Service Engine Soon Light - ZR-1 Net Registry Forums

bigd · 07-31-2005

The other day when coming home my '90 Z almost stalled when coming to a stop. This morning when I started it (and it took much longer than normal to crank) the SES light came on after 30 seconds or so of idling. It is throwing two codes; 45-Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was above 4% during closed loop operation. 65-Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7%.

I don't think both sensors would go bad at the same time. Is there something that could cause both sensors to give these readings?

Thanks, Don

Kevin · 07-31-2005

Did the car backfire under start up recently?

bigd · 07-31-2005

No, But I checked the MAP sensor vac hose anyway. Still attached. Any chance stale fuel could be a problem? It's been 6 1/2 months since last fueling.

bigd · 08-01-2005

Think I found the problem. Leaking injectors. The oil on the dipstick smells of fuel. It just seems strange that it would happen on both the left and right sides at the same time. Any recommendations on replacement brands or just stay with stock?

Z Factor · 08-01-2005

Quote:

Originally Posted by bigd

Think I found the problem. Leaking injectors. The oil on the dipstick smells of fuel. It just seems strange that it would happen on both the left and right sides at the same time. Any recommendations on replacement brands or just stay with stock?

While RC's are a good choice, if you are only going to replace the faulty ones, you would be better off sticking with matching injectors since they have different flow rates. I recently replaced one of my injectors rather than have the expense of replacing all 16. However, had I replaced them all, RC's would have been less expensive.

Good luck

bigd · 08-02-2005

Z Factor, I agree. If only replacing the faulty ones (the codes tell me I have a rich problem on both sides), stock would be the way to go. But I'm leaning towards replacing all while I'm under there. On a 15 yr old ZR1 could I expect some others to crap out soon?

Tyler Townsley · 08-02-2005

As a final check you should check the fuel pressure. If it bleads down after turning the car off then you got a leaker. You can probably tell which cyl by pulling the plugs, the leaker should be apparent.

You might try some injector cleaner as it may be because of a bad tank of gas.

Tyler

bigd · 08-02-2005

Thanks Tyler, It was on my list today to look for a fuel pressure gauge at one of the auto parts stores. Please expalin a little about the possiblity of bad gas causing the leak. The car has sat for about 6 months with 1/2 tank. (I was unable to get to the car to run it). No problems with the first 1/2 tank of gas though. Could it have gone bad setting for so long? Does it seems strange that both sides are runnning rich?

Tyler Townsley · 08-02-2005

THe stock injectors are very sensitive to water and just a minute amount will cause them to leak if they sit for any length of time. Depending on the amount of contamination injector cleaner can free them up. Old fuel can also cause problems and usually can be identified by a sour smell while the car is idleing.

Tyler

Kevin · 08-02-2005

If you can afford it change out all 16.

07-31-2005	#1
bigd Join Date: Apr 2005 Location: Tallahassee, FL Posts: 17	Service Engine Soon Light The other day when coming home my '90 Z almost stalled when coming to a stop. This morning when I started it (and it took much longer than normal to crank) the SES light came on after 30 seconds or so of idling. It is throwing two codes; 45-Left oxygen sensor voltage was over 0.75 volts for 30 seconds when the throttle angle was above 4% during closed loop operation. 65-Right oxygen sensor voltage was above 0.75 volts for 30 seconds of closed loop operation when the throttle angle was above 20% or below 2.7%. I don't think both sensors would go bad at the same time. Is there something that could cause both sensors to give these readings? Thanks, Don __________________ Don 1990 Dark Red Metallic #1587

07-31-2005	#2
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,633	Did the car backfire under start up recently? __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

07-31-2005	#3
bigd Join Date: Apr 2005 Location: Tallahassee, FL Posts: 17	No, But I checked the MAP sensor vac hose anyway. Still attached. Any chance stale fuel could be a problem? It's been 6 1/2 months since last fueling. __________________ Don 1990 Dark Red Metallic #1587

08-01-2005	#4
bigd Join Date: Apr 2005 Location: Tallahassee, FL Posts: 17	Think I found the problem. Leaking injectors. The oil on the dipstick smells of fuel. It just seems strange that it would happen on both the left and right sides at the same time. Any recommendations on replacement brands or just stay with stock? __________________ Don 1990 Dark Red Metallic #1587

08-02-2005	#6
bigd Join Date: Apr 2005 Location: Tallahassee, FL Posts: 17	Z Factor, I agree. If only replacing the faulty ones (the codes tell me I have a rich problem on both sides), stock would be the way to go. But I'm leaning towards replacing all while I'm under there. On a 15 yr old ZR1 could I expect some others to crap out soon? __________________ Don 1990 Dark Red Metallic #1587

08-02-2005	#7
Tyler Townsley Join Date: May 2005 Location: Nichols, FL Posts: 615	As a final check you should check the fuel pressure. If it bleads down after turning the car off then you got a leaker. You can probably tell which cyl by pulling the plugs, the leaker should be apparent. You might try some injector cleaner as it may be because of a bad tank of gas. Tyler __________________ 55 Polo White (Project) 61 Jewel Blue (Sold to buy above) 66 Nassau Blue 68 Torch Red 88 ZR1 Blue 90 ZR1 White

08-02-2005	#10
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,633	If you can afford it change out all 16. __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"