MonsterMaxx

Has anyone found a plug and play replacement for the stock computer ('94 3.0L)?

I've done lots of mods w/ very little performance improvement.

Watching EGT and O2 it sure seems to me like the computer isn't giving it the fuel when it wants it. Particularly below 3000rpm.
You can actually feel the power surge as it crosses 3k (was like that stock too.)

I know there's a place that I can send my computer and for $600 they will 'reprogram' it. But it's $600 every time you want them to tweak something.

I'd like to replace it with something that has a PC interface.

CrazyDiamond

Alot of that power 'surge' you feel isn't from the computer's adjustments, it's because you are hitting the powerband of the CAM. The camshaft has alot to do with that feel... Not to say that it's not in need of better (non-stock) computer tuning...just keep the cam profile in mind.

On another note, the reprogramming they do is primarily enriching the mixture and advancing the timing. 'IF' your car is up to it, you should try a quick little engine coolant temperature sender mod which allows you to trick the computer into thinking that the engine is colder than it is. The computer thus enriches the mixture and advances the timing. There is an article on it posted somewhere on Yotatech. I've been running it 24/7 for about the last 15k miles and it's like night and day for my little 22re. The lag between shifts is SO much firmer, too. Just be sure you have a good cooling system, etc so you don't ping.

Good luck.

midiwall

What kind of stuff have you done? The 3.0 can be an interesting engine to boost with just bolt-on's.


JET (or whoever you're referring too) is kindofa rip off - they toss in some timing advance and kick the fuel a bit, but as you know, you have no control over tweaking. You have the right idea in looking for a programmable module.


I run a box from Perfect Power called the SMT ("Smart Tuner").

A more popular box around here is the Split Second FTC1. (click on "Products" then "Fuel/Timing Calibrators")

Both boxes are capable of the same things, program via a Windows interface, gives total control of fuel and timing, and interface into your rig in the same way.The Split Second tends to be talked about more 'cause it's gotten more publicity from this guy who's got quite a reputation on the forum for his work on 3.4L engines.


fyi... the mod that Adam's talking about is here. It can have a varying level of success depending on altitude and climate, but in general, it's a quick way to get more fuel into the engine across-the-board.

Bigblock

i've seen no power up parts for the 3.0.if all you want is more fuel ,go adjust your a/f meter and drown it with fuel if you want to.

midiwall

update...


I just found the run-down of your truck over here.

With all the work that you've done on the engine, I dunno that simple timing/fuel work will help all that much. It may be that the combination of cams and injectors (how large did you go?) have thrown it out of whack and you really are running lean. But, if EGT and O2 is saying so, then...

Are you getting enough fuel pressure to feed the injectors? Maybe that's the place to start?


As an aside, when you say "6 channel EGT and AFR", are you doing on-board data collection, or are these just gauges?

MonsterMaxx

I've got 6 channel EGT and O2 sensor reading. I can SEE what's happening.

Below 3000, no matter what you do with throttle you will not see rich & hot. At hard throttle, right when it crosses 3k it goes full rich on 02 and temps build at egt and you feel a surge in your butt.
Every 3L truck of this generation I've driven has this feel right at 3k.

Absolutely true the cams effect it. My motor now makes good power once you let it build some rpm.

This spring I took a chunck out of my ring gear and had to drive the stock 91 for a while and really noticed the difference. The both feel about the same on the bottom, but the hopped up one will pull hard all the way to red line where the stocker gasps at the higher rpm.
The hipo motor makes good power for a wider rpm range.
I suspect that if we could fix this low end fuel thing we'd see it pick up more bottom end.

I think the map needs to be altered in the lower ranges to provide it with fuel.


It should operate like the powercommander on my V-Rod....

....PowerCommander doesn't make something that would work do they? {gone to PC's site...}

CrazyDiamond

What air/fuel ratios are you seeing below 3000? The computer tries not to enrich the mixture too far (unless the engine is cold) under 3k to reduce hydrocarbon emissions. That's why you can trick things a bit like I mentioned earlier with a potentiometer inline with your engine coolant temp sensor. You can make the computer think that the engine is colder than it is, and it will forget about watching the emissions so closely and enrich the mixture regardless (and throw in a bit more advance).

MonsterMaxx

I don't actually get a #s, just rich/lean in a 270 sweep type arrangement.

EGT is more precise, I'll see mid 1300s at high rpm & throttle, below 3k never over 1000°F

cruising on the highway afr cycles in the normal range & egt hovers around 1300.

midiwall

Yeup... then it sounds like the SMT or SplitSecond box would do you well.

Have you looked at those links up above? Any interest?

CrazyDiamond

The reason you probably never see above 1000 degrees below 3k rpm is that the EGR valve is operational at that range, and the additional EGR function will drastically reduce the exhaust temps. Try disconnecting your EGR and doing the same test...I bet you get temps 200 degrees higher.

Bumpin' Yota

woah!! EGT of 1300??? Isn't that just a weeeeeee bit high to say the least? In diesel powerplants, anything over 1000* post turbine will have a very very short lifespan....

MonsterMaxx

naa, good to 1400 on pump gas
avgas are up to 1700, leaded fuel and all that