7427 MPFI tuning

[EagleMark]

I'm sure 93V8S10 will find this and inform us on what we are missing...

[JeepsAndGuns]

I called Mr injector that has a add on here and asked if he could do the testing. He said he couldnt, and didnt know of anyone who could. He suggested I might find the offsets for a injector thats of the same design and as close to the same flow rate as mine. These, from what I find online, flow 238 cc/min @ 3bar, witch is something like 22.66 lbs/hr @ 43.5 psi. These are bosch EV6 injectors with the 4 hole spray pattern.

I called that place I posted the link to. Sounds like they can do it, but he wanted me to email him my specifics so he can send me a "quote". I have a bad feeling it might be expensive, if he has to send me a quote.

[dave w]

I am wondering if maybe modifying the factory setting by +/- 3% ~ 7%. If for example the table I posted, was multiplied by 1.03 (to increase 3%) or multiplied by .93 (to decrease 7%) it might be close enough to work? In my thinking, the injector is an inductor, so without going into electronics detail, I'm thinking the inductance is not going to vary that much between injectors. The injectors are designed around a nominal 14 volts. Not to confuse anyone, but 4 injectors are in parallel so figuring the inductance of the 4 injectors in parallel circuit would be a good idea. I'm thinking the impedance of one TBI injector is very close to the impedance of 4 port fuel injectors in parallel.

I really don't know, in a data log, if the changes in a voltage offset helps or not?

dave w

[93V8S10]

I'm sure 93V8S10 will find this and inform us on what we are missing...

You guys aren't missing anything, well except for a good offset table for JeepAndGuns.
Injector testing is expensive!
Maybe try this place, they have lots of good info, and are the same place as Yaw Power mentioned in the old FSC thread:
http://www.injectordynamics.com/GMDATA.html

[dave w]

Injector testing is expensive! http://www.injectordynamics.com/GMDATA.html

The injectors at Injector Dynamics are expensive! If they come with the correct offset table, BARGAIN!

dave w

[JeepsAndGuns]

You guys aren't missing anything, well except for a good offset table for JeepAndGuns.
Injector testing is expensive!
Maybe try this place, they have lots of good info, and are the same place as Yaw Power mentioned in the old FSC thread:
http://www.injectordynamics.com/GMDATA.html

Whew, thats a little over my head, but if I'm reading it right, it kinda sounds like the offsets could be calculated if you know the injectors static flow rate. So going by the numbers posted above, these, at 45 psi, should be flowing 23.04 lbs/hr. But it would take someone WAY smater than me to calculate the numbers. But would having the vac refrenced FPR effect the offsets?
All the ones I measured were ( + or - .1) 12.5 ohms, if that helps anyone. I forgot what the proper way to calculate ohms were.

Dave W, do you know how many ohms those injectors are? And is that screen shot you posted using them in batch fire mode with $0E? And lastly, when I set my bin up, I entered in my injector flow into the MPFI box, but didnt enter anything into the CPI box, should I have?

[Nasty-Z]

If it runs good I'd like to see it.

It runs real good , but......

Guess i'll have to wait till I get a chance to read it again , had all of that saved when I was still using Tunercats but that was about 3 laptops ago . Can't find a darned thing now . Only .bin I have is the one Ken listed on the HP tuners site in the netres mod thread , IIRC we used a derivitive of that original when we did mine experimenting with the PFI firing setup and the Edelbrock injection.

Anyways , back on topic , sorry to the OP , thought I had it saved......

TOM

[dave w]

Dave W, do you know how many ohms those injectors are? And is that screen shot you posted using them in batch fire mode with $0E? And lastly, when I set my bin up, I entered in my injector flow into the MPFI box, but didnt enter anything into the CPI box, should I have?

The injectors measured about 15.3 ohms. The values I posted are from an Edelbrock chip I read that was supplied with the 3502 MPFI conversion kit ( http://www.off-roadweb.com/tech/0310...tem/index.html ) which is now discontinued. The chip was $OD. It's my understanding the 3502 chip I read was from a modified PCM with the sense resistor mods. It's my understanding the information I posted is not the same information that would have been programmed by Edelbrock. It's my understanding that the truck using this information on the 3502 kit runs "Damn Nice" after I corrected the VE tables!


I use an online conversion website http://www.convert-me.com/en/convert/flow_rate_mass to convert flows.

dave w

[93V8S10]

And lastly, when I set my bin up, I entered in my injector flow into the MPFI box, but didnt enter anything into the CPI box, should I have?

Just use the one you need, they all access the same address, just the math is different.

[JeepsAndGuns]

Just use the one you need, they all access the same address, just the math is different.

Not sure I follow. Are you saying the ecm reads the flow rates of all of them? I assume when in tbi mode, it only reads the tbi values. But the flag to to go mpfi says CPI/MPFI. So how does the ecm know if you are using cpi or mpi?

Dave w, I had a brain fart, I ment to ask if you know the flow rate of those injectors, not the ohms...lol
I may try the offsets in that table you posted just to see if it makes any diffrence.


The email I sent to that one place bounced back saying its a invalid email address. I double checked what I wrote down and it was correct, and I read it back to the guy after I wrote it down. So IDK. Guess I will have to call him back.

[JeepsAndGuns]

Been doing a little looking around the net and have thought of something.
Now I am not 100% dead set on running these injectors. One of the biggest reasons I chose to run them was because I already had them, and they seemed to be enough to run the my engine. But it appears the battery offset is gonna be hard to get.
So I have thought about swapping to some injectors that the values could be found for. I want to stay with the EV6 design (4 hole spray pattern) and would kinda like to stay with the EV1 (jetronic) connectors like my current one are, that way I dont have to change my harness again.
Well some digging through injector options for the jeep stroker, the LS1 injectors came up. Specificly the 0280155752. They are identical to the 703's I am running now, except they flow 255 cc/min @ 3 bar (24.28 lbs/hr @ 43.5psi) Witch is only like 1 lb/hr more than my current injectors are, at the 45 psi I am currently running them at. So if I was to get a set of these I could lower my pressure back to 43.5 psi, and I am thinking, since these came from a fuel injected engine, that lots of people tune, the stock injector offsets could probably be found without much trouble. Mabey from someone with a stock tune for one? I do not know what year range or car the above mentioned injectors came in, but it appears there is also the 0280155931 witch flows just a weenie bit more, 258 cc/min @ 3bar (24.57 lbs/hr @ 43.5) Same as above, I do not know what year range or cars these were in. It looks like I could find a set online for not too much.

I'm thinking the little extra flow probably wont hurt anything, as the old 454 90lb injectors in my old tbi were too big, but I was able to tune them fine. And also, since these could be used in a jeep stroker, I could use them when I build my stroker, as by then, I hope to be running a tuneable gm ecm, and would probably need these values for it too.

Google has only turned up people looking for offsets when swapping bigger injectors in their LS1's so you chevy guys, could anyone find the values for the stock LS1 injectors?
Dave w, I think you fool around with those dont ya?

[one92rs]

http://www.thirdgen.org/techboard/tp...w-ratings.html

hope this helps some.

[93V8S10]

Not sure I follow. Are you saying the ecm reads the flow rates of all of them? I assume when in tbi mode, it only reads the tbi values. But the flag to to go mpfi says CPI/MPFI. So how does the ecm know if you are using cpi or mpi

I was only referring to the injector flow rate in the bin. The xdf is set-up with six versions of the "Injector Flow Rate". These are all the same address in the bin. The only thing different is the math in the xdf.

[34blazer]

the injectors you are using look like they are 28.5#ers, LS6. EV1/6 refers to the connector type, not the design of the flow pattern. dont LS6's have higher fuel pressure? this chart i have doesnt show the rating.

http://users.erols.com/srweiss/tableifc.htm

for bosch design III injectors its a good idea to zero out the low PW offset table, then find the offset v batt voltage.

see post #17

http://www.thirdgen.org/techboard/di...gn-iii-pw.html


HTH

[dave w]

Google has only turned up people looking for offsets when swapping bigger injectors in their LS1's so you chevy guys, could anyone find the values for the stock LS1 injectors?
Dave w, I think you fool around with those dont ya?

Check out the EFI Live Screen Shot. 2001 5.3 liter

EFI Live can be downloaded free: http://www.efilive.com/index.php?opt...=48&Itemid=124

The free version does not allow changes to be saved, but looking at injector voltage offsets would be free!!!

The ".tun" files can be found here: http://www.tunefiledepot.com/index.p...Type=P&Stock=Y

dave w