gmrulz4u Posted August 1, 2003 Report Share Posted August 1, 2003 My 89 Supreme has been running RICH and had overall performance problems for what seems like forever now! Yesderday I had ALL the vacuum lines replaced with brand NEW ones! The only one left that I haven't touched is the steel line that goes to the transmissions Vacuum Modulator. I replaced the 4 lines coming out of the Throttle Body, the PCV's line, and the brake booster line! I get 18" hg(vacuum) at idle, which is good. The O2 Sensor is new, the EGR valve is only 2 years old. Yesterday when I had the upper plenum and TB off, I cleaned EVERYWHERE with Throttle Body Cleaner, and it made NO difference. The Fuel Pressure Regulator is not ruptured and leaking any gas at all, none of the Fuel Injectors are leaking any gas at all, so I'm at a loss!? I recently bought a Fuel Pressure Gauge but haven't had a chance to check the pressure... The worst symptom I have right now is accelerating. It's not exhaust related because it's all New from the intake back...new muffler, new cat, new pipes etc...etc... I don't know whether it's related or not, but my 1-2 Upshift is poor. Every other shift is good, but the 1-2 is always HARSH, and usually delayed. The Vacuum Modulator is New, and from what I read online and in books, a bad or misadjusted Modulator will cause HARSHNESS in ALL shifts, not just one. Sometimes when I accelerate into 2nd, I let off the throttle quite a bit because it "feels" like if I don't, the RPMs will go too high, and the shift will be harder... I have a scanner and am able to see basically everything the ECM sees, and besides the RICHNESS, everything else looks good. One thing that I'm not 100% sure of though is this: Do most engines run LEAN for the first 3 seconds or so of acceleration? Because my O2 Sensor and Integrator(goes up to 160) numbers show that it goes quite LEAN for the first 3 seconds of accelerating. It's not enough to effect the Block Learn numbers though, because they're always way too low. Now I would normally think it must be a Fuel Pump problem, but how the hell could a bad Fuel Pump cause a car to run RICH all other times OTHER than acceleration?? I've never heard of a Fuel Pump causing a car to run RICH, because the Fuel Pressure Regulator REGULATES the psi. The one and ONLY thing I have NOT checked is the Charcoal Canister. I understand that this CAN cause an engine to run overly RICH, but I'm not too sure on HOW I can check it, or at least disable it temporarily? I'm almost at my whits-end... Anyone got any further suggestions?? Do you think the HARSH 1-2 Upshift could be related to the car running RICH, somehow?? THANKS! A few other important clues: The HOTTER the engines gets, the WORSE the RICH condition gets! Also, when the vacuum is at it's HIGHEST point, such as idle but mostly deceleration, the ECM is reporting an OVERLY RICH condition... Quote Link to comment Share on other sites More sharing options...
Vegeta Posted August 1, 2003 Report Share Posted August 1, 2003 unplug the return line to the cannister purge. I have mine ran to the wheel well. That will take care of it as a suspect. Definetly check the pressure, and the flow of the pump. You can have perfect pressure but low flow. Have you ran top engine cleaner through the intakes? How are your coils plugs and wires? Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted August 1, 2003 Author Report Share Posted August 1, 2003 Yeah my ENTIRE Ignition is brand spaking new...coils, module, plugs, wires etc...all AC Delco... I have to be under the car in order to disconnect the Return Line, right? Will that cause fuel to "spill" out of the canister?? THANKS! Quote Link to comment Share on other sites More sharing options...
Brian P Posted August 2, 2003 Report Share Posted August 2, 2003 How about replacing the ecm with a known good one Quote Link to comment Share on other sites More sharing options...
gmrulz4u Posted August 2, 2003 Author Report Share Posted August 2, 2003 Yeah, the ECM is going to be last on my list...after I've made SURE everything else is not the culprit... Quote Link to comment Share on other sites More sharing options...
NeverSayDie Posted August 2, 2003 Report Share Posted August 2, 2003 i would change the ecm now, before you've SURE spent a G! Quote Link to comment Share on other sites More sharing options...
Brian P Posted August 3, 2003 Report Share Posted August 3, 2003 change the damn ECM already Quote Link to comment Share on other sites More sharing options...
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