L99 S-10 transplant

[Kevin]

I have transplanted a 1994 L99 into an S-10. I am not a mechanic, or an electronics expert and I don't understand much about programming or hacking. I manufactured a cable as per dwg from http://www.mindspring.com/~amattei/aldl.htm (thanks, Andrew) and have tested it and it seems to work fine.

The engine turns over, has spark, and the injectors seems to be firing, but I still have a no run condition. I have installed the fuel pump from the 94, but haven't checked the pressure.

I think that my problem is with the VATS. I used Pcmread to read my PCM and emailed Dave @ carputing.com, he said that my pcm is VATS enabled.(thanks Dave.)

I was wondering how I can get any of the free software out there to show me the VATS enabled. I have dnloaded and looked at Data Master, Pcm comm, Efi live, Carbytes, and Cats engine tuner. None of these programs show me the VATS enabled or disabled.

I am not sure of the condition of the engine I have. I would just like to get it running, but I am not worried about making performance enhancements at this point.

Is there any way that I can disable the VATS in my PCM without purchasing an expensive PCM editor program?

My other option is to build a VATS module replacement. I have heard that my VATS module sends a signal that is 3 to 5 volts at 250 hertz. Can I just make an electronic device to generate this signal? If I can, how could I check that my PCM is satisfied with this signal? Where could I find a schematic to generate this signal?

Any help would be greatly appreciated. Thanks, Kevin.

[32v_dohc]

You can use an analog volt meter to check for injector fire.(or a niod lite) If the injectors are firing then VATS is not your problem. If the injector drivers are not switching ground then It is probably VATS. If you use a niod light tyou must check for 12V power on 1 terminal. If using the meter then check the other terminal for a dancing needle while attempting to start it. If the PCM is getting a reference pulse it should try to fire the injectors.

Best bet if it is VATS is to search the web for 555 timers. You should be able to find a site or two that will show your how to design a circuit that will give you the frequency you are looking for at 50% DC. The traditional frequencies have been 30 and 50 hz.

HTH

John

[RoboGeek]

I'm gonna put this out there just because I just ran into it on a swap this weekend. Is the oil pressure sender hooked up? My little headache had a gauge installed and so it had pressure.. i didnt even notice he bypassed the ECM. It cranked, sparked fuel pressure.. but no injector firing..

And now I must show my ignorance once again.. what is VATS?

I have the circuit design you need also.. variable duty cycle and frequency..

[Kevin]

Yes, the oil pressure sending unit is hooked up, and the fuel pump is running.

I put an incadescent bulb into the wiring harness for injector no. 1 and it is flashing. I have a spark plug into wire no. 1 and there is spark.

VATS = vehicle anti theft system. The way i understand it is- the vats module looks for the correct resitance in the key, when that is satisfied it genrates a signal of 50 hertz, square wave between 3 and 5 volts to pin 25 of the red connector on the pcm.

I do not have the vats module, but figure if I send the correct signal to pin 25 the pcm should be happy. I have read somewhere that the vehicle should run for 1.7 seconds, then when it does not receive the signal from the vats it will shut off the fuel pump. (I am not 100 percent certain about this.)

I am no electrical expert, but can follow a simple schematic, where would I find a schematic for a device to generate 50 hertz square wave between 3 and 5 volts?

[RoboGeek]

i'll try to get my scanner working and I'll email you a very simple circuit.. its a r/c 555 square wave generator circuit

never mind.. I'll post it ..

This can be tweaked for a perfect square wave but I dont know if that needed.. if so the circuit gets a bit tougher.. at any rate this should cost you less than $5 to try

[Lee]

In Tuner Cat

Read your chip,look in swicth box if a [X] in vats it is enable you need TDF for YR. You May want to get a reg.
copy of his program to turn off Egr and so on and codes.
I think you would be better of in long run.

Cost you 90.00 for all,could buy Tdf for 19.95 use his tuner for 30. days for free.

Lee

[RoboGeek]

i found the sensor variables and it looks like 33-66hz is what it wants - so aiming for 50 will work

[Kevin]

It is running now.
1, the injectors were stuck, they were getting a signal. but not opening.
2, once the injectors were fixed the engine would run for about a second and stop.
3, I built a VATS module and now it runs.

Thanks everyone for your help. Here is how I built the VATS module, I found this web page

http://home.hiwaay.net/~davida1/passkey.htm

Parts:
555 timer
16 pin DIP IC PC board
two 0.1 µF ceramic capacitors
1 µF electrolytic capacitor
3.9 K resistor
22 K resistor
100 Ohm resistor
14 Volt Zener diode
Plastic enclosure

Pin 1 is Ground. Pin 8 is + input. Connect a 0.1 µF ceramic cap between these
pins, with short leads, for filtering. Otherwise it may misbehave. Connect pin
8 to 100 Ohm resistor. Connect a 14V Zener diode between pins 1 and 8, banded (+)
end to pin 8, to absorb voltage spikes from starter solenoid or system overvoltage.

Other end of 100 Ohm resistor connects to ECM's "Crank" signal wire. This is
best since the oscillator signal is only needed once at cranking.

Tie pin 4 to pin 8.

Tie pin 6 to pin 2.

Add a 3.9K resistor from pin 7 to pin 8.

Add a 22K resistor from pin 6 to pin 7.

Add a 1 µf capacitor (electrolytic OK) + side to pin 6, - side to pin 1.

Add a 0.1µf cap from pin 5 to pin 1.

Output is on pin 3. Connect to VATS wire of ECM.

[RoboGeek]

so hows it running? fast?

those 555's are the best..

[Kevin]

I am still a long ways away from having it road worthy, I don't think it will be a real powerhouse, but it should have a little more get up and go than the 2.8 ltr it replaced.

[Kevin]

I purchased Tuner Cat and flashed my PCM to disregard the VATS, I read the PCM in DOS, but could only write from a DOS window, which TC warns me not to do! Hope everything works OK.

Seeing as I don't have any exhaust pipes yet I am running in open loop. The problem I am having is that my idle is about 1200- 1500 rpm. Is this normal for open loop? I cleaned the IAC because I thought this would be the problem, but that didn't help. Is there a parameter I can change that will change my idle speed in open loop?

[RoboGeek]

Check for vacuum leaks.. thats the most common thing that will do that. Tunercat has an idle speed vs coolant temp setting on some stuff. Theres a possibility if your definition file has that..

[Kevin]

My MAF seems to be incorrect for my application.
If the motor is running with MAF plugged in I read about 2 to 4 gm/sec, if I unplug the MAF the default setting is 343 gm/sec. Can anyone give me an idea of how much my flow should be?
I am wondering if there is an advantage to running the correct MAF , or is speed density a better idea? Where can I learn what the difference is between these two modes?

[Kevin]

I found the URL for LJ's PCM tutorial under the "basics" heading.
If I change to speed density mode, do I use VE X Rpm X MAP table to adjust my A/F ratio? How do I know if I am running rich or lean? Or is this taken care of by the BLM?

[RoboGeek]

Your running MAF right now?

From what I understand you replace the MAF with the MAP sensor (same leads, diff connectors. not sure of the wiring)
Then with the MAP bin you can change the VE vs MAP vs RPM, the PE - basically anything you could change under the MAF setup.
The theory is pretty much the same with the sensors being different. You would use the same procedure to tune it (chip).

If you decide to go that direction let me know and I'll research it alot more.. good luck!

[Kevin]

I disconnected the MAF, and reflashed PCM to use speed density. It is running a lot better now, just has the odd hesitation about 1/4 throttle in 2nd gear.
I am still trying to decide if it is better to run a MAF or not. Any opinions on this?
The original ratio for the Caprice was 3.23, I am running 3.73, so I changed some of the shift points. This motor is out of an old police cruiser, and it was programmed to stay in 3rd gear if you had more than 50% throttle.(IE: 3 to 4 shift at 255 mph) I am not sure if that is a police thing, or common with all Caprice's.
I try to not push it too hard in 1st, but get plenty of wheel spin when shifting into 2nd.
Still lots of fine tuning to go.

[Kevin]

I am now running without the MAF.
What do the values in the AFRx10,open loop vs coolant temp, vs map represent?
Are they the ratio? ie 81 = 8.1:1
If I read the table correctly I would need to make the values smaller to enrichen the mixture, is this correct?

[RoboGeek]

the numbers are just a representative value.. they dont correlate to any specific value. The number is usually plugged into a formula to get a real world equilvalent

here's some.. they are for 747 ECM but I think the conversions are close to universal..

conversions and formulas

[Kevin]

Thanks, Robo, but I am still wondering if I need to make the values smaller to add fuel to the mixture?

I concluded this because the values for 100 map are smaller than the values for 20 Map, and the values for warmer temp are larger than values for cooler temp.

I am also still wondering if anyone has an opinion on running MAF or not?