Weird 93 LT1 start/no start condition
#1
Race Director
Thread Starter
Weird 93 LT1 start/no start condition
Go to take it out for a drive, start it up cold in the garage. Starts up perfectly fine. Let it warm up for a few minutes while I moved my other car out of the way.
Pull the 93 out, shut it off for about 5 minutes. Come back to start it, and just cranked and cranked.
Hurried to grab the noid light. Disconnected injector connector on cylinder 1. Cranked it, and the light lit up. It is day time, and the light didn't seem to be strong, but did light up none the less.
Then, I tested fuel pressure. At 3 key cycles, it was at 30 PSI. Curious to see if it would start with that amount of fuel pressure. And it did. Running, fuel pressure was at 36 psi. Snap throttle test, went up to 42 psi. Disconnected vacuum on the fuel pressure regulator, and it also went to 42 psi. Turned it off, and fuel pressure stayed at 42 psi for a while.
I was like, ok weird. Put up my tools to take it for a spin. Again, no start. At one point it wanted to, but didn't.
Has a code H16 in module 4, but that code has always been there since I put the opti in December 2016. Also has an h32 which is because I very rarely get an EGR code on the highway. It's the solenoid. That's it, as far as codes go.
Car is on LTCC, so that eliminates the coil and ICM.
Pull the 93 out, shut it off for about 5 minutes. Come back to start it, and just cranked and cranked.
Hurried to grab the noid light. Disconnected injector connector on cylinder 1. Cranked it, and the light lit up. It is day time, and the light didn't seem to be strong, but did light up none the less.
Then, I tested fuel pressure. At 3 key cycles, it was at 30 PSI. Curious to see if it would start with that amount of fuel pressure. And it did. Running, fuel pressure was at 36 psi. Snap throttle test, went up to 42 psi. Disconnected vacuum on the fuel pressure regulator, and it also went to 42 psi. Turned it off, and fuel pressure stayed at 42 psi for a while.
I was like, ok weird. Put up my tools to take it for a spin. Again, no start. At one point it wanted to, but didn't.
Has a code H16 in module 4, but that code has always been there since I put the opti in December 2016. Also has an h32 which is because I very rarely get an EGR code on the highway. It's the solenoid. That's it, as far as codes go.
Car is on LTCC, so that eliminates the coil and ICM.
#3
Race Director
Thread Starter
This morning. Couldn't find my spark tester. Just disconnected the plug wire for cylinder 1. No spark coming out of the coil pack, or plug wire during cranking. Was that even a valid way of testing for spark?
Last edited by 1993C4LT1; 04-02-2018 at 02:02 PM.
#4
Le Mans Master
IDK I would look at the connections and grounds. It the LTCC seems to be ground sensitive. Having to cycle key several times to get to 30 psi which still below spec. I would look at fuel pump and relay operation. Maybe check fuel pump sending unit assembly to besure everything is correct. Leaving DIS plug disconnected is not a good idea. Coil can generate 100kv spark will find away to ground if it has to arc thru itself. It cause coil to fail. Is there a trouble shooting guide or call center?
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1993C4LT1 (04-02-2018)
#5
Race Director
Thread Starter
I read the manual that comes with LTCC last night. Only thing it mentions is red and green light. The red comes on at 1 second during key ON, as a power on self test. Which mine does. When it started last night(out of luck, I guess) I checked the lights in the LTCC computer. And it was steady green. Which means LTCC is controlling the ignition. I'll check them with someone cranking the car, and I'll observe the lights in the LTCC box.
So during cranking, with the plug wire disconnected at the coil pack, should I have seen a spark during cranking?
So during cranking, with the plug wire disconnected at the coil pack, should I have seen a spark during cranking?
#6
Le Mans Master
You probably should have heard an arc. Are you using 8 or 4 coils? 4 you could disconnect 2 wires on the same coil it should arc between the towers. 8 coils you need a spark tester.
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1993C4LT1 (04-02-2018)
#8
Race Director
Thread Starter
First it had spark, car started. This a screenshot of a video I took. As you can see, strong blue spark. Turned it off, thinking it was only due to fuel.
As you can see, no spark. But 5 minutes later, car started up after I put the spark plug back in and plug wire.
I did see some moisture in the LTCC brain box. Won't show up in pics, but here goes nothing.
So basically, it only has spark when it wants to lol.
As you can see, no spark. But 5 minutes later, car started up after I put the spark plug back in and plug wire.
I did see some moisture in the LTCC brain box. Won't show up in pics, but here goes nothing.
So basically, it only has spark when it wants to lol.
Last edited by 1993C4LT1; 04-02-2018 at 08:43 PM.
#9
Le Mans Master
Since you said the leds light , I guess it means the module is get signal. I would contact Bailey and see what they say to do. It still could be poor connections. Good Luck.
#10
Race Director
Thread Starter
Emailed him last night. Actually, now the lights are not doing the self test correctly. Instead of red and green coming on at 1 second, during key on, they stay both stay lit for ever. System only uses 3 grounds. All are clean and tight.
#12
Le Mans Master
There's not much for troubleshooting. If the red led on is code one cylinder sequence error I would check how the opti is connected. I would also be sure opti is sending consistent signals. Did you reset the internal switches. The corrosion pointed out is curious
#13
Drifting
#15
Race Director
Thread Starter
So this is what it was doing yesterday. Green and red light steady on.
And 2nd vid is what it did just now. I've never seen the lights blink like that. For a self test, it goes green then red very briefly and nothing after that, they turn off.
Last edited by 1993C4LT1; 04-03-2018 at 09:45 PM.
#16
Maybe you reach out to 'bogus' as well. He's mentioned in the past a 'water intrusion issue' and actually I believe is responsible for maybe the current kit content instructions. I believe he just maybe cleaned up the presentation.
In '16 he mentions the return of one for the 'water intrusion' and recommends sealing.
https://www.corvetteforum.com/forums...post1592079432
Doesn't fix yours but I'd think the 'sealing' after a fix.
In '16 he mentions the return of one for the 'water intrusion' and recommends sealing.
https://www.corvetteforum.com/forums...post1592079432
Doesn't fix yours but I'd think the 'sealing' after a fix.
Last edited by WVZR-1; 04-04-2018 at 05:22 AM.
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Red 91 (04-04-2018)
#17
Race Director
Thread Starter
Good read, thanks! Yeah he did write the current instructions. I wish Bob Bailey would answer the email I sent him. That would clear up a lot, in my opinion.
Last edited by 1993C4LT1; 04-04-2018 at 08:28 AM.
#18
Melting Slicks
That white paste looks weird. Pretty sure mine does not have that.
I would do an opti test on the connector. I had the instructions somewhere but cannot find them. It is in the FSM IIRC. You just use a volt meter, real easy to do. Do the test cold and hot.
When my 94' had weird starting issues where it just cranked and cranked and I could not pin it down to the Opti, it ended up being the fuel pump pulsator. I replaced the entire fuel pump with a Racetronix walbro unit and submersible fuel line in place of the pulsator. I was however, able to catch the issue on a fuel pressure gauge when it was just cranking with no start. This was back in 2015, and have been issue free since.
I would do an opti test on the connector. I had the instructions somewhere but cannot find them. It is in the FSM IIRC. You just use a volt meter, real easy to do. Do the test cold and hot.
When my 94' had weird starting issues where it just cranked and cranked and I could not pin it down to the Opti, it ended up being the fuel pump pulsator. I replaced the entire fuel pump with a Racetronix walbro unit and submersible fuel line in place of the pulsator. I was however, able to catch the issue on a fuel pressure gauge when it was just cranking with no start. This was back in 2015, and have been issue free since.
Last edited by TorchTarga94; 04-04-2018 at 08:58 AM.
#19
Race Director
Thread Starter
Yeah I know what test you are talking about. I'll do it when the car decides to not start. My fuel pressure is weak as well. 29 psi at key on, not 42 like always. Doesn't answer the no spark though, but I'll figure it out.
#20
With LTCC missing in the thread title there may be many that actually aren't checking in. At this point I believe you you reach out to those with LTCC.
You've had one response from an LTCC conversion guy and I'd say he's 'thrilled' with his. Where was your box located?
A simple search for LTCC in the C4 'community' search this forum function resulted on 20 pages of results. Doesn't mean there's a solution there.
Try 'bogus' - maybe.
Try a new thread titled 'Bailey LTCC LED Diagnostics Help
You've had one response from an LTCC conversion guy and I'd say he's 'thrilled' with his. Where was your box located?
A simple search for LTCC in the C4 'community' search this forum function resulted on 20 pages of results. Doesn't mean there's a solution there.
Try 'bogus' - maybe.
Try a new thread titled 'Bailey LTCC LED Diagnostics Help