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98 blazer rough idle

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Old Nov 10, 2024 | 01:17 PM
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Also I couldn't upload the last screenshot as I have poor WiFi.
This is the data...
Fuel trim Bank 2 Sensor 1, Latest value. - 3.12%
 
Old Nov 10, 2024 | 01:27 PM
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Also, after thought I have just posted at Idle.
I will redo and come back at 2500rpms
 
Old Nov 11, 2024 | 05:50 AM
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Hello,
Any upload the images of the results so I will post them instead....
START UP. IDLE. H RPM.. 2500RPM
COLD
​​
FTLT B1 7.03%. 7.03,%. 7.03%. - 7.03%
FTST B1. 0%. 3.12%. - 0.78%. - 0.78%
FTLT B2. 1.56%. 1.56%. 1.56%. - 8.59%
FTST B2. 0%. 3.91%. 0%. -9.38%
 
Old Nov 11, 2024 | 08:08 AM
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Originally Posted by John bates
Hello,
Any upload the images of the results so I will post them instead....
START UP. IDLE. H RPM.. 2500RPM
COLD
​​
FTLT B1 7.03%. 7.03,%. 7.03%. - 7.03%
FTST B1. 0%. 3.12%. - 0.78%. - 0.78%
FTLT B2. 1.56%. 1.56%. 1.56%. - 8.59%
FTST B2. 0%. 3.91%. 0%. -9.38%
Those values suggest a significant vacuum leak. Have you gone through that process yet?

George
 
Old Nov 11, 2024 | 10:33 AM
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Originally Posted by GeorgeLG
Those values suggest a significant vacuum leak. Have you gone through that process yet?

George
No I haven't looked into vacuum leaks too much.
I changed EGR valve, Maf, IAT
Made sure air intake was sealed along with pipe that goes to valve cover
 
Old Nov 11, 2024 | 10:39 AM
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Originally Posted by John bates
No I haven't looked into vacuum leaks too much.
I changed EGR valve, Maf, IAT
Made sure air intake was sealed along with pipe that goes to valve cover
I would go through the process. There’s a few different ways to approach this, usually with some combination of pinching off hoses and spraying propane, brake cleaner, or water, and watching RPMs.

Have you done the lower intake, manifold gaskets yet?

also, if we’re going to start getting in the misfire detection, you’re gonna need to make sure your CMP retard is within spec.

George
 
Old Nov 11, 2024 | 12:18 PM
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Ok, the car still runs good for a minute or so from cold before running rich.
What android app can I use to check cam retard?

Back history for the truck,
Cylinder heads changed for new 1 year ago
New intake gaskets
Ran great to start with but slowly deteriorated.
It would alway spluttering on acceleration after deceleration and braking.

 
Old Nov 11, 2024 | 01:37 PM
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Cmp is - 5.8 degrees
So I need to sort this.
Must of been when I done the intake manifold.
Distributor was a pain to get right.
 
Old Nov 11, 2024 | 02:22 PM
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Originally Posted by John bates
Cmp is - 5.8 degrees
So I need to sort this.
Must of been when I done the intake manifold.
Distributor was a pain to get right.
Youdo need to get CMP retard sorted but you’re not off by a tooth. You just need to modify the hold down and rotate the distributor until you get within spec. How do you know the truck is running Rich? I thought you said the spark plugs were clean

George
 

Last edited by GeorgeLG; Nov 11, 2024 at 02:29 PM.
Old Nov 11, 2024 | 02:41 PM
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Originally Posted by GeorgeLG
Youdo need to get CMP retard sorted but you’re not off by a tooth. You just need to modify the hold down and rotate the distributor until you get within spec. How do you know the truck is running Rich? I thought you said the spark plugs were clean

George
The spark plugs are clean but just assuming its rich as smells like raw fuel out of the tail pipe with black and sooty around the tip of the exhuast too.
 



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