1985 Grand Marquis 2-Door

[87GrandMarq]

Didn’t even think about that. Good catch.


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[sly]

If the pair are fired at the same time, then yeah... no issues. If they fire individually, then the side to side firing order change may affect it. If the intake manifold is a single plane, it shouldn't be much of an issue, but a dual plane that separates each side will keep fuel from getting to the correct side for the correct firing time. I think the stock stuff is all single plane and the injectors fire together, so it shouldn't be an issue.

Firing orders vs engine side:
LoPo
1-5-4-2-6-3-7-8 P-D-P-P-D-P-D-D

HO
1-3-7-2-6-5-4-8 P-P-D-P-D-D-P-D

[sluggish91]

I got my 52lb injectors in the mail today and swapped them onto my CFI unit.
Didn't seem to make an immense difference, quite frankly.
It might be the fact that I also swapped the fuel filter out (something I hadn't done in about 12 months) but the tip in acceleration seems a touch stronger.
I only drove it around for like 10 minutes when I was done.
What I did notice was that the 46lb injectors had that single pointy nipple at the end of the injector. It kinda looked like a firing pin.
The new injectors had 4 small holes and were sort of tucked into the injector body.
If anyone has ever seen the Jetronic 19lb injectors off of an explorer, the injector ends sorta resembled that.
I'm just happy that it runs normal!
I will update with any more events if interesting things happen.
The ECM was complacent with the injector swap.
So far.
I will post pictures soon.
Thanks for looking and thanks for your interest in my build.

[Brown_Muscle]

This is one of the most interesting threads im following right now because of the originality of what you're trying to do
If you get a wideband sensor and gauge I think it would help you with modifications quite a bit, that way you can see exactly how your engine is responding to the modifications your making.
The more modern 4 hole injectors supposedly atomize the fuel better than the older pintle style ones

[sluggish91]

I've been driving around with these new "52lb. injectors" for the past couple of days and I've come to the conclusion that they are not responding as well as I had initially suspected. Sure, they are delivering a great amount of fuel between idle and 3000rpm, the engine feels real strong, but something is going on past 3000rpm where the engine is just falling flat on its face and shuddering, like it is needing even more fuel. These are just conclusions I've come to based on what I feel the car is doing, I have no legitimate data to back up my theories.
Maybe it has something to do with the spray pattern on these new injectors and the fact that they are shorter.
Maybe its the ECM not compensating well over 3000rpm.
Maybe its the fact that the CFI throttle blades open from front to back and all fuel is getting dumped into the back of the intake manifold.
Either way, the car runs great if I don't give it the beans.
It idles perfectly just like it did with the 46lb injectors and accelerates normally throughout each gear, so long as I don't go over 3000rpm.
I'm going to find the time to put the 46s back on and see what happens.
My biggest concern from this point forward is the way the throttle blades are opening.
They are completely biased to the back of the manifold.
I was getting this crazy idea: what if I tapped two nitrous nozzles into the spacer and used only the fuel jets to fire a dose of fuel into the front portion of the manifold?
I don't know.
It is all for the phuck of it anyways.
I guess I'll see what happens.
Thanks for your interest in this little project I'm messing with.
Here are some pictures of the injectors side by side and fitment of the 52lbers in the CFI unit:

[sluggish91]

This is one of the most interesting threads im following right now because of the originality of what you're trying to do
If you get a wideband sensor and gauge I think it would help you with modifications quite a bit, that way you can see exactly how your engine is responding to the modifications your making.
The more modern 4 hole injectors supposedly atomize the fuel better than the older pintle style ones

If I were to get a wideband I'd get something like an Innovate LC-2 with the gauge. The question I have for you is where would you mount the sensor? Considering there is already a sensor on the passenger side bank of the h-pipe, would it be ok to just install on the driver side bank of the h-pipe? Would this create inaccurate readings? Should I mount lower at the h-pipe crossover? Thanks for your input and for your interest in this weird stuff I'm experimenting with.

[87GrandMarq]

I wouldn’t mess with it until you can get an afr reading when it’s acting up. I don’t see why you couldn’t use an 86-91 drivers side header with an o2 sensor bung.

I’m not sure it’s the injectors, you’d think they’d cause issues with the stock injectors too since the throttle plates didn’t change. You could pull the plugs and check to see if the front cylinders are being starved for fuel to rule that out.


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[sluggish91]

I wouldn’t mess with it until you can get an afr reading when it’s acting up. I don’t see why you couldn’t use an 86-91 drivers side header with an o2 sensor bung.

I’m not sure it’s the injectors, you’d think they’d cause issues with the stock injectors too since the throttle plates didn’t change. You could pull the plugs and check to see if the front cylinders are being starved for fuel to rule that out.


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Thanks for the response and input. I would hesitate to use a 86-91 drivers side header as I already have BBK shorties on the car.

What should I be looking for in the front spark plugs?
We are talking about cylinders 1,2 and 5,6 yes?

[87GrandMarq]

Thanks for the response and input. I would hesitate to use a 86-91 drivers side header as I already have BBK shorties on the car.

What should I be looking for in the front spark plugs?
We are talking about cylinders 1,2 and 5,6 yes?

Well if you really think it’s biasing fuel to the rear cylinders check the fronts for signs of lean mixture and the rears for rich running.


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[Brown_Muscle]

Interesting, its also possible its going significantly richer in the upper RPM's and making it lose power. You can definitely install it in the other bank. The reading will be very close side to side. The closer to the header the better, for a faster response reading, don't mount it any farther away from the header than you need to. I have that same Innovate setup, I like it. I also kind of doubt that its biasing richer in the rear compared to the front...but spark plugs would tell you. Light beige is really the ideal color, darker, or black means too rich. Theres lot of charts/guides online for reading plugs

[gadget73]

Fuzzy memory here but I want to say there was some sort of metal diverter thing in or below the HO CFI units that did something to even out fuel distribution. I don't remember particulars but I think it was designed to deal with the off-center spray that happens by firing above the throttle plates.


read the plugs individually and see what the fuel distribution is like. That will tell you. The stock manifolds are a typical split design, one injector feeds the middle two on one bank and the outer two on the opposite. That will also tell you if its an injector problem or an injector location problem. If its one funky injector you'd get two inner and two outer that read odd. If its a distribution problem you'll get the back or front plugs on both sides reading funny. Probably need new plugs for this, or at least extremely clean ones to get an idea of what its really doing. Uncle Tony's Garage actually recently did a video on reading plugs to work out fuel distribution problems. He's messing with a 4bbl on a slant six but that doesn't really matter.

https://youtu.be/7ILJd2Ytx0w

Advantage of doing it with the plugs vs a gauge is you can see what each cylinder does rather than the average of what all 4 are doing. The ECM looks at the average of all 4, but you could have 2 fat and 2 lean and it averages out close enough to right for the ECM to be happy with that. Engine won't run for shit that way but the O2 sensor or the wideband will be happy enough that you won't know why.

[sluggish91]

What's up there fellas, been a while since I last posted on this thread. I did end up throwing a wideband on the car. From the bit of knowledge I have, AFRs are at the correct target. Very surprised at how well the CFI system does its thing, it just keeps on chuggin along. I'm still rocking it and I've been more than happy with it, even with the weird injector swap I did last year. Car is peppy and fun to drive like always. I haven't had any weird drivability issues or anything either which is great. Just been keeping up with maintenance, oil changes, just did the fuel filter.

I am going to the 1/8th mile track again tomorrow to race my Dad's car. I am shooting for a sub 9 again in the 70mph range. Since the last time I took it out I dropped like over 100lbs with a bunch of different stuff, biggest chunk probably being the spare. I will be ecstatic if I hit a 9.5 @ 71 or 72 , but that is shooting for the moon. Other than the weight reduction and the addition of the wideband, nothing has changed. I still have that fuel pressure regulator I can throw on but haven't bothered with it.

Well anyways, I'm hoping to set a new personal best tomorrow and also beat my dad. He is on an all season tire and I am on a drag radial.

This is his build if anyone wants to see what the CFI car will be going up against: http://www.grandmarq.net/vb/showthre...-Grand-Marquis

Thanks for reading, and thanks for your interest in the build.

[sluggish91]

Two things that sorta went over my head that I did switch out in the last year (and since the last track outing) were going from the tiny race crank pulley and a spacer, to the appropriate ASP underdrive crank pulley, and also going from a Motive 4.30 gear to a Ford Racing 4.10 gear. We will see how the different gearing affects the ET and MPH. I will be racing with the same tire as last time, so that factor will remain the same.

[packman]

Nice!!! Let 'R rip potato chip!

[sluggish91]

Went to the 1/8th mile track last night. Beat my dad and got a new personal best. I can confidently say I own the fastest CFI powered anything to the 1/8 mile.

Best time was a 9.65 @ 70.7 with a 2.100 60ft.

And IÂ’m not done just yet. Still have a hydraulic roller conversion to do, I can still bump the fuel pressure with that adjustable regulator, I can still retrofit a 190lph fuel pump into the tank, and I can still get some ADTR control arms to lower the 60ft. Next track outing we will hopefully continue to go faster.

Thanks for your interest in the build.