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Looks like a fun day !.. got any more !? Didn't sound like there was too much tire slippage... looked like it was going where you were pointing it.
On some of the corners the back end looks like it was getting loose, but I couldn't tell if the that was throttle induced our genuine overseer. What is your current front and rear suspension setup, including springs and sway bars?
I'm jealous. Looks like so much fun!
Can you elaborate on why you are thinking about modifying the fuel pump tray/sump holes based on fuel loss while idling? The engine should be consuming very little fuel at idle and if your return is going to the tray there no reason it would empty at idle and not under load. I don't think?
Well, I had assumed that the tray was higher and that the holes smaller/fewer, and that driving would cause the tray to be sucked dry rather quickly, but that doesn't appear to be the case. Here's what I've been able to calculate based on photos from my fuel system album:
It appears that my fuel pump mount plate is 6"x6", which makes my tray 6"x6"x1.5", or about a quart capacity. There are 10 holes, which appear to be 1/4" each, leading to a total cross-sectional area of .491 sq-in (this is equivalent to a single .791" diameter hole).
I've reached out to Aeromotive to get their thoughts.
Also, the guys with the Nova wouldn't say what they did (to be honest, they have been ******** both times I've tried to talk to them), but it was modified beyond just the Watt's link. Lowers looked unmodified, but I didn't get a chance to check it out in-depth.
Got to love guys like that more worried about you getting thier top secrets than you maybe being a better driver. The car looked good out there and you did a nice job driving it.
Last edited by Motown 454; 11-22-2016 at 02:46 PM.
Clearly they weren't paying attention to my runs... I am not out-driving anyone out there.
Update from Aeromotive. They (unsurprisingly) recommended I replace the $15 Wix filter/regulator with $400 in Aeromotive parts, and move the regulator to the engine compartment. Maybe I can get mine tested at the fuel lab at work...
We’ve seen the Corvette filter regulator be a consistent problem, especially with high flow fuel pumps like the Stealth 340 pump. In fact I commonly get calls that the 340 pump has ultimately failed when used with this filter/regulator combination. As nearly as we can determine the filter in this assembly is significantly restrictive and after a relatively short run time, especially in a new system, it becomes clogged, eventually dead-heading the pump and running the brush and commutator assembly out.
I would recommend installing a proper Aeromotive filter and regulator as soon as possible, it sounds like you’re on the verge of permanently damaging the fuel pump.
If you can measure current to the pump, you should be able to estimate the pressure it's pushing. That will tell you if it's pushing significantly more than the regulated pressure. Based on this curve it should be pulling around 14 amps.
An excellent idea. I'm going to fab a fuel pressure test gauge while I'm at it, since the kits you can buy/rent don't have hoses that are long enough to snake out to the windshield.
Id like to try this badboy out. I have random stalling as well. Car runs perfect. no check engine light, no nothing. Come to a stop light and nothing. starts right back up.
You can tell Clint is a engineer the way he thinks. LOL
Originally Posted by -TheBandit-
If you can measure current to the pump, you should be able to estimate the pressure it's pushing. That will tell you if it's pushing significantly more than the regulated pressure. Based on this curve it should be pulling around 14 amps.
News. I finally pulled fuel pressure and pump voltage/current. It was 50psi at idle, with 13+ v and 11a. This dropped significantly under load. I'll upload a video shortly.
The amperage correlates with almost no pressure, per Aeromotive's graph (see modified version below).
This was taken in 2nd gear under light load.
I used an oil pressure test kit modified to fit an R12 hose. The 90° elbow is an R12 adapter with Schrader valve so I can leave it on the rail.
The black horizontal lines represent 10 and 11 amps, respectively.
I would throw out the Aeromotive graph since it looks like you are able to get around 48psi with 11.2amps /13.6v. I would also throwout Aeromotive's advice that the pump is pushing against a bad filter since the current draw is not high. 50psi at idle is low, but you should check that gauge to make sure it's reading accurately. I don't know how much you can expect it to dip under load, but I suspect fuel pressure will drop some. Look forward to the video.
When it was being tuned, did you have any problems with A/F at WOT / high RPM? Do you have an OBD2 reader so you can log your fuel trims? I have a cheap ELM327 Wifi reader and the Torque app that I can use that to read and log - they're insanely cheap and well worth the cost. If your fuel trims / injector duty cycle are spiking under throttle, that would tell you it's going lean and the engine is trying to compensate. Here's a link to the generic adapter: link
Going to rent a pressure tester to check the gauge. Might be able to borrow a near-new FPR from 70novaSS, since his isn't up and running yet. But it seems that the pump is failing.
To answer your other questions, it was initially tuned with a Walbro 255 inline pump. I have that bluetooth OBDII reader, and LTFTs are near-zero. I hadn't thought to check STFT though.
New regulator, new fuel pressure tester, same results. I borrowed 70novaSS's FPR, which we know has 58psi at idle.
I've reached out to Aeromotive for ideas, but I'm leaning toward the pump. My only issue with my test setup is the use of the 90° fitting shown below (installed due to the proximity of my alternator to the fuel rail), what effect that would have on the dynamic pressure readings.
So I'm looking at a whole new fuel system setup. $600 for Aeromotive, or try for a 5th gen Camaro in-tank guy, which will require additional tank modification.
There would be no dynamic effect for that 90 fitting because nothing is flowing through it. Maybe you do have a pump problem considering the oddly low current draw. I don't know that it warrants a new fuel system though. You might have an internal leak in the tank or the pump may be bad.
On some of the corners the back end looks like it was getting loose, but I couldn't tell if the that was throttle induced our genuine overseer. What is your current front and rear suspension setup, including springs and sway bars?
I'm jealous. Looks like so much fun!
Can you elaborate on why you are thinking about modifying the fuel pump tray/sump holes based on fuel loss while idling? The engine should be consuming very little fuel at idle and if your return is going to the tray there no reason it would empty at idle and not under load. I don't think?
I know.. a bit late in the response....
I have POL Front Tube A-Arms, KYB Gas-A-Just shocks (rear shock are a POL relocation setup) and Hotchkis full TVS 1-1/2" suspension (springs & sway bars). Other than that it is pretty stock. Camber is about -1* and Caster is 3* to 4* (need to recheck).
Now on to more updated replies.. sorry, been short on time but still following you and the other guys threads.. giving input when I can.
1) I checked your Photobucket pictures, I can't see what the setup is for the pump to outlet tube/port is like. I would check to make sure that if there is a transfer tube/hose, it is the correct type that can be submerged in fuel. That E85 or ethanol can cause incorrect hose type to deteriorate quickly.
And that the tube is secure and not leaking. If leaking too long, that could cause pump failure and low pressure (over time).
2) I don't see any filter/sock on the end of the pump, if none, garbage could be sucked into the pump and causing restricted fuel flow and low pressure.
3) What is the clearance between the pump and the bottom of the tank. Too tight of clearance between the pump/tank could be causing flow issue and low pressure.
4) I would check pressure right at the pumps assembly outlet port to see what is coming out of the pump (or inlet side of FPR). Might need to buy some extra fittings and tubing with a Tee in it for the pressure gauge. Remove it once checked.
If anything less than 58psi regulated, there is a problem (yes it will start up and run with less, but ...). The pump unregulated pump should be able to see 80-120+ PSI output, depending on the pump.
Every single one of you planning to install an automatic trans in your car.
Just re-read yours and Clint's threads from the very beginning, as I realized I didn't know or had forgotten a lot of the steps you guys have gone thru.. and came across this little gem of advice from you.. ain't it the truth!
BC, I did some poking around and talked to some people. The pump appears to be bad. I have elected to go the 5th gen Camaro SS fuel pump route. I got a fuel tank from the junk yard for the pump mount ring. Expect a write-up like so soon(ish). Still looking at spending less than an Aeromotive pump/filter/regulator, albeit at the cost of additional labor.
Edit: Also, Joe, you've got a bit more time and fabrication into yours. My build is quite pedestrian by contrast.
Last edited by hookemdevils22; 01-28-2017 at 07:11 PM.
Reason: to add, uhh, actual details
My pump is bad, so I'm looking at about $300-350 in regulator/pump/filter alone, not including AN hose/fittings (which I have access to). By contrast, I bought a Camaro pump for $85, a late-model tank for $27, and Vaporworx parts to make it work for $115. While it will take some fabrication, I expect it to alleviate those <1/2-tank hiccups associated with the pump-on-a-stick design.
11-21-2016, 12:38 AM
