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[Thainglo]

Just finished installing my new engine with a TPI setup in my 85 Trans Am. Using the '7427 as I'm familiar with it from installing a TBI system in my 78 Vette.

The 7427 has been modified with the jumpers in the MEMCAL and the resistors on the board. I've confirmed it is batch firing with a JimStim I built for a much earlier Megasquirt project.

Here is everything I've checked so far:
1. Confirmed spark getting to the plugs, so I'm thinking coil, cap and rotor are ok
2. Confirmed injectors are getting signal from ECM to fire through a test lead. Did test on each bank of cylinders, both good
3. Fuel pressure steady at 43 psi
4. Confirmed no vacuum leaks with smoker

Timing still needs to be set, so I have been slowly rotating the distributor while cranking over the engine. When installing the distributor, I checked twice that I was installing it at TDC on #1 compression stroke.

After a few sessions of cranking while rotating the distributor, was getting a fuel smell in the garage, even with door open. Made me wonder if too much fuel getting into the cylinders? I pulled #1 plug and it was not wet, although had a gas odor to it. Going to let it sit tonight and air out, plus let battery recharge.

Attached is my BIN file, in case anyone has an opportunity to poke around and see if there is anything amiss in my programming.

Any help would be much appreciated!

[steveo]

in my experience a smallblock with good compression, the proper spark advance, a strong spark, and a decent amount of air will mostly start with nearly any amount of fuel you throw at it.

if it's not starting at all, something fundamental must be wrong.

even with half your sensors disconnected, every constant in the ECM wrong, and in total limp mode it should at least be trying to start.

datalog without the engine running and make sure things like the tps and coolant temp sensor look right, though.

open the throttle plates 1/4 of the way, and spray some fuel in there. any fuel. gas, lighter fluid, whatever burns. keep your face out of the way. what happens?

you need to go back to basics

[Thainglo]

Thanks! Last night I was able to shoot the timing light down the front of the engine, while turning it over. No sign of the balancer mark, so I'll be pulling off the cap and figuring out what is amiss.

[tayto]

have you changed anything in the calibration like injector flow rate?

[Thainglo]

Yes, I think I completed every step to run multi port fuel injection on the 7427. There are several flags, constants and a couple tables to change. Plus, I'm running Bosch III injectors.

Thinking my timing is still off? I can get it to run a bit with carb cleaner, and even got it to stumble a bit but couldn't rotate the distributor much.

Keeping on the chase!

[tayto]

bring #1 to TDC and put balance mark on 0. point rotor at #1 cylinder and check the firing order accordingly CCW. it helps to have a helper crank the vehicle while turning the distributor. when working solo I hook up a remote start button so i can turn dist while cranking. was engine a runner before your conversion?

[Thainglo]

UPDATE: Got the engine to run yesterday afternoon, although it is idling like garbage. RPM's surging between 700-1000 and its running pig rich. I lowered the Injector Offset vs. Battery Voltage to 75% of the corresponding numbers for a 1227730 AUJP bin as I'm running the Bosch IIIs and found that recommended on an older TGO post. The Injector P/N is 0-280-155-700, 19lb/hr. I had mistakenly listed them as 22# in the Injector Flow Rate (MPFI) table, so revised it downward. Oddly enough, my grams/sec were correct at 2.30. Had pulled the original info from Southbay Fuel Injector website.

During the cranking and working on getting it to start, I believe enough fuel has washed down the cylinder walls that my oil is contaminated, so heading into town to grab a few more 5qt bottles.

Aside from the Injector Flow Rate constants and the Injector Offset vs. Battery Voltage, is there another area where bulk changes can be made to the amount of fuel? Of should I go in and adjust the fields in the Idle VE vs. MAP vs. RPM table?

Attached is a log I took of the idling fluctuation. Any thoughts would be greatly appreciated!

[tayto]

there is a zip file that contains an excel file with all the necessary parameters to change for mpfi, have you done all that? have you tried a bin already set up for MPFI?

[Thainglo]

Yes, those files are a huge help for the software and hardware mods. I updated the fuel tables based off the AUJP bin from a 1227730 ECM, similar car and TPI engine. Waiting on new oil as the stuff that was in there got fouled from too much gas washing down the cylinder walls.