42lb injectors running bad

[minytrker]

What is the trick to running them? I have put two sets in two differnt cars and re-scaled them with no luck. The cars will both run and a/f will be right but both cars drink gas and the exhaust stinks really bad. On both cars the plugs ended up getting fouled out over time. Im guessing I have to mess with the pulse with (B4003).

[Bruce Melton]

I have been fooling with them all summer (SVO42 lime greens). They are probaly too big, mine run @64% max but min pulse width does not seem to be the issue. If you log their pulse width it probably is not close to minimum.
They are very fussy as to having good 02 sensors and tune spot on with respect to fuel trims.
In the end mine are fine with MAF back in. Could not keep them happy in SD as they would load up the plugs as you describe.

At idle mine run ~2.2 ms 2%DS @1000 rpm.

[Alvin]

What brand?

You shouldn't have any issues with them just being big. I've had 60's in stock cars awaiting turbo kits or superchargers.. etc.

[eboggs_jkvl]

What is the trick to running them? I have put two sets in two differnt cars and re-scaled them with no luck. The cars will both run and a/f will be right but both cars drink gas and the exhaust stinks really bad. On both cars the plugs ended up getting fouled out over time. Im guessing I have to mess with the pulse with (B4003).


Not to ask the obvious but what did you use in the rescale table?

Elmer

[minytrker]

This is what I had on SVO 42's.
48.487790
48.797814
49.107838
49.417862
49.665882
49.975906
50.285930
50.595954
50.843974
51.153998
51.464022
51.712042
52.022066
52.270085
52.580109
52.828129
53.138153

[TAQuickness]

That seems a tad low for SVO's.

What fuel pump, and what's the rail pressure?

I run the racetronix pump + hot wire and log and average of 63psi at the rail.

[eboggs_jkvl]

This is what I had on SVO 42's.
48.487790
48.797814
49.107838
49.417862
49.665882
49.975906
50.285930
50.595954
50.843974
51.153998
51.464022
51.712042
52.022066
52.270085
52.580109
52.828129
53.138153


Numbers look ok if the fuel rail pressure is 58.


Elmer

[Doc]

That seems a tad low for SVO's.

What fuel pump, and what's the rail pressure?

I run the racetronix pump + hot wire and log and average of 63psi at the rail.

Interesting, I have the same racetronix kit and I see 64 @ idle and~60 @ WOT. When consulting the manufacture's ratings and filling in the table on the spreadsheet are we not supposed to put in the Static or "WOT" value at the fuel pressure we actually have on our car?

Seeing how most manufactures published injector ratings are @ 3 bar or 43.5 PSI you have to convert to the actual value you see on the rail. To determine this use this formula.

New flow rate = old flow rate x sq root of new PSI divided by the old PSI

Thus, injectors rated at 36 @ 43.5 PSI going into a vehicle that has 58PSI
would be 58 divided by 43.5 = 1.3333
The sq rt of that = 1.1547
Thus, 36 x 1.1547 = 41.57#/hr

This seems to work for me, would love to hear from others...

[TAQuickness]

I used the RHS spread sheet and used the average (63 psi) as my rail pressure. Granted, this average was derived from idle and normal driving (no WOT) as this is where I spend most of my time driving.

Average WOT (WOT only) comes in at 53 psi.

Are you logging your fuel pressure or monitoring a gauge?

[Doc]

Only a mechanical gage on the dyno so far. I want to get a monitored setup going.

[Tordne]

Has anyone determined the actual minimum pulse width that and SVO 42 can get down to?

[eboggs_jkvl]

I know if you go below 1, the darn thing causes a miss. I think I've posted this on here about the SVOs. I chased a miss for months and finally replaced the SVOs and cleared the problem. I ended up with Lucas 42s and the miss went away.

Elmer

[Tordne]

Mine seem to not flow below around 1.7-1.8ms as reported by the GM.IBPW1 PID.

[eboggs_jkvl]

http://www.efiforum.iqd.co.nz/showpost.php?p=31877&postcount=41

[minytrker]

I also tried another brand of 42s with the same problems.

[Alvin]

I would suggest building a histogram in the format of the injector pluse width vs. battery voltage and your IFR tables. THen look for running trends.

Another table of interest is small pluse adder.

[Tordne]

LMAO.. Been there done that.

The scenario I find is that at light (< 3%) or no throttle they run pig rich - we're talking AFR's in the 12's. on moderate throttle to WOT they are perfect. The scaling is spot on in my case as the VE table has basically changed less than 2% with is pretty good given the 60% increase in injector flow.

Is this what you’re seeing as well Lorenz?

[Alvin]

Did you try the small pulse width adjust?

They are really not to bad.. What IFR are you using? I put these in my GF's car that came out of my blown LT1... There is nothing wrong with them.

Heres one I came up with for green top SVO's

LABELS Injector Flow Rate (Grams/Second)
Manifold Vacuum kPa {link: GM.MANVAC} Value
0 5.671875
5 5.718750
10 5.742188
15 5.773438
20 5.828125
25 5.843750
30 5.875000
35 5.914063
40 5.945313
45 5.984375
50 6.015625
55 6.039063
60 6.085938
65 6.117188
70 6.148438
75 6.179688
80 6.210938

[minytrker]

LMAO.. Been there done that.

The scenario I find is that at light (< 3%) or no throttle they run pig rich - we're talking AFR's in the 12's. on moderate throttle to WOT they are perfect. The scaling is spot on in my case as the VE table has basically changed less than 2% with is pretty good given the 60% increase in injector flow.

Is this what you’re seeing as well Lorenz?

Pretty much the same thing. I can even get the a/f at 14.7 at idle but the car still stinks like gas and fouls out plugs. Im messing with all heads and cam cars if that matters. Im sure big cams have something to do with it but still. I went from the svo 42's to fast 36lbs and its much better. The car made the exact same hp on the dyno with both injectors. My fuel milage also went up about 5mpg going to the 36's. I still have to get the 42s to work right since they are in several customers cars.

[TAQuickness]

Only a mechanical gage on the dyno so far. I want to get a monitored setup going.

Let me know what you see when you are logging FP vs mechanical gauge.

Myni - what's your rail pressure?

I'd have to agree with Tordne that the 42's are a bit hard to control on the lower pulse widths. Mine "appear" to shut off at ~1.79x ms. I was able to tune around it, but am still looking for a better solution (me thinks dropping the fuel pressure a bit would help alot).

[minytrker]

I think the rail pressure is 58 on camaro's and vetts. I have them in both.

[TAQuickness]

should be 58, but what is it?;)

[Doc]

Ok, FYI I am running Accel Yellow "32"s which at my FP work out to 37. Unfortuneatly, I am not in a position to be hands on right now- I had my first hernia operation yesterday. Feels like my car kicked me in the balls!

[TAQuickness]

Good luck with your recovery. one of these days I might pony up for a gauge, but V2 has me spoiled.

[eboggs_jkvl]

Ok, FYI I am running Accel Yellow "32"s which at my FP work out to 37. Unfortuneatly, I am not in a position to be hands on right now- I had my first hernia operation yesterday. Feels like my car kicked me in the balls!


Shoot.... I'm gettin good at the "operation" crap. 4-6 weeks and you won't remember how bad it was! :D:D

[minytrker]

should be 58, but what is it?;)


Ok, ok I will get out the gauge and find out. My guess is 58 still. :D

[TAQuickness]

It's probably real close to 58, but, you'd be surprized how much a psi or two will skew the tune.

I used 58 as my rail pressure when I had my Racetronix 32's (pre-ability to log fuel pressure). Once I dialed in my tune to 1.00 BEN, if I changed commanded AFR, BEN's would be off anywhere from 1.02 - 1.10.

After installing the SVO42's and using my actual rail pressure, changing commanded does not skew my BEN's.

This (http://www.forum.efilive.com/showthread.php?t=3661)should get you going logging fuel pressure, and when you get a V2 unit, I don't think it would be too hard to adapt this to a portable set up.

[minytrker]

Thanks for the info. I guess I will be installing a fuel pressure sending unit. My V2 should be here next Im hoping. The camaro's I am messing with are all using after market fuel pumps due to the large amounts of nitrous they are using. So there fuel pressure may be off. My vette still has the stock pump in it atleast for a little while longer.

[Bruce Melton]

I just ordered SV0 36s which should be harder working.

[joecar]

Ok, FYI I am running Accel Yellow "32"s which at my FP work out to 37. Unfortuneatly, I am not in a position to be hands on right now- I had my first hernia operation yesterday. Feels like my car kicked me in the balls!Doc,

Ouch... Get well soon.

Joe
:cheers:

[eboggs_jkvl]

Oh Doc, a little iddy biddy action like that and you're the walking wounded! :D:D:D


Hang in there. Some of those "doctor" things have been known to cause discomfort on a rather large scale.

Elmer

[minytrker]

Any ideas on getting these injectors working (SVO 42). Three sets of plugs later Im about to just put in a set of 36's that I know will work. The car is just using to much fuel at idle even with a a/f of 14.7 at idle.

[Bruce Melton]

I just find after using SVO42s that if they are loafing in terms duty cycle and they are inconsistent. I was only 65% max and close to min on idle and the idle was unpredictable. Dropped back to 36s (again) and everything is just more precise. Idle is fine. Seems to me you are better off to use full range of any injector.

[minytrker]

Yeah I had the same results on my Z06. This is a customers car, though. Its a h/c car with a lot of nitrous so it may need bigger than the 36's.

[Tordne]

I have been playing with these SVO42 injectors A LOT lately. I bet you can get the idle down to 17:1 if you wanted using the offset table etc.

I just have not managed to find the sweet spot for all the tables. My car is stock so these are really too big (they were for my canceled 408 project) but they are much more accurate at higher loads!!

I'll have a bit more of a play soon and see if I can get them any better. And if so will let you know.

[pkincy]

I suspect one of the problems is that most folks think the SVOs are rated at 3 bar=43.5 psi.

I don't believe that is true. It was pretty standard operating procedure in the 90s to assume that the SVOs were rated at 39 psi.

That is the way I have my 2 sets in my LT1 383s set and they work well. Therefore I have set my 30# SVOs at 32 lb/hr at 43.5 psi in the LT1 pcm.

There is a very comprehensive table of injector information floating around and there are few Ford injectors that are rated at 43.5 psi. Most are rated at something in the 30 psi-39 psi range, but that data source does not list the SVO injectors. GM is one of the few companies that rates most everything at 3 bar.

Perry

[redhardsupra]

Perry, there's been a LONG discussion on tech about this. i found 3 different documents, that looked quite authoritative, and they gave different rated pressures: 39.15, 40, 43.5psi.
i use 43.5 cause i've done it on multiple cars that were tuned before, and with only IFR change, they'd still scan very very close to what they were like before the injectors swap/IFR change.

how about someone just spends 10bux and send one in for cleaning/flowing, and all this mystery would just go away?

[pkincy]

Excellent point. I have a set sitting around somewhere. I may send one in (30# SVO) and have it flow rated at 39 psi as well as 43.5 psi.

However I built my own flow bench and I gotta say that I am not certain that it is accurate within 10%. Precise and repeatable, but not real accurate unless you put a very large number of pulses through it.

Like you are comfortable at using 3 bar, I am comfortable at calling the 30 # SVOs; 32 #/hr flow rate in an LTx motor at 3 bar. Works pretty well on both my SD 383s, so I have let it alone all these years as I see posts referencing 43.5 test pressures. Remember it is only 10% difference and if we get the IFR within 10% we are good to go with the pcm making up the difference. Than we simply adjust PE to give us what the wide band wants at wot.

Perry

[redhardsupra]

ehh..10% off on fuel size is HUGE. let's say you're commanding 13.0 AFR and instead you get 14.3AFR 'close enough' is good for horseshoes and handgranades, not EFI fueling... ;)

[dfe1]

how about someone just spends 10bux and send one in for cleaning/flowing, and all this mystery would just go away? How about this-- PM me if you have an injector you'd like flow checked. I can get it done at no charge--providing the injectors are new or in excellent condition. (Dirty, trashed injectors have to be cleaned first or they contaminate the flow-check fluid.) I'd like to get one each of common sizes so we can build a solid data base.

[pkincy]

ehh..10% off on fuel size is HUGE. let's say you're commanding 13.0 AFR and instead you get 14.3AFR 'close enough' is good for horseshoes and handgranades, not EFI fueling... ;)

That, of course is the beauty of the pcm. It will adjust fueling 15% to either side of correct.

If you can start within 10% you are well within the capability of the pcm to correct for fuel. Then you can adjust to your desired level of accuracy.

If you rebuild a motor and you are off by over 15% you risk the motor being too rich or too lean to be within the computers ability to correct.

Perry

[Chuck L.]

How about this-- PM me if you have an injector you'd like flow checked. I can get it done at no charge--providing the injectors are new or in excellent condition. (Dirty, trashed injectors have to be cleaned first or they contaminate the flow-check fluid.) I'd like to get one each of common sizes so we can build a solid data base.


willing to send them to DFE???
Part numbers on the injs in question are???
Bump for you, DFE.:cheers:

[redhardsupra]

That, of course is the beauty of the pcm. It will adjust fueling 15% to either side of correct.

If you can start within 10% you are well within the capability of the pcm to correct for fuel. Then you can adjust to your desired level of accuracy.

If you rebuild a motor and you are off by over 15% you risk the motor being too rich or too lean to be within the computers ability to correct.

Perry

well, i guess that's just a difference in expectations. if all you want to be is within 15% why are you tuning at all? the computer can do it by itself right?

see, to me 15% off means that the car is going to run dangerously lean or inefficently rich, be knock prone or hesitate. that's just the whole reason to tune this thing, to get in more like within 2% so it knows exactly what it flows, what it wants, and command proper paramters all the time, not 85% of the time.

[MSURacing]

I bet you can start taking fuel out at idle and your A/F ratio is going to go down!!! We all need to remember that when raw fuel gets poored out the exhaust due to increased overlap that it WILL NOT get read by the 02 sensor. I bet you can take alot of fuel out at idle before seeing the right A/F ratio. I would just start taking out fuel and see what happens. Maybe even take it out of closed loop at idle and run it at 17:1 and see what happens. Big cammed engines like to idle lean with a lot of timing.