rough runnuing 4.3

[soberdude94]

I have a 95 jimmy that is running rough at idle and surges under load. I have replaced the wires and plugs. tried to adust timming but it does nothing when I turn the distributer in either direction. I also have a few vacum lines that are just pluged 1 is in the middle of the fire wall on drivers side it is about 3/8 in size the other 2 are at the back of the engine 1 above the fuel inlet it is capped off the last is a line that comes up around the distributer it is also about 3/8 in size I also need to add there are no Engine codes at all. please help if you can.

 

[Vacdaddyt]

Rough running

Does it almost stall at idle? There are two variations of 95 ignition, early is similar to the 94 year with vertical towers on the cap. The later uses a crankshaft sensor and the wires come out the side of the cap.With both the timing is non-adjustable with the computer setting it. The distributor is there more as a fixture that delivers the spark to the plug and is for base timing only.If it is almost stalling the egr is stuck open with carbon, I also ran sea-foam through it for awhile. If it is loping like mine I had to change the fuel pressure regulator under the intake plenum. The egr problem should code and it happens more often with short trips. After that you need to get a scanner that can diagnose the system. There probably is other things but that is what happened on my 95 Jimmy. Good luck.

 

[soberdude94]

Does it almost stall at idle? There are two variations of 95 ignition, early is similar to the 94 year with vertical towers on the cap. The later uses a crankshaft sensor and the wires come out the side of the cap.With both the timing is non-adjustable with the computer setting it. The distributor is there more as a fixture that delivers the spark to the plug and is for base timing only.If it is almost stalling the egr is stuck open with carbon, I also ran sea-foam through it for awhile. If it is loping like mine I had to change the fuel pressure regulator under the intake plenum. The egr problem should code and it happens more often with short trips. After that you need to get a scanner that can diagnose the system. There probably is other things but that is what happened on my 95 Jimmy. Good luck.

The EGR is pretty new and there are no codes at all what kind of scanner are you talking about? yes when it is warm it wants to and does at times stall and surges intermitenly while driving.

 

[Molson02536]

I have a 95 jimmy that is running rough at idle and surges under load. I have replaced the wires and plugs. tried to adust timming but it does nothing when I turn the distributer in either direction. I also have a few vacum lines that are just pluged 1 is in the middle of the fire wall on drivers side it is about 3/8 in size the other 2 are at the back of the engine 1 above the fuel inlet it is capped off the last is a line that comes up around the distributer it is also about 3/8 in size I also need to add there are no Engine codes at all. please help if you can.

Your timing chain may be worn out and stretched and will need to be replaced.
1. The timing mark should line up at TDC of # 1 piston.
2. Crank damper/pulley mark may be off or slipped pulley or wrong crank damper.
To check for slack in timing chain move crank left and right hand turn and feel for the slack in chain.
If pointer is not lining up set # 1 piston at TDC compression stroke.

Timing is not adjustable but the dist rotor pointer will need to be set to line up with plug wires terminal.
You will need to get a engine capable scanner and set camshaft retard reading in scanner as close to 0 degrees - or + as you can get it.
The engine will need speeded up over 1K rpm for the reading to readjust after moving dist.

If engine runs good your timing chain is good.
To check camshaft timing and chain set no one piston TDC and on compression stroke. Then watch the rocker arms on opposite firing cylinder no 4 on V6. They should be rocking one opening and one closing as no 1 cylinder rolls over TDC compression. If so chain and gears are set right and are good. Let us know how yours checks out.

 

[soberdude94]

Your timing chain may be worn out and stretched and will need to be replaced.
1. The timing mark should line up at TDC of # 1 piston.
2. Crank damper/pulley mark may be off or slipped pulley or wrong crank damper.
To check for slack in timing chain move crank left and right hand turn and feel for the slack in chain.
If pointer is not lining up set # 1 piston at TDC compression stroke.

Timing is not adjustable but the dist rotor pointer will need to be set to line up with plug wires terminal.
You will need to get a engine capable scanner and set camshaft retard reading in scanner as close to 0 degrees - or + as you can get it.
The engine will need speeded up over 1K rpm for the reading to readjust after moving dist.

If engine runs good your timing chain is good.
To check camshaft timing and chain set no one piston TDC and on compression stroke. Then watch the rocker arms on opposite firing cylinder no 4 on V6. They should be rocking one opening and one closing as no 1 cylinder rolls over TDC compression. If so chain and gears are set right and are good. Let us know how yours checks out.

All checks out well it wants to die sometimes at idle when hot other times very smooth surges like it is starving for gas when running down the road almost like it is about to run out of gas. but not always just most of the time./