KnightmareCS

iTrader: (7)

So the car was running all well and good. This was with an ECU I bought from a member on here. Since I was still in a troubleshooting mindset, the ECU was sitting on the passenger floorboard for easy access and not in the normal mounted location. The car is now registered and I decided to button everything up for driving. I removed the ECU with the battery wires still connected so I could transfer over the mounting studs from my original blown ECU. Then I put it back together with the battery still hooked up.

Now the car won't start very nicely, if at all. If I unhook the 4-pin distributor connector, it'll start and idle fine. As soon as I plug it back in, the car dies. When starting, it'll act like the timing is jumping all over the place and spit and spudder. If I unhook the battery long enough and start it, it'll hold an idle, but die after a few seconds. When I turn the key off after it dies, the carb will shoot a quick puff out. Weird.

Pulling codes gives 41 and 42.

So do I need another ECU?

Schrade

Possibly the ECM is re-calibrating for some of the sensors. TPS for one...

IF so, it might have to do a couple of Closed Loop cycles.

Do you have FSM for the car?

KnightmareCS

iTrader: (7)

Funny thing is, originally when I was looking over why the car was acting up, the TPS was unplugged for some reason. So when I pulled the codes after plugging it back in, I saw code 21. I pulled the negative terminal again and let it clear. Now it's only giving 41/42. How would I get it to recal/CL if it won't idle with the 4-pin distributor connected?

I do not have a Flying Spaghetti Monster for the car. lol jk. If FSM means Field Service Manual, I do not.

Schrade

You really gotta' have it.

Once you get the first diagnostic done, all other DTC's start falling into place (correction) - LITERALLY.

KnightmareCS

iTrader: (7)

I don't know what a manual will tell me differently besides trying with the ALDL jumpered, which I tried already.

Also, my tach stops working randomly. Before it would operate smoothly. Not it works sometimes. When it does, it's pretty jumpy.
Can this be a bad pickup? ICM?

KnightmareCS

iTrader: (7)

Managed to get the phenomena on film:

It's a fresh start of the day, sitting since yesterday. Turned it on with the 4-pin disconnected. It sat and idled ok. Turned it off and plugged the 4-pin back in. It turned on and that is the point where I started filming. You can see the tach bounce. If you notice, when I click the key back to remove it, there's a slight rumble like the carb/engine is relieving something. Must be related to the tach.
With the 4-pin disconnected, the tach doesn't bounce and I'm able to rev/drive.

Schrade

I KNOW EXACTLY what the FSM will tell you - how to do proper diagnostic procedure for the DTC 21.

That is a concrete clue.

EVERYthing else is pissin' in the dark. REALLY. And no one's 'wrench' is long enough in that case, to wiggle around and listen for the water to splash. It will just make a mess!

Dominic Sorresso

Not meant as an "I told u so", but I never do anything with the ECM without disconnecting the battery. I could be a bit hyper but its just really not worth the alternative.

Schrade

XFire! What's UP!!!

KnightmareCS

iTrader: (7)

So something like this:



If so, I can't do step 1 as I cannot get it to stay on long enough to warm up with the 4pin still connected.

Also, I don't have code 21 anymore after plugging the TPS connector back in.

As far as not disconnecting the battery, ya that was a bad mistake. Should've slowed down and thought it out.

KnightmareCS

iTrader: (7)

Inputs anyone? ECU, pickup coil, ICM, fuse??

KnightmareCS

iTrader: (7)

Replacement ECM installed. Car started up with 4pin connector connected and no CEL light turned on. Idled higher than normal (cold start) at ~1000 RPM. Let it sit and idle for a while. RPMs dropped when the car was hot enough. The tach needle was twitchy, but in the correct area and not jumping all over the place. I turned the car off and back on, and it was the same thing: no CEL and twitchy tach. Then I turned it off and on again, and the CEL came on and it was idling like the 4pin was disconnected (rock steady 750 RPM, no twitch tach). I checked it again and am getting the same 41/42. Although now the car can start and turn on with the flat4 connected. Strange.
Seems like ignition issue: ICM or pickup coil. Thoughts?

KnightmareCS

iTrader: (7)

Since last post I've changed the header to block gaskets with copper style ones. Thought my exhaust leak was coming from there. Didn't make much of a change to anything, so I'm guessing the paper ones I had on there were alright.

Then I changed my original distributor with an AutoZone refurb, changed the spark plugs, spark wires. The cap/rotor/coil/EST-wire were carried over from the my original distributor. Helped somewhat, but there was still some twitch/misfire noticed on the tach. Took out my 3rd ECM and put in my 2nd, and the tach was twitchier. Tried my 1st ECM and it was way worse. So I figured those two are kaput. Put the 3rd one back in and had that same twitch. This was all with the flat-4 EST connected.

On my way home from work, the driver's side exhaust disconnected. When I looked under the car, I saw the collector flange to exhaust pipe flange screws were completely gone, leaving the exhaust hanging. When I looked at the passenger side collector flange, the bolts were backed out and the gasket was missing. I'm guessing both gaskets blew out and left a gap which caused the bolts to back out. They were the cheap felpro paper gaskets. This time around I went with Percy's soft aluminum gaskets. They completely fixed my exhaust leak. Only thing to do with these is use lock washers and Loctite with the provided bolts/nuts.

The car started running much nicer.

One day I was driving home and the car started popping left and right that I had to pull over and turn it off. So I got really pissed off and ripped apart the undertray to the ECM. I pushed and pulled the harness/connector at the ECM with the KOEO and noticed the CEL blink. I moved the harness one way and tried to start. No luck. So I moved it another way and tried again. And voila, it started and idled nicely. Drove home and played around with it some more.

Now just recently I took the car on a 200+ mile drive and it drove wonderfully WITH NO CHECK ENGINE LIGHT WOO HOO! Only on the way back I hit a bump and it started twitching/misfiring again then calmed down. My problem is definitely the ECM harness/connector. Couple of the wires get hot, but it could be the supply/grounds, which I would expect to get hot.

Summary of what I've changed:
ECM
Distributor (minus: cap, rotor, ignition coil, EST magneto)
Spark wires + plugs
Header gaskets
Collector gaskets

Last thing I need to is an adjustable rad fan controller and find/fabricate rad air deflector.

Anyways, if anyone else runs into a jumpy tach with the EST connected and running ok with it disconnected, CHECK THE ECM harness/connectors even if they look clean and clicked in.

Gecz28

iTrader: (5)

i know what the problems is, take that garbage off the top of the engine and put back on the holley and rpm intake !
why you running the cc crap anyways?

KnightmareCS

iTrader: (7)

The Holley+RPM intake didn't fit under my hood.
The Qjet+Non-RPM barely fits (cause the hood to stick up a bit).

Plus everyone on the boards is saying a properly set up CCQjet is the best route for streets when done right.

Anyways the problem is fixed. It had to do with the ECM connector. I do ~65 miles a day for work and it's been running and driving great.

The carb definitely needs to be tweaked for full on power, which I'm looking for someone who knows how. But you're right. I'm totally second guessing myself now as the early thirdgen computers have a VERY limited tuning ability. So I could get the carb set up right, but then face a problem with the stock timing advance.
I'd like to datalog with like WinALDL, but no one can give a straight answer if it works in 82/83 cars.
Then if I go to manual everything, I'd have to find someone who knows how to work those...