Help with MAP Sensor and Injectors

[Geoffray]

Hello all, i'm a french TJ owner and i'm searching information about my TJ and i think you are the only one that could help me!
I've got a TJ 97 4.L Sport with 24Lbs Ford Racing Injectors, AEM BruteForce Aire Intake & Body Throttle spacer, adjustable MAP, Borla Header, AirFlow Catalytic Converter and Dynomax SuperTurbo Catback.

I've got few questions for you :
- How many HP do you think i have with this configuration? And how much more with a 62mm body throttle instead of the AEM Spacer?
- Do you think that my injectors are too much for my configuration? Wich one does i have to have or what i have to change do have a good air/fuel ratio like stock value.
- How do you adjust the MAP Sensor value? Is there a target to aim? 0.9V from O2 sensor at WOT?

- If i have 23.2Lbs/hours injectors and 181HP with a stock 97 TJ, i need 208HP to run with 24Lbs@39PSI Ford Racing injectors, there would be a problem with my TJ, what do you think about that?

Thanks a lot. Have a good day.
Regards

Geoffray (From France)

[seanyb505]

I would say youre making around 190-195 at the flywheel, conservatively. The throttle body spacer doesnt really do anything. You would get some better part-throttle response with the 62mm tb. I had roughly the same setup on my 97 XJ, and I didnt need bigger injectors. the stock should be fine. I know they changed the fuel system in 97, so I think (I could be wrong) the 97+ 4.0L can handle dealing with a/f ratios on their own. Someone correct me if I am wrong, but I think the 97+ models flow 23.3 at 49psi.

PS - I see you didnt mention this, but I think you should build a stroker.

[Geoffray]

Yes, it's 23.2lbs/h for the stock injectors. Which Throttle Body you can advice for me, 62mm with or without electronics?
So I will change the 24lbs@39psi Ford Racing injectors, but i don't want to reuse my old stock injectors because they are 100 000km, so i have to buy stock one or i can choose another one to be better with my configuration?

And does someone knows how to adjuste the MAP value? Is there a value to aim?

Thanks a lot!

[Mgardiner1]

For the mods that you have, to benefit from modifying a map signal value, you'll need a wideband o2 sensor and gauge to monitor what your AFR's are doing. If you have a non programmable (potentiometer to tune the AFR) then i wouldn't even bother, your ECU should handle the job. As seanyb505 said, the likelyhood of needing the larger injectors is slim. However, the injectors you've selected are marginally bigger, but you haven't increased air in/air out of engine (IE ported and polished cylinder head, aftermarket camshaft) so the stock injectors will be ok

[Cheromaniac]

I've got a TJ 97 4.L Sport with 24Lbs Ford Racing Injectors, AEM BruteForce Air Intake & Body Throttle spacer, adjustable MAP, Borla Header, AirFlow Catalytic Converter and Dynomax SuperTurbo Catback.

You don't have enough mods to need injectors bigger than the stock 23.3lb/hr units, and you don't need the MAP adjuster either at this stage. I reckon you have about 205hp at the flywheel.
Don't forget that the fuel pressure on '96+ Jeep models is 49psi, not 39psi, so your Ford 24lb injectors will be flowing 26.9lb/hr at 49psi. That's much more fuel than you need and I'd be surprised if your engine isn't running rich. If you want to keep those injectors anyway, you'll probably need to reduce the voltage from your MAP adjuster down to about 4.3v.

[Geoffray]

Thanks that the question i would ask : Can i run with the Ford Racing if my mileage is good with the MAP Sensor Adjustor. But is there another risk to run with that?

I ask you because my TJ don't work well when engine is not cold, but not at the normal temperature (40-70°C).... Nothing in the first 200 meters, but lagging 50m-100m, and all is good after...
I don't want to inject too much than i need when the O2 sensor is not ready...and i think that's the problem i have. Do you think about something to resolve this? Is it dangerous for my engine to run with this Ford Racing Injectors?

And another (last) question. How do you adjust the MAP Sensor? How you know the good value to have? I adjust it reading the voltage from my O2 Sensor, and i aim 0.9V at WOT and open loop. Is that a good method? Do you proceed in another way?

Thanks a lot!

PS : If i run with this injectors, it's because i want to run with E85, so i need to inject more at OPEN Loop to be with the good mileage. I look at this with a O2 Sensor and i adjust MAP at WOT to have 0.9V from the O2 Sensor... and re-adjuste to have 0.9V when i run with fuel.

[Geoffray]

you'll probably need to reduce the voltage from your MAP adjuster down to about 4.3v.

Stock value was 4.49V and i have now 4.7V to aim 0.9V from the O2 Sensor at WOT and in OPEN loop mode.

Perhaps i don't have the good solution to adjust my MAP Sensor, i think i need help

[Texacoon]

How do you adjust the MAP/MAF Sensor?

I am certainly not trying to sell you something on EBay or selling there...
However, if you look on EBay you can find all sort of MAP/MAF Sensor adjusters for the Hyrdogen Generator modifications for your autos. These MAP adjusters are easy to install and setup .... I have one to test on my HHO system...



Here is an EXAMPLE: http://cgi.ebay.com/ebaymotors/HHO-Fuel ... 240%3A1318