help with chevy truck

doug schriener · 03-31-2011, 06:50 PM

Quote:

Originally Posted by Tod Lane

I too hyave a 95 Chevy truck with about 200,000 miles on it. Would this dist shaft problem cause low HP/Sluggish performance and lowered fuel mileage?

No missfire I can hear, you do have to pump it a couple times to start it.

Recent plugs wires and cap, maybe 15,000 miles

The truck burns no oil, compression is good in all eight Cyls. It almost feels like the Cat Con is plugged.

Tod-Have you checked the timing per the advice on this thread? Be certain that you're getting your full ignition advance-we all know how doggy that can feel-if you have never replaced the shaft in the dist. I would just in the interest of good maintenance.The timing tag under the hood will give advice on checking timing also so you should have lotsa help there-good luck. Doug Schriener

buzzinhalfdozen · 04-02-2011, 08:50 PM

Sound like Tod Lane hit it, I'd look at The Catalytic convertor. Still sounds as if you have a base timing issue after that is resolved if it still has no power remove the frt, o2 sensor and adapt a pressur gage to the hole start engine should not see more than 1-3 psi at 1500 RPM

Lew Silverman · 04-02-2011, 09:22 PM

The engine still should run with the brown wire disconnected. The initial timing should be enough to at least let the motor idle. Whatever the label says to set the timing, say 4-degrees before TDC, with the brown wire disconnected, should set the MIL light and a code in the ECM, so you'll have to clear both after you're done with the timing.

Did you have any codes stored in the ECM after the motor started to exhibit the stumble? OBD ll vehicles are usually (but not always) easier to diagnose because of the codes they throw. It might pay to have someone hook a scanner to it, if you haven't done so already. I had a neighbor who's Firebird had a terrible stumble off idle, hooked the scanner up and found the ignition system wasn't advancing the timing at all! No hair pulling necessary!

Just a few ideas...............

Lew

Ed Wright · 04-02-2011, 10:42 PM

If somebody previously set the timing without unplugging the tan/black wire it will be too retarded when it is unplugged. Most of those should show 12 to 16 deg BTDC with the wire plugged in. Might check it that way. If it's on zero, give the dist a twist so it will stay running when unplugged.

04-02-2011, 08:50 PM	#2
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: help with chevy truck Sound like Tod Lane hit it, I'd look at The Catalytic convertor. Still sounds as if you have a base timing issue after that is resolved if it still has no power remove the frt, o2 sensor and adapt a pressur gage to the hole start engine should not see more than 1-3 psi at 1500 RPM __________________ Joe Buchanan SS/BX 3117

04-02-2011, 09:22 PM	#3
Lew Silverman VIP Member Join Date: Mar 2010 Location: Newport News, VA Posts: 1,435 Likes: 371 Liked 129 Times in 59 Posts	Re: help with chevy truck The engine still should run with the brown wire disconnected. The initial timing should be enough to at least let the motor idle. Whatever the label says to set the timing, say 4-degrees before TDC, with the brown wire disconnected, should set the MIL light and a code in the ECM, so you'll have to clear both after you're done with the timing. Did you have any codes stored in the ECM after the motor started to exhibit the stumble? OBD ll vehicles are usually (but not always) easier to diagnose because of the codes they throw. It might pay to have someone hook a scanner to it, if you haven't done so already. I had a neighbor who's Firebird had a terrible stumble off idle, hooked the scanner up and found the ignition system wasn't advancing the timing at all! No hair pulling necessary! Just a few ideas............... Lew __________________ Lew Silverman #2070 "The Wagon Master" N/SA

04-02-2011, 10:42 PM	#4
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: help with chevy truck If somebody previously set the timing without unplugging the tan/black wire it will be too retarded when it is unplugged. Most of those should show 12 to 16 deg BTDC with the wire plugged in. Might check it that way. If it's on zero, give the dist a twist so it will stay running when unplugged. __________________ Ed Wright 4156 SS/JA