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Engine hard start

Tiny
RUSSCRYPTO
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
  • 91,250 MILES
My 99 c2500 Suburban with the 7.4L L29 engine is having hard starts when the engine is remotely warm. I've had the fuel pump and filter replaced, but it didn't help. Also, when it does finally start, there is a small plume of black smoke from the exhaust. Once running, there are no drivability issues except for a bad shake at 65mph. Any above or below that speed, no shake.

I think the start problem may be the fuel pressure regulator, is there any test that is more specific to the FPR than a normal leak down test?
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Wednesday, April 29th, 2009 AT 9:54 AM

77 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Its a little tough to get at, but remove the vacuum line (at the reg)and see if any fuel is present in it.If so the reg is bad and needs to be replaced, that is what it sounds like

This guide can help.

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

Please run down this guide and report back

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Friday, May 1st, 2009 AT 7:45 AM
Tiny
JOEL LANGLOIS
  • MEMBER
  • 2 POSTS
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 174,000 MILES
My wife has a problem with her suburban. When we drive it for a while it seems to lose power, adn will eventually stall if we try to climb a hill with it. It coughs and pops when this happens. At first I thought it might be a plugged convertor, but it will run good on level road, do 65 plus and doesnt get hot. It recently started not starting after a 5 min run, and even in the morning it cranks hard and wont start. I have also noticed a fuel smell around the vehicle. I have changed the fuel filter. And checked for codes. ( None present) I pulled a couple of the plugs to check them and it looks like the engine is running a little rich. The plugs have black on them. What do you think it could be? Im a heavy truck mechanic and am a little weak on car diagnostics
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
I would check the fuel pressure regulator and also check the map sensor.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
COOLGRAN
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
If its cold outside the first start usually starts fine. After it has been ran for a while it starts real hard. I have replaced the plugs the coolant sender and the upside o2 sensors thermostat. I am thinking issue wit fuel but I dont know
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuel pressure with a gauge 60-6psi auto parts rent it.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
CHUCKDGREASER
  • MEMBER
  • 2 POSTS
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Truck will not start unles I prime it
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Use a gage and check fuel pressure. Do you have the spider fuel system? If so, fuel pressure 60--66psi.
Sometimes the fuel poppets need cleaning. Some of the national brand autostores used to loan out a fuel pressure gage, if you don't have one.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
CHUCKDGREASER
  • MEMBER
  • 2 POSTS
Fuel pressure is 60-63, good pressure once I get it started it will run for about 5-6 miles the it will die out and I have to prime it agin to get it to run
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
The spider system may need cleaning? The best cleaning procedure is a shop procedure. Don't know if injector cleaner in the gas tank will help?
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JWASHINGTON
  • MEMBER
  • 6 POSTS
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
  • 164,000 MILES
We just replaced the Ignition Control Module in our 99 Chevy Suburban yesterday and from all appearances it seemed to run fine all day today. Then later this evening I was out running errands and ran into a store for 15 minutes came out and it struggled to start as it had before we changed the ICM. Took about 3 or 4 times to start. It eventually started except now the Check Engine light is now on (this wasn't on before). I'm assuming because of maybe a faulty knock sensor now because of the hesitation in starting of the engine? Could we now have a problem with the Knock Sensor and or the Ignition Coil?
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
You need to check what's missing if its fuel or spark issue-Do below to find out more-

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine at least 3/16 away from ground -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if so, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JWASHINGTON
  • MEMBER
  • 6 POSTS
Thanks rasmataz! We will try these out! As we are just at home do it yourself "ers". We did just have the fuel pump and fuel filter replaced by a mechanic in November.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JWASHINGTON
  • MEMBER
  • 6 POSTS
Replaced 2nd ICM. Check EngineLight was coming on intermittently when struggling to start only. Wasn't coming on when starting fine in the mornings (cold engine). Diganosed the codes at AUto ZOne. BAD ICM AGAIN! SO they said either a bad part OR might be a grounding issue? Gave us another ICM and we just replaced yesterday. Has been fine until this afternoon and it took a couple of times to start and now the check engine light came back on (no big surprise). So if there is a grounding issue that is making the ICM go bad, where would that be? Pretty soon Auto Zone is going to stop giving us ICM's even thought they are Lifetime Warranty's. LOL!
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
RAY HANE
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET SUBURBAN
139000 MILES ENGINE MISFIRES HARD STARTING
SCAN SAYS #5 MISFIRE PLUG WIRES ARE NEW
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Could be a bad plug wire, has it had new ones put on?That is a CPI engine and they had many problems with injectors, If miss still occurs with new wires (major tune up with A/C Delco parts) then I would suspect an injector. If you do it yourself, keep an eye out for the fuel pressure regulator leaking, those blow out too. There will be a clean spot under it in the intake manifold where the raw fuel has been running into the intake
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
ROBIN NICELY
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
I read a question on hear about a 04 suburban not starting every once and a while thab they went and got a new starter I just dont think it is that im thinking the neutral safty switch has any one else heard of this going out and that being the problim. Some times when it wont start I run it through the gears and than try it again and it starts up but now it is becoming more often and takes longer to start any help would be great thanks
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
DR LOOT
  • MECHANIC
  • 2,311 POSTS
Smart, the way to check if you have a bad safety neutral switch is to put the transmission in neutral if the vehicle starts the switch is no good, another thing you can do to hold the key like you are trying to start it and wiggle the shifter in park and a neutral and see if it will start let me know what happens.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
JIM RODMAN
  • MEMBER
  • 3 POSTS
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
I have a 1999 chevy 5.7 suburban. For the first start of the day it backfires and is hard to start. For the rest of the day it starts and runs fine. One backfire blew apart my muffler. Also, the service engine light is on. Was told it is a oxygen sensor. Which one I have no clue.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
What was the exact code stored from the check engine light. It's likely NOT caused by a bad sensor.
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Monday, November 5th, 2018 AT 4:47 PM (Merged)

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