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Hello all,
My 2007 Callaway has a long crank time before starting condition. I can smell gas from time to time and I think it’s more often after filling up. I think I have a broken fuel pump outlet. The car does not leak any visible gas. Here is a video of my fuel pressure:
Before watching the video I would say maybe a bad cam sensor or even crank sensor but I don't diagnose based on symptoms...when you say you it's harder to start after fill up I'd lean towards a stuck open purge valve but with that the car would run rich then lean after all the fuel vapors from the EVAP cannister are burned up then the car would run lean...in your case with the fuel pressure dropping to zero like that after shut down it may be a stuck open injector leaking a little fuel at shut down...I use this special hose by Kent Moore with a shut off valve to isolate the injectors and if the pressure holds after turning the valve off it's an injector...you can make your own...I would also scan for codes first to maybe give you some direction but unfortunately 99% of Corvette owners don't have one...an external leak of the fuel system would be more difficult in your case with the fuel pump on top of the tank...maybe get yourself a borescope and snake it up to the top of the tank if you can and take a look see !!
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The Kent Moore fuel hose tool goes between the fuel line from the tank and the injector rail correct? Then I turn the car to on and shut the valve and pressure should maintain at 60 unless an injector is leaking down, right?
My borescope didn’t really see much but I haven’t gotten the inner fender liner out yet either. Access will be easier after that.
Yes, the hose goes in line with the disconnected fuel line at the rail and you would pressurize the pump, close the valve and shut off the fuel pump…if pressure holds it’s a leaky injector…you can get the hoses on EBay or make one yourself with fuel hose, shut off valve and a GM 3/8” inch male and female fitting…there are other things that can cause the pressure to drop but the fuel smell may narrow it down.
System should hold prime for a touch when the motor is shut down.
So what pump(s), fuel regulator, and if a fuel return system in the car. Also have you isolated the fuel rail and injectors, so you can pressure test just them to make sure you don't have a leaking injector/rail, and the rapid pressure bleed down on shut down back in the fuel deliver system to the rail.
Next, your starter button is pretty quick to turn the engine over with no pressure on the fuel line, and should be into the pre-prime delay before the engine cranks.
Have you check the tune to make sure that prime time is still set to 2 seconds, as well as min fuel pressure before crank, set correctly as well?
first thing to check is your battery at 12.8 volts. I would test battery/starter/alt.
Fuel pressure is within spec at idle. how many miles on the fuel pump and injectors ? what fuel do you run ?
To me fuel does not seem to be the issue. Especially since you have no codes stored.
first thing to check is your battery at 12.8 volts. I would test battery/starter/alt.
Fuel pressure is within spec at idle. how many miles on the fuel pump and injectors ? what fuel do you run ?
To me fuel does not seem to be the issue. Especially since you have no codes stored.
His fuel pressure should NOT drop to zero that quickly after shutdown…it is a fuel issue !!
Battery is on a maintainer at all times and runs 13.9 on the scanner at idle. The car has 30,000 miles on it. The battery would have no effect on the fuel pressure dropping off that quickly in my opinion.
why would he have 60 pounds at idle ? that suggests a good pump. Also, no CEL.
takes one minute to load test a battery ....
My friend, idle pressure is good or having the pump activated for 2 seconds so we are not condemning the pump…fuel pressure should hold and not drop on my C5 more than 5 psi after one minute after the key is turned off and there are 6 items that may cause that pressure drop…a C6 is similar…the MIL would not be illuminated for this kind of issue unless the ECM is monitoring the fuel pressure which it does not…the MIL also does not illuminate for every DTC but only for anything that affects emissions…that’s it !!…it would not be a battery issue. If you can explain how a weak or bad battery can cause this I would like to know.
I did test the battery and charging system for fun with my Autel BT508 Battery analyzer and Autel Maxisys 906BT scanner and all checked out fine.
The receipts for all of the work done on the car came with it. The original owner (possibly the second owner...I'm not quite sure yet) still had the car on March 17 of 2017. It went to Dimmitt Chevrolet in Florida and states on the work order-
D C/S HE HAS A STRONG FUEL ODOR SMELL
CAUSE: SPECIAL POLICY
9900358 Evaporative Emissions Smoke and Flow Testing
At that time they replaced the fuel pump, an exhaust gasket and clamp, a lower control arm suspension nut, the fuel lines from the pump to the crossover tube in the drivers side tank, and the o-rings on the crossover tube.
The car has about 30,000 miles on it now. I can check the exact mileage when I get back to my shop later today. It should be noted that it still has a strong fuel odor, particularly after filling with gas. So it's quite a mystery.
I hoping to get away from my job site later today and re-assemble some parts of my fuel pressure test set to test for injector leak down. Injector leakdown would not really explain the fuel smell. The fuel smell appears to be coming from the drivers side fuel tank area.
I see you have an Autel…I use my MS906 occasionally so maybe to rule out anything in the EVAP as far as a leak causing a fuel smell (you don’t have any EVAP leak codes I don’t think) but with the ignition on see if you see 1.5 volts on your fuel tank pressure sensor…this is a standard GM voltage for the tank sensor at atmospheric pressure…go to output controls and close your vent valve…if it’s warm and the car is outside the voltage should increase as the sealed tank pressure increases…also if you have fuel tank pressure in H2O that should decrease in inches of water…vent and purge will be closed…kind of like a ballon…if pressure increases you don’t have anything like a crack in the tank etc…
Best bet, the pressure regulator in the replacement fuel pump is not working correctly /does not have a back-check vavle rated to 60 PSI, and why the fuel line/fuel rail is not holding pressure when the pump is turned off.
Also, system is not pre-priming before the engine does start to crank, the so that needs to be check in the tune as well.
Lastly, with the SC in play, the fuel pump needed was one for a LS9 at least, but most dealers will not install that pump, but the pump that came with the model stock isntead. So would first check to see what model OEM was replaced in the tank, if there is a secondary pump in play to drive the pressure upwards enough (or BAP in play). Then at that point if the pressure for the system has been changed with the new pump, was the tune adjusted as required as well (Dealer will not touch the tune).
So at this point, get Callaway on the phone to see what they did do with the fuel system so it was supplying the increased volume for the S/C, try to figure out what the dealer did on replacement parts, and then what needs to be replaced to resolve the fuel pressure regulator back check so the system is not bleeding off in seconds (if the problem is the fuel system, and not a leaking injector/rail isntead). Then have the tune check for problems with it, and corrections if the fuel volume has changed with the replacement parts.
I have been working with Callaway. They have been very helpful. The sc560 used the stock fuel pump and has a magnavolt fuel controller that increases fuel pump voltage when on boost above 3000 rpm. They sent me a test procedure to verify proper operation of the Magnavolt, although the sudden drop on fuel pressure leads me to think towards a bad check valve or leaking injector.
I should be caught up at work and able to go work on the car later today. I appreciate all of the help that you are all giving me. 🍺
So I isolated the fuel line from the tank by putting a manual shutoff valve in before the fuel rail. I ran the car and shut the valve off with the car running, then shut the ignition off. The fuel pressure dropped to zero immediately upon shutting the engine off. I have the following information on the fuel system:
Judging by this information it appears to me as though the pressure could leak down at either the right or left tank fuel pressure regulator, or the right side fuel tank check valve, correct? Considering the drivers side fuel pump was changed at a Chevy dealer recently do I just plain pull out the passenger side tank and change the fuel pump module on that side????
So I isolated the fuel line from the tank by putting a manual shutoff valve in before the fuel rail. I ran the car and shut the valve off with the car running, then shut the ignition off. The fuel pressure dropped to zero immediately upon shutting the engine off. I have the following information on the fuel system:
Judging by this information it appears to me as though the pressure could leak down at either the right or left tank fuel pressure regulator, or the right side fuel tank check valve, correct? Considering the drivers side fuel pump was changed at a Chevy dealer recently do I just plain pull out the passenger side tank and change the fuel pump module on that side????
What do you guys think,
-Justin
Why didn’t you tell us the pump was changed recently at the dealership…the first thing I’ll ask if any recent work has been done to the car !!…I’d take it back to them…THEY OWN THIS ONE !!…and don’t ASSUME that your new pump is good…I recently changed 3 sets of upstream O2 sensors on my car that were bad (Bosch) and bought 2 Denso’s that worked perfectly !!
01-10-2022, 08:04 AM
Long crank to start problem
