4.3 hard start

[hoosier]

 

newbie needs help i have a 4.3 that i replaced the factory plugs with bosch platinums to try and eliminate a hard start prob.have since had cat converter rplaced dist cap and rotary all by dealer but still have hard start was going back today and check to see if plugs were at the proper gap iassumed they were any ideas appreciated

[asepgrad98]

fuel pressure regulator?

[rdnkcpa]

You have to figure out if you have a spark problem or a fuel problem. If you don't figure out which, you'll just end up throwing a bunch of parts at it and spending way too much money.

[sjspor]

If you are sure this started with the cat replacement and cap rotor, I'd start there, the cap and rotor. A real bad one will have black goo inside, not just dried crud.

 

Make sure all the plug wires are in good, and if they are pull the cap look at it. Make sure they replaced it AND the rotor. What happens is the 01-03 Trucks the distributor was not vented enough to allow mostiure to escape. And when you add the Air Cond. Suction line that sweats all summer long right on top it, it makes a huge mess in there.

 

If they just replaced the cap, and left the rotor in there with its pitted contact to the coil, that may cause that too.

 

You'll need a small set of Magnetic TORX tools, I suggest a 1/4" drive set you can use with a handle. I keep em in the front seat of my truck.

 

 

Here's the bullitin. Bulliting #03-06-04-041 published on 08/26/2003.

 

-------------------------

Poor Engine Performance - Misfire, Rough Idle, Service Engine Soon/Check Engine Light Illuminated, DTC P0300 Set (Inspect DIstributor Ignition (DI) System Components and Replace As Necessary) #03-06-04-041 - (08/26/2003)

Poor Engine Performance -- Misfire, Rough Idle, Service Engine Soon/Check Engine Light Illuminated, DTC P0300 Set (Inspect Distributor Ignition (DI) System Components and Replace As Necessary)

2001-2003 Chevrolet Astro, Blazer, Express, S-10, Silverado

 

2001-2003 GMC Jimmy, Safari, Savana, Sierra, Sonoma

 

2001 Oldsmobile Bravada

 

with 4.3L, 5.0L or 5.7L Gas Engine (VINs W, X, M, R -- RPOs L35, LU3, L30, L31)

 

Condition

Some customers may comment on poor engine performance and the Service Engine Soon/Check Engine light being illuminated. Upon investigation, the technician may find DTC P0300 set.

 

Cause

This condition may be due to high levels of internal corrosion in the distributor, causing spark to go to the wrong cylinder. This corrosion is attributed to a lack of air flow internal to the cap caused by the EIP screens being clogged with debris.

 

Correction

Inspect the internal components of the Distributor Ignition System using the procedure listed below. A new distributor base has been released for service with improved airflow screens.

 

Inspect the distributor cap. You may notice a white residue on the cap walls. For higher mileage occurrences, the interior of the cap may have changed to medium brown in color.

Inspect the distributor rotor. You may notice the presence of black streaks on the plastic surface. More typical evidence would be visible green spots on the copper surface of the rotor segment.

Inspect the distributor base. You may notice high levels of surface rust on the distributor shaft or surface contamination on the sensor hold down screws.

Inspect the distributor EIP screen. The screens should be free of any debris and the mesh should be visibly porous.

All of these inspection can be done on-vehicle. If there is evidence of this internal corrosion, replace the affected component. Refer to the appropriate procedure in the Engine Controls sub-section of the applicable Service Manual.

 

In addition, it has been determined on the Sierra and Silverado applications with the 4.3L engine that the A/C accumulator line is routed directly above the distributor area and condensation from that line can aggravate the corrosion condition. For these vehicles, install the foam sleeve, P/N 15190971, to the A/C line. Cut a slit in the sleeve and secure to the line using tie-straps.

 

Parts Information

Part Number

Description

 

10452458

Cap, Distributor (V6)

 

10452457

Rotor, Distributor (V6 and V8)

 

93441559

Distributor (V6)

 

10452459

Cap, Distributor (V8)

 

93441558

Distributor (V8)

 

15190971

Foam Sleeve