pcmhacking.net

Hello -

I have a 1989 corvette that had some head leak problems, so I thought I would refresh the engine. I pulled the engine and had it stroked to a 383, added headers and stuffed it back in. Wow, was that a rookie move! The ECM has a devil of a time running that engine! I saw the info on Tunerpro, and wondered if anyone could help me understand what I need to interface it with this engine???

My car is a 1989 Auto, with pretty much standard everything, except the 383. Any recommendations would be greatly appreciated!

Thanks -

Wes

Unfortunately there are not too many US guys on this board, the thirdgen.org DIY PROM forum may have more users that can help.

If you post up some info such as the details from the sticker on top of the factory memcal and the ECM part number there may be a possibility someone here can help.

Wes,
I just joined and I reside in the USA. I am very versed with your car and the $6E ECM. I have Tuner Pro files similarr to TP postings. With a few exceptions. I am GM retired so I have the ins and outs of this package. You need to recalibrate the MAF tables *there are 6 IF I remember right 8 maybe) but this will pull in your A/F Rations. Use the MAF SCREENS.

I have the same ECM in a big block with twin MAFs. I have only one connected to the ECM and use the other as a flow device. Recaled the MAF tables and it works well through 5500 RPM where I drop off with the valvetrain limits. I use a 96 Diesel TCM to control my 4L80-E with a DRAC and electric speedo. TP Is what I use for all my vehicles.

Hope this helps.

This might be out of place as a reply to this thread, but it's related so rather than start a new thread...

I have an 1987 Camaro with the 1227165 ECU which uses MAF as stock, but I want to remove the MAF and use a MAP sensor instead.

The issue is that the voltage outputs from the MAF sensor and the MAP sensor are in reverse of each other. The MAF sensor pulls the voltage low with low air flow and has higher volts output with high air flow, whereas the MAP sensor has high volts output with low airflow, and low voltage at high air flow.

I tried to simply reverse the Volts Vs gm/sec in the tables but first couple of (6) tables doesn't acept a high gm/sec value (i.e. 255), then I noticed there is a scalar multiplier on each of the tables, i.e Table #1 has a multiplier of 23 and the values range upwards for each table to Table #6 which has a multiplier of 255.

The first few tables have 9 lines, the 5th has 8 lines and the 6th (#6) has 17 lines.

How can I rearrange these values to interpret the outputs of a MAP sensor?

Later, I thought it would be good to somehow compare the voltage outputs between the MAF and MAP sensors to find a common point from where to reorganise the MAF tables in the PROM.

Thanks in advance, and apologies if this post is out of place.

Maf and Map are a different type of signal. MAP is 0-5volts and represents manifold pressure, the idea being the VE table shows a % of how full of air the cylinder will be with that much pressure in the manifold. MAF is a frequency, measured in khz and the maf scaler tables translate that frequency to airflow. To swap from map to maf you would need to find a memcal that runs in your pcm, and supports map. EG if your ecu is a '165 you should be able to run our $12p in it, and compare wiring diagrams and swap a few wires around to suit the map program. If you cant find a program that runs on your ecu that supports map then you'll need to swap in a similar era ecu that does.

antus wrote:To swap from map to maf you would need to find a memcal that runs in your pcm, and supports map. EG if your ecu is a '165 you should be able to run our $12p in it, and compare wiring diagrams and swap a few wires around to suit the map program. If you cant find a program that runs on your ecu that supports map then you'll need to swap in a similar era ecu that does.

Thanks Antus, good information. I did a bit of research but didn't pickup that it was a different type of signal.

I have now removed the MAF altogether after installing NVRAM and $12P, and the vehicle is running pretty good with the BCLF bin. Just need to log some data and start tuning.

The "similar era ecu" you mentioned would be something like a 1227730? It goes by other part numbers, and there is also a weatherproof version that can be installed under the hood/bonnet or the vehicle. This unit is in the 1990-1992 Camaro (and other Chevys).

I have a 1227730 and I would like to get that running with NVRAM and $12P just out of interest. Maybe use it to make a test bench.

Is there an Aussie ECU equivalent to the 1227730?

for a 1227730 ecu you would use code59. But code59 does not support the nvram method. If you are running fine with 12p and a '165, I would use that as it will support your nvram and realtime edits and is very capable and well supported here.

I've only just recently got 'started' with NVRAM and $12P on the '7165 ECU... I'll stay with the '165 then.

Getting back to the gist of this topic... The 1989 Corvette has a 1227165 (new part number 16198259), same as my '87 Camaro. I would recommend getting a NVRAM board (VL400) and run it with $12P. Just remember to change the spark reference angle from 60 to 10.

To interface with TunerPro, well I haven't been able to do that yet with $12P... Still trying to figure it out.

I was able to connect with the stock Memcal, but not since the $12P upgrade.

To connect with the stock '165 Memcal, see this thread http://www.thirdgen.org/techboard/diy-p ... erter.html

The 10K resisitor mode does not exist in 12P, you must ask for data so need bi-directional comms. In a few emails I had suggested trying to use a feature added to 12P to get it sending data automatically for telemetary by grounding pin D11. Will need to use the attached ADX with D11 so it just listens though.

VL400 wrote:The 10K resisitor mode does not exist in 12P, you must ask for data so need bi-directional comms. In a few emails I had suggested trying to use a feature added to 12P to get it sending data automatically for telemetary by grounding pin D11. Will need to use the attached ADX with D11 so it just listens though.

So it's $12P that 'needs' the bi-directional comms (not me), and #12P requires bi-directional comms for both writing and reading data. Is that it, why I could connect with Tunerpro until it suddenly stopped when I was only running 12P?

I thought it was my virtual machine set-up, the wiring, ... tried everything.

So if I understood (this time) - it's not possible to flash, or even to log on $12P unless the system has bi-directional comms.

I just spent the last few days making a huge mess...

VL400 wrote:suggested trying to use a feature added to 12P to get it sending data automatically for telemetary by grounding pin D11

So this doesn't work on it's own? I'm going to use this ADX and ground pin D11 - then I will be able to log.

Sorry for all the repetition but, I just wasted a few days.