MicroSquirt.com read only forum (Jan.15,2018)

I have the GM TBI700 lo-z injector in my car, i know this one is also mounted on som smaller pontiac/chevy engines (typically 4cyl 2-2.5liter engines) and so.

Is there anyone running megasquirt on one of these here ?

Just want to have some feedback on PWM values for the injector current limiting. I´m running with series resistor on it know but i´m not pleased with that function.....

Noone ?, they should be mounted on :
¨
1987-92 Buick. Century, Skykawk, Skylark, Somerset.
1987-92 Chevy. Beretta, Cavalier, Corsica, Celebrity.
1987-93 Chevy tr. Astro, Blazer, S-10.
1987-93 G.M.C. tr. Jimmy, Saffari, S-15.
1987-92 Oldsmobile. Calais, Cutlass Ciera, Firenza.
1988-93 Pontiac. Fiero, Grand Am, LeMans, Sunbird, 6000.
ENGINE DIS: 2.0 ltr, 2.2 ltr, 2.5 ltr.

And also in the Magneti Marelli TBI injection systems from the same period. (fitted to some european cars, like mine).

They look like this:



Please, anyone who has a setup with this TBI injector, i badly need feedback on how it works with different PWM current limiting settings.

It looks identical to the injectors in my Holley 4bbl TBI. Holley regularly uses GM parts so it wouldn't surprise me. The only difference is the color which is changed to denote flow rate.



if it's the same injector, then I use an injector open time of 0.8ms with a PWM of 30%. Seems to work good.

BottleFed70 wrote:It looks identical to the injectors in my Holley 4bbl TBI. Holley regularly uses GM parts so it wouldn't surprise me. The only difference is the color which is changed to denote flow rate.



if it's the same injector, then I use an injector open time of 0.8ms with a PWM of 30%. Seems to work good.

Aha, there´s a flow rate coding by the color ?
Is there somwhere i can find out the flow rate on mine by that maybe ?

It looks like this:

That seem to work nicely

Thanx

And now.... my hunch was right, when i skipped the resistor and went for PWM current limiting on this "peak´nhold" injector my VE table was off.....

Think that was a good sign that a series resistor on this injector is not a very good solution. Idle was more stable also. Will turn out tomorrow when driving to work if it works as supposed then to.

One thing i worry about, says in the megasquirt pages that the V2.2 board flyback circuit does not handle lower values the approx 55% pwm current limiting very well ?

Or does this only apply when using several lo-z injectors connected in paralell ?

Since it´s a TBI it´s only one... and the RESISTANCE through the coil is 2.1ohm.

Ok, that didn´t work out, fried the injector badly . Don´t know why though. Perhaps it would have worked better if i had the proper flyback solution, namely the flyback board.

Had a Spare injector so i just wired up the resistor again and off i went.

I would also like to know the flow rating for these injectors. I just stuck in a guess early on, and I never have found a real number. Maybe I should rig up a flow bench.

I picked the TBI700s because the junkyard was full of them and I could modify them to fit a triumph TR6 manifold. Maybe a good place to start for anything using a stromberg CD175 carb. They do flow a bit more, though...

MS2/V3. I'm using a 1ms open time and 25% PWM. I don't think I have changed that for 150 miles or so.

I did have one event early on that took out an injector and a driver. I'm really not sure which one killed the other... Car didn't run very well on just 3 cylinders.

I have searched the net now until my EYES ARE WATERING without finding any substantial information about how to read out the flow rating on these injectors.

Some say that it´s the color on the body/filters that tells you what that. But if you look CLOSELY on the top of the injector (where the electrical connetor is) you can see veeeery veeeery thin, almost unreadable numbers, on my one row is (if you point the connector towards you) going from the top down reading "0069", and one row is going from left to right on the connector saying "52.77".

I bet you CAN read out the flowrate on those numbers if you have the right LIST of them .

As mentioned above... Holley uses them to but they have their own part numbers for them that starts with 522-XX.

Strange that it should be so hard to find a flowrate chart for ..really... such a commong injector type

I've been searching for TBI700 Injector details for many hours as well. I eventually discovered the following, so I decided I woudl join the site and post this for all:

The TBI I'm using came from a 1989 Pontiac Grand-AM 2.5L 4-cyl

The GM part # for the injector is: 17112123.
The Delphi part # is: FJ10043.

Check out http://go.delphi.com to get the following details:

Product Number FJ10043
Description Fuel Injector
Type Multec BF TBI
Operating Pressure kPa 70
Static Flow Rate gs 7.460
Static Flow Rate Lbs/Hour 59
Static Tolerance 2.5%
Static Flow at 300 kPa 15.444
Dynamic Flow Rate gs 0.559
Dynamic Tolerance 2.0%
Max Operating Pressure 700
Driver 4/1 P&H
Alcohol Resistance E0
ProductBrand Delphi
ProductApplication Car/LtTrk

A similar injector is GM#17111986 Delphi # FJ10041:

Product Number FJ10041
Description Fuel Injector
Type Multec BF TBI
Operating Pressure kPa 70
Static Flow Rate gs 7.030
Static Flow Rate Lbs/Hour 56
Static Tolerance 2.5%
Static Flow at 300 kPa 14.553
Dynamic Flow Rate gs 0.491
Dynamic Tolerance 2.0%
Max Operating Pressure 700
Driver 4/1 P&H
Alcohol Resistance E0
ProductBrand Delphi
ProductApplication Car/LtTrk

The site can be searched by part number and application quite extensively. You can even see which vehicles used a particular part, which can be very useful if you are searching at the auto-wreckers.

The site seems a bit strange in that sometimes it give more data for the part number than other times. There is also information on various engine sensors than may be very useful.

I'm still planning my MS2 setup, but it will be a TBI700 on a 1.9 litre Opel GT that has been converted to a 2.4 litre. I will be very interested in MS setups for a 4-cyl using a single TBI700.

ftl wrote:I will be very interested in MS setups for a 4-cyl using a single TBI700.

Mine is like that.... single TBI700 injector.

One thing i´ve noticed is that they´re REALLY low impedance, approx 1.6 to 2.1 ohms on different types.

And they need very little current to work.

I have a 6.8ohm series resistor on mine now and it works great. Had a 4 ohms resistor earlier but i fried 2 injectors so i went larger , also tried the PWM settings in MS but i think i need a GOOD flyback to make that work since...i fried one injector there to *BIG LAUGH*, good thing they´re not uncommon