Engine runs rough when hot
10-20-2007, 03:05 PM
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Engine runs rough when hot
Hi All,
I'm new and this is first post. I have a 1991 Corvette, 83,500 miles, and am having a hard time isolating my problem and finding a solution. The car started running rough so I figured it was time for a tune up. I replaced spark plugs, wires, distributor cap, rotary button. Seemed to cure some of the problem, however, now the engine runs fine when first started up but starts to miss as it warms up. At normal operating temperature the engine misses, will almost stall and sometimes does stall when stopping for a red light, and the engine surges (cycles) about 200 rpm at times. I have replaced the thermostat and water pump--needed it even though I don't think this is part of the problem. Replaced stopped up fuel filter. Replaced throttle position sensor. Replaced sensor on passenger side of injector rails--don't know the name of it but it is attached to vacuum hoses. I'm out of ideas. Anyone have any advise or is it going to be best to just take it to Chevy dealer for repair work?
Barry C Jolly
I'm new and this is first post. I have a 1991 Corvette, 83,500 miles, and am having a hard time isolating my problem and finding a solution. The car started running rough so I figured it was time for a tune up. I replaced spark plugs, wires, distributor cap, rotary button. Seemed to cure some of the problem, however, now the engine runs fine when first started up but starts to miss as it warms up. At normal operating temperature the engine misses, will almost stall and sometimes does stall when stopping for a red light, and the engine surges (cycles) about 200 rpm at times. I have replaced the thermostat and water pump--needed it even though I don't think this is part of the problem. Replaced stopped up fuel filter. Replaced throttle position sensor. Replaced sensor on passenger side of injector rails--don't know the name of it but it is attached to vacuum hoses. I'm out of ideas. Anyone have any advise or is it going to be best to just take it to Chevy dealer for repair work?
Barry C Jolly
10-20-2007, 06:06 PM
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My 89 did that also. Ran perfect in open loop. soon as it warmed up and went into closed loop it ran horrible. Checked everything, smog parts all sensors. it ended up being my injectors. Replaced the injectors and it runs good! Maybe check injectors. Just my .02
10-22-2007, 12:07 PM
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I checked the injectors with ohm meter. Guess this is a big part of my problem (injectors checked anywhere from 2.2 ohms to 16.4 ohms.) Only had two that were close to 12 to 14 ohms. One almost shorted.
Next question. I am not a professional mechanic. I can change out water pumps, sensors, do brake jobs, I have rebuilt a 4 cylinder jeep motor. Is this something an amateur can do or should I seek a professional mechanic to change out the injectors?
Next question. Internet listing for FiveO motor parts shows these Bosch injectors: (1) Yellow Top for 96 Ford Mustang OEM, (2) Bosch XF2E Design III, (3) Boshc LS1, (4) Bosch Blue Top. Any suggestions for a replacement? Is this a reputable vendor?
Next question. I have seen a post by Sam Lam. I think that's his name. He has a procedure for injector replacement. I cannot find this post. Anyone know of it off hand?
Thanks for any help you can give.
Sincerely
Barry C Jolly
Next question. I am not a professional mechanic. I can change out water pumps, sensors, do brake jobs, I have rebuilt a 4 cylinder jeep motor. Is this something an amateur can do or should I seek a professional mechanic to change out the injectors?
Next question. Internet listing for FiveO motor parts shows these Bosch injectors: (1) Yellow Top for 96 Ford Mustang OEM, (2) Bosch XF2E Design III, (3) Boshc LS1, (4) Bosch Blue Top. Any suggestions for a replacement? Is this a reputable vendor?
Next question. I have seen a post by Sam Lam. I think that's his name. He has a procedure for injector replacement. I cannot find this post. Anyone know of it off hand?
Thanks for any help you can give.
Sincerely
Barry C Jolly
