After initial start, acts like it's flooded
Thread Starter
Heel & Toe
Joined: Feb 2016
Posts: 15
Likes: 0
From: High Point North Carolina
After initial start, acts like it's flooded
Recently. the Optispark went bad on my 1993 (LT1). After replacing the opti, car starts and idles great. When I turn it off and try to start it again, it cranks, but acts like it is flooded. If you wait a while, usually a few hours, it will start again. I did the "paper clip" jumper on the diagnostic port and it is not throwing any codes. Any ideas?
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
Leaky injector? You can test this with a fuel pressure gauge seeing if and how fast it bleeds down.
however, you have a 93. Do you have any other symptoms? Does it crank strong and just not start? Do you have Service ASR light, security flashing and/or security light blinking while running? This could be the ECM. Although you should have codes.
What happens if you start it, shut it off and then start it again (while cold)?
ICM also a suspect…replacement Optis can be bad too (why did you replace?)?
First thing is to confirm what you don’t have on restart (fuel, air or spark)
however, you have a 93. Do you have any other symptoms? Does it crank strong and just not start? Do you have Service ASR light, security flashing and/or security light blinking while running? This could be the ECM. Although you should have codes.
What happens if you start it, shut it off and then start it again (while cold)?
ICM also a suspect…replacement Optis can be bad too (why did you replace?)?
First thing is to confirm what you don’t have on restart (fuel, air or spark)
Thread Starter
Heel & Toe
Joined: Feb 2016
Posts: 15
Likes: 0
From: High Point North Carolina
Possible leaky injector, but the fuel doesn't bleed down fast. Pressure at the Shrader valve is 42 PSI. Drops to about 40 when I turn it off and holds there. I checked after a couple of hours and it was still at 36.
It starts on the first try, but when I shut it off and try to start again, it cranks strong but won"t start.
No service ASR light or codes other than C12, which shows the ECM is performing diagnostics.
Replaced Opti after it left me stranded. I did trouble shoot the issue and saw that there was no spark. Checked the coil and ICM and ruled those out. The Opti wasn't sending a signal to the ECM. Replaced the Opti and it started after re-assembly. Then it wouldn't restart and acted like it was flooded.
Checked for fuel, air and spark at restart and those are there. I'm suspecting an injector issue.
It starts on the first try, but when I shut it off and try to start again, it cranks strong but won"t start.
No service ASR light or codes other than C12, which shows the ECM is performing diagnostics.
Replaced Opti after it left me stranded. I did trouble shoot the issue and saw that there was no spark. Checked the coil and ICM and ruled those out. The Opti wasn't sending a signal to the ECM. Replaced the Opti and it started after re-assembly. Then it wouldn't restart and acted like it was flooded.
Checked for fuel, air and spark at restart and those are there. I'm suspecting an injector issue.
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
I find it hard to believe a single injector would be able to flood the engine out where it wouldn't start (outside of hydrolock, which the engine would then lug or lock)?
What was your FP on restart? Did you check your FP regulator vac line to see if there is fuel in it? Any fuel in the oil?
So you are saying if you start it, let it run for a few seconds, shut it off and then immediately try to restart it will not? This is definitely...odd. I'd leave the FP gauge hooked up and watch it while running, after shutting off and then again at restart attempt....
What was your FP on restart? Did you check your FP regulator vac line to see if there is fuel in it? Any fuel in the oil?
So you are saying if you start it, let it run for a few seconds, shut it off and then immediately try to restart it will not? This is definitely...odd. I'd leave the FP gauge hooked up and watch it while running, after shutting off and then again at restart attempt....
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I think he already did that. It doesn't seem like there is a leaking injector.
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Advanced
Joined: May 2022
Posts: 69
Likes: 4
From: Central Florida
Recently. the Optispark went bad on my 1993 (LT1). After replacing the opti, car starts and idles great. When I turn it off and try to start it again, it cranks, but acts like it is flooded. If you wait a while, usually a few hours, it will start again. I did the "paper clip" jumper on the diagnostic port and it is not throwing any codes. Any ideas?
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
I wonder if FI enable is not triggering between the ECM and CCM on recrank. The lack of codes is throwing me…if no opti signal then you’d have no spark (op claims spark on recrank)..if opti signal but bad ECM CCM handshake then there should be a comm failure code…also maybe low vs high res opti signal issue (but again, there should be a code?)
OP - when it won’t restart have you confirmed the injectors are actually pulsing (noid light). You could also attempt to spray some starter fluid in and see if it tries to run…. I know you said you checked fuel but was that just pressure?
with all of that....it's an odd one. A noid light would be useful.
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
I have a 93, and I had that problem with my ECM. That is why I asked some very specific questions about codes/behavior.
This is not manifesting the same way, and there are 0 codes. ECM is in the back of my mind but I don’t think it’s time to go there, especially since the Opti was just messed with.
We know nothing until the OP confirms some more details.
This is not manifesting the same way, and there are 0 codes. ECM is in the back of my mind but I don’t think it’s time to go there, especially since the Opti was just messed with.
We know nothing until the OP confirms some more details.
Instructor
Joined: Apr 2022
Posts: 142
Likes: 48
From: Central NY State
Following. I’m having the same issue. I recently replaced the ICM and cleaned the MAF sensor which was caked with oil from a soaked k&n filter the previous owner had. Just brought it to my mechanic for inspection. Ran like a top there. They inspected it. Then wouldn’t start. They started checking coil, spark, icm snd injectors. They all get power but no ground signal. Therefore no spark. They are thinking ECM in that it’s no closing the ground circuit. I got a ride home and they are going to check a few other things if they have time. Worst case it sits a couple hours and it starts and I drive it the 1/2 mile back to my house and figure it out on my own. I just want to drive the car!!!
Drifting
Joined: Jun 2020
Posts: 1,355
Likes: 396
From: Northwest Ohio
Following. I’m having the same issue. I recently replaced the ICM and cleaned the MAF sensor which was caked with oil from a soaked k&n filter the previous owner had. Just brought it to my mechanic for inspection. Ran like a top there. They inspected it. Then wouldn’t start. They started checking coil, spark, icm snd injectors. They all get power but no ground signal. Therefore no spark. They are thinking ECM in that it’s no closing the ground circuit. I got a ride home and they are going to check a few other things if they have time. Worst case it sits a couple hours and it starts and I drive it the 1/2 mile back to my house and figure it out on my own. I just want to drive the car!!!
Instructor
Joined: Apr 2022
Posts: 142
Likes: 48
From: Central NY State
I would start a new thread with every detail you can supply while you follow this one. ECM diagnosis has some specific hallmarks in my experience that would make it obvious, there may be other failure modes than I experienced too…you just don’t want to preemptively send it out for reflow when something else is the problem as that will just delay your enjoyment of the car further!