Alumicraft getting a new computer mid season

acefuture said:
Following up on this thread. Took the car to Steve at Powertrain Dynamics today. He is very knowledgeable and a pleasure to work with. Thanks for the suggestions to him, and I highly suggest anyone who needs a tune to give him a call. 
 

After about 40 minutes of us talking about the history of the car, what I’ve done, and what I expect out of it, I explained how the car has never completely felt like it has the guts that I think it should. So he jumped in and started doing his thing. He noticed quickly as well the car was flat, the fuel tables were going out of wack and the computer was trying to make wild adjustments when in closed loop. So he hopped out and sprayed some water on the headers and 2 were cold. He pulled the plugs and they were firing, but no fuel. I kick myself because of all the things I checked and replaced, I didn’t check the injectors, and that’s a no brainer. He thinks that since the MEFI doesn’t have a “learning” capability that when it wasn’t seeing proper fuel flow, it was popping, sputtering, trying to make the adjustment, and just killing the motor. That would describe my condition to a tee. So while it could’ve just been a couple injectors and be on my merry way, I had to jump through the hoops to get here. The positive is that I now have a solid computer with the tune-ability and data logging that this car should have which is great. 
 

I’ll throw a new set of injectors in it and take it back to him hopefully next week and have him finish the tune. Will follow up with results 
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Glad steve was able to help you out!

Steve helped me with a few issues- my motor blew up once on his dyno before i went to LS and he helped me solve alot of issues.  Hes a sharp guy and glad to see your getting it sorted! 

 
Well all of those updates didn’t fix it unfortunately. Went from running on 6 to running on 7 cylinders so it’s narrowed down to 1 now, but I’m genuinely stumped. Sent the datalog to the tuner and he was stumped too. The only odd thing was the TPS sensor went from 0-8% 4 times in .5 seconds. So I replaced the sensor again and it didn’t fix it. Did an Ohm check on the harness from ignition plug to coil and it was fine, replaced the coil, spark plug, wire, new injector and cleaned the fuel rail as well. I’m going to pull the valve cover next and check the rocker measurements to see if maybe it’s a bad lobe on the cam. But I’m grasping for straws at this point. 
 

And to rub salt in the wound the truck wouldn’t start when I tried to leave this morning…Ball buster of a weekend, at least the weather was nice and the beers were cold

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damn, sorry to hear. hopefully it's something simple. 

 
Going to keep following up on this thread until the car is 100% just so anyone who is potentially having issues can reference. I headed out on Thursday with the sole intention of figuring my car out, and getting the blue alumicraft I put together all worked out (blue car in it's own thread). On Friday morning my Dad and I focused on the one dead cylinder as we felt this is the new focus of the issue. Started by checking to make sure the plug was arching. Went to take off the plug wire and it felt as though it wasn't fully connected. So I checked all of them and they weren't completely snapped in. Checked the cylinder again and it wasn't the issue. Put a stethoscope on the injector and it wasn't firing. My dad shook the connector and it would intermittently start working. Pulled the connector off and the wires just fell out of it. Brand new harness from CBM...

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While this fixed my dead cylinder issue, it still wasn't the source of my problem. Went to drive the car and it was still popping and sputtering. So Saturday morning I plugged in the computer and did some data logging. I noticed the AFR was going crazy lean, up to 35.7. Everything else looked stable, so I figured it has to be some sort of impedance or sensor. Did a quick search on an LS forum and saw a comment about checking the coolant temp sensor on the head. At low temperatures the computer will look to the coolant temp sensor to make some adjustments to the AFR. That was the only sensor I hadn't replaced. My dad picked me up a new one in Yuma and plugged it in. I went for a quick run and bam, that was the best the car has EVER run. Storm came in shortly after and I parked the car for the night. Yesterday morning we went for a ride in the absolutely perfect conditions. The car popped, sputtered and died, I restarted and the car ran fantastic. Stopped for some photos and off we went again, the car popped and sputtered a few more times, but felt as though the car was going into closed loop and learning. It's currently set to 10%, so I figure this may take some time. Stopped for a second time, and when we headed out towards camp the car ran perfect. No pops or sputters, hitting on all 8, felt fantastic. So i'm HOPING I have this thing figured out. Headed out again in a couple weeks to dial it in. Fingers crossed

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In the troubleshooting I went through over the last few days I came across this video...watch it. It's a new feature with the latest terminator software that lets you test a bunch of things.  Turn your fans on, fuel pump, pule the injectors, coils, etc. Pretty cool.



 
14 hours ago, wesinls said:

In the troubleshooting I went through over the last few days I came across this video...watch it. It's a new feature with the latest terminator software that lets you test a bunch of things.  Turn your fans on, fuel pump, pule the injectors, coils, etc. Pretty cool.

Click to expand...
Awesome! I'll check it out. Thanks for the heads up

 
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