DIY_EFI Digest Saturday, August 7 1999 Volume 04 : Number 454 In this issue: DRAC and Tranny computers. Electronic transmission controller fuel starvation and stalling UEGO AFR Precision Re: DIY_EFI Digest V4 #453 Re: DIY_EFI Digest V4 #453 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Fri, 06 Aug 1999 09:40:18 -0400 From: "Peter D. Hipson" Subject: DRAC and Tranny computers. At 05:00 8/6/99 -0400, you wrote: > >Look up input ratio on chart to find proper jumper settings. > Chart, what chart? You have a chart? I'd really, really like to see a copy of it (fax, scan, whatever). >Subject: Electronic transmission controller? > >Anybody ever worked on a controller for the GM electronic trannies? >Specifically the 4L60-E? What about a commercial one? Is there one >available that's stand-alone and adjustable? > >Were the OEM controllers stand-alone or part of the EFI computer? > >Is there an aftermarket efi controller (Haltech, TEC, Wolf, etc?) that >can also control this tranny? Well... yes, and no. Actually both. The NA diesel engines use a TCM to control the transmission, there is nothing electronic/electrical to managing the engine. The gas engine uses a shared PCM, which controlls the transmission and engine at teh same time. These units are not directly interchangable however. Aftermarket... Jet is a good bet for a standalone unit. All this is for a 4L80E, but the concept is basically the same. Thanks, Peter Hipson (founder, NEHOG) 1995 White NA Hummer Wagon ------------------------------ Date: Fri, 6 Aug 1999 18:13:36 -0400 From: "the Fredericks" Subject: Electronic transmission controller Felpro now markets a stand-alone transmission controller for the 4L80E and 4L60E called the TCU. The MOTEC systems are the only aftermarket controllers I know of which can control these transmissions. Art Carr, for one, offers diesel transmission computers with reprogrammed shift characteristics. Kendall Frederick Date: Fri, 06 Aug 1999 06:34:47 -0400 Subject: Re: Electronic transmission controller? > > Date: Thu, 5 Aug 1999 16:03:52 -0700 (MST) > From: d houlton x0710 > Subject: Electronic transmission controller? > > Anybody ever worked on a controller for the GM electronic trannies? > Specifically the 4L60-E? What about a commercial one? Is there one > available that's stand-alone and adjustable? > > Were the OEM controllers stand-alone or part of the EFI computer? I don't know about the 4L60E, but the diesels with mechanical injection and 4L80E had a trans controller. There's a company that reprograms them to use with NA diesels, I can't remember their name. Any car or gas engine truck with the 4L60E should have EFI, and trans control is in the same computer as EFI. Shannen > > Is there an aftermarket efi controller (Haltech, TEC, Wolf, etc?) that > can also control this tranny? > > thanks > - --Dan > houlster@xxx.com > ------------------------------ Date: Fri, 6 Aug 1999 17:14:56 -0500 From: Mike Strausbauch Subject: fuel starvation and stalling GenevaHello all, my subscription atempt to get on the list bounced so you will have to respond by email to "strausbauch@xxx.edu" I have a fuel problem that is driving me nuts. I have a 1988 dodge caravan with the 3.0 liter v6 multiport fuel-injection system (130K miles all original fuel system componets). I have what I believe to be a low pressure or no fuel delivery problem on extremely hot days. This has occured 2 years ago on a trip thru South Dak. near Sturgis during Harley Days (of all the times to be stuck on the interstate this was it because of the wall to wall people there was a lot of company and assistance.). Now It's happened again under similar circumstances. After driving all day in record Hot temps for this part of the country @xxx. on a clear day with the sun beating down on the road and cruising at the speed limit (70) in the middle to late afternoon the car will have a very light stumble. About 30 sec's later it will stumble again and and they will come more quickly and more violent so that over the course of 4-5 min the car will stall and the engine die. At the end the surges are quite violent. If you ease off the gas the car will run smoothly but there isn't enough power to maintain speed and in the end you end up about the same distance as you would otherwise. After sitting 10-15 min you can get about 1/4 mile down the road- further if you wait longer. During a surge the engine seems to be able to pull the van normally. But it won't start at all if you try imediately. The car might fire but will die before you can get it in gear. Sometimes I think I can hear the fuel pump running quite a bit while the car is trying to stall out. I have been using 10% methanol reg gas (we are in the corn belt), and the engine doesn't seem to be overheating. And the oil pressure is good as far as I can tell and I can hear the fuel pump running so I don't think its cutting power to the fuel pump. I have Just changed the fuel filter thinking that the flow of fuel might be reduced and might have a vapor problem up at the fuel rails but the old filter didn't seem to be blocked after I replaced it. Could this be a cavitation problem at the fuel pump or a vapor lock in the fuel line since it runs the length of the van right next to the exhaust system? (I thought it was near impossiable to vapor lock a pump-in-the-tank system.) please, any suggestions would be helpful, strausbauch@xxx. ------------------------------ Date: Fri, 06 Aug 1999 15:46:01 -0700 From: garfield@xxx.com (Gar Willis) Subject: UEGO AFR Precision On Sat, 07 Aug 1999 03:03:04 +1000 Phil Lamovie wrote: >Be wary of any O2 sensor voltage vs A/F ratio inferences. If you >don't correct for temp there is a drift of 1.5 A/F over 400 deg >c. And that's for the expensive BROAD BAND device. Whoa, not so fast; you wanna always QUALIFY *which* so-called UEGO you're refering to. The last generation Bosch non-current-pump wideband varieties, such as the LSM-11, I wouldn't be too surprised if they DID vary 1.5AFR over 400degC (their spec is only given for a 250degC range, so I dunno), but that does NOT apply to the NTK current-pump sensors, nor the Bosch LSU current-pump sensor. Hell, that'd be bloody 10%, mate! I hope that's not what you're getting from some broadband UEGO equipment you are using! Sadly, Bosch hasn't published much of anything on their "LSU" sensor itself AFAIK, so I dunno what the raw sensor specs are like, but I have seen a operator's manual for their LA-3 meter that's based on it, and their box, unlike most of the NTK-based devices, DOES regulate the heater voltage, using no less than a PID controller (for those unfamiliar, that's control system jargon for a "Proportional Integral Differential" controller), basically a fairly powerful controller method, just for the heater current/temps. But the NTK data seems to indicate that this isn't really necessary until you wanna reach "lab equipment" precisions. The rumor someone spread a couple years ago, BTW, that the NTK sensor's heater would burn out if connected directly to batt. is a myth, a veritable automotive urban legend. Course I imagine if you DO tightly regulate smack at 12V, you're right in the middle of the operating range temp-wise AND you've eliminated most of the temp dependant variations. That's noice. :) Bosch may have also opted for a construction on the LSU that minimizes exh. pressure dependencies, at the expense of temp. variations (see below), and that's maybe WHY they need to go so such extremes in heater regulation, for their AFR meters. Since you're a confessed SAE addict, you probly have the seminal SAE paper on the NTK/NGK sensors, and in there (#920234), you'll find a graph on pg. 30 (figs. 14 & 15) where the AFR is within a band of +-0.2AFR on both lean & rich sides of stoich, over the usable operating temp range of the sensor (600degC to 950degC), which is also within the heater's range of temp authority over a varying batt. voltage of 10-14.5V. I've confirmed these AFR delta specs in testing the soon-to-emerge EGOR systems, but then again, I haven't tested a bazillion diff. sensors, admittedly. Because of the strongly positive temp. coefficient of the heater element, even if the heater voltage were regulated, the heater current would adaptively increase/decrease with corresponding decrease/increase in EGTs, so I think that graph is meant to demonstrate the sensitivity of those sensors to tip temperature overall, as well as the variation IN tip temperature that can be expected over varying battery voltage alone. The article, I have to acknowledge is kinda old ('92), and it appears that the sensor "design" they actually deployed, in OEM applications at least, is NOT as sensitive to exhaust pressure as they indicate. I wanna test a lot more sensors before releasing any exh. pressure compensation data for EGOR, so that's all I'll say at this point. They mention in this article that they have a tradeoff point they must pick when constructing the sensor, between temp sensitivity and pressure sensitivity, and that they opted for reduced temp sensitivity. That discussion is on the bottom of page 28, and is pretty interesting. We haven't found NEARLY the level of exhaust gas pressure dependency that the paper suggests in their graph on the same page (fig. 11), so I think they must have made some 'other' tradeoffs in the process of actual mfg. & deployment in the field. Suffice it to say, it doesn't appear they've done anything to mess with the low temp sensitivity, tho. When EGOR-the-module get's announced here shortly (real soonium, now), I'll discuss some of the details on the testing apparatus we've used on the Honda/NTK sensors, for both temp & pressure, AND some special surprise tricks on calibration if you wanna get REAL high precision with EGOR. >DISCLAIMER .......I am a hopeless addict of the SAE book store >and would buy everything if I could. I'm sure you'd be welcome to join the nearest SAE bookaholic's anonymous chapter. You'd find there, MANY souls just like yerself, from all walks of life. :) [Just too damn bad the drugs are soooo blinkin spendy!] Gar ------------------------------ Date: Fri, 6 Aug 1999 15:39:27 -0700 From: "John Dammeyer" Subject: Re: DIY_EFI Digest V4 #453 - ------------------------- > >Date: Sat, 07 Aug 1999 03:03:04 +1000 >From: Phil Lamovie >Subject: Acceleration enrichment Re: DIY_EFI Digest V4 #450 > >Hi All, > >For a simple solution to acc enrichment start by creating a FIFO >stack of say >ten counts. Read TPS every 10 ms. Algorithm should respond in a >linear fashion to the diff b/w first and last. Say 100% of >additional fuel for 200% change in A/D value. A single integer >value of X ms will give you an adjustable ramp rate. This is a >simple feed forward system Hmmm. I'll see if that technique will work for my system. > >The harder part is to arrange a proportional decay vs rate of >change of rpm > >Of course for an engine that has a very poor chance of acc >quickly relative >to say a blipped throttle during a down change this is really of >little import. Yes, a propeller at 2500RPM (6000 Engine RPM) has a fair amount of momentum (or lack of it at low RPM). 8-) But that brings up an interesing point that we discovered today. The MAP sensor vent for the Honda engine is located about 5mm behind the throttle plate. Once the throttle is opened wide my MAP goes to atmospheric. At 5200RPM and wide open throttle the MAP stays at ambient. I see very little change or no change as the RPM increases. Al Grippo in his fuel injection document discusses acceleration enrichnment and derivative of MAP and TPS as the signal to do acceleration enrichment. That's all find and good but when should the enrichment stop? For a car engine in first gear a safety could trip it at max RPM. A car going up the hill in fourth with the pedal to the metal would either a) slow down and stall if the hill is too steep or b) drop to a given speed and go up the hill with perhaps a 12:1 A/F ratio. (I'm guessing) In the case of a propellor load for water/air (assuming no cavitation) the prop is usually sized so that the engine turns just under maximum RPM at WOT (static). The prop can turn faster if the vehicle is moving. Carburated engines just smoothly increase in RPM to their limit given the engine/prop combination. So I think I can assume that if the delta TPS is large or for that matter if the TPS is at maximum value, that the mixture can be increased to WOT at Max RPM. (as a guide). Then, if either MAP or TPS changes in the negative direction, switch over to normal A/F curve. ie: If at WOT and max RPM pulse width was 12.5ms then run injectors at 12.5ms until TPS or MAP changes. At that point switch over to the normal closed loop control algo. and the engine shouldn't miss a beat but mixture should even out and fuel economy will return to expected value. (fuel economy on aircraft is _really_ important). My SAAB Turbo has a switch at 70% TPS that tells the engine computer to put the boots to it. I would assume that a smaller change in TPS will just increase the mixture based on a number of engine parameters with a corresponding slow increase in acceleration. That I already have since I can slowly reach 5200RPM (loaded) with the gradual opening of the throttle; it just doesn't have a rich enough mixture when the throttle is opened wide. Suggestions, comments? > >On the matter of duty cycle it's more to do with lousy linearity >of an injector >at either end of the scale 0-2 ms is considers to be unusable due >to lack of repeatability. With 0.5 - 1.1 ms just to open this >gives rise to variations cycle to cycle of more than 8 %. Makes >it hard to pass US pollution laws. > >At the other end of the scale the rate of collapse of the >magnetic field and the fuel pressure together with pintle bounce >mean that 90 % duty cycle could in fact mean that the injector >never closes. That's what I've read too. Also too long an on period causes heating with a subsequent possibility of a stuck pintle. > >F1 engine at 16,000 rpm has 3.75 ms per rev losing 0.5 to open >and 0.65 to close would give a max. of 2.6 ms. Thus one injection >per 2 revs. >And you were worried about timing the injection to coincide with >valve train events. sigh... I worry way too much. > >Be wary of any O2 sensor voltage vs A/F ratio inferences. If you >don't correct for temp there is a drift of 1.5 A/F over 400 deg >c. And that's for the >expensive BROAD BAND device. A single wire sensor can't be >trusted >at all. For any peace of mind use a 4 Gas analyser and EGT. Yes. I've found that it seems to work well under steady engine loads but doesn't respond well as the engine load is changing. Doesn't matter much. Loop opens up for accel, and decel and engine warmup and then mixture defaults to pure table values. This works well enough and just on the rich side. Today we ran the Hovercraft Fan (Giant Computer Fan really), up to 5380RPM and ran it for a few minutes. Smooth and mixture sat nicely at slightly rich. Be nice to have EGT for this part. Best with carburator has been 5200RPM. Man is it loud. > >Be sure to refer to the properties of steel/wire/bailing in the >BLUE BOOK >to aid with exhaust mounting redesign Do I look in the index under SWB or steel/wire/bailing? ;-) > >For the key to all things in auto tech The Bosch Automotive >Handbook > >SAE order no is BOSCH4 (4th Edition) It's blue !! ISBN >1-56091-918-3 > I'll order one tomorrow. Sounds good. >DISCLAIMER .......I am a hopeless addict of the SAE book store >and would buy everything if I could. SAE book Store? Try any book store for me. We don't have paintings on our wall, we have bookshelves. Regards, John Dammeyer ------------------------------ Date: Fri, 6 Aug 1999 23:12:50 -0400 From: "Clare Snyder" Subject: Re: DIY_EFI Digest V4 #453 > Some where in the box with the TPI stuff is a harness adapter that is > suppose to convert the TBI injector harness to an eight injector harness for > the TPI. > > But the big question. Does anyone know of a chip maker that makes a chip > that will allow my TBI computer run a TPI system? > > If you have the right injectors the tbi computer for the SBC400 should run a tpi system effectively. You are still not sequential, so as long as your injectors each flow 1/4 of what each of the two tbi injectors flow, you are pretty well home free. ------------------------------ End of DIY_EFI Digest V4 #454 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".