Hi all. It’s about time I signed up here. I bought a 1988 Camaro with a very poorly done lm7 swap.

I bought it because the cars body is decent and the mechanical aspects of the swap look decently done. It’s hooked up to a 700r4 at the moment.

It also has 50lb injectors and a big maf. It also has a SS2 cam and springs etc.

I was looking for something to build with my son. I was planning to one day build a decent muscle car with my dad but sadly we never got to it. The plan is to maybe add a turbo later so the existing setup seems somewhat future proof, at least the engine. D the driveling will need upgrades of course.


So now is the time.

I’m working through getting the wiring harness connected correctly and working out some details. I’m using HP tuners and have a zeitronix zt2 installed and connected into the pcm

Next up is AFR/VE tuning with the map and then I’ll decide if I want to run the MAF too or just stick to speed density

Ive tuned old school gym ecm $59 syone/typhoon and Honda and some Cummins before but never GM800. Looks interesting for sure.



Chay

 

Welcome aboard. I am always pleased to see a new project shared on the forum where we can all learn from each other. Looking forward to see your story as it develops. Pictures are always good.

 

Cool project...

 

Here are a couple of pics of the car from when I bought it

I now have the sd enhanced hp tuners loaded so I can real time tune the ve. There was a lot of tuning to get the sucker to idle. I finally found a smoking gun. Someone had set the over rpm timing cut to -8 across the board. No wonder the idle timing was jumpy!!

I figured out how to get the wideband to work with the ac pressure input on the pcm. Interesting that this works as the pcm is from 1999 or 2000 which didn’t use this but it’s still there and the pid works

i tried to use the pintle position feedback for the egr but I think someone disabled it in the past and now there is no access in hp tuners to reenable it. The voltage just shows up as 0 no matter what

I also figured out how to get the original tach to work and it even seems fairly accurate

I wired in the vss input from the existing gauge cluster mounted vss buffer from the Speedo. I bench tested it with a drill and it seemed to work but I haven’t given it the real test yet.

So I’m almost done the initial stages of the wiring work so I can start ve tuning.

I can’t wait to cruise it around a bit!!


Chay

 

A couple more pics. New wiring, messy and untucked but working.

The po kept the stock lm7 +12 post from the truck and put it in the car. It seems like as good a way as any to tie in the alternator and power feeds so I kept it

I ran multiple individual fuses just because I already had them. Cheap and easy and hopefully you never have to touch them anyway

I I ran much the same as the 1999 stock distribution:

1 feed hot at all times

1 feed for each of:

PCM
Odd injectors/coils
Even injectors/coils
MAF/wideband O2 and any other accessories
Fuel Pump


The fused feeds are assigned one to each of 5 relays. 4 are energized with ignition power (On in run/start) from a pink wire on the back of the stock ‘88 fuse block and the fuel pump is controlled by the pcm output of course

Next up is getting the TV cable right. There is a very specific geometry to it and the po didn’t get it right. No biggie there. I can tig weld so I’ll make a proper bracket for it. And then I need to check the speedo cable at the trans. Something is weird there.

It’s coming along now though…..





Chay

 

Well I jacket her up and found out why the speedo doesn’t work. Someone disconnected the cable and installed a sine wave generator. Looks like the typical Dakota one which is cool.

But it is not the pass through type so it won’t work with the original
speedo

So I was wondering if the pre buffer or post buffer signal would run the pcm vss input and the answer is no they won’t. The frequency is off by a factor of 10 (30 ish hz for the buffer and 300+ for the Dakota for the same speed input)

Also the signal type is incorrect. I’ll put in a picture of the Dakota signal. This is at approx 100kmh as per the original speedo

I didnt take a pic of the buffer signal but it’s a square wave and never crosses 0 to negative. It did not drive the pcm input adequately. HP Tuners says 0 regardless of speedo input rotation speed

So I ordered another Dakota from Summit, this time the pass through type

Its called SEN-01-4160

I also verified that there is no TCC wiring installed so I ordered a plug to fix that up. I’m toying with making my own lockup electronics with a microchip pic similar to some info I found online where someone made one with an Arduino (Another microprocessor device). That’s in the future though

Chay

 

Good work with the investigation. I am guessing the square wave was "pulse per mile" (PPM) which can be understood by an electronic speedometer like in Firebird or later Camaros. The calibration for our cars is 4000 pulse per mile . But I think you're right, the ECM rrequires a sine wave directly from the mag pickup.

 

I’m pretty sure the square wave was for a different style obd1 ecm like the 1227730. I had a similar setup on a 3.4 turbo fiero I built.

I think the newer pcms use zero crossing detector so it doesn’t matter if the signal is squared up, it just has to cross 0.

All speculation of course!

Chay

 

While I’m waiting for the parts and plugs to show up I decided I’d do something about the gauge cluster plugs

I cleaned mine up but I don’t like the press for idea. The plugs have lost some ‘spring’ so I don’t think they are a great long term solution

So I set about soldering some ribbon cable onto the cluster pads.

They are a bit touchy so I cleaned them with a pencil eraser (old school trick) and then tinned the pads. Then I tinned the wires. Then you melt them together one at a time.

the trick is to have a really hot soldering iron and get on and off the pads as quickly as possible

Chay

 

 

Now I’ll need to cut off the car side connectors and use some quick connects between the ribbon and the original car side wiring loom.

It’s a bit messy but should make for some high quality connections. And all the mess is buried anyway so who cares lol


Chay

 

I made a little more progress. I fixed up the geometry and adjusted the tv cable for the 700r4.

It now has a little more than 1 1/2 inches of pull and the degrees are pretty close to the spec

I finished the cluster install and it’s good also. It’s nice to be able to check stuff out and troubleshoot with the cluster sitting out from its mounting spot. It’s a real advantage when troubleshooting

Chay

Specifications

Test location

Closed throttle

Open throttle

 

A couple more days and a couple more items completed.

I received and installed the pass through VSS...I also fixed up the wipers 'good enough' so that they will work. Very rainy around here these days!

Here's a pic of the VSS install:


700R4 End

Cable connection...very bendy but doable...not sure how long the cable will last this tight!


Perhaps I'll have time for my first tuning drive tonight!


Chay