What knock sensor are you using? Manual and automatic are different and read differently within the pcm. The knock sensor must match what is on your chip.
What knock sensor are you using? Manual and automatic are different and read differently within the pcm. The knock sensor must match what is on your chip.
Correct me if I’m wrong, I wouldn’t necessarily say manual vs auto is the deciding factor. Perhaps ECM vs PCM maybe more accurate. If at all possible try to read the resistance of the knock sensor. The 8625 is looking for 4k ohms. If it measures 100k ohms you have the wrong one.Originally Posted by Stokes1114
On second thought having the esc on the memcal vs escm may have a lot to do it.
Last edited by stew86MCSS396; 05-16-2018 at 11:18 PM.
Edit.. manual and automatic are 2 different sensors. Read different ohms. Can cause all sorts of havoc. V6 uses 2 knock sensors, v8 used the one depending on trans and that decided if your using a pcm or ecm in this year. Later years used all pcms no matter what trans.
Last edited by Stokes1114; 05-17-2018 at 05:37 AM.
I’ll have to respond to all of this in the morning and try to test the knock sensor resistance in the afternoon! Thanks for keeping the didcussion alive.
I forgot to mention in the main post that I also have a serious BLM problem. The integrator part swings around a lot but the BLM value is usually way up above 145 and 160. I’ve been keeping track of my highway fuel economy, and it isn’t so stellar around 13-15 mpg. I’ve fixed the exhaust leak for the most part, so now I’m on to brain storming what else could be causing this. Unfortunately I don’t know what injectors I have nor the actual fuel pressure from the pump. I’m going to try to install something this weekend that allows me to check that. The best estimate I have is that it’s a brand new O’Reilly’s brand 1995 TBI 5.7L fuel pump.
Last edited by Coopesam; 05-19-2018 at 01:29 AM.
Going back to your first post, did you and pops do anything to the 350 that would make anything other than stock? ie camshaft, headers Was anything borrowed from the 4.3l particularly the throttle body w injectors? What I'm alluding to is if your engine is bone stock and you're using the correct 350 throttle body, you shouldn't be seeing those lean BLMs of 145-160 and it's a physical/mechanical condition rather than a tuning issue.
Last edited by stew86MCSS396; 05-17-2018 at 10:26 PM.
So originally the V6 had the linear stepper motor type EGR valve. That we left on the the V6 and got ahold of a brand new one of these which I think might be the EVRV that you mention, though I'm not sure of the difference. We wired up the EVRV(/solenoid?) as indicated on this wiring diagram which shows both of those on the same system, wired to the same pin on the ECM. I don't have the official GM diagram for my motor, so maybe finding that would help.
Can I ask what an ESC or ESCM is? I think I know the MEMCAL to be the small blue container with the EPROM chip in it but all this time I thought the rest of the circuitry inside the MEMCAL is just analog limp-home-mode circuits. At any rate, this resistance test is very good to know. I have been working too much this week to check right away, but as soon as I'm home for the weekend I'll give that a look and see what resistance I measure.
Interesting, I'm still new enough to this field that prior to your reply, I didn't know the difference between a PCM and an ECM and have been using those words interchangeably. Since I'm using the 8625 computer, does that mean I have an ECM, and the 16197427 computer we have on the shelf at home is a PCM? Is there any reason I'd expect that computer to be the appropriate driver for my setup?
Thanks for giving such helpful guiding questions! I'm not sure the most logical way to put the response together, so I apologize if how I organize the information is hard to piece together the whole picture. So, we didn't try to make it anything other than stock, but it has been pieced together with some of the documentation is missing meaning it's definitely not perfectly stock. We got the long block, without the intake from my Dad's friend who had the motor rebuilt for some other project, potentially a hot rod of some sort. The bore has been done 0.030" over, so I guess that's an important detail. In terms of other compression factors, I'm not sure. For the cam I have an envelope but no document inside for what cam was purchased for it. So far, all the information I have on the cam is that the preset idle of 550 had a pretty noticeable miss, so I moved the idle up with the idle adjust screw on the throttle body to be right around 650 and now it's much smoother. My dad seems to think it's possible there is an RV cam in there.
As for the origin of the intake, throttle body, and injectors, that is also somewhat of a mystery. We got those parts separately from another friend who pulled those parts off of a vehicle some 10 years prior. We rebuilt the throttle body and fuel pressure regulator using a run of the mill cheap stock rebuild kit from Advance Auto. The injectors seem to function fine, but I also have no idea what the flow is there. Come to think of it, fuel pump is a swap out from a 1993 TBI S10 Blazer for ~12-18 PSI in place of the 50+ PSI fuel pump that used to be in there for the CPI V6 we pulled out. We adapted the old CPI fuel lines with rubber hose to the throttle body, so I need to modify the tubing to put a Schrader valve test port in there to see the actual fuel pressure.
Lastly, the swap kit I purchased came with a pair of Hedman Swap "Hedders" so the exhaust breathing is probably different and creeping into the BLM problem.
This is what I have been thinking. The BLM's are high indicating a lean condition (right?), and the O2 sensor is usually below 600 mV, (also indicating a lean condition?), but my gas mileage is very bad. The mileage made me think that it's a false lean condition, and the vehicle has been running actually rich due to a exhaust leak before the O2 sensor. But, I fixed the major part of the leak over the weekend, and the BLM problem persists as well as the low fuel economy. There' still a small leak near the header to head flange, so I'm going to also tighten that up, but I don't think this is the source of the BLM's being high at this point. I figured next that it could be that I don't have the current fuel delivery and breathing components in the EPROM, and if I were to get that right, my BLM will stabilize and my fuel economy might get up to 18 or so mpg.
I've attached some datalogs, but I'm not sure I've done that correctly or if they're any use at all. One corresponds to the first drive of the day where motor nearly stalls when I try to accelerate at a stoplight in the morning. It seems to be worse if the night before was colder. The other file is when it runs fine, but there is definitely a problem with the BLM values. Any help is appreciated! Thanks a ton.
Electronic Spark Control Module, most ECMs use it and if you don't have one then ESC circuitry is built into the MEMCAL.
Are you at elevation? Seems your key on engine off (koeo) MAP starts at 85 kpa.
Looks like you're logging with EGR coming on and that's when you'll see the BLMs spike to 160. Anytime the EGR is off, BLMs seem to go back down to 135ish. Perhaps a bump in fuel pressure by making your fuel pressure regulator adjustable or search for "quarter mod." It don't look bad. I'm sure the bin could use some fine tuning but not much you can do without the chip burning capability.
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