truck bogs and dies, code 55 ECM?

[knishiya]

Hello, i was handed down a 1982 S-10 2.8L truck for free! Yippee. But, it didnt pass Cal. smog and bogs down. The code, according to some paper work i found in the glove compartment, was code 55. Is that the ECM? Do I need to replace it? It was running pretty good at idle, no problems starting, doesnt die at idle or miss. On the highway, it runs fine at high speeds. However, when you accelerate it totally bogs down, and doesnt kick in. so i have to baby it up to speed. I replaced the plugs which were fine, spark plug wires and accelerator pump in the carb and still not better - even worse now. Now its it total bog mode, wont go past 5mph and even cuts out. So now i took the carb off, thinking about rebuilding it. havent check out the fuel filter, need a bigger wrench. Questions: Could it just be the ECM and im doing the carb for nothing? Could it be simply the fuel filter? Electronic spark control module? I dont think its the timing, ran good previously.
any help is appreciated. ken

[OverBoardProject]

Well Ken, You got the deal of the day

you've done 1/2 a tuneup why not finish and let us know how it runs then.
Replace the PVC, check ut the EGR and do the timing.

Run some carb cleaner through.

It'll probably run a whole lot beter then and might just pass smog there.

[Tedster]

How do you check codes on an 85 s10?

[knishiya]

in order to find trouble codes your computer stores, there is a ALDL? connector underneath the passenger side trim. you connect a paper clip in the in the two top right side holes. do this with the keys out. after you put them in, turn the ignition to on. but dont start the car up. the check engine light will start to blink. 1 then 2 times. it will do this three times. then if there are any codes stored, it will blink that code., eg. 4 blinks, 4 blinks = o2 sensor lean.

[BlazerLT]

Originally Posted by knishiya

in order to find trouble codes your computer stores, there is a ALDL? connector underneath the passenger side trim. you connect a paper clip in the in the two top right side holes. do this with the keys out. after you put them in, turn the ignition to on. but dont start the car up. the check engine light will start to blink. 1 then 2 times. it will do this three times. then if there are any codes stored, it will blink that code., eg. 4 blinks, 4 blinks = o2 sensor lean.

Listen, do a COMPLETE tuneup before you start into the PCM.

Cap and rotor, fuel filter, air filter, pcv valve, timing, etc.....

Get focused man....you are all over the place and getting nothing accomplished.

[knishiya]

i have done a complete tune up. cap, rotor, wires, plugs, fuel filter, air filter, breathers, pvc, egr, o2 sensor, ig. module replaced.

THe code is not 55, as written by the mechanic in the print out. or at least it is not now.

It is code 44. O2 sensor reads lean. Haynes said check ECM wiring connections, esp at terminals 8 and 15. Well, i looked at the ECM wiring terminals .... and there are no wires going into terminals 8 and 15! Is this my problem? Is the O2 sensor disconnected to the ECM?

Do i need to track o2 sensor wiring from o2 sensor to connector to wiring harness to ECM?

Thanks.

[BlazerLT]

You need to rest the base timing with the timing wire disconnected from the PCM.

Your timing is probably overly advanced causing the lean exhaust.

[smokey041369]

the o2 senors is a purple wire that runs from the sensor to the ecm

[BlazerLT]

There is nothing wrong with his O2 sensor, it is working properly seeing it is sensing a lean exhaust.

[knishiya]

After a month of trying to figure it out, I took it to a trusted mechanic. He reset the timing and ran a complete diagnostic on it. Problem was with the Air Management System. Seems like the Air Control Valve/EAC Valve/Divertor Valve was not diverting the air. It was continually diverting cold air into the exhaust manifold. When the engine warms up, the ECM degenergizes the EAC valve, diverting air flow from the exhaust manifold to the intake manifold. It wasnt diverting so the o2 sensor is constantly getting cold air, so ECM reads lean. Thus more gas is added to the mixture = rich. So, i didnt want to pay $300 for a new EAC valve so im beginning the search for a used or cheaper one. Anyone have one? Its the larger valve on the air managent system, not the check valve. Thanks for the thoughts!

[OverBoardProject]

is that the trap door type thing located in the air filter assemboly?

If so I might have a good one in my 85 (still carburted) parts truck. I might not be able to look for a few days. Possibly a week or 2.
If I do have a good one I'll private message you, and let you arrange the shipping.
My parts truck is a nasty drive up my bosses driveway (whom always puts me to work during my time off if he sees me) so I really don't want to go up there unless I really need something

[knishiya]

thanks for the help with parts location. Actually, its not the trap door thing on the air cleaner. Its an electric valve near the passenger side exhaust manifold and o2 sensor. I think its called an EAC valve or electric air control valve. Its got a connector from the wiring harness. Its in between the thin silver tubes from the exhaust manifold and the vacuum line to the intake manifold. If you have one, Im looking. Anyone? Thanks

[OverBoardProject]

Sorry, I don't think that they had that part here in Canada. Although I suddenly need a couple of parts for my Blazer, so I'm going up there tomorrow and I'll take a look just to be sure