9C1 cam with stock TBI?

[blackdeathmessenger]

Right. Well, I didn't just swap chips, I swapped the entire computer without opening it

 

[PlayingWithTBI]

Well, I didn't just swap chips, I swapped the entire computer without opening it

Do you know where this ECM came from? Was it the same engine size, trans, rear end gears, etc? Just because the connectors plugged in, doesn't mean they're all pinned to the same locations.

 

[Erik the Awful]

One of the biggest issues, is, and has been, the idle. It keeps surging/searching for the idle. I also have less vacuum, which I can definitely feel in my brake pedal, and most recently, I've had issues with extended cranking time before starting and now when it does start, I have to hit the gas and rev the engine to get it up to normal idle... The only thing that makes sense after all my checking and testing is the camshaft.

These are not camshaft problems. Try pinching off the vacuum hose to the brake booster and see if that affects your idle.

 

[Schurkey]

These are not camshaft problems.

Well...could be camshaft "degree" issues; cam is not properly synched with the crank. This is why I spend the time with the degree wheel and dial-indicator EVERY time I install a cam.

A compression test might reveal gross cam-timing errors.

Depending on how fast the lifters bleed down, putting a cylinder on TDC-Exhaust (NOT TDC-Compression) and looking to see that the intake valve is farther open than the exhaust valve would be an excellent indication.

Try pinching off the vacuum hose to the brake booster and see if that affects your idle.

I'd pinch every vacuum hose, one at a time. The only one that should affect idle is the PCV suction hose. I remember from decades ago, GM had problems with the canister purge valves. They'd affect idle quality, but they also screwed-up driveability and fuel economy, too.

 

[blackdeathmessenger]

Well, I pulled it from a truck in the junkyard that looked like it hadn't been there long. I did check engine size and transmission, and as far as I could tell, the differential looked the same, thought I honestly didn't check the gear ratio. The glovebox was missing the sticker, so I didn't feel like laying under the truck to count the teeth. I still haven't gotten to pulling my glove box insert to check the numbers on the ecu/prom. What numbers should I be looking for, for compatibility?

 

[blackdeathmessenger]

These are not camshaft problems. Try pinching off the vacuum hose to the brake booster and see if that affects your idle.

These could easily be camshaft problems, like if a lobe goes flat, or the cam timing changed suddenly, for example. I've had a chain skip teeth while I was driving it. That was not a fun experience to get it home

 

[blackdeathmessenger]

Well...could be camshaft "degree" issues; cam is not properly synched with the crank. This is why I spend the time with the degree wheel and dial-indicator EVERY time I install a cam.

A compression test might reveal gross cam-timing errors.

Depending on how fast the lifters bleed down, putting a cylinder on TDC-Exhaust (NOT TDC-Compression) and looking to see that the intake valve is farther open than the exhaust valve would be an excellent indication.


I'd pinch every vacuum hose, one at a time. The only one that should affect idle is the PCV suction hose. I remember from decades ago, GM had problems with the canister purge valves. They'd affect idle quality, but they also screwed-up driveability and fuel economy, too.

Sadly, I wasn't the one that built this engine since I didn't have time to do so with how much I was working at the time (a couple years ago). I've tried doing the pinch off thing with the vacuum lines, it didn't reveal anything new. With how it's running, it's hard to narrow down, aside from a possible computer issue, as pointed out by PlayingWithTBI

 

[PlayingWithTBI]

What numbers should I be looking for, for compatibility?

If it's an 88 with an automatic trans odds are, you should have a 1227747 ECM.

Here's one, you can see the service number and .bin (ANLW) on the sticker but, you should pull the cover and look at the chip itself hopefully to confirm which one you have. In this picture I have a ZIF socket with a flash chip in that spot.

You must be registered for see images attach

Your BCC (AKCW here) should look like the one on the right here in its plastic holder.

You must be registered for see images attach

Once you find out what you have, post it here and we'll look it up.

 

[blackdeathmessenger]

If it's an 88 with an automatic trans odds are, you should have a 1227747 ECM.

Here's one, you can see the service number and .bin (ANLW) on the sticker but, you should pull the cover and look at the chip itself hopefully to confirm which one you have. In this picture I have a ZIF socket with a flash chip in that spot.

You must be registered for see images attach

Your BCC (AKCW here) should look like the one on the right here in its plastic holder.

You must be registered for see images attach

Once you find out what you have, post it here and we'll look it up.

So, it is indeed a 1227747 ecm. The .bin showing on the case and prom is ARJT, with number 7409 below it if that matters

 

[PlayingWithTBI]

it is indeed a 1227747 ecm. The .bin showing on the case and prom is ARJT, with number 7409 below it if that matters

OK, that .bin is for a 5.7L, 700R4 trans so, it MAY not be a source of your issue.