Discussion in 'Engine Performance + Maintenance' started by LA2SD, Mar 31, 2019.
Good points all around. I'll pay my local spot a visit and see what I can come up with.
Well, I'm encountering some issues.
Before going out and rummaging around for an ECM, I wanted to make sure that the ECM in my truck is correct. The GM parts sites weren't any help, because they list remanufactured part numbers.
So I checked out Moates' site, because I plan on tuning my ECM, and I remembered reading his guides for OBDI and OBDII GMs.
According to his site, memcal based ECMs were installed in:
1986-1993 TPI & LT1 trucks
94-95 TBI trucks
The ECM that I pulled from my truck is memcal based, but my truck is a 1993 TBI L05. It seems that I should have a different ECM.
"94-95 TBI: Unlike all other TBI ECMs (which use a G2 chip adapter) these ECMs are memcal like their TPI cousins and work with the G1 memcal adapter. Take the cover off the ECM and if you see a memcal, you probably have one of these. The 16168625 is an example."
I also checked out his ECM spreadsheet, but that only added to the confusion. There are 5 other ECMs that might be the correct ECM for my truck. Oddly, the 16168625, which is the ECM that was in my truck, is not listed for 94-95 TBI trucks. It's only listed as a "one-off" ECM for my '93.
The build sheet for my truck doesn't have the ECM listed, but the build date for my truck is 08/21/1992.
It's a 1993 model year truck, with a 5.7L gasoline powered V8, and 4-speed 4L60E.
It has heavy duty suspension (F51), and a heavy duty radiator (V02). Does that make my truck HD?
I also read in the forum that it doesn't matter whether a truck is auto or manual, but it looks like they have different ECMs for each application.
8625 will run 93 and if I'm not mistaken 4 and 5. It just lacks the pwm lockup tcc circuitry and prom garbage. 93 60e's use a lockup on off tcc control while 4/5 use pwm. These are 60e transmission pcms. They have all the guts to run electronic transmission. The manual trucks don't need the auto transmission functionality. The 92 and older pcms use an external electronic spark control module. The 93 and later pcm's to 95 use a built in electronic spark control module on the prom calpak. Your truck is light duty. Anything "hd" tended to have the 80e. Just grab another 8625. There are plenty out there since no one wants them. Ask for a 1993 g1500 van pcm with 60e. Same shit.
^ Thanks for explaining the difference. I figured I was overthinking things, and ended up picking up an 8625 ECM at the junkyard. Swapped out the PROM calpak, and my truck started right up.
Now I just have to work on an overheating issue...
I'm guessing you have the 193 swirl port TBI heads? Try compression check and leak down test before tearing it apart. After replacing T-stat, water pump, put in a 3 row radiator, and finally Bars Leak head gasket sealer (as a last resort) I got it to run cooler. Turns out the head gasket blew between cylinders 4 & 6 and 5 & 7 ( where the EGR ports are). After that I got a little carried away - new heads, cam, intake manifold, 46mm TBI, etc.
Make up your mind how much you want to spend, and achieve, before you get into it.
I was hoping it wouldn't be the head gaskets, but after checking everything else, that's what it boils down to. No pun intended lol.
Actually, I'm down to the head or intake manifold gaskets. Gotta run some tests this weekend to see which set is the culprit.
I'd love to upgrade to some aluminum heads and other go fast goodies, but I'll probably just replace the head gaskets, if necessary, for now.
The truck needs new bushings and ball joints, so I'll do those first, and add a lowering kit while I'm at it.
I've had extended overheating issues. But I have a 4.3. I finally alleviated the issues with a bigger rad with some oddball combo of hoses. But if you're pushing coolant rent a hydrocarbon tester for the filler cap. It tests for hydrocarbons in the coolant. It's called a block test. I have used it several times to diagnose headgaskets or some other issue. It tends to be pretty accurate. Just make sure you get a sealed bottle of test liquid. I found that people dump the liquid back in the container causing it to become useless.
Where did you get that spreadsheet? I couldn't find it on the Moates site. I have a stock 1995 K1500 I bought new, and I would like that information for the 95's.
Here's a link that may help...
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