In anything but Async fuel, the injections pulses are even, regardless of engine cyl count in MPFI applications. It is linked to DRP.
Async fuel fires the injectors every 12 ms IIRC regardless of DRP.
In most if not all stock bins it seems that Async is disabled anyway. I have tried to use it on a couple engines and have always turned it back off rather soon after, just because the engine didn't seem to want to run stable in that mode.
The man who says something is impossible, is usually interrupted by the man doing it.
yes, Async is a 12.5mSec loop.
<-- also not a fan of async.
1995 Chevrolet Monte Carlo LS 3100 + 4T60E
So far this weekend I managed to swap the fuel pump for a tpi unit to go with an 18 psi spring, huge driveability improvement. Then install AC, the truck was originally built without it. The AC conversion required some junkyard diving for pig tails and the lower hard line. A 93 350 tbi suburban with a 16168625 lost its computer and pigtail in the process.
Its not a weather pack ecm, but I need to learn how to use the autoprom in a closer to stock application. The good news is that it works with the stock bin and runs with the autoprom. So I'm feeling better. It idled uncontrollably at 2,000 rpm after a couple of changes and had a massive disagreement with the truck's electronics when the stock bin was reloaded for a fresh start. So that is pulled apart and will get more testing sometime this week. It crapped out before the ALDL was plugged in.
For the 7727 part, the injectors will fire consistently with a 5 amp fuse and 14v. So I've ordered a pair of ssr's from Newark. thy are 5 amp continuous and 60 amp surge with a max 500 hz PWM. A v8 at 6,000 rpm will need 200 hz, so they should be more then capable. Has anyone attempted to wire in a ssr in place of the injector driver? The system is purely on/off, so there should be no reason it will not work. Assuming the response time is adequate.
Thoughts?
Relays came in today. I wired one in to fire one side of the throttle body. It is working without a problem so far. If it makes it through tomorrow I'll wire the second one in. If I can get through next week with out a problem the 7727 will go in. So far everything is connectorized, protected by a 5 amp fuse and running on the stock vcm. If there is a failure, the stock tbi connector can go back on no foul, just back to the drawing board.
If there is still interest in this, then I'll post part numbers and the wiring scheme. I've got about $60 in the relays and connectors including shipping.
What are you doing with this relay?
The man who says something is impossible, is usually interrupted by the man doing it.
It is acting as one of the injector drivers. It seems to work ok.Originally Posted by Six_Shooter
Unfortunately the 5 amp fuse didn't survive my 4 mile drive to work. May try the next size up and see if the relay survives
I have it in and running. I still can not get a datastream in tunerpro, so I have no idea what is happening in the ecm.
The biggest problem is the engine bogs, then pops through the intake under a heavy throttle from low rpms, below 1,500 or so. It doesn't happen when the throttle is increased gradually. This has been a problem for a while. The truck did this before I swapped the heads, intake and cam. It does it worse now. It seemed like a lean mixture problem at first. When I bumped the fuel pressure to 18 psi there was a huge improvement, then swapping the injectors to 305 injectors helped again. Now I'd like to tune the problem out, but don't know where to start. Any changes seem to make it idle faster, not help. Increasing the AE and PE tables produced a bigger flame. Cap, rotor, wires and plugs are new today. The timing is set at 0.
Any suggestions?
Usually a pop through the intake when throttle is increased radily, is known as a "lean pop." More AE, usually TPS based is needed. Sometimes a combination of TPS and MAP AE works best though.
First get the datalogging connecting to Tuner Pro, then make changes, otherwise you could be shooting in the dark, and actually adjusting the wrong thing or going the wrong way.
How are the serial and data outputs from the ECM connected and what have you tried to get Tuner Pro connected to the ECM?
The man who says something is impossible, is usually interrupted by the man doing it.
The ecm is now wired in. I took a ALDL connector of a car in the boneyard and have been connecting the OBD1 Moates cable through it. The truck has the OBD2 style plug, so I adapted an OBD1 plug in place. White/Black and Black/White are plugged into the corresponding terminals of the same color, the orange OBD1 Serial Data line is plugged to the Tan OBD2 clone serial data line. Only those 3 wires corresponded between my truck and the donor car. So nothing else is connected.
One thing that is off, might just be a part of the emulation, but jumping the terminals does not flash the ECM light. It stays on steadily, no matter what.
The relays are not needed. The reason the injectors would not fire in the earlier attempt was operator error. I did not connect the dist ref wire.
Here is the link to the tread I started: http://www.gearhead-efi.com/Fuel-Inj...ECM%29-for-TBI
I was not able to complete bench testing of the '7727. I also had a Cylinder Select Error.
Early on, I looked into the Quad 4 underhood ECM. "I've also researched wiring schematics for the Quad 4 using ECM 1228708 which uses 4 port PnH mode injectors. I suppose the 1228708 would be an optional ECM to use for under hood V8 TBI? My thinking now, is to try the Quad 4 ECM for TBI.
dave w
If you don't get a response when jumping the A & B pins, something isn't right. Make sure the ground to the ALDL connector is present, it not only effects code retrieval, but datalogging as well, giving a common voltage refernce between the ECMand the laptop.The ecm is now wired in. I took a ALDL connector of a car in the boneyard and have been connecting the OBD1 Moates cable through it. The truck has the OBD2 style plug, so I adapted an OBD1 plug in place. White/Black and Black/White are plugged into the corresponding terminals of the same color, the orange OBD1 Serial Data line is plugged to the Tan OBD2 clone serial data line. Only those 3 wires corresponded between my truck and the donor car. So nothing else is connected.
One thing that is off, might just be a part of the emulation, but jumping the terminals does not flash the ECM light. It stays on steadily, no matter what.
The relays are not needed. The reason the injectors would not fire in the earlier attempt was operator error. I did not connect the dist ref wire.
The man who says something is impossible, is usually interrupted by the man doing it.
good luck finding a 1227808.... only application was quad4 W-bodies, and those were only offered in 90 and 91.... and were incredibly rare when new, let alone now.
1995 Chevrolet Monte Carlo LS 3100 + 4T60E
Your thread got me going on this again. I tried, but could not get it to run. And was thinking about trying to hack the stock underhood vcm. Moates support replied and said they do not offer anything to work with it though.
The ground is OK. Is there a way to tell if the circuit in the ecm is faulty? I need a good excuse to buy a scanner.
Also, the 1227727 wiring shows the serial data coming from 2 ports. B5 and B11. I tried both, separately and together. No change. Could there be 2 aldl ports? I haven't seen indicating there is, but you never know.
B5 and B11 (assuming those are the correct pins for the ALDL circuit) are bridged internally in the ECM. doesn't matter which one you're connected to, either should work.
1995 Chevrolet Monte Carlo LS 3100 + 4T60E
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