Sabre 86
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3rd Gear
Joined: Dec 2005
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Sabre 86
91 L-98 running hot, rich, surging bad at idle to the point it wants to quit then does. Replaced IAC, MAF, EGR, Distributor, plugs, wires, rotor, thermostat, knock sensor, O2 OEM, timing about 7 degrees, new catalytic converters and mufflers. Injectors are pulsing correctly, Fuel pressure regulator was giving the right pressure. Auto shop totally stumped. Changed ECU to troubleshoot but did not replaced. Engine continued to the same thing. Has plenty of pull and runs real fast cold. Warms up and goes to pot. Other than changing the injectors (Multitec) Any body have any ideas
Last edited by sabre86; Jun 25, 2007 at 11:16 AM.
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Joined: Oct 2003
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From: Cave Creek AZ
91 L-98 running hot, rich, surging bad at idle to the point it wants to quit then does. Replaced IAC, MAF, EGR, Distributor, plugs, wires, rotor, thermostat, knock sensor, O2 OEM, timing about 7 degrees, new catalytic converters and mufflers. Injectors are pulsing correctly, Fuel pressure regulator was giving the right pressure. Auto shop totally stumped. Changed ECU to troubleshoot but did not replaced. Engine continued to the same thing. Has plenty of pull and runs real fast cold. Warms up and goes to pot. Other than changing the injectors (Multitec) Any body have any ideas
One thing you could try is to disconnect the plug going to the O2 sensor and run it in open loop. If it runs good in open loop then you may want to look for sensor feeback problems. You haven't replaced the MAP or engine coolant temp sensors yet.
Is this engine stock? Did you check the resistance of your injectors?
One thing you could try is to disconnect the plug going to the O2 sensor and run it in open loop. If it runs good in open loop then you may want to look for sensor feeback problems. You haven't replaced the MAP or engine coolant temp sensors yet.
Is this engine stock? Did you check the resistance of your injectors?
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3rd Gear
Joined: Dec 2005
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Changed the coolant sensor last night. I thought that might do it.
It got a tiny bit better but the surging did not totally go away. It still goes fast but you can mildly feel that surge at a sustained speed of 60,70,80 etc, mph. Funny thing is the car went into the shop never having a surge problem at an idle. Haven't changed the fuel pressure regulator diaphram but have put two new 02 sensors in it. Do I now have to change the injectors? From all that I have read it seems as though many people have this surge problem. Surely by now other than changing every component to fix it isn't the answer. The auto shop total me the injectors were good by what their analyzer told them. Do you think the next step is injectors?
It got a tiny bit better but the surging did not totally go away. It still goes fast but you can mildly feel that surge at a sustained speed of 60,70,80 etc, mph. Funny thing is the car went into the shop never having a surge problem at an idle. Haven't changed the fuel pressure regulator diaphram but have put two new 02 sensors in it. Do I now have to change the injectors? From all that I have read it seems as though many people have this surge problem. Surely by now other than changing every component to fix it isn't the answer. The auto shop total me the injectors were good by what their analyzer told them. Do you think the next step is injectors?
