I have the ability to burn new eproms. What I don't have is your files to be able to copy and burn a new chip and alter what you've got going on over there. For what it's worth the factory engines were tuned to run at about 2:10 to 15 normally in their native applications
In reply to Dusterbd13-michael :
Thanks, we may have a discussion in the future. Can the fuel pump initial run time be changed? I have several things to address there, there is no check valve or a bad one, pressure goes to 0 immediately. On the temp it may be better to just install another sensor and wire it without ECU control. A long term item on the list is O2 sensor(s), only one is wired up and I do not see wiring under the car for the second one. Not an immediate issue as all 6 plugs look the same.
I seem to buy, fix then sell abandoned project cars. Not a bad gig in retirement. This one has earned a name due to that. Futz, a yiddish term that is very appropriate.
In reply to porschenut :
7730 ECM would only had one oxygen sensor. And in that General era for that ECM it would have been a one wire oxygen sensor but with the conversion that was done on that car they probably at least upgraded it into a heated O2. Prime pulse on the fuel pump is not something that can be changed in the tune. Fan kick on and kick off temperature is. Sounds like you may have a bad fuel pump module in the tank. However I'm trying to remember my old bd1 GM fuel pump pressure Behavior outside of throttle body cuz it's been a minute of slept since then
Just for additional data, the computer that was probably originally attached to that engine (I used a 2007 Malibu to grab one at random) had a two speed fan, low speed came on at 223F and high speed at 230F.
So the fan coming on at 220 isn't hurting anything, exactly.
If it has the original thermostat, the thermostat doesn't open until 195F, so if you want to try to make the engine run cooler, you may need a different thermostat, and a larger radiator to cool the engine down with a smaller temperature delta.
In reply to Dusterbd13-michael :
TBI and MPI worked the same, they had a prime pulse when you first turned the key on, and it wouldn't allow a second prime pulse for a certain number of seconds. You can't just cycle the key in rapid succession to get many prime pulses. TPI was something low like 26psi, MPI was 43psi base pressure but they did go to 58psi later.
No matter what, they all had a check valve in the pump. Could be a bad check valve, could be bleeding pressure elsewhere. A pair of needle nose pliers and a rubber section of fuel line can tell you where.
I don't think GM ever had multiple oxygen sensors except on later engines like Northstars and LT1s that had much more powerful computers. The way they routed the exhaust on V6s would have had two sensors impossible anyway, as one bank fed into the other bank's exhaust manifold. Even on some of the V8s!
You guys are extremely helpful, thanks. I will leave the manual fan switch for the summer and maybe change the thermostat. Taking control of this without the computer can be a winter list thing. For this car just not worth an EPROM revision. The second O2 bung may end up as a wideband monitor gage port but not needed for now. I will also wire a momentary fuel pump button, the tank is a custom and not messing with it for now. But I suspect the pump is the cause, the check valve may free up with use but I doubt it. Right now is driving season and I want to get some use out of these new tires.
One thing I really need to do is put a cam on the throttle body to slow down throttle to gas pedal movement off idle. A touch on the pedal gives way too much throttle so it is very tough to take off without a rookie style lurch. But again I just want to drive it.
That was actually a GM thing, they had very rapid throttle tip in in that timeframe to give the illusion of having a much more powerful engine. I know that the three bolt throttle bodies (LS, and Vortec V6/V8s) had different cams, some round and some progressive, to tailor the tip in.
In reply to Pete. (l33t FS) :
Yes good in a big heavy car, not so much in a 2000 pound car. My starts from a stop are making me look like a manual trans rookie!
So the manual fan switch helped but the thermostat is part of the problem. Still bounces to over 200, I really don't care for that. Put new seat belts in, the old ones tended to unlatch at random. Last week while running errands 3 MGs and a RHD toyota drove by. Figured they must be going somewhere interesting so I joined the parade. Local brit car shop was having a thing so the morning was spent looking at cool cars and talking about car stuff. Futz got some attention, an MGB with flares and big Falken 615s made for some interesting comments. So I popped the hood and the V6 justified the rubber.
Someone commented and I should have noticed one valve cover is vented to the intake but the other one is capped. Probably not the best setup. So should I vent both to the intake, install a catch can or clean the cobwebs off my NOS EMPI breather box?
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