94 Silverado

[pitterpatter]

I have a 94 ecsb, 6 inch lift, shorty headers, Edelbrock intake manifold. No check engine light but it doesn't seem right. Started this adventure with aldl Data logger stuff to try to understand what problems I've inherited. The truck has been regeared to 4.11 from 3.73, sitting on 35s. If I can figure this all out I'll be happy.

[dave w]

:welcome:

Post a data log, .xdl most of the time other gearhead-efi members will have helpful ideas to share.

dave w

[woody80z28]

I've been tweaking my 94 for 10 years and am actually rewiring my new 92 to be a "94" now, too.

Post up a log and let us know what's "not right."

[pitterpatter]

Ok, I'll get a log up shortly

[pitterpatter]

I think its here..Truck has edlebrock intake, stock tbi, shorty headers. The base timing is 0.. knock sensor is unplugged in log titled 3rd because of what i found in log titled 1st. I did it for testing. I have the BJLH bin loaded with the 16196395 ecm, bot positive on what adx or xdf to run. I have been using 0E_TPV5_v250.xdf and A219_0E_31_v250.adx my cable is the 10 dollar ftdi doohcikey off amazon. I did find mention of the knock sensor reading actually being bat voltage but got confused on that.

[dave w]

According to this link: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?303-16197427-PCM-Information-0D BJLH is for a 4L60E transmission.

The link above have has the correct .adx and .xdf for BJLH

dave w

[pitterpatter]

According to this link: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?303-16197427-PCM-Information-0D BJLH is for a 4L60E transmission.

The link above have has the correct .adx and .xdf for BJLH

dave w

Yeah. That's where I got most of the files. Some from tunerpro website. I have the 4l60e...don't I? It's a heavy half 6 lug 1500hd with the 14 bolt semi float. 9.5.

[pitterpatter]

Actually, i spoke too soon... You kind of pointed out one of the things that has me confused....my ecm says SERV.NO. 161963965 BJLH. I popped the cover and it has BJLH on the chip. Most of the RPO codes are rubbed off, I can only see maybe 1/2 of them legibly. Gt4 LO5 f44 are the important ones I think. But BJLH is associated with 16197427. if figuring this out is this confusing tuning must be a treat.... I have megasquirt on my VW Baja turbo build so I'm not completely in the dark

[1project2many]

Mostly, a person is OK switching a program between the 3965 and the 7427. Shift logic is different between the 4L60E and the 4L80E transmissions. You would truly have "wierd" stuff going on if you were running the 4L80E with 4L60E code. But it's a good idea to crawl under the truck to confirm the transmission type.

This image should help with trans type. The "700R4" pan is the same as the 4L60E pan. Look at the shape of the edge of the pan, count the number of bolts, and match it up to the picture.
http://www.700r4transmissionhq.com/wp-content/uploads/2017/01/4L80E-Has-17-Bolts-on-the-pan-1024x768.png

There are websites what will give you original RPO codes based on a VIN if you're curious. Compnine seems to be pretty accurate although they are not free anymore. Also a dealer can usually print out the list of RPO codes from your VIN for free. I'm not sure how much remains stock in your truck so RPO codes may not be useful anymore.

[pitterpatter]

So it's definitely a 4l60e. I'm still banging my head against a wall on this though. I'm looking through my last log and here's what I see:
3100 rpm
85.1% throttle position
93.4 kPa
My spark advance is showing as 8.4 degrees.
4.0 knock retard
114 blm
99 integrator
Closed loop
A/e and p/e inactive.
What causes such messed up spark advance? Truck has no power with my foot in it. Only out of load and light throttle has drivability.

[pitterpatter]

I'm looking at this log still and watching knock retard. Map vs tach vs knock retard is 4.043 in every cell halfway through the log. Is there a significne to 4.043???

[Fast355]

I'm looking at this log still and watching knock retard. Map vs tach vs knock retard is 4.043 in every cell halfway through the log. Is there a significne to 4.043???

Maximum knock retard at that RPM when not in PE perhaps? Possibly not real knock.

[typhoonss92]

I had an issue when I upgraded to the 7427 computer with the altitude spark bias. I zeroed it out and fixed my timing issue and got me going. I could barely push on the gas and it was flat on it's face. I would try that and see if it helps.

[stew86MCSS396]

Actually, i spoke too soon... You kind of pointed out one of the things that has me confused....my ecm says SERV.NO. 161963965 BJLH. I popped the cover and it has BJLH on the chip. Most of the RPO codes are rubbed off, I can only see maybe 1/2 of them legibly. Gt4 LO5 f44 are the important ones I think. But BJLH is associated with 16197427. if figuring this out is this confusing tuning must be a treat.... I have megasquirt on my VW Baja turbo build so I'm not completely in the dark

Soooo...with that said are you using the correct '7427 adx for your datalog???

[pitterpatter]

I would say no to that because I pulled the adx from the 16196395 thread on here.. at this point I'm really uncertain what xdf and adx to run for this. I feel like I'm over thinking this half the time, and the over half it seems over complicated .

[pitterpatter]

Hahhah. I'm getting somewhere. Today I discovered the aftermarket magnaflow cat had the front honeycomb break at some point, so it was broke up and shot through the rear Honey comb causing one heck of a restriction. I suspected a clogged cat early on , but cond guessed myself. Don't do that fellas, just follow your gut. Cut the cat!