Cold start mess>???

dogdays · June 17, 2002

My 93 Suburban is stock except for Gibson cat-back and Accel 300+ ignition. For the last 80,000 miles, or since I got it, it has had a definite problem with cold starts. and the colder the temp the worse it is.

As I turn the key for the first time the injctors will dump fuel for about 3 seconds, and then go to more normal operation. The engine will run rough for the first 30 seconds or so, and it's running so rich that the fumes outside make your eyes water! I have replaced the injectors and fuel pressure regulator with those from another running truck, changed the coolant temp sensor, nothing wrong with the old one, messed with the EGR to make sure it was closed, cleaned uptthe idle air control valve, seems to work fine. and went to new plugs, wires, cap, module, and Accel 300+ which helped a LITTLE. I have also replaced the O2 sensor with no noticeable difference.

WHAT the heck is going on?

Rich

dogdays · June 18, 2002

Oh, forgot to say that I checked out the TPS, no glitches, and that after disconnecting the battery for a couple of days no change.

R.

Colorado Kid · June 21, 2002

Still got the warm air system set up? (The stock air cleaner and snorkle, with the little tube to bring air up past the exhaust manifold, and the little door in the snorkle working properly)? You don't say where you are from, but at high elevation this is pretty common. The warm air system helps, and I always recommend just start it up and drive it off (gently) to get it warmed up quickly. (I know what you are all going to say, but it hasn't noticably damaged my '91 in the first 178,000 miles).

Not surprised that the O2 sensor made no noticable difference, ECM doesn't even look at it until it goes "closed loop" at normal operating temp.

MAP (Mannifold Absolute Pressure) sensor is still a suspect, but not likely since it runs OK warm.

I'll have to go back to the books to see if it has an IAT (Intake Air Temp) sensor, but if it does that is a suspect (and a pretty good one) as well.

Good Luck.