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Hard starting


northerncountryboy
08-25-2011, 11:15 AM
I have a 97 blazer 4.3 and it cranks for at least 5 seconds before starting does this cold or hot. I have replaced the filter filter fuel pump and fuel pressure regulator, pump was changed about 6 months ago, all with delphi parts now is it possible the pump has a bad valve in it and it bleeding the pressure off, if i turn the key on and off 3 times let the pump cycle it starts right away. Any advice would be greatly appreciated.

NHRA
08-25-2011, 12:21 PM
check the control module.....................

MT-2500
08-25-2011, 03:05 PM
i have a 97 blazer 4.3 and it cranks for at least 5 seconds before starting does this cold or hot. I have replaced the filter filter fuel pump and fuel pressure regulator, pump was changed about 6 months ago, all with delphi parts now is it possible the pump has a bad valve in it and it bleeding the pressure off, if i turn the key on and off 3 times let the pump cycle it starts right away. Any advice would be greatly appreciated.

What are the fuel pressure readings?
Any codes or check engine lights?

Allegretto
08-25-2011, 09:56 PM
check the control module.....................


where is the control module located because im having a similar problem

NHRA
08-25-2011, 11:33 PM
where is the control module located because im having a similar problem

look for the coil its right beside it
some older modles are under the distribtor cap

Tech II
08-26-2011, 08:23 AM
I agree.....put a fuel pressure gage on it...has to be above 60psi and not bleed down....

northerncountryboy
08-31-2011, 04:26 PM
Thanks everyone for the info i will check pressure this weekend and post readings and yes the check engine light is on but no scope, has been on since i bought it. and if fuel is good then replace module, i think this one is under the cap.

MT-2500
08-31-2011, 05:13 PM
Thanks everyone for the info i will check pressure this weekend and post readings and yes the check engine light is on but no scope, has been on since i bought it. and if fuel is good then replace module, i think this one is under the cap.

Also get code no and post back code no.

northerncountryboy
09-23-2011, 02:04 PM
Ok sorry for not getting back on here right away but i figured out the problem, its the check valve in the fuel pump cause once i shut it off fuel pressure drops instantly to zero and i can hear it draining back. Service engine light is on beacuse of the check valve inside the tank. replaced the fuel pump cleared code and all is good, thanks all for the advice!!!!

MT-2500
09-23-2011, 03:23 PM
Ok sorry for not getting back on here right away but i figured out the problem, its the check valve in the fuel pump cause once i shut it off fuel pressure drops instantly to zero and i can hear it draining back. Service engine light is on beacuse of the check valve inside the tank. replaced the fuel pump cleared code and all is good, thanks all for the advice!!!!

Thanks for posting back fix and how it went.
We hope you used a Delhi pump.
If not you may be doing it again.

Check engine light and fuel pump/check valve are 2 seperate problems.
Outside of setting a engine lean code.

Did you check for codes and then clear codes and see if light comes back on?

northerncountryboy
09-24-2011, 08:47 AM
Thanks for posting back fix and how it went.
We hope you used a Delhi pump.
If not you may be doing it again.

Check engine light and fuel pump/check valve are 2 seperate problems.
Outside of setting a engine lean code.

Did you check for codes and then clear codes and see if light comes back on?

Yes i used delphi pump, that was the brand that the check valve went out of so hopefully i dont have the same problem with the new one. Codes where clear and my buddy that works at a gm dealership said that the pressure dropping like that could show a vaccuum leak somewhere in the system. also said that egr levels were low and i started it once with out the mass air flow plugged in.

old_master
09-24-2011, 12:44 PM
I agree with MT-2500: a leaking fuel pump check valve has absolutely nothing to do with the check engine light coming on. The PCM does not monitor fuel pressure or leakdown, so it can't set a code if there's a problem with it. Depending on what DTC you retrieved, it might have something to do with a vaccum leak, but not in the fuel delivery system. If the EGR readings are out of range, the PCM will set a DTC for it. No EGR DTC in memory.... there are no problems with EGR.

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