of the plugs is not correct and you are suppose to read down in further. If this is what you are doing, then I am concerned. Regardless of where you are reading though, it sounds like one of he most basic missed trouble shooting problems, a vacuum leak. A vacuum leak would create the problem you have indicated. Very easy and cheap fix. Go buy a can of carb cleaner and verify there are no leaks and then let us know if the problem is solved.
 

·
Registered
Joined
·
35,904 Posts
It ought to run well at 40 psi. The vast majority of the time, street engines are run barely loaded at very small throttle openings. All the computers are designed to allow very lean mixtures under those conditions. Anyone who's been on the dyno will show you curves -- when you first start the run before you nail the throttle, and for a second or two til the computer switches from closed back to open loop (w.o.t. is open loop), the mixtures are always very lean - 15-18:1. The computer is designed to run as lean as it can while reducing fuel use and still meeting emissions. The proper way to read a plug if you're trying to determine what the engine's doing under full load was described above. You run w.o.t. for a good blast in 3rd or 4th gear up to around 5000 rpm, and then you immediately shut it off and let it coast to a stop. Pull the plug and read it. It's easy to do at the track - very difficult to do on the street.
 

·
Registered
Joined
·
167 Posts
If we get the chance we will try to go the track this sunday weather permiting. We will try to keep you all posted
 

·
Registered
Joined
·
54 Posts
Discussion Starter · #18 ·
wow you guys have some great ideas I really appreciate all the help you are giving and am very sorry for acting like a jerk the other day when i posted this thing is just getting on my nerves I dont understand this thing and why it is doing this. today i was checking things out on the motor i checked the coil packs with my ohm meter they are both good the wires need to be replaced badly but are still within factory levels of resistance the plugs are new I know I am getting plenty of fuel with my 90 lph pump and vortech t-rex pump, and I would think that this thing isnt putting out enough power to have to have bigger injectors right now I may be pushing the 19lb injectors too much but they should work for now. After I was through checking everything out b 89 called me and said I should try and turn the fuel pressure down to 32 psi so i tried it and it didnt sound much different at least no poping but it lost a lot of power does that tell you anything? then i tried 42 psi still a lack of power it still seems like it is starving for fuel like the injectors cant keep up what do you think? and once again thanks for the help
 

·
Registered
Joined
·
54 Posts
Discussion Starter · #19 ·
oh yeah in case you are wondering why b89 suggested to turn the psi down is to try and fool the computer into lengthening the pulse width sounded like a great idea but it didnt work
 

·
Registered
Joined
·
618 Posts
ouestion,on hegos are you using all 4 or just 2 primary and mil elims out back.is cam sensor adjusted right?.there may be a problem using a 96-97 stang comp.different cam sensor,and pats requirment.let us know how you make out
 
1 - 20 of 23 Posts
Top