Help with AFR and INJ pulsewidth problem

[Mstansbury0704]

Hello, have a 2000 procharged ls1. deka 60s, dead headed 340 with 8an/6an return. BR regulator. Just a week or so ago it was probably 40-50 degrees out. Made a trip to the store etc. Car ran well. Have logs. Today it was 60 degrees out. Was driving for a while. made some hits, it ran out of fuel. dead lean. Oddly enough I Cleaned my meth nozzle just earlier that day and discovered the filter assy had backed out and the hypersonic thing inside was just floating around. I would assume it could be the cause, however on my 10GPH nozzle the orifice is smaller and the same on my 6gph. Appears they change flow just with the size of the hole. Before I blindly made changes I noticed my inj duty wasnt the same. My inj pulsewidth prior was high 17s to 18 on the good log, my log that was lean they were high 16s to low 17 around the same rpm..I.E at 6,000 rpm and kpa within 5 my injector duty went from 92% down to like 87 or 88% or around 5% less...What gives? Could my meth nozzle being borked really skew it that far? Also, why would that change anything about my pulsewidths etc?

[edcmat-l1]

How is anyone supposed to be able to answer any questions WITH NO TUNE FILE OR DATA LOG???

[Mstansbury0704]

leaN.hpl
rippp.hpl
March 1st half degree spark.hpt

Sorry, meant to post this but boss had dinner ready. Nothing has changed tune wise between the two.

[edcmat-l1]

Pretty easy explanation. Load vs. no load.

[Mstansbury0704]

Pretty easy explanation. Load vs. no load.

Load vs no load?

[edcmat-l1]

You're asking about differences in injector on time and AFR from 2 data logs that have completely different load situations. You're in different gears in each log. The load on the engine is different. It is substantially less in one log than the other. You can't really compare them. Both the IFR and the AFR will be different because the load on the engine is different.

[Mstansbury0704]

They are both logs containing WOT 3-4 gear pulls on a 6 speed car. One AFR is low to mod 11s and the other is cutting out lean. Only change was I fixed my meth nozzle. I also noticed my pulsewidths are a lot different. I know they won?t be identical but 1-2MS on injectors that are 72ish lbs/hr is likely a lot of fuel right? Do you think this is tune related or possible maybe the fuel pump going out? It?s been pretty much winterized until recently it?s been nice a few days.

[edcmat-l1]

OK, first, disregard my previous posts. I had each data log open in 2 different scanner windows and the time base was off so the line graphs looked very different at a quick glance.

Now that I got them both setup the same, there's a few things here.

First, you have to remember that a data log is a series of snapshots or samples. Depending on sample rate and when exactly the picture is snapped, the same RPM/MAP/IPW may be slightly different in 2 different logs at the same point. They're not going to be dead nuts to the tenth time after time.

I've attached 4 screen shots. I tried to get the cursor as close to exact RPM as possible all logs, for the sake of comparison. First set, at 6000 RPM the MAP varies slightly, one bank varies slightly in IPW and the other bank varies considerably more at about 1 ms. Even at 1 ms difference at that MAP it isn't going to make a full point of difference in your AFR. It will account for some of it but not all of it.

If you look at the 5th line graph down there's AFR in white. What's more telling in the entire log isn't the difference in IPW at any given point, but the AFR trend. Compared to the other log it looks dead nuts like a pressure problem or some other fuel supply (meth inj?) problem. The IPW trends just slightly leaner if you look at it point for point. Some places it damn near dead nuts others it varies slightly.

run1.jpgrun2.jpg

Here it is at 5500ish.

5500ish 1.jpg5500ish 2.jpg

At 5499 MAP is 158, B1 IPW is 15.4 and B2 is 15.1.

Second log, at 5504 MAP is 154, B1 is 14.7 and B2 is 14.8.

Both of those seem to correspond yet the AFR difference is over a full point and trending upward.

[SiriusC1024]

Very good explanation, edcmat

Load vs no load?

OP, log dynamic airflow if you still don't understand. You'll see.

The VE table validates the diagnosis of fuel pressure problems.

[abc]

The water/meth could change the AFR by a full point or more depending on how much your engine was ingesting when tuned with it functioning properly. Is it functioning properly now? Do you remember how much fuel you had to pull out when tuning the water/meth?
Looks like you have two things to check, fuel psi at WOT full load and water/meth injection at full load.

[Mstansbury0704]

Yes EDC! You had me lost on what you were talking about for a moment lol, I?m at work however I will take a further view of those photos when I get home tonight. And I was leaning on something with fuel as I was prior stuck in traffic and potentially had too much heat in the fuel. I thought I had solved that issue as I replumbed stuff last year and put my 340 back in after my 525 had the lean issues in hot weather, but it was even showing on STFTs and all. Never had another issue until yesterday. Just with my meth nozzle being essentially gutted I wasn?t sure exactly how much meth I was dumping prior to putting my nozzle back together so I was questioning myself. I?m hoping motor isn?t hurt as it actually started to cut out from being so lean, I thought I hit my spark cut..motor sounds fine and heads are on with ARP studs. Still it?s an 11:1 comp setup.

So my fuel setup is a single 340, 8AN feed and 6an return. Dead headed setup into stock rails. Meth nozzle is 12GPH progressive, max injection around 5 or 6 PSI. I?ve ordered some Racetronix rails and going to decide how to run the rails? series or parallel? I?m a bit afraid that it will exacerbate my overheating fuel issues, what do you think? Could my pump just be overheating? It?s ran with the Hotwire kit however I ran the wire along the factory fuel line in the tunnel, maybe it?s getting too hot from exhaust and getting resistance? It?s not an alternator amp problem as I have a power master alt.

[edcmat-l1]

I would put the reg after the fuel rails and run the return back. Get rid of the dead head. That should help with any vapor lock as it should push through. I've never had vapor lock issues with return systems setup with the reg after the rails.

You should have a FP sensor and gauge in it at all times. All the FI builds I do get both a WB and FP gauge. You can also log it in HPT.

If it's a forged piston engine you should be fine as long as the top ring gap is right. If it's a stock bottom end, need to be careful with it.

[Mstansbury0704]

I think my fuel issues are actually on the pump side with cavitation?hopefully having a flow through will not create more heat in the tank. If not I?ll be having to pull the pump and evaluate some other things. Perhaps return line need to be higher instead of dumping right back into the pump. And as far as I know it?s SBE however it was fully rebuilt by PO and it has lived a lot longer than I thought it would through a lot of abuse.

[Mstansbury0704]

Also, would you Y the feed or run them in series with a crossover?

[edcmat-l1]

Y to the back of the rails. Front of the rails to the reg. Reg to the tank.

[Mstansbury0704]

Ah. I was thinking like a Y at the front and then the rears as returns. Only problem is I?ll need to make a union with fittings since my feed line will be probably be a few feet short. Both my return and my feed break into the engine bay near the brake booster. I ran them inside my front quarter panel where the fake vents are in front of the doors on the WS6 cars. I have my FPR mounted in front of the shock tower near the fuse boxes.. Something I?ve seen a few times, is there any reason people tend to Y their 8AN line into two 6ANs? I plan on just a straight 8AN Y because my rails I ordered are 3/4 with 8ORB. From the Y, do the lines have to be of equal length or does that not matter?

Due to the price of the fragola fittings I?m going to tear the car apart and just get the new rails mounted up and then decide on how I want to do it. Imagine nearly $40 for a damn glorified compression fitting Also , do you have any thoughts on maybe my power wire to my pump is getting too hot being ran in the tunnel with my brake lines? Possibly making voltage drop at the pump? Especially during slow traffic etc on a lowered car..

Also, I have an AEM wideband and was checking out their fuel gauge. The photo didn?t appear to have breakouts for my prolink to log it, do you have any experiences with them?

[gtstorey]

No way brake lines are going to be hot enough to cause voltage issues.

[Mstansbury0704]

My I pipe runs in there as well. And I have it hooked to alt stud with heat shielding on it near where it?s in the transmission area. But it still is close to the primaries in some spots. I would tie to direct to battery, however my alt is tied direct to battery with 0 gauge from the same stud so it is kind of a moot point IMO.

[SiriusC1024]

It's not going to all of a sudden vapor lock at high rpm/load. This happens when the engine has sat and fuel rails heat soak. Vapor lock occurring as fuel flow increases makes no sense.

The 12 gauge power wire itself increasing resistance with heat isn't a factor.

I thought I had solved that issue as I replumbed stuff last year and put my 340 back in after my 525 had the lean issues in hot weather...

You're burning up pumps. It's either too much backpressure (filter or regulator bypass circuit can't meet pump output), low voltage (high current generating heat), or starvation (no fuel cooling the pump and acting as a lubricant).

Verify ground of hotwire kit to the battery. Clamp a wire to the battery ground then run it back to the fuel pump ground location. Don't connect the wire to the ground, but place the meter inline instead. Have the DMM set to VDC, not ohms, with the car running. A good ground will show max 150mV. After the ground is confirmed, verify power side voltage at the pump. Check for loose connector pins and crimps as well as corroded contacts.

https://ls1tech.com/forums/fueling-i...l#post18907289
"The plastic factory venturi tubes are dry and brittle. They should not be reused. If this tube leaks or comes off it will cause fuel starvation, low pressure and pump damage. Racetronix now includes a superior conductive Teflon tube with all FPA-001B assemblies."

Did you replace the sending unit yet?

[Mstansbury0704]

I am using an Aeromotive regulator basically as a dump valve before the rails so this probably hurts the back pressure situation a bit. But This was purchased as a new drop in unit from ws6store, maybe a year or so ago. If I recall, the Hotwire draws power from the alt using a relay with factory plug and the relay is grounded directly to the body above the tank?shitty of me but I replaced the pump years prior and had the updated wiring harness. I just cut it back off and direct wired to racetronix?s adapter plug. I?m using the FPWK-017A harness. I will have to take some time underneath and refresh myself on the hookups but I believe relay grounds right to the body frame in front of the tank.. However the battery is tied into the body with 0 gauge. Alternator is also grounded to the body with 0 gauge if I recall. 6AN should be enough for a return right? I suppose I could make sure my screw I used to secure the relay/grounding wire didn?t come loose or something crazy too.