Help -Whipple Issues & Fuel Pressure Port

[hesster]

Really would appreciate help from the Forced Induction Heavy weights on this maddening issue.

I am trying to root cause my start and die issue on my 2010 SS Whipple & Cam set up. Developed this condition where the car is difficult to stay running after start-up, and can crank 2-3+ times before it stays running. I have a heavyweight well known tuner from this web site analyze many Data Logs and revise my tune, it is better, but still has the issue, especially when hot. He say's it can't be "Tuned Out", and is probably mechanical. When it runs, it really rips, but lot's of back rap and popping with the Long Tubes and Borla Atak w/o Cats. Normal? - I don't mind it.

Back Ground - new TB, Accel Pedal, New fully charged battery, new tune. No Codes! Drained the old gas and put in fresh 93 Tier 2 - used a ingenious procedure I found on this site to do this. Kept pumping fresh gas into old gas over a number of years as the car is basically infrequently driven (car shows, a romp, etc.) My Tuner said disconnect and bypass the MSD BAP, which I did. Used MSD View software to analyze it and it seemed to function OK, but bypassed it to rule it out. IAT readings seemed high, ranging from 61 deg cold to 118+ at hot idle. Insulated the CAI Air box some more, and wrapped the inlet tube. Inlet tube was warm and blower hat was hot after a drive - normal?

What I am doing now - checking and cleaning all grounds, wire harness integrity, connections, etc. Looking for the obvious. The car is immaculate and not like there is a lot of corrosion anywhere. My tuner said to check if my injectors were leaking. Getting a fuel pressure tester to do this. Is the FP Tap Port on the Whipple Fuel Rail as shown in the attached pic? Just connect to that, key it, and look for leak down over time?

Possible Root Causes:
1. Bad Injectors leaking causing a hard start and excessive back rap/pop on decell?
2. Intermittent Fuel Pump issue? Did the MSD BAP not play nice with the FP?
3. Intercooler Pump intermittent? Seems to flow when looking into reservoir, but noticed the ground wire connection at the terminal was not in the best condition.
4. Bad Ground(s)?
5. WTF Else to check?

Appreciate any insight and recommendations!

[BigMatt]

My money is on bad grounds. Check the back of the cylinder heads there's a ground on each head for each bank of injectors

[larry_g]

Are you on the stock fuel system with just the BAP? My return style system does not hold pressure when the pumps are off.

You should be able to use the port you show for testing pressure, but be careful when you pull out the plug.

Also, if you are on HP Tuners, you can monitor fuel pressure with that.


Edit: I'm not on here as much but feel free to message me questions.


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[hesster]

Stock Pump with (or currently disconnected) MSD BAP.
That port worked great to attach a Fuel Gage.
I think data says I don't have injector issues, or do I?
12 lbs in a hour, 58 to 46.

[cc-rider]

No. That leak down test is normal. That’s why your pump primes when you turn the key on after it sits for a while (but it doesn’t prime every time you turn the key on). Normal for fuel pressure to leak down over time. Note that with a larger return style pump like I have…the fuel pressure leaks down to zero almost immediately. And it still starts ok. The fuel pumps can prime the system enough to start very quickly. I’ll also say that I think your running a bit dangerous with a stock SS fuel pump with your set up. I would at least put in a ZL1 pump and get the FPCM tuned to make the most of it. Though this has nothing to do with your starting issues. Just might take out your motor under big boost pulls if it can’t keep up! Lastly, I also highly doubt the BAP is any part of the problem here. They only kick on under boost.

Have you checked all your potential source of air leaks / vacuum leaks?

Note that I have a Kenne Bell and a cam as well. Mine starts a bit more difficult when hot too. My guess…is it’s all in the tune. I saw your post over at HPT as well (I tune myself as well). You may want to consider paying one of those guys over there for a full on tune. I bet they would fix it. They are helpful over there…but they withhold some of their tips and tricks. Which I can’t blame them.

[hesster]

Originally Posted by cc-rider

No. That leak down test is normal. That’s why your pump primes when you turn the key on after it sits for a while (but it doesn’t prime every time you turn the key on). Normal for fuel pressure to leak down over time. Note that with a larger return style pump like I have…the fuel pressure leaks down to zero almost immediately. And it still starts ok. The fuel pumps can prime the system enough to start very quickly. I’ll also say that I think your running a bit dangerous with a stock SS fuel pump with your set up. I would at least put in a ZL1 pump and get the FPCM tuned to make the most of it. Though this has nothing to do with your starting issues. Just might take out your motor under big boost pulls if it can’t keep up! Lastly, I also highly doubt the BAP is any part of the problem here. They only kick on under boost.

Have you checked all your potential source of air leaks / vacuum leaks?

Note that I have a Kenne Bell and a cam as well. Mine starts a bit more difficult when hot too. My guess…is it’s all in the tune. I saw your post over at HPT as well (I tune myself as well). You may want to consider paying one of those guys over there for a full on tune. I bet they would fix it. They are helpful over there…but they withhold some of their tips and tricks. Which I can’t blame them.

Thanks for all of that input. I had linked up with a well known tuner on camaro5 and he had me data log with a purchased MPVI3 HP, and sent me a few new tunes, loaded them and car ran great but still had the hot start issue, and he said he can't tune the issue away. Hmmm. Unless my issue is bad grounds, then I suspect the stock pump and return less setup allows the fuel to perc in the rails and spike fuel pressure, making for the start and die issue. My DL data shows 70+psi when keyed to start hot, and that is a really good clue that excessive pressure may be screwing up the start cycle. A return less system would flush the fuel from the rail.
So at this point - any recommendations on a return less setup? Difficult installation? I am well versed is wrenching so it is something I could complete, and maybe put this maddening issue behind me.

[Ashen 6.2]

What is an "Accel Pedal"?

[cc-rider]

You may very well be getting some sort of vapor lock going on in the rails from all the heat. The superchargers are massive heat sinks and certainly put more heat to the rails than the plastic stock intake would.

I went with the AGP twin pump set up. Pretty good overall. I’d recommend it.

Also, you can relocate the stock fuel pressure sensor from back at the gas tank to the under hood fuel pressure regulator when switching to a return style pump. Then you can still monitor fuel pressure within HP tuners.

[hesster]

Originally Posted by BigMatt

My money is on bad grounds. Check the back of the cylinder heads there's a ground on each head for each bank of injectors

Have been methodically going thru every ground I can access. Some are buried, and very difficult to get to, especially with a Whipple and it's plumbing. Expect to get "Hamburger Hands" reaching into places not meant to be accessed with big hands. Attached a compilation of ground locations for the LS3 and L99, and a great reference for the general location where to look. Most so far have been in good shape, but not like the one in the attached pic. It was down on the drivers side attached to the middle of the inner frame rail. And in the last attachment pic, that folks is where the large engine ground wire attach's to - right on the E-Coated ECM bracket. Really GM?

[BigMatt]

Originally Posted by hesster

Have been methodically going thru every ground I can access. Some are buried, and very difficult to get to, especially with a Whipple and it's plumbing. Expect to get "Hamburger Hands" reaching into places not meant to be accessed with big hands. Attached a compilation of ground locations for the LS3 and L99, and a great reference for the general location where to look. Most so far have been in good shape, but not like the one in the attached pic. It was down on the drivers side attached to the middle of the inner frame rail. And in the last attachment pic, that folks is where the large engine ground wire attach's to - right on the E-Coated ECM bracket. Really GM?

Yep, I found that mine was in the same condition (garaged its whole life 42k miles). I sanded all ground points to bare metal, cleaned all of the ring terminals, added an additional ground wire from the block to the drivers frame as well as passenger frame and it finally fixed my issue.