My engine is hard starting?

Tiny
TONYB63
  • MEMBER
  • 1999 CHEVROLET BLAZER
1999 Chevy Blazer 2WD 4.3 Vortec. I know this problem may have been addressed before but I have never seen it exactly stated as I am going to explain my problems in full detail so I can hopefully get the problem addressed, so here goes.

Possible repair options (So I've been told/so I've read so far):

A. Fuel Pressure Regulator

B. EGR Valve

C. Mass Airflow Sensor (MAF or VAF code given at AutoZone)

D. Fuel Injectors / Fuel Injector Spider Assembly

The truck runs terrible. At first, the problem started with it being harder and harder to start. At first I would crank the engine a little longer each day until it finally stopped starting. Now I have to dump about 1/4 of an ounce of gas (a splash) in the throttle body to get it to start every morning. Sometimes, when I shut it off, if I restart it within 2 to 3 minutes, I don't have to dump gas in the throttle body to get it to start. In addition, I have been dumping gas in the throttle body for about 3 months now. If I have the truck pushed and I “pop the clutch”, the engine starts.

In addition, and way before the truck stopped starting when cranking the motor, the truck had and has no pickup. When I give it gas, it "hesitates" and "bogs down" when gas is given. To take off from a light or at any time I am at a standstill, I have to push in the clutch and rev the engine and then "feather" the clutch with the engine revving high to get it to move and then it will either go or "bog down" again but if I do this, it eventually goes.

If I am stopped at any "uphill incline", the truck seems like it is not getting any gas and will shut off. It will idle on an incline but will not go and will die when I give it gas. I have to push in the clutch, hold the break and rev the engine with my hand (what seems like) to get any gas into the engine to get the engine to run. Then I feather the clutch like stated above to get the truck to go. In addition, if I am at an incline and I let it roll back and get the truck on a level surface again, the truck revs when I give it gas.

At first, about a year and a half ago, I went to AutoZone and was told the codes given were telling me to replace the O2 Oxygen Sensors, which I replaced all three. Still no help.

I was then told I need to replace the entire "Spider Injector Assembly" ($800.00 total parts and labor) because (as it was explained to me by the mechanic) "the injectors are bad and it is losing its "prime" which is why it won't start unless I dump gas in the throttle body whenever I want to start the truck". This repair attempt will be my last resort.

Also, I have vacuum lines running from the driver’s side under the hood right next to the master brake cylinder running into a connection on the side fender inside the engine compartment. The vacuum lines were all dry rotted so I replaced them. The vacuum lines started at the connection point on the driver’s side inside the fender and went to a "one way" vacuum “part” that had 2 vacuum lines attached to it. One of the vacuum lines went to a vacuum line that goes “downward” and I cannot find where it terminates but I think it goes to the Master Cylinder, although I cannot be certain. The 2nd vacuum line goes to a sensor directly behind and (if you are standing in FRONT of the truck) to the right of the throttle body. The part has a black plastic piece that appears to be able to be removed if you give it a 1/8 turn. The black plastic part the 2nd vacuum line goes to also has a rubber hose connected to it on top that goes to the valve that is mounted into the valve cover.

1. Is the part the second vacuum line attached to, mounted behind my throttle body, my Fuel Pressure Regulator?

2. What is the part that is mounted into the valve cover?

In addition, I have been told that when I start the truck, I “might” smell gas and that is telling me that my membrane on my Fuel Pressure Regulator is ruptured, and I do smell gas when I start it but I cannot be sure if it is gas leaking from the Fuel Pressure Regulator or if is because I just dumped gas in the Throttle Body.

So, the day I replaced the dry rotted vacuum lines (3 days ago), I had the guy at AutoZone run the codes on my engine since the “service engine soon” light was on. It came back with “MAF or VAF Signal Low” as well as one of my O2 sensors was bad again.

In addition to this, I moved from Maryland to Florida 2 weeks ago. One morning while driving, the truck just started to lose all power as I was driving. I was going 80 mph and then all the sudden, no matter what, the truck just kept slowing down. The more gas I gave it, the more it would bog down. I pulled over and after checking most everything; I pulled the cover off the Air Filter Housing to make sure there was nothing inside the air filter housing stopping air from entering the engine. The engine was running and when I stuck my hand inside the tube that takes the air from the air filter to my throttle body to make sure there was nothing in front of the MAF (Mass Airflow Sensor), the engine started to “bog down”.

Important note: I made sure I didn’t disrupt or “stop” the airflow going into the throttle body while checking the MAF and it started to “bog down” with what just seemed like the heat from my hand.

I disconnected the MAF sensor connector as well as the other sensor wiring (Which I am assuming is the VAF sensor which is mounted directly behind the MAF sensor in the rubber tube) and the I was able to get the truck back up to 80 mph on the highway but it still “bogs down” and stalls out when I give it gas from a standstill and I still have to feather the clutch but at least I can drive on the highway now. In addition, I still have the wires/connectors to the MAF and other sensor located directly behind the MAF disconnected. Also, it takes like forever to get the truck up to 60 mph.

3. I have read that if I “clean” the MAF sensor, all my problems will disappear. How do I clean the MAF sensor, with gas or some solution? What can't I clean the MAF sensor with? And please, I don’t need any “safety warnings” about using gas to clean anything, just tell me if gas or something else is better to clean the MAF with.

On another forum, I read that the possible problem in the EGR valve which I have mounted where it is supposed to be. I read that I need to “strike the housing of the EGR valve with a hammer or a piece of pipe so I can reach the housing” when the engine is running and listen if the engine runs better. If so, I need to replace the EGR valve.

I have read that the 2 most common problems are the A) Fuel Pressure Regulator (Which I cannot find on my trucks engine) or the B) EGR valve sticking.

I’ve used assorted fuel injector cleaners multiple times in an effort to perhaps help the fuel injectors. I keep the truck tuned (cap, rotor, plugs, filters, etc) and change the oil every 3,000 miles with the manufacturers specified oil.

4. Where oh where is my Fuel Pressure Regulator on my truck?

5. Is there some other way to check the EGR valve without beating it?

6. Can I “bypass” the MAF sensor the check and see if this is really the problem?

Please help me! Tell me how to fix this truck without having to take it to a dealership to have the codes read on a real analyzer or without buying part after part and “shooting in the dark” all the time.

In addition, I can add pictures at any time as I have a digital camera at my disposal at any time!
Thursday, November 1st, 2007 AT 8:23 AM

37 Replies

Tiny
CHEVY22
  • MECHANIC
  • 1,375 POSTS
Hi,

i am going to try and make this easy , all of the parts you had listed could be failed and i could probably give you a dozen more , start simple , don't replace parts that aren't known bad . my suggestion would be to borrow a fuel pressure gauge and check the pressure on prime , it should be 55-62 psi and hold , if you have the correct pressure and it bleeds down withing 10-15 minutes it may be a regulator which is located under the upper intake in the rear and mounted to the metering body by one c clip , now if the pressure is low it may be a fuel pump , but check the pressure first , and let us know after this part is done and we will work on anything else after.

These guides will help us fix it

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

and

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run down these guides and report back.

Jim
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Tuesday, May 26th, 2020 AT 11:45 AM
Tiny
TONYB63
  • MEMBER
  • 2 POSTS
Jim,

2 things.

1. About 2 years ago, I replaced the fuel pump. I also replaced the fuel filter which was insanely clogged which is why I am assuming is why the fuel pump failed in the first place.

In addition, the fuel pump makes the sound for 2 seconds as soon as I turn the key forward before starting the engine so I know its at least pumping fuel to the engine. When I replaced the fuel pump, the engine ran fine but then it slowly started getting harder and harder to start until it stopped starting and I have to dump gas in the throttle body before I crank it to start it. I will check the fuel pressure this week or this weekend.

2.I do not understand where you are telling me the "fuel pressure regulator" is located. Do i need to remove the "intake manifold" to get to the fuel pressure regulator? Is it actually mounted on the fuel rail? Are there any pics or diagrams you could show me or direct me to so i can see exactly where the regulator is located?

I found this image online on another website. Is this fuel pressure regulator (92 thru 95 4.3 Vortec) in the same place as mine (1999 Vortec) located under the intake manifold?


https://www.2carpros.com/forum/automotive_pictures/112705_IM000109_1.jpg

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Tuesday, May 26th, 2020 AT 11:45 AM
Tiny
CHEVY22
  • MECHANIC
  • 1,375 POSTS
I can't find a picture, but yes the upper intake has to come off, once it is off the regulator is back by the distributor.
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Tuesday, May 26th, 2020 AT 11:45 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
After reviewing all this info, I am pretty confident that the issue is fuel related. We just need to limit down the possible causes. The regulator could definitely be the issue and needs to be tested. I attached the process to replace and disassemble the regulator but more importantly is the testing of the fuel system.

We need to completely run through this test and identify the issue in the fuel system. I would highly suggest this is done prior to removing the intake manifold to replace the regulator.

As stated you should have above 60 PSI when you turn the key on and if you don't then that confirms it is a pressure issue then it is a matter of identifying the cause. Don't get caught in the trap of having replaced the pump or any other part in the recent past. Unfortunately we get faulty parts out of the box. We have all been burned by that so if it has been a few years, it could have definitely failed.

I think it is clear that you and others suspect this is a fuel issue so the only way to track this down is run through this material. Please report back and we can go from there. Thanks
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Tuesday, May 26th, 2020 AT 11:45 AM
Tiny
JCLR5KIDS
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET BLAZER
Engine Mechanical problem
1999 Chevy Blazer Four Wheel Drive Automatic

I have to turn key on and off 4or 5 times so fuel pump will pump gas to carb. After it sets for more than 12 hr. What causes the problum?
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
You have to either have a bad / weak fuel pump or a leak. Have you checked fuel pump pressure and fuel pressure drop off?
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
DELOVALY
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET BLAZER
Engine Performance problem
1999 Chevy Blazer 6 cyl Two Wheel Drive Automatic

I suspect the PCV valve but cant locate it per the manual It shows at the top of the engine but cant locate Please help
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Positive Crankcase Ventilation Valve Location:

Throttle Position (TP) Sensor, Idle Air Control (IAC) Valve, And Positive Crankcase Ventilation Valve (PVC)


https://www.2carpros.com/forum/automotive_pictures/12900_pcv_13.jpg



https://www.2carpros.com/kpages/auto_repair_manuals_alldata.htm
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
BILL LOWE
  • MEMBER
  • 2 POSTS
  • 1999 CHEVROLET BLAZER
  • 18 MILES
It cranks fast and trys to start but I can smell rich fuel odor. Checked the fuel pressure its ok. The firing is good and after it does start the first time its ok all day unless it sits for a long period of time.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
CADIEMAN
  • MECHANIC
  • 3,544 POSTS
Check your charging system and battery and for a draw on the battery.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
What is the fuel pressure readings? FPR or Nut Kit could be leaking making it to run rich
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
BILL LOWE
  • MEMBER
  • 2 POSTS
Fuel pressure is between 55 to 60 psi
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
TURBO_TM
  • MEMBER
  • 1 POST
  • 1999 CHEVROLET BLAZER
Other Category problem
1999 Chevy Blazer Engine Size unknown Four Wheel Drive Automatic 115736 miles

I recently have been having troubles with my 1999 Blazer starting. I thought at first it was water in my gas. I put some dry gas in it and after holding the gas pedel to the floor for about 5 minutes it started. Well I recently figured out that that wasn't the problem. I have noticed that if I don't drive it for about 10 hours or so is when it acts up. What could be the reason for this? Please HELP!


http://www.2carpros.com/forum/automotive_pictures/129692_100_0436_1.jpg

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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Have the coolant temperature sensor tested-this is the one that calls for fuel enrichment during initial cold starts-then the computer lengthen the pulse width to increase fuel till the engine comes up to its normal operating temperature at which time the oxygen/s takes over the fuel control.

Might also want to get the fuel pressure checked.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
JPATTON8
  • MEMBER
  • 12 POSTS
  • 1999 CHEVROLET BLAZER
  • 4.3L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 184,000 MILES
My vehicle starts right up first thing in the morning. Then it will start right up if I restart it within about ten to fifteen minutes of turning it off. Anymore than that and it has to crank for three to six seconds before starting. After starting it runs fine.
I have replaced the fuel spider, crank sensor. And fuel pump and filter two years ago. At first it just did it every once and awhile, but now every time it sits for more than about fifteen minutes. But like I said it starts right up first thing in the morning and always runs fine after starting.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening.

You need to start by monitoring the fuel pressure while this happens. There is a port on the fuel rail back by the cap and you need a pressure gauge to attach to it. If you do not have one, you can rent one at a parts store for this test.

Roy
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
JSPATTON
  • MEMBER
  • 4 POSTS
  • 1999 CHEVROLET BLAZER
  • 4.3L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 183,500 MILES
I started having a hard start problem awhile back. It started out only happening every once in awhile, then got to where it would have to crank for a few seconds before starting after sitting for ten to twenty minutes or more. Normally my truck starts right up as soon as you hit the key. I looked in the throttle opening and it looked like one side was washed out so I replaced the whole spider assembly with an updated unit with individual injectors at the ends instead of the poppets. It ran fine after for about a week or two then started having the same problem. I replaced the fuel pump and filter two years ago and I have checked the fuel pressure and it seems fine. I also replaced the distributor cap, rotor, plugs and wires when I replaced the pump. Now it has gotten to where it cranks longer all the time except if I restart it within about ten minutes or less. Then I starts right up. It runs fine once it starts and the are no codes. I have used a scanner with live data and the fuel trim and everything seems fine. I cannot figure it out. It cranks for three or four seconds then sputters just a little, then runs fine. It has gotten to where it does it whether it is hot or cold. Like I said, the only time it does not do it now is if I restart it within about ten minutes.
Fuel pressure is about 60 when primed and 50 when idling. It goes to 55 when engine is shut off.

These are all reading at idle:
load pct (%) 3.1
ect(f) 172
shrt trim (%) -.8 to 1.6
long t .0
short t 0 to -1.6
long -4.7
map (psi) 5.2
spark adv (degree) 18.5 to 20
iat (f) 68
maf (lb/s).01
t.P..0
o2b1s1 (v).15 to.86
shrt ft b1s1 (%) 1.6 to -5.6
o2b1s3 (v).39 to.63
shrt ft b1s3 (%) 99.2
o2b2s1(v).28 to.92
shrt ft b2s1 (%) 1.6 to -1.6
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
The fuel pump has a check valve (aka, one way valve) in it that helps hold fuel pressure in the line when the truck is not running. A weak or leaky check valve will allow the pressure to drop, requiring you to prime the fuel system before you start the engine.

Also, a clogged fuel filter would make the pump take longer to build the fuel pressure. I know you said that you replaced it two years ago, but I would go ahead and get a new one. It is cheap and easy to do.

Try turning the key on for three seconds, then off, and then on again for two or three seconds, and then cranking it. I bet you will notice that it gets much easier to start when you do that. My 2002 has been the same way for a few weeks. Like you, I have recently replaced the pump and filter, along with a full tune up, and have no check engine light.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
JSPATTON
  • MEMBER
  • 4 POSTS
Went ahead and did a leak down test and it is leaking slowly. All the other videos I have seen shows the pressure leaking off in a few minutes or less. Mine is much slower, but it is leaking off.
When I turn the truck off it is at 55 psi.
After ten minutes it only goes down to 54 psi.
Then after twenty five minutes it is down to 45 psi.
After thirty minutes 35 psi.
After forty five minutes 28 psi.
After one hour twenty minutes 19 psi.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)
Tiny
JSPATTON
  • MEMBER
  • 4 POSTS
Also, I cycled the key on and off five times and it did not help it start any better. It still took three to four seconds of cranking to start. I do not know if that changes anything or not.
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Thursday, September 10th, 2020 AT 12:42 PM (Merged)

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