Hi.

Can someone tell me the steps to install a used ECM / ECU on my B2000?

I tried disconnecting the battery, removing old ECM, waiting 30 minutes, installing new ECM, reconnecting battery, turning key to on position for 5 minutes and then starting/driving it. Drives like crap.

Any advice on user error before I return the ECM?

 

Are you 100% sure its a exact match? Same part number? Why do you need to replace your ECM?

 

Just get a Weber carb and ditch the ECM all together. It could also be the that the factory carb is having issues. The ECM is behind the passenger kick panel. There is also an ABS module under the driver seat make sure you are replacing the right one.

 

Hi. Thank you for responding. I am sure the computer is an exact match. The reason I'm trying a new computer is because a smog shop here in California said that there is no ground signal from the computer. Therefore, it's either a bad ground wire somewhere or the computer. It was cheaper for me to try a computer first. However, the computer I installed is not communicating properly and stalls whenever under 10mph and let off the gas. I was wondering if I needed to do anything special to install the computer or just install it? As for a Weber Carb... I wish i could but I believe those are illegal in Ca. thank you!

 

Oh, I didn't realize you were in Cali... I am in Cali too, I've got a B2200. I do have EFI though (Fuel injected) and have been dealing with the smog ***** my entire life. Been able to get away with a lot though

The ECM doesn't typically cause an issue on the carbed B's. What made them think it was a bad ground, is the check engine light on? How did they come up with that answer.

If you weren't having issues with the old ECM I would go back to that and track down the bad ground, if there is one.

The main grounding blocks are usually in the engine bay along the inner fenders (both sides) there are many more but those are more exposed to weather than the others. I will try to find the wiring diagram for your B and see where the ECM grounding pin/wire goes to.

 

Also check to see if your choke wire is hooked up (from the carb to back of the alternator) check for vacuum leaks, check your idle adjustment screw and check your EGR to make sure its not clogged or hanging open. all will cause driveability issues.

 

Thanks for your feedback.

Fortunately [or unfortunately], the truck runs perfect. It just won't pass smog.

I rebuilt the carb because it was running rich and now it's running too lean. It's emitting a large amount of NOX and won't pass smog.

The shop thinks it's a bad ground wire going to the computer. Well, they thought it was either a wire or the computer and I was just trying the computer first. The problem was not solved. So it must be the bad ground wire. I guess?

I am looking for someone who can find this bad ground as it's beyond my ability but I don't want to pay the smog shop $300 to find it.

I posted an ad on Craigslist for a mechanic.

Thank you!

 

No problem, I highly doubt your problem is with the ECM. I would assume your carb needs adjustment and your EGR valve needs to be cleaned out. High NOx means high combustion temps(over 2,500*F) usually this is from running lean like you said.


I usually dump a bottle or two of 90% rubbing alcohol in my tank and fill it up, the alcohol will burn cooler and help lower your combustion temps a little. Gas has alcohol in it to absorb moisture so don't worry about it causing any issues. Also make sure you heat up the Catalytic converter before you take it in to the smog shop, and leave it running even if you have to wait a little for the test.

 

Some Smog info:
CA smog high emissions failed....need help


some carb tuning info:
how do you ajust Fuel-mixture on stock B2000 carb


Also if you haven't already, there is more traffic and knowledgeable people on www.mazdatrucking.com and www.mazdabscene.com that are specific forums for these trucks. I am on those sites a lot more than this one. Get on those forums and do a search for "smog" or related search words... or start your own thread.


Good luck! I know how tuff CA smog is.

 

I would also check out the EGR, these fill up with carbon on these trucks. Three 10mm-head bolts hold it on (plus the vacuum connector and the electrical harness).

With a hand vacuum pump you can test the EGR without removing it from the cylinder head.

I found the black hard carbon a b*tch to clean out, but worthwhile. New EGRs for these typically sell for about $250; I've got two working ones (used, tested with vacuum pump) for sale tons cheaper than that, as I have Weber carb in on mine in Arizona and don't need EGR.