Trying to make my first post, and for some reason, it doesn't seem to be working...
Trying to make my first post, and for some reason, it doesn't seem to be working...
Okay, well, it did post, but apparently it's not particularly happy. Anyway, 4th try...
My last EFI conversion was using a 7747 with a TBI-220 and 40 lb-hr or so injectors on a rather aggressive Chevy 250 inline six marine engine.
That was over a decade-and-a-half ago.
This time, I'd like to use something that doesn't require me to row a ZIF lever and wear a sweater of EPROMs in a tanning-bed... and the application will be a Grumman Step-Van (Chevy P30 chassis) with a Buick 455/TH400... would like to use junkyard donor parts, and flash the ECM from a laptop.
Open to any and all suggestions!
The budget suggestion would be to use a Moates.net Ostrich 2 emulator with TunerPro RT. The emulator flashes like an OBD II computer using TunerPro RT software installed in a Laptop PC. The emulator can make changes to the chip file, even while driving! The 16197427 PCM is a TBI PCM which can be upgraded to MPFI port fuel injection like the older TPI system. The 16197427 PCM will work with manual transmissions, TH350 / TH400 / TH700R4, 4L60E and 4L80E. The 1619747 PCM is abundant and a low cost in the salvage yards. Aftermarket 1227747 TBI wiring harness will need to be re-pinned / configured with red / blue connectors. The 16197427 PCM requires a 2000 Pulses Per Mile (2K) Vehicle Speed Sensor (VSS).Originally Posted by davekamp
dave w
Last edited by dave w; 05-25-2014 at 05:08 PM.
Dave has the right idea for a flash OBDI ECM/PCM and when done either leave it there or burn a final chip and remove the Ostrich to use again elsewhere.
There's not a good choice for flash OBDI and to go to OBDII is complicated and expensive.
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
That's exactly the kind of feedback I was lookin' for- thanks Dave and Mark!
Dave has the right idea for a flash OBDI ECM/PCM and when done either leave it there or burn a final chip and remove the Ostrich to use again elsewhere.
There's not a good choice for flash OBDI and to go to OBDII is complicated and expensive.
Since I"m running a TH400, there's no electronics... don't think I'd need a VSS for any other reason. I'd probably start with a 454 as the base mapping, and then just bring in the values to suit the 455's breathing character, particularly when pushing around an oversized aluminum mailbox.
The Ostrich sounds like what I would have loved to have seventeen years ago... of course, if I had one now, I'd probably put it in the boat and rework the mappings. The 250 turned out to be an extremely effective engine for the boat, but there's a few combinations of load and temp that could use some touchup. I'll do some sport reading, as I'll obviously need to put together the complete shopping list.
Thanks guys!
I might have been a little confusing with my earlier post? The 16197427 TBI is a PCM and MUST use a VSS regardless of the type of transmission used. The 16197427 PCM has two timing and fuel tables, Off Idle / Near Idle. The transition between Off Idle / Near Idle is determined by MPH. The 16197427 PCM does not have a "Park / Neutral" input like the older 1227747 TBI ECM did, which is why the VSS is mandatory.
The older 1227747 can also use the Ostrich 2 with the Moates.net socket booster, some ECM modification required. The budget difference between the the 1227747 ECM vs. 16197427 PCM is about $53 more expensive if using the 16197427 PCM. Usually the ECM / PCM are equally priced.
Budget for a 1227747 using Ostich 2.
Socket Booster $40. ( https://www.moates.net/socket-booster-10-p-171.html )
Dip Socket $2. ( https://www.moates.net/d1-24pin-dip-....html?cPath=26 )
Install dip socket $25. ( https://www.moates.net/installation-....html?cPath=64 )
Total $67.
Disadvantage, a replacement ECM is not a simple plug and play for the Ostrich 2.
Budget for 16197427 using Ostirch 2.
G1 Adpter $35 ( https://www.moates.net/g1-memory-ada...-etc-p-32.html )
VSS 2K $85 ( http://www.jagsthatrun.com/SpeedSensors_Order.html )
Total $120
Advantage, a replacement PCM is a simple plug and play for the Ostrich 2.
dave w
Last edited by dave w; 05-26-2014 at 02:07 AM.
Just get the 16197427 and use a VSS!
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Hmmm... yeah. Well, I'd probably go that way, but if I support the 7747 in my boat (the 15+ year old conversion) then I'll be in for BOTH configurations... and putting a VSS in the boat isn't substantially practical, so I can't do a swap to newer hardware unless it can operate sans VSS.
An aside note, which may have no bearing whatsoever...
In the boat, I've got the 250 running 11.5:1 with 202/160 valves with full-roller rockers in a lump-port head, an Elgin .512" lift / 270 @ 0.050 degree cam and MerCruiser underwater exhaust, however, the exhaust boot has been removed, so that I'm not faced with 34" of water column backpressure at idle, it's only about 6". The MerCruiser drive does NOT tolerate shifting into gear at much above 700RPM- the shift dogs get torn off pretty darned quick, so to make this whole combination actually WORK, I've got Rhodes lifters keeping the lift and duration restrained below 1400rpm or so. Once the boat is up on plane, the exhaust does NOT have backpressure other than cooling water going overboard, so it flows nice. The CATCH... is that at idle, there's very LITTLE MAP signal... and if I set the idle ignition and mixture right, it'll idle fine at 650rpm and hold steady, but once in-gear, it takes about 3 pulses of fuel and 7 degrees of additional advance to prevent stalling.
I made this work by triggering the park/neutral map off the drive's shifter handle... actually used a relay to invert the neutral-start-circuit's switch contact.
Another nasty bit, is that in order to shift from forward or reverse to neutral, marine drives have a 'shift interrupt' feature that momentarily kills the ignition when the shift cable tries to move the drive's shift dogs from engaged, to disengaged. IF the engine's torque is NOT interrupted, the clutch dog's face force is too high for the dog to release to neutral. Needless to say, this kind of thing makes an ECM rather angry, so I've got it interrupting the ignition, but NOT chopping power to the ECM. Not pretty, but fifteen-plus years ago, that's what I had available.
But for illustrative purpose, when it's sitting at the dock, at 650rpm, the windshield... and the hull, and the front deck... shakes. I've had guys come up and say "Dude, there's something really wrong with your engine"... and my answer is "Yep... it hates sitting at the dock"... they don't seem to 'get' it, until I put it in-gear, and it shoves me away from the dock at 6mph. They don't expect a 45 year old runabout to do what it does, and are usually quite shocked to see me fly by. If it weren't for TBI, I certainly couldn't have made it do it, especially without directing the exhaust straight out the back of the hull (and making a heckuva racket in the process).
There is the option of EBL Flash, ( http://www.dynamicefi.com/EBL_Flash.php ).
dave w
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