E2SE Carb Tuning

[trymes]

OK, so I have dug around on the net and found a bunch of information on working with these CCC carburetors, but a lot of it seems to assume that you are already familiar with all of the parts and where they are, not to mention that lots of the information seems contradictory. I plan to replace the plug wires and plugs, and then I was going to see how the car is behaving using a meter.

1.) The TPS is adjustable, but I cannot get a proper answer as to what the voltage should be for one of these cars with the 2.8L V6 and the E2SE carb.
2.) The plunger on the TPS does not make contact with the actuator arm at idle. Is this likely to be an assembly issue, or an adjustment issue?
3.) There is a screw on the throttle body, closest to the passenger (RH) side of the car (the side with the alternator, etc). It has a tapered end, and it's unclear if that's for mixture at idle? I thought that the MCS was supposed to control idle mixture?



Can anyone shed some light here?

Tom

[Zaloryan]

Hi Tom,

1. Do you have a factory service manual for your vehicle? I used to own a 1984 6000 STE with the Varajet. The general descriptions in my service manual were pretty descriptive as to helping me understand the proper OE settings for the carburetor.

2. Unfortunately, I cannot speak to TPS plunger adjustment as none of the feedback carbureted cars I ever owned or worked on ever needed TPS diagnosis. However, I would encourage you to check other items like vacuum leaks or the float level before condemning the TPS setting. (See #3)

3. The factory service manual will specifically call out the location of the Idle Mixture Screw. My understanding of the Mixture Control Solenoid is to vary duty cycle as needed (depending on engine load) to ensure a proper air/fuel ratio. It should not require any serious diagnosis. Either you hear it clicking away like a bad hydraulic lifter, or it doesn't work. It has been several years since I have had the car, but my recollection of physically setting the Idle Mixture Screw was to use a Dwell Meter with the engine at a prescribed RPM (according to the OE Service Manual). The Lisle 55250 Carburetor Adjusting tool should have an adapter to work with all Rochester Carburetors.

[trymes]

Thanks for the follow up. I don?t have the manual. Is it available digitally, or should I dig around on eBay?

The TPS adjustment looks to be pretty straightforward, but I can?t get the scanner I bought (Innova 3140g, I think) to connect with the car to show the voltage and the solenoid duty cycle. I?m going to see if I can get it to connect to my brother?s ?84 Z28 and rule out a hardware issue.

Hopefully I can get the scanner working, as I don?t have a swell meter. I think I had a multimeter that supposedly included that function, but I couldn?t figure out how to make it work back in the day with an ignition system. 100% user error on that.

[Pontiac6ksteawd]

Check your fuses. If the fuses for the cigarette lighter is blown, it will not be able to connect.

[trymes]

Check your fuses. If the fuses for the cigarette lighter is blown, it will not be able to connect.

Thanks. The lighter was working, but I will check again, just in case. The Check Engine light starts flashing 1-2 when I connect the scanner.

[Pontiac6ksteawd]

I will be honest, I have never owned a GM with a Carb. So the fuses may not even be relevant, but they should be in regards to the ECM.

[tlc1976]

I will be honest, I have never owned a GM with a Carb. So the fuses may not even be relevant, but they should be in regards to the ECM.

I had a carbed 86 Celeb wagon. Every time I would push it too hard it would blow the ecm fuse. Guessing a wire was shorting against something. It was a beater so I just replaced the fuse with an auto reset circuit breaker. It would run with no ecm but sucked gas like no tomorrow.

[Zaloryan]

Thanks. The lighter was working, but I will check again, just in case. The Check Engine light starts flashing 1-2 when I connect the scanner.

When you connect the scanner, the electric radiator cooling fan should also kick on. Code 12 indicates that the self-test diagnosis is working normally. What this really means is, if there are no other codes, the ECM is not detecting any problems severe enough to flag another code.

As for acquiring a manual, I have had good luck in purchasing old service manuals via Fleabay. There are plenty of sellers on there with lots of service manuals stocked up. If your specific manual isn't available, try getting the service manual for a sister X-Body of the same year. I.E., if you have an X-Body Skylark, an Oldsmobile Omega service manual of the same year should serve most purposes that you'll need(except for interior/exterior panel removal/installation instructions).

[trymes]

Yeah. I don't think the cooling fan is turning on when I plug it in. I suspect that the scanner I bought was only usable for '85+ 8196 baud ALDL, and not earlier 160 baud cars? Tried it today in my brother's car and it didn't work there, either.

[Pontiac6ksteawd]

84-86 have the same ECM, so I dont think that would be the issue. The only difference inbetween the models is the MEMCAL. As far as I can tell, its even the same ECM in a 4 cylinder Camaro/Firebird, just with a different MEMCAL.

ECM appears to have been used in over 240 different cars and trucks...
https://www.ebay.com/itm/REMAN-OUT-O...wAAOSwqaNciEJ0

[Zaloryan]

Instead of using a scanner, take a paper clip and jumper Pin A & B of the ALDL connector, then turn the key to Ignition On. See if the cooling fan kicks on using this method.

The Check Engine Light (CEL) will start to flash Code 12, then repeat the code two more times. If any additional codes are in the ECM's memory, those codes will be 'flashed' by the CEL three times before Code 12 is repeated again.

[trymes]

Thanks, Zaloryan, but I?ve already done that. The cooling fan does not come on when I do, but it does come on if I turn the A/C on.

The reason I was hoping to use a scanner was a quick, easy way to see the TPS voltage, MCS duty cycle, and closed/open loop status, all in one place. I?ve managed to get the TPS adjusted to 0.26V with a meter and some jumper wires, and I think I can get the MCS duty cycle with the same meter and the diagnostic port. It just would have been nice to have it all instantly visible, and it should be possible.

[robertcladner65]

thanks for this post, my problem has been fixed too.