i am losing pulse to injectors i had the vats removed from ecm awhile ago,street and performance built a wiring harness for me and instaaled a vats bypass if that went bad would it cut out the pulse even though it's no longer in the ecm .

 

Its programmed out of the ECM? I would think this should eliminate the ECM as a possible cause, but if the bypass goes bad, maybe there is not proper communication with the ECM... I have no idea, so here...TTT

 

Have you scanned the PCM for codes?

You need to provide details regarding the vehicle. Why not add a "signture" with the basics - year, model, engine, tranny and any major mods.

 

was 1 code low resolution #? been awhile since i got into this this job 85s-10 blazer lt1-383 stroker 4l60e replaced opti and plug same code then replaced with ltcc coil kit same thing.

 

The only "low resolution" code is for the loss of the low resolution pulse signal from the optical cam position sensor in the Optispark distributor. When that code sets, the PCM shuts down the fuel system.

Clear the code (pull "PCM BAT" fuse for 30-seconds) and see how fast it comes back. If it sets when you try and start the car, and the car won't start, you've confirmed that the Opti signal is not reaching the PCM. First thing to check is both ends of the short Opti harness.

 

replaced short wire harness but i'll go over everything again on friday and see what happens,i'am new to the forums and asking advice on repairs. Thank you all your help

 

I pulled pcm fuse re-installed then i checked scanner ,no codes,cranked it over got#16 low res.,cleared and checked again,same thing.This vehicle ran great 6 months ago then 1 day it would'nt start,wiggled short plugs goin to opti it started for a few seconds.So i replaced short harness it still did'nt start,thought bad pin in opti replaced, same thing, replaced again? I'am a diesel mechanic 29 yrs.would not be the first time i've gotten defective parts.any help would be great i have fried my brain on this job BUT i will not give up, i realize i'am missing something ,but i don't know where to go.I know it's not a diesel so no one needs to remind me.

 

I checked injector pulse again with a noid lamp ,at first very bright then after a few seconds dim then nothing at first it sounds like it wants to start. BUT i do still have code 16 low res. can that be related,or am i back to the vats question???????Thanks

 

VATS has nothing to do with the low resolution code. The PCM is not happy with what it sees from the opti. Possibilities are the opti and everything in between it and the PCM.

 

now,i was checking the injector harness with noid lamp,as before,but this time i removed the fuel pump relay and proceeded to check pulse,now i have perfect pulse,did not fade away stayed strong also did not get code#16 low res.(possible shorted fuel pump ,it's also new)are any of these things related or just coincedence.Brain is on fire now.

 

What part of what I posted did you not understand?

 

It's a new plug and wire were tested with ohlm meter ,wires were good,.so yes i do understand .What does that have to do with unpluggin the fuel relay, then no more code when cranking and injector pulse working perfectly.Question is what does all of this have in common,does All this still point to the opti or plug if so please explain how.Thank You for your help

 

DTC 16 sets based on the PCM not being able to read the pulse signal out of the Opti. That's the only thing that sets that code. You didn't get DTC 16 on your latest test, and your injectors were pulsing. Obviously, you have an intermittent problem with the low res pulse.

 

I pulled the plug out of the opti and plugged it in to another used opti and spun the rotor and the injectors have pulse,plugged the other one back in had interrmitent pulse so i pulled the opti off of motor spun it and sometimes it works and sometimes it dont.Is their something that can cause the sensor to go bad,i've read about some lasting forever and i've been through two already.Thanks for pointing me in the right direction i think i'am starting to understand this engine a little better.

 

What year is the LT1? Vented (95-97 = less problems) or unvented (93-94 = more problems)? Do you possibly have an oil leak that is allowing oil to enter the Opti? Corrosion can cause problems with the conductors in the harness connector tower. Excessively high voltage can increase ozone production, increasing corrosion.