454 T.B.I. Problem

[burbboysgc]

  I have an 87 r20 suburban with a 454 N. It has Calf. emissions (don't know the difference, everything is in the same location as any other tbi big block). The check engine light stays constantly on. No flash when key is turned on, or no diag. codes when A and B terminals are grounded together. It also has no knock sensor, from what I can tell and have researched it's not supposed to. The engine acts like the timing is out of whack,(misses and stumbles, has to be given gas until warmed up, back fires through intake and exhaust) but checks out fine when checked. Sometimes when motor is warm, the light goes out, but always returns. The plugs are black, bt look oily to me also. I guess it could be fuel. Or could have a bad ring seal, or valve seals. This problem began when I had a no start condition. I changed the dist, module a few times , but they kept going bad. I eventually bought a parts store e.c.m. The no start issue was fixed, but the other problems started. I put the chips/proms into the new from the old. I did overlook that it had two chips, and started it with the larger one. I think the smaller one is called the calpack. I did get both of them put in within minuets. Just wondering if I may ruined the new e.c.m. by starting it w/o the calpack, or if I need to look in another direction, like I had been sold the wrong e.c.m. The obvious question would be, did the part numbers match, but like an idiot, I trusted that the part sales guy knew what he was doing, and now my core has been sent off into limbo. Sorry so lon. Thanks for any help.

[Captkaos]

So is anything missing with the ECM now?  The CLE does nothing with the ALDL jumped?

[burbboysgc]

 No it's all there now. One thing I noticed is there are two different part numbers for the computer/e.c.m. on my vehicle 1227747 and 1228747. I think one is for engines with a knock sensor and one is for an engine without, but unsure of which one is the one I need. My 454 does not have the knock sensor. I wish I would have looked at the part number before trading it in. The parts guy probably just gave me the first one he could grab that said it would fit. Also, No it doesn't do anything with the ALDL jumped. I turned ign. off jumped the A and B and the light just stays lit. Doesn't flash at all when I turn key on.

[VileZambonie]

Swap in a known good ECM. Check your ECM grounds as well.

[burbboysgc]

 Where would the e.c.m. grounds be? Under dash or in engine compartment?

[burbboysgc]

  Could it be possible to have a bad chip(s)?

[roboticjunky]

Things to check:
1.Check the numbers and letter on the PROM chip (computer chip) in the ECM and find out what motor it is for.

2. Look at your ESC module, there should be a blue wire coming from it and that is suppose to go to your knock sensor.

3. Is your timing set right?

FYI: 747 ECM is on early TBI motor (V8,V6, I4)
       Your CEL is on because you don't have your knock sensor hooked up.
       Your ECM needs the knock sensor to know how far to advance the timing until it senses a knock.
If you do get a new knock sensor, make should it's for that motor size and ecm.

[burbboysgc]

 There isn't a knock sensor. It is supposed to be on the pass side in front of starter. There isn't an empty hole, wire hanging or anything. I have looked and looked, no sign of one ever being there. It must not be on certain big block engines. I did some home work and found out there are other tbi 454 trucks with out them. So I was thinking maybe the computer I have now (from the parts store) has a hook up for one and it's not reading anything, and the comp. I'm supposed to have has the ESC deleted and that might be why the light is staying on. I don't know how to find out for certain. There is limited info about this "no knock sensor/esc big block" , what the part number for the computer is supposed to be, or if there even is a different comp. The part store shows 2 part numbers when I put in my year,make,model,engine size, but they both say exact fit. Like Vile said, I'm going to have to make sure I have a good computer to start with. Is there a way to test the computer to see if it's even good?

[VileZambonie]

This is the problem with random parts changing, it makes it even more difficult to diagnose. Even if it did have a knock sensor and it was disconnected it would not affect drivability. So why did you change the ECM to begin with? If the SES light was not staying on before you swapped ECM's that should tell you that you have the wrong ECM. Make sure the PROM is seated correctly and be careful of ESD when you are handling these items. Was any engine work done? Check the grounds at the front of the engine