PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

will not start after flashing

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Old Apr 7, 2014 | 08:19 AM
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Default will not start after flashing

98 formula ran and was adjusting the tune. let it go through a warm up idle sequence then came out the next morning with a very slight change to the VE table, flashed and then crank but no start.

The pump makes a very short thump sound and an LED test light very briefly lights up when used like a jumper at the fuel pump relay. When I command it throught HP Tuners it will mostly everytime seem to run the 3 seconds and the jumper led lights up. I even hook up the scanner and crank away I see fuel injectors duty cycle going and even see a timing number but still does not fire.

It ran great before I even disconnected the battery for an hour, got the battery up to a full charge, it may have been mid to low 11volts surface charge when I flashed it. I have flashed the ECM a bunch of times over the past year messing with it.

Any coincidence for downloading the 2.24 update just before the last flash?

I have also read that some have seen the 98 ECM's fry since the update or more so than the 99+.

Any thoughts would be great.

thanks
Eric
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Old Apr 7, 2014 | 08:23 AM
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Try to read the PCM's flash. If you can download it's contents it can be repaired. If it does not communicate at all then the PCM is fried.
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Old Apr 7, 2014 | 09:35 AM
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Originally Posted by MontecarloDrag
Try to read the PCM's flash. If you can download it's contents it can be repaired. If it does not communicate at all then the PCM is fried.
Interesting I will try that tonight. I have read where some have flashed the 98 ECM and then lost the Fuel pump operation and had to replace the ECM. I was worried about that so that is why I commanded the pump via HPTuners and then tried to run a jumper wire to turn it on all the time, but still it did not fire.
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Old Apr 7, 2014 | 12:57 PM
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There was a problem with one of the earlier betas damaging 98 PCMs, but I haven't heard of any problems with 2.24
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Old Apr 7, 2014 | 09:35 PM
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Originally Posted by MontecarloDrag
Try to read the PCM's flash. If you can download it's contents it can be repaired. If it does not communicate at all then the PCM is fried.
It reads it fine so it says, opened and saved it. The fuel pump cycles too. So now what? Still cranks no fires. I did not try to reflash after the Read.

I even tried to log a file showing reading while cranking. It shows 2-3% duty cycle like it was when it was running, cranking 13 degrees timing and all the other stuff seams to be looking and reading fine during the cranking and watching the HPScanner.
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Old Apr 8, 2014 | 07:35 AM
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Originally Posted by gto65lvr
It reads it fine so it says, opened and saved it. The fuel pump cycles too. So now what? Still cranks no fires. I did not try to reflash after the Read.

I even tried to log a file showing reading while cranking. It shows 2-3% duty cycle like it was when it was running, cranking 13 degrees timing and all the other stuff seams to be looking and reading fine during the cranking and watching the HPScanner.
If you can read it the PCM is not fried.
Flash your stock tune or the last good and try again, use Write entire and make sure the battery is fully charged.
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Old Apr 8, 2014 | 08:25 AM
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Originally Posted by MontecarloDrag
If you can read it the PCM is not fried.
Flash your stock tune or the last good and try again, use Write entire and make sure the battery is fully charged.
Tried that, full write, before bed last night and it did not fire. I loaded a couple different saved adjusted tunes that I have as I have made minor changes and that did not work either. I even had the charger on to fully charge the battery prior to doing it yesterday afternoon to take that out of the equation.

I have checked every single underhood fuse and flip flopped relays around also and still no fire.

Everything in the scanner window points to the fact it should fire and start. It shows all the readings when cranking.

My wife is so pissed at me because it was a perfect stock 30k mile car just a few months ago.
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Old Apr 8, 2014 | 09:32 AM
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Do some basic troubleshooting. Is there spark at the plugs. Is there fuel pressure at the rail. Is there injector pulse at the injector plug. Use a noid light to test.
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Old Apr 8, 2014 | 01:02 PM
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I agree, you need to troubleshoot the no-start condition.
If you can read and write the PCM it's not fried

Check the usual, fuel, spark, crank sensor, etc
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Old Apr 8, 2014 | 04:15 PM
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Ok I will buy a noid light and fuel pressure gauge and see what I come up with. Ugggh I hate my luck or lack there of lately. ;(
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Old Apr 12, 2014 | 02:12 PM
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I have fuel and I have spark it cranks like crazy yet will not fire. I have disconnected the battery multiple times even overnight. Battery is kept fully charged. I have done a full read, full writes and calibration only with different saves from my tunes. I all my fuses test good and everything else.

I am told if the PCM can be read it is good but something is not doing something and it was fine up until a very minor change and re flash.

Any other ideas before I waste money on another PCM and credits to mate to my car. If I spend money on a PCM I may as well upgrade to a 99+ 411 but then I know with me something will not work after the re wire of the connectors.
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Old Apr 12, 2014 | 05:07 PM
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You have fuel where? Do you have injector pulses at the injector checking with a noid light? Do the plugs come out looking wet after cranking?
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Old Apr 14, 2014 | 08:33 PM
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ok bought a noid light and it does not light up upon cranking, I have the proper fuel pressue at the rail and I did not disconnect anything from the time it ran to the time I re flashed and it stopped firing. Spark plugs are dry and the IAC tester lights up both bulbs red then after I crank it and turn off the key they change colors and I think one was red and one turned green.

I have checked all my under hood fuses, the grounds on the back side of the drivers head are still attached.

Where do I go from here
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Old Apr 14, 2014 | 09:37 PM
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Check for +12v on the the injector harness. If you don't have +12v, even if the PCM is pulsing the injectors, the noid light won't flash. And are you checking your fuses with a test light to see if they have +12v on them or just visually looking at them to see if they are blown?
Attached Thumbnails will not start after flashing-98-injectors.jpg  
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Old Apr 15, 2014 | 04:29 PM
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Yup checked all fuses with test light. Like I said it was just fine until a flash. Batt. Voltage got low during flash because of drain the night before playing with the tune. Batt goes weak real fast now so prob got too low and fried he ECM. cranking I get the p0601 every time I clear and try it. Checked with a couple ECM rebuilders both said same thing they cannot unlock it would need a new chip as it is fried if it gets the 06... Code especially on the 98 ECM.
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Old Apr 15, 2014 | 04:31 PM
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Got a stock 98ecm on the way will give it a go. Also warrantied my car battery to help avoid a repeat. Just don't feel like doing the re pin thing right now my luck something will go screwy
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Old Apr 15, 2014 | 05:46 PM
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Originally Posted by gto65lvr
I get the p0601 every time I clear and try it.
Yo should have started with this.
P0601 means corrupted PCM, it won;r start no matter what. It can't be fixed with your tuning cable, you need to send it to be repaired but shipping may be more expensive than a new one.

Before you brick your new PCM, make sure you have the newest software release, some versions had a bug which bricked 98 PCM's
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Old Apr 15, 2014 | 07:29 PM
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Originally Posted by MontecarloDrag
Yo should have started with this.
P0601 means corrupted PCM, it won;r start no matter what. It can't be fixed with your tuning cable, you need to send it to be repaired but shipping may be more expensive than a new one.

Before you brick your new PCM, make sure you have the newest software release, some versions had a bug which bricked 98 PCM's
I know never looked for dtc's how do I get the latest software version on it?
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Old Apr 16, 2014 | 11:00 AM
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Originally Posted by gto65lvr
I know never looked for dtc's how do I get the latest software version on it?
Log to your customer center, there is a download link (the first one to the right). That link always has the latest version
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Old Apr 16, 2014 | 11:28 AM
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Originally Posted by MontecarloDrag
Log to your customer center, there is a download link (the first one to the right). That link always has the latest version
x2 to update your version. i bricked 3 98s before i knew what happened and the version i had back then was 2.24. my finale remedy was swapping and rewiring to a 411 pcm 99+ year. the 98 PCMs are the bitch year for the fbody.
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