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Attn: Mark

jekquistk5

jekquistk5

Weld nekid
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After seeing data in Tuner Pro RT I replaced a few things. CTS, and MAP. Now it idles nice and smooth but falls on its face when you give it the go pedal. Sputters backfires a bit. I logged a run and was watching it, it went into closed loop and idled great.

Things I have questions about:

spark advance - Should this change with RPM and not randomly go up to 100 then back down to 0 and start climbing again?

BPW?
BLM?


Unless its a bug in tuner pro i'm guessing my ESC is bad. I may do a log with the timing connector unplugged. Engine is set to 0Degrees idles perfect just falls flat when you give it gas.

it wont let me upload the log but I can send it to you if needed.
 
After spending the last 3 hrs reading. I have answered a few of my questions. Looks like SA can not be monitored in the 1227747 ecm while logging but can be looked at by enabling data tracing in the log file.

Learning way more about the GM TBI system then I wanted to know
 
Zip the .xdl log file and attach it here.

Spark Advance is not in GM data. I've made a patch to apply to the .bin/chip so it will show in data, same with BPW so it can be used for Injector Duty Cycle. So you won't see some things until the patch/hack is applied and then run that chip.

Your symptoms are classic low fuel pressure or flow. I can see that in BLM/INT data but the pressure itself is not there. Need to check it with a gauge. Sometimes this is hard as well because you will have good pressure like 12 PSI at idle and it drops with load while driving, or accelerating.
 
I was watching the BLM and INT they stay right at 127 at idle BLM goes up to 136, INT goes down to 107 or so.


Could you post screen shots of what you are looking at so I can help myself understand better. If not I understand.

Thanks

I'll buy a new fuel filter on my way home and give that a try
 
Looked at your log and the BLM and INT are doing some strange things? But not sure if your low on fuel.

First thing to do is disconnect Batt to clear codes, you still have that MAP set. This may throw off data.

Second is no MPH? Do you not have a VSS? Looks like manual trans as it's always in Drive, never Park?

Third something is way off on your TPS? At idle it reads .96v and should be closer to .54, this is probably your issue?
 
eagle mark said:
Looked at your log and the BLM and INT are doing some strange things? But not sure if your low on fuel.

First thing to do is disconnect Batt to clear codes, you still have that MAP set. This may throw off data.

Second is no MPH? Do you not have a VSS? Looks like manual trans as it's always in Drive, never Park?

Third something is way off on your TPS? At idle it reads .96v and should be closer to .54, this is probably your issue?
Click to expand...

I have 1/2 tank of fuel ~14 gallons in the tank.

Yah VSS is disconnected as my cable fed drac box took a dump when I had a cable failure. It ran strong with the box disconnected for almost 2 years.

I guess I'll clear the codes, and throw a new TPS on there and see what happens. I am going to the parts store soon so why not.
 
Sorry I didn't mean low on fuel in tank... I meant low on fuel delivery to engine.

May not need a TPS, but something is wrong to be that far out of adjustment. Sometimes you need to file out oblong holes to get it to twist, then snug up and check voltage.

Still may not be your issue? But is an issue!
 
adjusted tps down to .53V no change. Installed new fuel filter, no change. I removed the ground thinking that would clear the code(MAP HI) but it did not. It still existed after hooking it back up. I'm thinking my dual battery isolater is not working as even with the grounds disconnected to the main cranking battery I still had power at the ecm and all my gauges. :dunno::dunno: Gonna let the ECM sit disconnected on the bench over night and try it again tomorrow.


It did start right up and purred like a kitten at idle. Gave it gas it backfired a bit.. May revisit my timing with a light that does advance to make sure timing is where it should be.
 
Its running a bit better now, but still not 100%. Still running rich in my eyes but idles and starts like a dream now. Let it warm up to opperating temp and tried again. When it stab the throttle is still hickups but if I gently increase the go pedal its nice and smooth no back firing now.

Heres a lil video

[YOUTUBE]23EBM_koLxs?[/YOUTUBE]

Ignore my howling power steering pump
 
I'd still be looking at fuel pressure during that dead spot your seeing off idle?

How about a new data log with TPS voltage set correctly? Do this idle to off idle stumble a few times at end of log. Also leave some idle time at end of log.

I'd like to see if the strange BLM/INT has changed...

What is the chip BCC (four letter code)?
 
ADSU is probably the best chip that ever came in a GM truck of this era!

I'll look at the log later...
 
eagle mark said:
ADSU is probably the best chip that ever came in a GM truck of this era!

I'll look at the log later...
Click to expand...

Thanks its a long one you can skip the first like 10 minutes because I just let it idle to warm up but wanted to look at the data myself. I do believe its fuel pressure issue. Gonna buy a gauge and then go from there.
 
That log would have been great if we were looking for a drive ability issue from cold start... but it ends before engine is warmed up.

I need one that starts at warmed up! For tuning purposes you always use a log that starts at warmed up and even driven a little.
 
Also need some information on the engine? Stock? Transplanted? Fuel pump? Injectors size? Ever serviced? More info, more better...
 
Alright it may be a week or so unless I can sneak out this weekend. I'll let it warm up and and start logging.

Engine :Goodwrench factory replacement 350 crate with edelbrock TBI intake, headers heated O2 and thats it.

It used to run great but sat for awhile due to a leaky rear main. Replaced rear main and then started to have all these issues.

Sorry I'm new to the whole tuning/logging world. Learning alot. Thanks for the patience. It just worked great before and never had any issues.

Fuel pump is stock in a 31 gal blazer tank.
stock injectors.

I'll try to drive it as well
 
Logged more data today. Overall drivability is way better, but still stutters a bit when stabbing the go pedal. I tried to test fuel pressure but the adapter and gauge set I rented from autozone leaked like crazy. I'm gonna try and rent another one from a different store this week. Its almost there I can sense it.
 
jekquistk5 said:
Engine :Goodwrench factory replacement 350 crate with edelbrock TBI intake, headers heated O2 and thats it.
Click to expand...
When you add headers you move the O2 sensor down stream in exhaust. Using a heated O2 sensor helps with the sensor cooling off and going Open Loop, I once used a set of ceramic coated headers and they keep heat in and never had an issue there.

But moving the O2 sensor does change the amount of time in Milliseconds that the burned exhaust reaches the O2 sensor for next reading. This is a setting in the chip that needs to be changed whenever the O2 sensor is moved.

Also the aftermarket intake needs more AE (Acceleration Enrichment) like a carb pump shot.

jekquistk5 said:
It used to run great but sat for awhile due to a leaky rear main. Replaced rear main and then started to have all these issues.
Click to expand...
How long did it sit? Fuel does go bad, if not totally then at least stale and does not work as well. You may see some improvement from filling up if the tank is low.
 
For 6 months but I used stabil and put 15 fresh gallons in less than two months ago. Like I said this setup although not ideal ran like a dream before the last run then stuff started acting up.
 
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