GSLSE Running rich but idles fine, Expert help needed
04-03-16, 01:01 PM
#1
RE-active Again
Thread Starter
GSLSE Running rich but idles fine, Expert help needed
Hi everyone,
I've been tracing an issue with my stock 110k se for a couple of months now. I have tried pretty much everything as I have another running se which runs great and swapped out every major component. The issue is: starts right up, idles fine, except when engine speed goes past 1,100 at cold start or if you feather the pedal, it starts running very rich, brap brap or just very dirty firing. It runs rough all the way to high rpm. Everything is checking out ok so far expect for the split air solenoid, it is not checking as it should per the service manual. Really frustrated! Any experience with anything like this? btw TPS has been adjusted properly, no vacuum leaks, coolant sensor checked, afm checked, air temp sensors checked, neutral and 5 gear sw checked, new fuel pump, filter, etc this is a clean unabused car. I have checked all the wiring to the ECU and everything is checking good too. Any help will be much appreciated. I did a search but nothing came up. If anyone prefers to talk about it via cel, I can be reached at: 6177846478.
I've been tracing an issue with my stock 110k se for a couple of months now. I have tried pretty much everything as I have another running se which runs great and swapped out every major component. The issue is: starts right up, idles fine, except when engine speed goes past 1,100 at cold start or if you feather the pedal, it starts running very rich, brap brap or just very dirty firing. It runs rough all the way to high rpm. Everything is checking out ok so far expect for the split air solenoid, it is not checking as it should per the service manual. Really frustrated! Any experience with anything like this? btw TPS has been adjusted properly, no vacuum leaks, coolant sensor checked, afm checked, air temp sensors checked, neutral and 5 gear sw checked, new fuel pump, filter, etc this is a clean unabused car. I have checked all the wiring to the ECU and everything is checking good too. Any help will be much appreciated. I did a search but nothing came up. If anyone prefers to talk about it via cel, I can be reached at: 6177846478.
04-06-16, 02:09 AM
#2
84SE-EGI helpy-helperton
I am here, my Master...
I read your note twice; have you checked the '6'-port actuators to be sure you're getting good pressure (4-6psi at WOT) and that they're rotating the sleeves properly? The ghetto check is to put a dab of grease on the shaft at rest, and then go drive the everlovingshit out of the car, then check to see if the grease has been displaced by the actuator rods moving up and down. This would give a slow rise to RPM under WOT, and could lead to rich mixture at anything more than idle speed.
Secondly, Injectors - If yours haven't been cleaned and flow-balanced in awhile, it might be worth a trip to RC performance or a local injector shop. These are 680cc x2 injectors and a bad/leaky injector will flow enough to cause rich mixture at high duty cycle. Along with cleaning, put in new seals to be sure you're not getting a vacuum leak at the injector bungs to the block.
Thirdly, Fuel Pressure Regulator (long shot, but there it is) - Vacuum-actuated, the fuel pressure regulator bumps up fuel pressure at WOT conditions through a vacuum source on the RE-EGI chamber. If you have a vacuum leak here, or a stuck Regulator, it may not shunt the return line enough to get proper fuel pressure. This would suggest lean mixture, but have a look anyway.
Fourthly, Airflow Meter - A sticking AFM will lead to lean mixture, but at the age of these cars, it's worth sticking a chopstick in the air filter channel with the filter out and making sure the air door moves freely and smoothly across the entire range. If you get any sticking, you may need to retrofit/replace. A sticking door would prevent the car from ever hitting RPM, so that's why it's further down the troubleshooting list.
Fifthly, (*or is that 'filthy'?) Plugs - Old plugs or fouled plugs won't fire cleanly and will cause rich exhaust symptoms. Check and/or replace plugs with the proper heat range.
Sixthly, Plug Wires & Cap/Rotor - Plug wires carry the high tension electrons and bad or shorting wires will kill conductivity and cause misfires. Cheap insurance and replace the coil leads, too. The Cap/Rotor can crack or build up carbon-traces on the inside which will cause internal shorts and lead to misfires. Clean it thoroughly inside and out and put conductive grease on the contacts to coil leads, coils, and plugs. Ignitors are the only other thing, and you'd know if your trailing ignitor was bad because you wouldn't have a tach signal - or fuel injection timing, for that matter. Bad leading ignitor will cause rough starting if it starts at all, so unlikely to be leading. Swap ignitors lead to trail to see if it changes anything - if not, ignitors are fine.
Seventh, because there's always a 'seventh' on this forum; in-tank fuel pickup - A crappy corroded tank will cause flakes of stuff to gather on the 'sock' which surrounds the fuel pickup float. Enough crap there will occlude the intake line and prevent enough fuel from reaching the pump, but that would look/feel like lean condition - so it's last on my list.
Have a look at those things and report back. Good luck,
I read your note twice; have you checked the '6'-port actuators to be sure you're getting good pressure (4-6psi at WOT) and that they're rotating the sleeves properly? The ghetto check is to put a dab of grease on the shaft at rest, and then go drive the everlovingshit out of the car, then check to see if the grease has been displaced by the actuator rods moving up and down. This would give a slow rise to RPM under WOT, and could lead to rich mixture at anything more than idle speed.
Secondly, Injectors - If yours haven't been cleaned and flow-balanced in awhile, it might be worth a trip to RC performance or a local injector shop. These are 680cc x2 injectors and a bad/leaky injector will flow enough to cause rich mixture at high duty cycle. Along with cleaning, put in new seals to be sure you're not getting a vacuum leak at the injector bungs to the block.
Thirdly, Fuel Pressure Regulator (long shot, but there it is) - Vacuum-actuated, the fuel pressure regulator bumps up fuel pressure at WOT conditions through a vacuum source on the RE-EGI chamber. If you have a vacuum leak here, or a stuck Regulator, it may not shunt the return line enough to get proper fuel pressure. This would suggest lean mixture, but have a look anyway.
Fourthly, Airflow Meter - A sticking AFM will lead to lean mixture, but at the age of these cars, it's worth sticking a chopstick in the air filter channel with the filter out and making sure the air door moves freely and smoothly across the entire range. If you get any sticking, you may need to retrofit/replace. A sticking door would prevent the car from ever hitting RPM, so that's why it's further down the troubleshooting list.
Fifthly, (*or is that 'filthy'?) Plugs - Old plugs or fouled plugs won't fire cleanly and will cause rich exhaust symptoms. Check and/or replace plugs with the proper heat range.
Sixthly, Plug Wires & Cap/Rotor - Plug wires carry the high tension electrons and bad or shorting wires will kill conductivity and cause misfires. Cheap insurance and replace the coil leads, too. The Cap/Rotor can crack or build up carbon-traces on the inside which will cause internal shorts and lead to misfires. Clean it thoroughly inside and out and put conductive grease on the contacts to coil leads, coils, and plugs. Ignitors are the only other thing, and you'd know if your trailing ignitor was bad because you wouldn't have a tach signal - or fuel injection timing, for that matter. Bad leading ignitor will cause rough starting if it starts at all, so unlikely to be leading. Swap ignitors lead to trail to see if it changes anything - if not, ignitors are fine.
Seventh, because there's always a 'seventh' on this forum; in-tank fuel pickup - A crappy corroded tank will cause flakes of stuff to gather on the 'sock' which surrounds the fuel pickup float. Enough crap there will occlude the intake line and prevent enough fuel from reaching the pump, but that would look/feel like lean condition - so it's last on my list.
Have a look at those things and report back. Good luck,
04-14-16, 08:40 PM
#3
RE-active Again
Thread Starter
Much thanks LongDuck! I know it is hard to troubleshoot without seeing or hearing the car. But I had checked all of those things you recommended already. Keep in mind I've been at this for over 2 months. I finally found and resolved the problem yesterday. The car had shut off on me a couple of time for no reason but it started again not allowing me to troubleshoot for a real issue but rather an intermittent one which proved to be difficult to nail down but finally!!!! It had a BAD MAIN RELAY. I went to start it yesterday and would not start due to no spark. I traced it and voila! found power coming into the relay but not coming out. Something to keep in mind for everyone out there with cars over 100K. It could leave you stranded without a warning. Have you seen this issue before? How often? Thanks again for coming to the rescue!! 
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