HELP! "stock" CTSV lots of KR and SLOW!

[Stroked06Goat]

I was going to say run an external pressure gauge inside and verify it drops from 55psi (or whatever those V's run for pressure). If you are losing pressure its got to be that pump. Why so expensive yikes!

Edit: sorry just saw you did replace the pump.

[pannetron]

VaporWorx sells a kit to upgrade the actual pumps in the OEM CTS-V2 pump module for MUCH less money than a complete new module. I added a fuel pressure sensor to my car at the fuel rails and log its output to one of the analog inputs on the MPVI-PRO.

[happysem]

Update...

Thanks for the replies, yea I replaced the pumps with brand new AEM ones, inside the stock basket easy plug and play and are said to support PWM no changes required.

When these problems first started happening I put a mech gauge on fuel rail and verified pressure (at least at that time) was the same as what is reported electronically. The 09 V runs like 36-38psi on low flow and around 60 at high flow I believe.

So here's what I've found out.
Stabbed the 4 fuel pump wires that go into the top of the fuel hat (2 wires for each pump).

They both get 5V when idle and cruising normally.
3rd gear WOT about 4000rpm gets up to 6V, 2nd gear WOT 6000rpm gets to about 9V on both sets of fuel pump wires.

SO, I'm pretty sure they should be getting up to 12V at WOT, correct? My AFR during this quick test was 16...sorry car lol. Feels clean, just not as fast as it should be.

I'm guessing something is keeping the car from getting 12V at WOT. At this point I am on 100% stock tune, new reprogrammed FPCM, new injectors, new pumps, and I believe the car is stock. No evidence of BAP installed, but I will investigate more tonight.

[gtstorey]

I'm not sure how much good you have done yourself buying parts off of amazon. To many counterfeits on there to be worth any savings, especially when trying to trouble shoot.

Not sure why you are worrying about voltage at the pump if you are sure its maintaining pressure at the fuel rail.

[BigTuner]

If you have fuel pressure then there are a couple of things that could cause you to be lean, due to all of the issues I am not going to assume everything is actually stock, these are all pretty general and some are very unlikely I am going to throw them all out there.

The injectors are not stock and therefore your calibration is off, I know you said you tried new injectors but there are a lot of counterfeits out there.
The MAF sensor is bad or contaminated, or not stock, check the part number and hit it with some MAF sensor cleaner and/or force the car into speed density mode to ignore the MAF sensor and see if things improve.
The intake is a larger pipe diameter at the MAF sensor than stock which would cause your MAF sensor to read lower than actual airflow with a stock calibration, causing you to be lean.
Bad O2 sensors could cause issues but unlikely as they have little effect over WOT fueling and would cause codes.
Injectors could be clogged or sticking.
Massive vacuum leak after the MAF sensor. There are multiple methods to hunt down vacuum leaks but one big enough to make things this lean at WOT would be pretty obvious.
Misfires would cause an O2 sensor to read lean due to excess oxygen in the exhaust from an unburnt mixture.
An air leak before the O2 sensor could give a bad reading but since you are losing power and seeing knock this is unlikely.

[sgod1100]

Not sure if this is going to make a difference, but it looks like your "min injector Pulse" isn't stock. You are on stock injectors correct?

[happysem]

Thanks for the replies, I'll try to answer all the questions and suggestions.

I'm sure the amazon parts are fine (some from rock auto as well), based on the fact that the car literally ran the same before and after stock/original parts and new purchased ones. Ran exactly the same with both sets of injectors, fuel pumps, TB/TPS.
Voltage at the pump definitely seems like an issue, since the tune is commanding like 11.5 AFR and I get 16, pretty sure you should get around 12V at the pump and I can't get that.
It maintains pressure, but never really seems to get all the way up to that high pressure high flow state. My last couple of quick tests after replacing things at the dealer showed like 36-38PSI no matter what.

Injectors look stock both what it came with and whats in it now, and it ran the same before and after install.
MAF - I had a code 1 time, but cleaned it with isopropyl alcohol and never had an issue again.
Intake - all factory stock, and I highly doubt a intake pipe would cause you to run this lean.
O2 sensors - no codes, corresponding values look normal to what I'm seeing with my wideband.
Vacuum leak, no other symptoms, but technically still possible I haven't ruled it out.
Misfires, almost none logged ever. Had 1 or 2 but I wouldn't be surprised if it did since AFR is massively out of wack.
Air leak (exhaust?) Can't hear one and didn't notice anything when I welded the bung in for the wideband.

Now...
I did some digging and I've found probably several issues with the wiring harness on the back of the car. Attached some pictures (never mind I'm illiterate, click the links). Trying to find a wiring diagram but any help ID'ing these wires would be massively appreciated.
https://freeimage.host/i/HCLYlzN
https://freeimage.host/i/HCLY75v
https://freeimage.host/i/HCLYTqF
https://freeimage.host/i/HCLYYeR
https://freeimage.host/i/HCLl75b


Check out the weird wiring splice job on the grey wire that goes into FPCM terminal 3 ports behind the big grey wire...Then it goes to a bare wire and runs somewhere inside the car, and was taped in with the big red and grey wires.
Then the brown and brown/black wires have had some work done to them as well.
Finally, found a set of grey wires that pair down into 1 it looks like that go into the fuse block that screws in above the battery.

Definitely looks like some issues here.

[gtstorey]

At some point it might be easier to put in a referenced fuel pump/regulator in and tune the car to work with non-stock settings than to keep tracking down your issue.

[happysem]

gtstorey, does that bypass the FPCM entirely? Able to run returnless? I'm still learning about this fuel system...the more I learn the more I get confused, seems overly complicated.

[gtstorey]

I would likely put in a return style system with a regulator that references pressure/vacuum, without the FPCM. Maybe somebody with more experience will way weigh in, but all you really need to ensure that you have enough pressure and enough injector to supply your power needs. There are plenty of swaps that don't use a FPCM. Not exactly cheap but in relation to the time/money already spent not that bad. It will totally change one of your variables and if it still can't be tuned then either you have an injector/wiring issue or a bad ECM.

But again if you are maintaining pressure at the fuel rail, you problem is likely elsewhere anyway. The statement "The 09 V runs like 36-38psi on low flow and around 60 at high flow I believe." concerns me. Have you confirmed this with a factory service manual or random internet posting?

[BigTuner]

I looked through your logs and never saw fuel pressure, please log the Fuel Pressure PID, I bet the problem will show up clear as day, dropping during WOT. The cause does look a lot like it could be that wiring, maybe it used to have a BAP, I am unfamiliar on the wiring for one. You should probably go through all that wiring and redo it.

[GHuggins]

The heat shrink ones can go either way - factory or not factory - you won't know until you cut into it and look at the splices themselves. Factory splices will have a horseshoe piece of metal crimping the wires together and then as long as the factory worker was doing things right - it'll be soldered... This is how I personally prefer to do any important splice myself.

The electrical tape ones definitely aren't factory - looks like a possible cheesy rip out of another device or cheesy dealership repair.

You honestly should have around 14v with engine running going to the pump under for power/boost. If you don't then sounds like you're going down the right road.

Do you know how to do volt drop test? That and a schematic will have your trouble areas isolated in about 30 minutes to an hour. BUT I would start with these splices - peel the tape off and see if the wiring is soldered or just half ass wrapped together.

[happysem]

gtstorey thanks for the info, but honestly I'm so turned off by the car the last thing I want to think about is redesigning the fuel system now that I have nearly a grand in new stock fuel system parts lol.
Based on what I've read online and looked at tune wise (both ECU and what the FPCM have in HPTuners) 09 CTSV is different, they run 36psi low flow, then 60psi for high flow situations, they updated the tune in 2010 and on to like 60psi all the time.

BigTuner, I didn't log fuel pressure on the logs from the initial post, but they are in the logs on post #8, basically the car runs at 36psi all the time, except when revving in neutral.
I have fuel pressure logged in this most recent log with all the new fixins and the car in its current state. 36psi no matter what.

GHuggins, I don't know how to do that, but I'll do some research and at least try to repair the most obvious wires in the back, but I think you're right about the voltage to the pumps.

Thanks a lot everyone, may actually get this figured out.

[happysem]

Minor update;

Really hard to find a pin out of the FPCM online, especially for an LSA car. But I found one with diagnosis procedure on the 07+ trucks.
Followed this video and directions here; https://www.youtube.com/watch?v=QIE_HLSeFrc&t=1s
http://gmflash.com/fscm-diagnosis

All tests good as in that video so I don't think the FPCM/FSCM is the problem.

The only thing I've noticed is when I jump across the FPCM connector to hotwire the fuel pumps, they both stay on at a constant 9.8V, no higher. Pretty sure that should be 12+ and I think thats my problem. PSA - if you do this use BIG wire. My like 14ga test wire lasted about 10 sec before it started smoking lol.
I have no idea why or where to go next, but I think this is it.

Also, many of the wires in the back have tape over them for no reason, 2 sets of brown/black wires into the connector are just taped together no connection or cut, like someone else was marking them only.

The bare wire I believe is a FSCM shield ext wire...based on the truck diagram, so maybe its supposed to be like that? Idk still looks shoddy.


EDIT I didn't want to bump this thread up, but if anyone is having a similar issue I wanted to say sorry I never found it out. Sold the car. I'm still fairly sure this post here is the closest I found to solving the problem. Carfax shows the car was in a minor rear collision, and I think a shitty wiring job is causing the pumps to never receive 12-16V at full throttle, even when hot wired. Would probably work if I bypassed FPCM for testing but I stopped caring about the car after a year of diag. Good luck!

[gtstorey]

Wiring diagrams and pinouts should be available here https://www.acdelcotds.com/subscriptions# $22.00 for 3 days and you should be able to grab screen shots of all of the wiring diagrams and pinouts.

Also should have diagnostics, tests and pressures for the fuel system although some of it may call for tools you might not have.