HELP: 2000 LS1 Mafless Tune wont start or idle (for long)

OK I give up. I have read so many posts and double checked so many things I don't know what to do but to ask.

I pulled a complete 2000 LS1 engine, trans loom and wiring out of a donor car for my 58 Chev Truck build. I wired it all up factory with no mods on open headers and i ran. If you are interested there is a youtube video here

After I confirmed that the engine ran at least I pulled the engine down, gave it a once over and threw some new goodies at it as follows;

• TEA stage 2 - 5.3L 862 truck heads
• TFS stage 3 cam (Duration: 228/230, Lift: 585/585, 112lsa)
• Trunion upgrade
• Edlebrock super victor intake
• 4150 throttle body
• 1 7/8" to 3" headers

Anyway - with the factory tune it did run (kind of). Here is Another Youtube Video before covids and during that time I decided to make the required mafless changes.

So i have done a number of changes to the tune (all from this site) and I got it to the stage it kind of wants to start (but not really).

• Changed "Engine Diag / DTCs P0101, 102, 103" from "no mil light" to "mil first error"
• Unticked "Engine Diag / DTCs P0101, 102, 103"
• Changed "Engine Diag / Airflow / Maf fail hi freq" from "11.25" to "0hz"
• Copy the "high octane table" to "low octane table" in "Engine / Spark / Advance"

The bit that I am lost on is how to change ?Engine / Airflow / General / Main VE? to use the Secondary VE Table for 97-00 (not primary ve). Is this an automatic thing or something I need to switch somewhere? So far I have copied the primary table to the secondary table (where I could as the secondary has less values - refer image).

Attachment 102814

Question 1
Can you add lines into the secondary table or is it not required.

Question 2
Could my issue be fueling as I still have the stock LS1 injectors in the rail (it ran before i made any mafless changes)

I just want to get it to start and idle so I can then get it on a trailer and to the tuners.

Any help appreciated
Q

best to post tune and log for any help

I know these are only basic ones. If you need more please let me know which ones and I can retest.

For both these attempts the engine cranked but didn't try to fire at all (battery getting a little flat - on charge now).

When it does try to fire it jumps to about 300-350rpm and the oil pressure raises also. If I continue to crank it either stays like that or the rpms jump again.
Its almost like its firing on 1 cylinder then the next then the next and so on but never all at once to get it going.
I never changed the spark or firing order from the factory tune and Ive checked the injectors and coils all have power before cranking.

Attachment 102831
Attachment 102832
Attachment 102834

Apply the speed density enhanced OS in the OS tab, that will remove the secondary VE table and make VE tuning way better. And it will let you keep the high/low octane timing tables like factory where the low octane table has less timing in it.

Thanks 5fdp.

The PCM currently has Version 005 loaded (with the changed fields as per my first post)

When I went to OS and selected the first option (Speed Density - Enhanced RTT) I got the following warning box
Attachment 102852

Should I save the current Version 5 as version 6 like it suggests
or
go back to version 4 (without the mods as per first post) and then run the "speed density enhanced" like you suggest.

I only ask as V4 still has all the original tables where V5 has the mods (as per first post) and by the looks of it , once you run that mod theres no going back as the other options 1 bar, 2 bar, 3 bar disappear.

Just letting you know I decided overnight to reload my very first tune (unmodified GM tune) and start again in case I had turned something on or off inadvertently

I ran the Speed Density Enhancement first and completed the "write entire" to flash PCM

After that I did a few small mods and wrote calibration

• System/VATS Control = set to none
• Engine Diag/P1626/1630/1631 = SES Unchecked
• Engine Diag/P1626/1630/1631 = changed from "No MIL" to "No Error reported"
• Engine Diag/P0101/P0102/P0103 = SES Unchecked
• Engine Diag/P0101/P0102/P0103 = changed from "No MIL" to "MIL first error

I tried and while it cranks nothing happens just like yesterday.

Im going to get the mutimetre out and double and triple check all the power feeds and wires to the injections and coils.
It must be something simple because it did run before.

Did some testing today and can confirm I have no issues with power to all injectors and coil packs (all getting a 12v signal).

I can only think there is something wrong with the earth trigger the PCM supplies or the timing of it.

Is there anyway to check this in HPTuners ?
Is it possible to test each circuit individually (like turn on fuel pump circuit does for fuel)?
Ideally I would like to remove #1 sparkplug, signal #1 to trigger and check the spark plug jumps the gap, then repeat for other 7 cylinders.
At least I would know my wiring was correct in this way as I?m sure it?s a timing issue.

Can the same be done for injectors. I could just leave the plug out and crank. If I get fuel vapour coming out the sparkplug hols I know im getting fuel in but that seems messy to me. Would rather hook an led into each wire and test individually ? can this be done.

Regards
Quintin

I certainly hope you can get a knowledgeable response to this as I am looking for a bridge to jump off of!!! Transplanted an 08 Trailblazer SS 6.0, E67 ECM into a 68 Camaro and it has been a total nightmare! Purchased an ECM that had my VIN and stock tune preloaded and it ran for about 3 seconds and stalled, repeat, repeat and now it won't start at all. I too have 12v at coil harness and injector harness but no spark. Very frustrating! I have already spent four credits on the two ECMs and really don't want to spend another two for a replacement ECM until I can prove/disprove this ECM is working properly. Keeping my fingers crossed you get a response so I can build off that. Good luck!

Quote:

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Originally Posted by QBRacing74

I know these are only basic ones. If you need more please let me know which ones and I can retest.

For both these attempts the engine cranked but didn't try to fire at all (battery getting a little flat - on charge now).

When it does try to fire it jumps to about 300-350rpm and the oil pressure raises also. If I continue to crank it either stays like that or the rpms jump again.
Its almost like its firing on 1 cylinder then the next then the next and so on but never all at once to get it going.
I never changed the spark or firing order from the factory tune and Ive checked the injectors and coils all have power before cranking.

Attachment 102831
Attachment 102832
Attachment 102834

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On the second log PCM voltage is wayyy below 10 volts.

It will never start with that low voltage...even if it still cranks..

I have spent the last 4 days checking earths and feeds , replaced a couple of suspect wires and no change.
Everything has 12v when key is on run but the HPtuners is recording 11.5
When I crank everything drops to 10v and HPtuners is recording 8.5-9v at the PCM.

Im about to go away for a couple of weeks for work so wont be able to test until I return, then I will unplug everything not required to run the engine and see if something is draining the battery and try another starter if I can find one.

thanks for the help.

Q

by a crazy chance is the tip of spark plugs have any paint on em....or bad injector harness ground....at rear of cyl heads

Hi all. Back from training and back into it.

Today I wired up a second battery (in parallel) which only powers the PCM. On cranking the voltage is better than before but the car is still not starting.

I'm thinking it has to do with timing or firing order now.....

I've attached 2 log files, the first it coughed a couple of times but the second ... nothing but crank. there is also an image of the firing order from VC editor.

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The first thing that stands out to me is the firing cylinder. sometimes it goes to 8, others 0 then it counts down in reverse. What the... ?

I've read a few posts and they talk about a crank relearn or something. Also I thought the crank signal was a square wave, why the weird numbers in the log?

What are the chances you have the injectors and coil plugs on the wrong bank?

You can test the injectors individually. Take them off the car, look for the polarity of the two pins on them, connect a wire between pins and appropriate battery terminals directly. connect and disconnect the circuit, and they should click like a small relay. No click and the injectors not operating, stuck closed. I just went through this pulling my hair out trying to get my engine swap to start, with only a small sign of life, problem was 7 of the 8 of my injectors were stuck closed after sitting with out fuel pressure on them for an extended period of time.

If you have spark, and these injectors had fuel in them at one point, but have since been sitting for an extended period of time, That is where I would look.

@ffdp - yes. It ran before I changed the intake and before I moved ...
First start
Just before move

@Murfie - thanks for the advise. will look that way and check and report

OK. so I have ordered an injector tester which is going to take about 8-10 days to arrive from the USA. In that time i hope to pull the pcm in the cab and check my wiring and both coil and injector earths.

In the mean time would this error (P0795 trans range sensor) be causing my problem?

Does the pcm think the trans is in gear so it wont start or fire ??? Is this a thing?

Attachment 103875

Think I figured it out, or at least it sounds feasible in my head....

When I started my build I was 75% sure I was going twin turbo route. Being the tight arse I am, I am 95% sure I decapped my stock injectors after having seen it done by a number of youtubers.

As per my first post, I decided hair driers are for hairdressers and went the NA (+NOS) route instead so I didn't have to upgrade the differential or trans (it is only a 4l60e after all).

I didnt think about this during the rebuild until I bought the injector tester.... but that means on the stock tune I was dumping twice to 2.5 times the fuel when the injectors pulsed..... meaning it was hellishly rich.

This would explain why each of the four times its run since the rebuild its gotten worse to start or idle and I expect when I pull the plugs in the next few hours they will be totally fowled up. It also wouldnt have helped that it went into storage for 4-5 month during covids and moving house twice.

Late yesterday I manage to find some 2002-03 VX/VY ls1/ls6 Commodore injectors at a wrecking yard nearby and negotiated a fair price for them but I cant get them until next week.

Once I do get them and clean my plugs, I expect the engine will at least then start and run to a degree (and a sheite load better) compared to the few times I have started it previously. This will allow me to load it on trailers/transporters or move it around the yard and to get it to a dyno shop for some propper tuning...

Q