SlugHog

Just looking for opinions as I have some concerns. Will try to keep this short.

This is a 1994 4.3 litre Vortec with "W" in the VIN. Just for clarity.....

As I was about to leave a car wash, while attempting to start my Jimmy, it actually fired, then back fired. Towed the truck home and found my cylinders to be full of fuel and determined my CPI had failed open. Replaced the CPI, actually quite an easy procedure but now my engine runs very rough and when I took it for a little spin, there was some pinging. I actually let it idle for about ten minutes before taking it out on the road hoping the computer needed to lean with a new CPI in place and adjust some settings.

Did the oil change of course, new plugs, cap and rotor. Plug wires are fairly new so I decided to wait and see on those.

Does this sound like timing to you good folks?

I had done some searching here and appears I have to locate a brown wire on the passenger side inside the cab. Can anyone be a little more exacting on it's location and type of connector it uses.

I have a Chiltons book on my Jimmym and this is a quote from it.
Most later model vehicles are equipped with a single wire timing bypass connector. On these later model vehicles the bypass wire is usually a tan wire with a black stripe. This wire usually breaks out of the wiring harness conduit adjacent to the distributor. But on some vehicles this may brealk out of a taped section just below the heater case in the passenger compartment.

No where though does it explain what I should do with this.

SlugHog

MT-2500

EGR valve?
Check for a carbon ball under the plunger.

__________________
Remember proper testing gives us the answer to many problems.
MT

SlugHog

About four months ago I had the EGR off doing just that, was fairly clean, replaced the gasket and mounted the EGR. It must of been about then when my CPI started to periodically act up and was a month ago when it finally failed. It took a few weeks to get a replacement CPI. Durring this entire time I did not see the "Service Engine Soon" light and there were no codes as I checked for them by shorting out A+B at the diagnostic connector.

Checked for leaks before replacing CPI and after all the reading I have done here, will check periodically for this potential problem. That is if I can get this Jimmy back on the road.....

SlugHog

MT-2500

That looks like it. a single brown/black stripe wire.
If setting the base timing does not help have a look at the egr valve.
Good Luck.
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

SlugHog

Got it fixed and it was such a stupid problem and of course, my fault. The number six plug wire though snapped on to the distrubtor end, there was play. I have to assume an intermittent connection. Squeezed it a little, it snaps on and does not wobble up and down like it was doing. Looks like new plug wires on my list but it's runing not too bad. Just need to borrow a distributor wrench and advance the timing as it is slightly retarted, about 1 1/2 degrees.

Sorry about the large image, so I removed it. This site is awesome and I am telling al my buds about you folks here.....

Thanks and I am sure I'll be back....

SlugHog