Those settings put it at 30kpa KOEO and no luck in getting it to start at allOriginally Posted by gtstorey
Those settings put it at 30kpa KOEO and no luck in getting it to start at all
I'm back to blindsquirrels diag.
Spraying "CARB" cleaner in the throttle body should get it started if it has compression and spark.
You are missing one the the three.
To get bad fuel pump cars and trucks in my stall I would spray while laying under the hood while someone drove it into my stall.
Pops with spray but that's it
Pops with spray but that's it
Engine is fully rebuilt, Cam timing is set, have triple checked dot to dot with cylinder 1 at TDC, stock base circle on the cam, LS7 lifters, stock length pushrods, stock rocker arms with trunnion upgrade. Great compression across all 8 cylinders.
Also has good spark
Then it's not what the label claims, or it's broken, or there is a wiring problem. MAP settings are not something you fiddle with until it reads right.
I don't know where to go on the injector issue, a L59 with LM7 injectors is just a LM7 and would have a 'T' as the 8th VIN. GM never built them that way, ever.
Regardless, I have my injector flow data set up correctly in the computer so this is a real head scratcher with what's going on. It is EXTREMELY finicky. I can't think of or find any other mechanical issue with the engine that would cause an issue either.
I would do a compression test. You could disconnect the MAP and MAF, and disable the fuel pump and it will still start on carb cleaner.
You either have a bad sensor or a wiring problem. The offset and linear is 312.50/-11.25. GM Genuine or Holstein?
Wouldn't hurt to confirm the injector part number.
Compression is good on all 8
GM Genuine
Injector number is 25317628, stock 25lb injectors
The next step needs to be 'make it run on brake/carb cleaner', this is going to continue to go around in circles until that happens.
I think getting an accurate MAP reading with the correct sensor config should be the priority.
And if the MAP issues are figured out and it still doesn't run, then what? It should start and run on spray even without a valid MAP. Injectors need to be disabled to rule out over-fueling, otherwise a result of still-does-not-run is useless.
If the MAP issue is figured out and it still doesn't start then do the monkey tricks. MAP is a definite problem. Start there.
I believe it's over-fueling. I'd recommend trying a Corvette cranking VE table as a test, but still that MAP reading is the priority.
STFT OL is enabled, but the log shows the O2's are unplugged. Needs to turn off STFT OL and CL or get the O2's working again.
This would be a better baseline...also monkey tricks without a working MAP sensor.
Last edited by SiriusC1024; 03-22-2024 at 02:22 AM.
Unplug the MAP, and pull the fuel pump fuse.
Has to be able to start with compression and spark using carb cleaner or even squirting some gas.
Same as if you had dry fuel bowls on a carb vehicle.
If the proper settings for his map sensor makes it read 30kPa there must be a wiring issue to that map sensor.
the pinout between a LSA/LS9 sensor and the sensor this came with have two wires crossed. That would cause this.
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I've been trying to tell these people that. Let's calibrate a line with a single point then farmer it to death with some carb cleaner instead.
Last edited by SiriusC1024; 03-22-2024 at 09:02 AM.
Wires were crossed for the MAP sensor, reads correctly now.
Will start and run on carb cleaner after letting it sit for a while.
I'm led to believe it was having an overfueling condition yet it also was seeming like a spark timing issue only during cranking but something has been leading me on a goose chase. Will update once I know more.
03CateyeBaseTuneChopacabraTurbo4L80EMAFDisabledClosedLoop3BarSpeedDensityBoostEnrichAdjusted25lb.hpt
CateyeStartAndRun.hpl
StartFailAfterRunning.hpl
Managed to have it start relatively easily first thing in the morning while cold. Heres a log file while running, along with the current tune. Only change i made with the tune after running it was added 4g/s to the Base Running Airflow table, had too little so it stalled while trying to get it to idle when it got to operating temp. Also pulled another 10% from my 400-1200rpm rows in the Main VE table. Next log is attempting to start it while hot after i ran it and added Base Running Airflow. No dice. Just pops from exhaust while trying to start. Checked a plug and wasnt wet. Very frustrating. Its some progress atleast, but still not sure whats going on with it being so temperamental to start.
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