Hard start

Tiny
RSEVILLA86X
  • MEMBER
  • 1998 OLDSMOBILE CUTLASS
  • 3.1L
  • V6
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
For the past two years my car has struggled to start and has gotten worse as time passes. I have to turn the key 2-3 times and give some gas to start. If the car has been sitting for 2-3 days, it the starts up like a champ first time I turn the key without stepping on the gas.

Starter and charging system are good. I checked fuel pressure, read 30 psi and then would drop quickly, about 10 psi in under 2 minutes. I replaced the fuel filter and fuel pump. Noticed the snap ring on the tank a bit bent but was able to get it back using force. New pump holds pressure better but still low at 38-40 psi and still drops slowly, about 1 psi per 5 minutes. I've also changed lower crankshaft position sensor, camshaft position sensor, spark plugs and cables.

Prior to doing all this, I also had a few emissions system warning lights. I replaced a few things that eliminated the warning lights: the tube that runs from the intake hose to the crankcase, the EGR valve, the MAP sensor and cleaned out the throttle body and the passage to the EGR valve.

Also worth mentioning, I dropped in a used motor with 50,000 miles a few years ago, it was in great condition, passed compression test with flying colors. Motor has about 90,000, transmission about 200,000.

GM 3100
Tuesday, April 28th, 2020 AT 7:47 PM

20 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

when it does not start, does the tachometer work on the dash showing engine RPM? There is a second crank sensor in the back of the motor that controls the fuel injectors.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

You would need a full scan tool to monitor the signal from it to the ECM.

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

I am concerned about the fuel pressure. It should be around 45 pounds as a target. I attached the spec below for you.

The other possibility is the pressure regulator. It is on the end of the fuel rail by the throttle body. Remove the hose and see if there is any fuel in the hose. This is a common failure for hard start hot as you have.

Roy

Removal Procedure
1. Relieve fuel system pressure. Refer to Fuel Pressure Release.
2. Remove the upper intake manifold. Refer to Engine / Intake Manifold.
3. Remove the fuel pressure regulator vacuum line.
4. Remove the fuel pressure regulator retaining screw.
5. Using a shop towel to catch any spilled fuel, lift and twist the fuel pressure regulator in order to remove the fuel pressure regulator from the fuel rail.
6. Remove the retainer and spacer bracket from rail and discard.
7. Remove the fuel pressure regulator from engine fuel return pipe.
8. Remove the fuel pressure regulator inlet O-Ring and discard.

Crank sensor

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Crank steering wheel fully to the left.
3. Raise vehicle on hoist.
4. Sensor electrical connection
5. Bolt/screw.
6. Sensor from engine.
7. Inspect for the following:
7.1.Inspect the sensor for wear, cracks, or leakage. Replace the O-ring if necessary.
7.2.Lubricate the new O-ring with clean engine oil before installing.

INSTALL OR CONNECT
1. Install the sensor to the block.
2. Install the bolt to hold sensor to block face and tighten to 8 Nm (71 lb in).
3. Connect the electrical connector.
4. Lower the vehicle.
5. Connect the negative battery cable.

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Wednesday, April 29th, 2020 AT 9:42 AM
Tiny
RSEVILLA86X
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Sorry for the late reply and thank you for answering.

I forgot to mention that I changed out the regulator. I went back and got another regulator and gas pump from AutoZone in case my Rock Auto parts were defective. Exact same results though. The sensor in the image was actually the one I changed out. I have not yet changed the other crankshaft sensor. The one you have to take off the timing belt cover to get to.

A friend hooked up his computer to check the sensor signals to the engine and he said everything checked out, that "nothing wrong was detected." And there's no check engine light so I have codes to clue me in on something.

So still struggling to start and when it finally does start up, it sometimes expels fumes from the exhaust.

When you say fuel in the hose, are you talking about that vacuum line or the steel line coming out of the bottom? I've attached a picture.
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Saturday, May 2nd, 2020 AT 4:28 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, I was referring to the rubber line.

What about the EGR valve? I would remove the EGR and check to be sure the pindle is not being held open by a piece of carbon

I attached a picture for you to view. It has one electrical connector and 2 10mm bolts that hold it to the intake.

Roy
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Saturday, May 2nd, 2020 AT 4:45 PM
Tiny
RSEVILLA86X
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It shouldn't be, it is a brand new EGR valve. I will check it and get back to you.
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Saturday, May 2nd, 2020 AT 6:10 PM
Tiny
ASEMASTER6371
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Keep me updated.

Roy
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Saturday, May 2nd, 2020 AT 9:21 PM
Tiny
RSEVILLA86X
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Okay, took off the EGR valve but I am not sure what you mean by check the pindle/pintle? If it is what I think it is, star head on the left in the picture, it appears to be closed. I can push it in and a spring pushes it back out. Lots of carbon coating on the walls but nothing holding it open.
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Thursday, May 21st, 2020 AT 4:33 PM
Tiny
ASEMASTER6371
  • MECHANIC
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That is correct. Carbon chunks were common to not allow the valve to close and it causes a massive vacuum leak.

Did you re install and see if it still has the issue.

Roy
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Thursday, May 21st, 2020 AT 4:36 PM
Tiny
RSEVILLA86X
  • MEMBER
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I'm going to clean or replace the idle control valve. Let you know how it goes.
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Thursday, May 21st, 2020 AT 4:41 PM
Tiny
ASEMASTER6371
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Sounds like a plan.

Roy
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Thursday, May 21st, 2020 AT 4:44 PM
Tiny
RSEVILLA86X
  • MEMBER
  • 12 POSTS
There were no carbon chunks.
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Thursday, May 21st, 2020 AT 4:44 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Did you check the actual fuel pressure?

What is the fuel pressure? I know you replaced it but need to know what the actual pressure is at the time of the hard start.

Roy
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Friday, May 22nd, 2020 AT 4:34 AM
Tiny
RSEVILLA86X
  • MEMBER
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I replaced the idle air control valve yesterday and there is some noticeable improvement at idle and the start has also slightly improved. Before I changed it, the start sounded ugly and took a lot of gas pedal. Now just a little gas pedal and doesn’t sound so bad. Still the long start though.

So I had posted the following initially but I haven’t checked it since. I will check it this weekend and get back to you.

New pump holds pressure better but still low at 38-40 psi and still drops slowly, about 1 psi per 5 minutes.

Thank you Roy!
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Friday, May 22nd, 2020 AT 7:06 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, 41 is the bare minimum. If you are that low, either the pump or the regulator is the issue.

Was there any fuel in the vacuum hose from the regulator?

Can you tell me the long term trim reading on the scan tool with it idling?

Roy
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Friday, May 22nd, 2020 AT 7:32 AM
Tiny
RSEVILLA86X
  • MEMBER
  • 12 POSTS
No fuel in the hose. I replaced the fuel filter, pump and regulator. I went back and got another regulator and gas pump from AutoZone in case my Rock Auto parts were defective. Exact same results though. I'll report back tomorrow on the current fuel pressure during hard start and the long term trim reading when idling.
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Friday, May 22nd, 2020 AT 5:23 PM
Tiny
ASEMASTER6371
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Sounds like a plan.

Roy
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Friday, May 22nd, 2020 AT 5:30 PM
Tiny
RSEVILLA86X
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Okay, still need to check fuel pressure but here is the idle trim value:
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Tuesday, May 26th, 2020 AT 4:56 AM
Tiny
ASEMASTER6371
  • MECHANIC
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-29 tells me there is not enough fuel in the engine.

Did you recheck the fuel pressure? What was the pressure?

The other possibility is injectors. If they are clogged or restricted, this will be the result.

https://www.2carpros.com/articles/how-fuel-injection-systems-work

There no additive that will clean them. You need to have the fuel system disabled and the injector cleaner added directly into the rail and engine running on nothing but the cleaner.

Roy
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Tuesday, May 26th, 2020 AT 5:17 AM
Tiny
RSEVILLA86X
  • MEMBER
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You were right about the injectors. Turned the key to "on" with the plenum off to see what the injectors would do. 3 started internally leaking. Replaced them and it starts brand new. The spark plugs would be wet which of course was causing the hard start.

Thank you!
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Monday, December 21st, 2020 AT 4:23 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Happy Holidays!

Roy
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Tuesday, December 22nd, 2020 AT 2:48 AM

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