[CAnAm]

Hi knowledge pool.
I’ve restored over 30 cars/bikes but the first time I’ve delved into the dark world of EFI .

Factory setup is:
- Vacuum advance / retard distributor
- Cam driven fuel pump
- NormalAir (Garrett) T3
- Stromberg CD175 (draw through setup)
Modifications:
- Magna (Mitsubishi Diamante) Hall effect distributor with Cam & Crank sensors
- Electric fuel pump & adjustable regulator
- “LS1” Coil
- Patton Machine CD175 adaptor with side entry TBI Injector.
- AEM 30-0300 wideband
- TPS
- Air Temp
- Water Temp
- MAP

I started the project late 2022 and had it in and out a couple of times as I had to put it back to standard dizzy & carby setup to get to race meets.

So here is hoping you guys can throw an eye over the setup (I’ll attach files) .

In my latest attempt I have added one piece of the puzzle at a time & got it to the point that I have had it running on everything but the adaptor, ie; still with carby.

I have tried Paired & Sequential, 1&4 injectors, different ‘dead time’ settings but it won’t fire let alone run.

I have confirmed that the injector is pulsing with the aid of a Noide light.

I ran out of battery so my next test will be to sit the adaptor in a glass bowl and crank it to see what sort of flow is happening…….

Thoughts from the gurus??

*EDIT* - I tried to include hyperlinks to parts but the forum doesn't seem to like that....

[PSIG]

Please post:

• a short log of key-on through cranking of your no-start.
• a tooth log
• basic info of injector size, fuel pressure, etc
• ZIP the logs together with the exact tune file you used to take the logs.

[CAnAm]

Cheers @PSIG

Would the log type be the "Graphing & Logging" tab , assuming the tooth log is the "Diagnostic & High Speed Loggers" tab ?

Unfortunately, there is very little info on the GM TBI 5235277 injectors (something I didn't realise before heading down this road. I have contacted several reconditioning firms but it must be state secrets as they all just say they don't know - which means I'm keeping my data to myself
Some possible info is :
"There is precious little posted about Rochester TBI injectors. All or at least all with that same footprint are low impedance. I have a note that the 277 injector delivers 46.3 lbs at 12 psi. Pressure can be increased for more flow and I've seen them run as high as 25psi. Duty cycles usually run up to 80 %. You might try moates.net for more info."

Being LowZ & using the Speeduino resistor calculator I came up with: 5 Ohms 17 Watts, but for the life of me now I can't find the Ohms/Watts ratings that I used to get those numbers. Also, such a resister was unavailable in Australia so I used 2x 10 Ohm 10 Watt in parallel.

I am pretty sure the 5235277 won't be big enough for the application & I grabbed some modfied Supra HighZ side injectors, however, not all side injectors are the same, the profile doesn't sit in the adaptor plate.
I was hoping to get it to at least run on the 5235277 before modifying the adaptor plate & rendering it useless in case the whole exercise is a waste of time

[PSIG]

Would the log type be the "Graphing & Logging" tab , assuming the tooth log is the "Diagnostic & High Speed Loggers" tab ?

Correct. To get longer run-logs or any tooth logs, TS must be registered. Get used to making run-logs, as you will use them a lot in tuning, and assist if you need troubleshooting. You will know when logging is no longer required, and until then "log everything".

Unfortunately, there is very little info on the GM TBI 5235277 injectors … I have a note that the 277 injector delivers 46.3 lbs at 12 psi.

If anywhere near reality, that covers about 70+hp/50+kW, and pushed to 20 psi fuel pressure close to 100hp/75kW — still not to the NA rated power for your engine, stock. To make things worse, the flow must be even greater to allow testing more injections per-cycle in order to improve fuel distribution.

So yes, you could set-up and run that injector, but very limited use. Proof that it will run at idle and just above is about it. I would look into similar injectors of much greater flow that would drop-in. The older Holley Avenger injectors may be the right type and higher-flow, or check with your adapter supplier for options. Without options, the adapter is not of much use.

[CAnAm]

@PSIG

Thanks for getting back to me. I have been a busy with work, but, have noticed with some testing the injector has stopped flowing all together now.
I did get the chance to run diagnostics, though, it only seems to have saved the one file (attached).
I've bitten the bullet and dropped the adapter off with an engineering mate to get the Supra style HighZ injector to fit & then we'll try again

[CAnAm]

@PSIG, did you get a chance to look at that file - did it make any sense?

Project stalled since then, I had the adaptor modified to take a HighZ Supra side entry style injector.
When I got that back I installed the injector and it was faulty - always open.
Replacement arrived today but no luck getting it started yet.
Battery back on charge.

Then I'll try to log the cranking again - I don't think it is possible to do more than one log at a time through??

[PSIG]

@PSIG, did you get a chance to look at that file - did it make any sense?

Yes, and there is no tune with it, so we cannot see the settings that are making the logs. Always two files - the tune and at least one log of the issue made with that exact tune. In a ZIP file is convenient to keep them together.

Next, the first thing that jumped out at me was your very low cranking voltage. This will make starting very difficult even if all settings are close to perfect. I would do something about your cranking voltage, and to get the cranking speed higher if possible.

Next I would inspect the spark plugs, as they are probably fouled from starting attempts. A fresh set or a good cleaning may be required to get spark under pressure. At this point you may be washing the cylinders down with fuel. Get it started. Use a dash of starting fluid if you must, but prove it can run and clear it out with a start.

[CAnAm]

@PSIG - I am claiming victory, albeit a small one - I got it started!

I have a slight weep from one of the Injector 0-rings so will swap that out & see if that cures that problem.

Got it running - like a billy goat - but then I realised I didn't have the MAP line connected to ECU, so next run was much smoother.

Got 4 runs out of it tweaking RPM / trying to seat injector better etc - by then it was 10 at night and figured I'd better pull the pin before the Neighbours complained about the noise - and it is running hell rich (so no mosquitoes out LOL ) . Super pumped even though after this victory I've still got 99% of the work to go. All good, only 3 weeks to next race meet and it's only taken 15 months to get this far.

Managed to make separate "Graphing & Logging" files which I'll attach.
I got 1x "Diagnostics & High Speed Loggers" as I only realised at the last minute even though you tell it to log it doesn't auto save it (like the other tab) - you have to click on "Capture Log File" when you're finished to save it. So, the only one I have is from the last MLG file.

So, it's all a foreign language to me atm, but, I will play the file(s) a few times and build some knowledge.

If you spot anything obvious feel free to slap me

[CAnAm]

OK, spent another day on the project.

Got it running for an extended period. (attached)
- No vacuum/pressure line connected to ECU.
- AFR is about 9 even with target set to 14.7
- (A) When I go to connect the line RPM ramps up as it leans out (watching AEM AFR gauge rocket to 23+)
- (B) Pull it off drops back down and RPM/AFR (9's) stabilises,
- Push it back on go back to (A), take it of (B), trying it for longer periods backwards & forwards....same same.....

Eventually try "ON/Connected" for too long and it leans/stalls out.

Now I can't get it started again - lost spark.

Looking through every setting I can't find anything that changes 'start-up' / blocks ignition based on coolant temp - which I am assuming is the onl thing it can be.

So now waiting for the next day I can work on it when it has gone cold to see if I can get it started again.

One thing I noticed was that the "Spark Table" values on the vertical axes was all "0" - I reset them to match the VE table, but then I couldn't get it started so now I am wondering if resetting those values impacts anything - or was it just a co-incidence that I can't get it restarted when it is at operating temp??????

What on this earth made me think that playing with EFI would make it better LOL

[PSIG]

Please answer each of the following questions. It would seem your issues are fairly simple, but more info is needed to find the primary issues:

1. Have your sensors (CLT, IAT, MAP, O2, etc) each been properly calibrated?
2. What trigger sensors are you using, and where are they?
3. What is the rated flow of your injector, and at what pressure?
4. Confirm this is a 2.6L Astron engine?
5. Do you know your base or total ignition timing?
6. Did you begin your tune by modifying a Base Tune, or from nothing?

Without making any other changes, below is your tune (renamed) with only the Spark Table adjusted for engine starting. IT IS NOT SUITABLE FOR DRIVING, and is only an example table for initial startup, and re-tuning once warmed. It is a gross estimation, based only on that type of engine in that era. I would adjust Trigger Angle while cranking (FP or injector unplugged) with cranking timing set 10° and verified with a timing light. Enable fuel and connect (calibrated and tested) MAP. Test start. Re-check running timing.