ECM/Dizzy

[akchevrolet]

Did this guy just delete the ECM with that dizzy and he says mallroy did he mean Mallory.

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[74 Shortbed]

Guy tells the truth anyhow, lol, just don't know how to read, it is a "Mallory"..

 

[akchevrolet]

hmm seems to work better then the stock ECM. I have the same engine just a 1987 tbi. so I wonder if i could do the same. have some issues that i read on here could be related to the ECM. Rough idle on start but when warms up idles fine. Then while driving give it a little bit of gas and it kinda bogs down for a few seconds then gets back up into the right acceleration. or sometimes while driving and give a little more gas she'll lurch a little then get back into regular acceleration. I've read it could be a circuit in the ECM that could be fried.

 

[74 Shortbed]

Hmmm, sounds just like one of mine is doing, and just like the guy in the video says it's a total POS, and it belongs in the trash can headin for the dump, lol...

 

[akchevrolet]

Well I think I might try this was trying to see if anyone had done and had more information.

 

[1987 GMC Jimmy]

hmm seems to work better then the stock ECM. I have the same engine just a 1987 tbi. so I wonder if i could do the same. have some issues that i read on here could be related to the ECM. Rough idle on start but when warms up idles fine. Then while driving give it a little bit of gas and it kinda bogs down for a few seconds then gets back up into the right acceleration. or sometimes while driving and give a little more gas she'll lurch a little then get back into regular acceleration. I've read it could be a circuit in the ECM that could be fried.

Ehh, I fervently disagree with the guy in the video. Problems arise sometimes, but 9.5/10 times, they can be addressed easily and expediently. What all have you done to it?

 

[akchevrolet]

Ehh, I fervently disagree with the guy in the video. Problems arise sometimes, but 9.5/10 times, they can be addressed easily and expediently. What all have you done to it?

nothing I was going to check the fuel filter. well change it. the rough idle on start has been happening since I have had it for 2 years.

 

[chengny]

Ehh, I fervently disagree with the guy in the video. Problems arise sometimes, but 9.5/10 times, they can be addressed easily and expediently. What all have you done to it?

X2. And not to mention that - in many cases- the ECM does a lot more than just control spark timing. Think TCC operation for one example.

 

[1987 GMC Jimmy]

nothing I was going to check the fuel filter. well change it. the rough idle on start has been happening since I have had it for 2 years.

I’d do that first. They’ll run crappier over the years without replacing certain things when they start to have issues. I’d check for vacuum leaks and fuel pressure first. This could include a faulty PCV valve, bad TBI base gasket, stuck or leaky EGR valve, play in the throttle shaft, or any of the lines and fittings going to the vacuum stuff. Besides the base gasket, you can plug things off and see if it idles better and go from there. For the gasket, you should get a baby can of starting fluid and spray around the edge to see if there’s a change in idle speed. If going through those systems doesn’t net any improvement, it sounds at face value like you might have an issue with your IAC valve and possibly your TPS. It never hurts to do an ignition tuneup, which should include a coolant temp sensor on a TBI. Finally, I think the circuit you’re talking about is the ESC circuit. That wasn’t integrated until 92-93 when they switched to a PCM instead of an ECM.