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360 tbi questions

11K views 13 replies 6 participants last post by  s ÇťoÉľ 
#1 ·
hey guys newbie to the site but I bleed chrysler blue and have for twenty plus years.
soon as I found the site had to be  SUPPORTER or gold member what ever you call it not real computer savy as far as online but do plc cnc and robotic programming so this may sound silly
but always been carbed and now have a 89 rc 318 tbi 110k miles old indiana state truck 100% rust free and original looks like a 89 poster child for dodge but this being my 4th rc and lord knows how many dodges never played with fuel injection.  Just have a couple simple questions for the tbi challenged .  would like to keep this one a daily driver but need some HORSEPOWER but want to put remote start and all the goodies on it .  I already have 15x10 centerline convo pros and all new rancho shocks for 6 inches of lift and a 74 360 short block getting ready for the machine shop I've checked all the posts and just need to know if I can keep this one simple with a 360 throttle body and ecu will do the mods to the tbi ( cut the wall between venturies and polish heads will be port matched and so on but will the stock tbi and sh.. feed it enough  I figure with a mild cam a little breathig room in the tbi and heads it should do what I want for decent mileage and power .  I've read all about the mega squirt but trying to stay low key with this one what's the most mpg vs hp anyones got out of stock or mildly modified tbi???  I have a 92 3/4 w250 cummins salt / plow truck for a full transplant. but want to put that in a 92 or 3 canyon sport.  any info welcome  not a rookie on la mopars just on tbi
 
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#2 ·
Since you can operate machining centers, consider this project.

Consider taking a 4bbl carb gasket and a tbi gasket. Over lay them over one another. Basically I mean to form a tbi to 4bbl adapter plate. This allowing the smaller tbi to fit on a 4bbl intake manifold. Keeping injection and increasing airflow.

Gotta be careful when doing the cam dance. Everyone likes the lopey sound and that in itself is enough reason for them to upgrade. Well, the MAP sensor does not take too kind to lopey inconsistant airflow and reversion. It needs smooth constant airflow. So, any larger cam, should still have a wide lobe separation, which reduces lope, which basically reduces the desire for the cam in the first place.

Yes a 360 tbi and computer will work.

A tbi 360 engine would be a great upgrade LOL ;D

Those teeny tiny intake valves prove to be a bottle neck as well. 1.75ish inches compared to larger 1.88 or even 2.02" valves found on other small blocks.

The remote start is cake walk. No brainer.

I don't expect excellent fuel mileage or power from the tbi. It's benefit just comes from easy driveability. Enjoy easier cold starts, less hot start problems and a smoother cruise. That's where the beauty lies. Not to say power cannot be increased maybe as much as 215-220hp maybe. Mpg should remain in the 12-14 mpg range.

Wait, after typing all this about a 318, are you installing 360tbi stuff on a 360 short block? Definitely try to find some 360 tbi heads. You have a bit more power potential here.
 
#5 ·
340SHORTY said:
Mopar Perf has a nice TB to 4 bbl adapter........looks better than a plate adapter....
That might be a exaggeration, since the adapter you describe is basically the same thing.



P5007865 Throttle Body Adapter 45.50
http://www.mopartsracing.com/parts/fuel.html
(way down at the bottom)

I do have a treat for interested parties though. (I didn't make it)



Holley 4bbl to Dodge Truck TBI Adapter $49.95
 
#6 ·
i know this is sort of an old thread, but im trying to find someone that could point me towards reprogramming the stock ecu, or possibly later model stock ecu?

i know a speed density computer can idle fine with a big cam, but it has to be recalibrated.

has anyone cracked the stock ecu? or even a slightly newer magnum ecu?  i would like to stick with an oem style injection setup...and just tune the fuel and spark curve to suit the new engines needs.

piggybacks? chips? tuners? anything? lol...there has got to be SOME WAY to tune this pig!!

plan to raise compression and cubes, replace heads/top end, cam... basic stuff. this thing is LAZY right now.

is there any sort of mopar EFI big block that is not crazy money and/or a giant turd?


 
#8 ·
kawgomoo said:
i know this is sort of an old thread, but im trying to find someone that could point me towards reprogramming the stock ecu, or possibly later model stock ecu?

i know a speed density computer can idle fine with a big cam, but it has to be recalibrated.

has anyone cracked the stock ecu? or even a slightly newer magnum ecu? i would like to stick with an oem style injection setup...and just tune the fuel and spark curve to suit the new engines needs.

piggybacks? chips? tuners? anything? lol...there has got to be SOME WAY to tune this pig!!

plan to raise compression and cubes, replace heads/top end, cam... basic stuff. this thing is LAZY right now.

is there any sort of mopar EFI big block that is not crazy money and/or a giant turd?
The 360 in good shape should have decent power. I'd wonder if maybe you have a problem or a worn engine. Check your fuel pressure, check codes, check compression.
 
#9 ·
i have the 318 {i think?}. its an 89 RC super base model.

have a code {maint required light is on}, but my snap on scanner is on the fritz {of course} and the cheapie obd scanners wont plug in.

also lifted on 33's with the stock gearing, which is 3.00 i believe.

definately will do a compression test on this mofo this week. Throttle cable is jerry rigged with zip ties on the gas pedal....still need to check for WOT.

reguardless this thing has no torque. my 90 k5 blazer with tb 5.7 was a monster compared to this dog.  i wonder if my cam is flat? its got no muffler and is soooo quiet. just the cat.

i am absolutely 100% mopar clueless. i dont even know where to start diagnosing this thing.  i guess compression test is it! ;)

tranny seems to shift pretty early, and doesnt really want to kick down..so im sure some sort of recalibration is in order.  works good, just like i said...gutless.
 
#11 ·
Don't know much about MS.  There is a whole combined thread on it fo your reference.  And don't bother with a carb.  You won't gain any power that way.  If this is a 318, it's just a dog - reliable but little power (head and cam are very mild).  Biggest issue is likely your gearing.  It's probably 3.21 and you would benefit a lot from something steeper (3.90's).  I have 3.55 in mine now with a torque monster 408 engine.  I am very happy :)
 
#12 ·
yeah man, in no way am i stuck on this motor.

but i do need some torque. is your 408 a stroke 360?

carb or efi?

i wouldnt swap to carb and keep this motor...i wouldnt swap to carb ever, actually. but if a later model motor, lets say a 5.9 magnum was capable of being chip tuned. well that would solve all my problems!

then i could build the 5.9, put whatever crap i wanted to in it and then still make it idle by chip tuning or whatever to the factory electronics.

is that at all feasible?
 
#13 ·
kawgomoo said:
yeah man, in no way am i stuck on this motor.

but i do need some torque. is your 408 a stroke 360?

carb or efi?

i wouldnt swap to carb and keep this motor...i wouldnt swap to carb ever, actually. but if a later model motor, lets say a 5.9 magnum was capable of being chip tuned. well that would solve all my problems!

then i could build the 5.9, put whatever crap i wanted to in it and then still make it idle by chip tuning or whatever to the factory electronics.

is that at all feasible?
ya, the 408 is a stroked 360. Mine is carbed. It started that way, but my goal is to TBI it. I have a few options but no hurry and no budget for it now. Still need tires, finish AC install, and a long punch list of small things.
 
#14 ·
I can answer a few of the newer questions:

EFI big block? No, not really. You CAN do it, I meant most (save for maybe some experimental) didn't come that way. Intake manifolds are now available off the shelf to accept standard bosch style multi point injectors, add your favorite brand of stand alone pcm. There are a few throttle body alternatives, adapting tbi to carb intake, once again with a variety of controllers.


Chip a dodge? Yes, no, maybe, kind of. In truest sense, physical replacement of the chip, it is possible but not yet accomplished. The circuit boards are coated in 1/2" of crap polyurethane, which makes removal difficult. The chip is soldered in place, which means the board needs to be desoldered and socketed to accept a removable chip. Then the requirement for a chip burner and a bunch of blanks, along with the appropriate tuning aides. Final straw is the fact dodge wrote code in some format that is so hard to decrypt, no one spent the effort to do this to a truck that never sold that well in the first place. A few hard core gurus have cracked the 4 cylinder turbo code and rewrote it to their liking, one has recently offered to do the same for tbi trucks if there was enough interest. Personally, I view it as not worth it.

Then there is this thing called a "JET chip" just say no. Also say no to the stupid resistor tricks.

Finally, OBD2 (96-03 magnum v8) can be flash tuned via SCT. If you tuned dodges for a living, this is a viable option, because you can go in there and tell the JTEC controller to ignore all kinds of sensors that would be missing when you install this engine in an older chassis. Without the racer pro package, (lots of money) flash tuning alone isn't worth the trouble. SCT for big3 vehicles is like hondata for hondas, although hondata is by far the most feature packed oem tuner.

Gear Ratios? Most all had 3.21, a select few had 3.55, I am not sure if 3.91 was available in a ramcharger, maybe. The under geared scenario is the root of all evil on these trucks, especially with oversized tires. Your old chevy likely had atleast 3.42s, although I could be wrong. I don't really care what it had honestly lol. Dodges like some more gear. Plain and simple.

Megasquirt vs cruise control? Yes and no. MS will not control cruise. It is a fuel and spark controller, that is about it, although it has some other basic outputs like fan/nitrous/ ect ect. BUT yes, you can still have cruise and a stand alone pcm. Before efi, carbed vehicles still had optional cruise as well. They had their own control module built into the cruise actuator itself. Cruise wiring is relatively simple, there are 3 solenoids inside the actuator. Furthermore, hot rodders like to install cruise on their hot rods. They sell aftermarket controllers for around $100 which look stock and handle speed control even if the vehicle didn't have a speed sensor (flying magnet). It can be done, and can be done cheap.

Pulling MIL codes on a dodge? I assume you have the red brick MT2500? NOT NEEDED. Almost all obd1 vehicles have a method of retrieving codes without any scan tools. Fords using test light and STI pin, GM jump ALDL connector A-B pin, and dodge....turn the key on/off 3 times within 10 seconds. All produce a flashing morse code type display of the MIL light. Count the flashes, write them down, compare to the list. Dodges use a 2 digit code. 3 codes are of no concern for 4x4s. #12 (batt disconnected in last 50 cycles) #37 (lockup solenoid circuit failure- 4x4 didnt have lockup converters ;)) #55 (end of test)

MegaSquirt and reliability? It seems to have been proven as a very robust pcm, and cheap. Must more durable than that junk 88-89 SMEC pcm dodge used. Which is actually 2 separate circuit boards (power board for outputs, logic board for inputs) and using a spider web of internal jumper wires to connect the 2. If any of those wires break or otherwise become damaged, the pcm is junk. In a worst case scenario with the MS, you can always carry a spare since they are cheap. It can already be loaded with what ever program you so choose. Whether it is fully refined or merely a crude limp home tune. Furthermore, the board itself can be repaired instead of replaced, and every single part is available individually and widely available through local electronic outlets. Sure you can buy a replacement stock pcm from autozone....it might be back ordered for a week and most definitely any custome tune you had before is for ever gone.

Mopar clueless? Nah, it's just an engine....with very little different from most any other efi engine as far as the basics go. Uses the same 5v reference, same analog signals (MAP, ECT, TBTS, TPS, O2), same waveforms for most of it, same pulsed ground commands, low impedence (2ohm) injectors, coil testing is the same principle, the 1 single difference is the 8v square wave hall effect distributor sensor. Nothing major there.

No power, quiet exhaust, only cat Perhaps you simply have a plugged and failing cat? Its 20 years old, anything is possible. Simple backpressure test could tell you. Or cutting it off. Or possibly even some WOT testing with the o2 sensor unscrewed. (they run in open loop at WOT anyways) and the open hole may relieve some pressure, freeing up a little power, indicating a potential clogged cat.

Doing a compression test WITH THE ENGINE RUNNING can immediately indicate a worn cam lobe. Yes I understand most people do a static cranking compression test....no one said you have to do it this way, you still get numbers, they are just different, and must be interpreted differently.

Simple vacuum gauge will also tell you a lot.
http://www.secondchancegarage.com/public/vacuum1.swf

Big cams on mopar efi? Well they won't help a truck with acceleration problems, but it can be done. The secret is to use a wide LSA. Most reputable cam companies such as comp cams will provide a custom ground wider LSA variant for very little extra. 114* might be a good place to look. This will provide a smooth idle which will provide a smoother MAP sensor waveform as viewed on a scope. Less rapid fluctuations=happier pcm.
 
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