Loosing the ECM......

[Freddie's Buick]

Well,

I'm giving up on the '81 ECM. It seems that this model year ECM is just a basic emissions control mechanism.

I' ve tried all the settings on the TPS, put in a new ECM, went back to a 160 degree thermostat and my problem remains. My next step would be a Hyper-chip.

A chip goes for well over a $100.00 and I am not convinced that this would make much of a change. Going retro seems to cost less. (And you guys pretty much know how cheap I am by now so that's were I'm headed).

Here's the problem:

(This only happens when the engine is well run and at peak operating temperture). Something causes knocking at every shift change. This is detonation and the rattle I hate. (And it ain't cheap gas because I only use 93 octane Chevron).

If I remove the Distributor EST plug the knocking at shift change stops. But by running it this way the timing will not advance when one throttles up. So it is a slow crawl.

Going retro would be a possible solution. I've got the Pre-EST/HEI distributor and a pre-EST non-TPS Q-jet that I have to soop up some. All that is left to deal with now is the TCC. Once I'm done I'll give an update.

I tried this once before and noticed that the EST set-up was better, but this was before I had all the mods I have now.
We'll see what happens...... :cool

 

[fc227]

You could use the earlier ESC , HEI ignition system and keep the Knock sensor.

The earlier carb is a good Idea in my mind. If you want you could install a MSD with timing control , still keep the earlier ESC with knock sensor. and use a Three step to take timing out in each gear. (this can be done on the TH350 tranny , I'm doing it for High
gear) you would have to install pressure switches in the trany that would trigger the muti step retard. This would take some tuning but it can be done.

 

[Freddie's Buick]

I did'nt know that a ESC system was available for an N/A application . I really don't know much about ESC systems. I'm doubtful that I can find an entire working system.

As for as MSD, I have one. But not the one with timing control. I'll look into that. Thanks Fred!

 

[fc227]

Sorry , thought your where talking about a turbo engine. You could get a HEI dist & remove the module & harness (in other words get rid of all the wiring from the Turbo HEI dist inside the dist except the pickup assy).

And get a 4 pin module and a regular HEI 3 wire connector that connects the Module to the coil in the Cap. This should all bolt in . I have some extra modules & harness if you need them.

 

[Freddie's Buick]

Thanks Fred. I pretty much already got everything.

 

[Ttype83]

Originally posted by fc227

And get a 4 pin module and a regular HEI 3 wire connector that connects the Module to the coil in the Cap. This should all bolt in .

I have a Dist like that, it's from a 4.1, but not sure of the year???

 

[Freddie's Buick]

Here's an interesting tidbit on the earlier HEI 4-pin distributor; If one uses MSD ignition like I do, one no longer needs the use of the GM module and condenser! It's bypassed by the MSD!

Wow that's great! 'El Cheapo' strikes again! (Eventhough I already have a new 4-pin HEI module). Hopefully I'll be finished rebuilding the Non-CCC/TPS carburetor by the end of the week.

Now if I can only figure out the TCC bypass for non-ECM control........

 

[RCI2990]

freddie, it's ironic that i just found this thread.i just got done this weekend after about a month or so eliminating the ecm system.for anybody that wants to do this it's worth it's weight in gold.the difference is night and day.heck the carb only was 15 bucks,the intake i used is a holley that i got for next to nothing.the dist. was the hardest to find in my local boneyards and only cost me 25 bucks.with a 10 inch chrome air cleaner and hardly any wires it looks sharp.i even shaved the bracket off of the ps valve cover.as for the tranny i already had the non ccc 350t with the shift kit.i know how to get the pics on my computer but how do i get them on here so you guys can see them? oh i also forgot i did that mod that i saw on your site with the valve train.works good.

 

[Freddie's Buick]

Hey Marc,

Sounds like you've been busy. I'm curious....you got rid of the OEM intake? (I thought you had a 4.1).

Anyway, can you peel out?

Oh yeah, get the MSD ignition too! It kicks royal butt! If yours is a 4-pin HEI distributor, you won't need an H/P modulator, ( like the Accel I got).

 

[b4black]

Originally posted by Freddie's Buick
This only happens when the engine is well run and at peak operating temperture. The ECM retards the timing at every gear change. This causes detonation and the rattle I hate. (And it ain't cheap gas because I only use 93 octane Chevron).

I don't understand this about the ECM retarding the timing. Does it rattle before, during or after the shift? Why does it do it, how much and how do you know what the actual timing is? Are you refferring to the timing change based on the RPM? Wouldn't a non-CCC distributor retard as well with it's centrifugal advance (or more appropriately "loose advance" as RPM go down)?


If you get a Turbo Control Center from a 78/79 Turbo V6, you could have knock retard/ESC. Or you could get a 83/87 sensor/controller and run a knock gauge. (Not really recommending either, just something to consider).


For the time being, find the wire that grounds the TCC and tap into it. Insert a switch and you can force the lock/unlock.

 

[RCI2990]

yeah freddie i was using the oem 4.1 intake but a friend of mine had a holley dominator intake that he did'nt need so i used that one instead.as for peeling out, OH YEAH.with the shift kit and the 3.08 peg leg when it hits second it rips the tires and jerks the ass end a little sideways.even when it hits third at anywhere from 60 to 70 it jacks you in the seat. how much does the msd ignition cost,and do you have a part # for it? as for the ecm retarding the timing from what i understand the ecm will retard the timing to 15 degrees constantly under any driving conditions.

 

[Freddie's Buick]

Re: Re: Loosing the ECM......

Originally posted by b4black
I don't understand this about the ECM retarding the timing. Does it rattle before, during or after the shift?

The rattle or 'knocking' as it is refered to, only happens right after each shift change as one is accelerating. Once she's at cruising speed the knock stops. It feels like one is running on cheap low octane gas, but it is'nt.

Originally posted by b4black
Wouldn't a non-CCC distributor retard as well with it's centrifugal advance (or more appropriately "loose advance" as RPM go down)?

The 1980 Distributer I have is still an HEI, but without centrifugal weights. Neither does it have Electronic Spark Timing, or more appropriatly no-ECM control. My guess is that the ECM is causing the problem at shift change.

Originally posted by b4black
Why does it do it, how much and how do you know what the actual timing is? Are you refferring to the timing change based on the RPM?

Beats me why it does this. I don't know what the timing is exactly at shift change. As the shift occurs the rpm's drop and as it throttles up it knocks. So it might be based on the rpm. I can only assume that the ECM is retarding/advancing the timing at this point. The knocking happens on all 3-shifts.

Originally posted by b4black
If you get a Turbo Control Center from a 78/79 Turbo V6, you could have knock retard/ESC. Or you could get a 83/87 sensor/controller and run a knock gauge. (Not really recommending either, just something to consider).

I won't even go there...

Originally posted by b4black
For the time being, find the wire that grounds the TCC and tap into it. Insert a switch and you can force the lock/unlock.

I'm working on this....thanks Rich....

 

[Freddie's Buick]

Marc,

www.Summitracing.com. MSD-6A goes for $149.95. If you're peeling now you'll rip tar with this gadget. One instantly feels a difference. (And a quicker response at the pedal).

Forget the modulator you won't need it anymore. Did you keep the Q-Jet stock?

I got my distributor from a V-6 Chevy engine. It's not a direct fit for Buick but I modified it and it fits and works perfectly. The Q-Jet came off of a 1980 Pontiac 301W V-8 engine. It's in a hundred pieces right now as I am sooping it up some. I'll post pics later as I update.

As far as pics go I don't know how others do it, but I upload mine to my DSL domain that sponsers my website. Most ISP's provide free domain space for their customers free of charge. Heck some even provide technical assistance. Ask them.

 

[RCI2990]

yes the q-jet is stock for now .so if i get the msd ignition i can take the module and condenser out or should i leave them in.

 

[Freddie's Buick]

The instructions require them to be removed...

 

[RCI2990]

thanks.

 

[b4black]

Re: Re: Re: Loosing the ECM......

Originally posted by Freddie's Buick
The 1980 Distributer I have is still an HEI, but without centrifugal weights. Neither does it have Electronic Spark Timing, or more appropriatly no-ECM control. My guess is that the ECM is causing the problem by retarding at shift change way too much and causing the knock.

Still confused. Retarding timing should prevent detonation. (That's what an ESC does - retards when it senses knock) Maybe it's not retarding enough during shifts (or in other words leaving to much advance)?

I thought a distributor either has EST (ECM), or vacuum & centrifugal advance (pre-ECM). It has to be one or the other, right?

 

[Freddie's Buick]

Re: Re: Re: Re: Loosing the ECM......

Originally posted by b4black
I thought a distributor either has EST (ECM), or vacuum & centrifugal advance (pre-ECM). It has to be one or the other, right?

Nope. The pre-ECM/HEI has a pick-up coil just like the ECM/HEI's, (this gizmo electronically does the same job the old weights and springs did with a special magnet and a pole piece). Pre-ECM/HEI's have a vacuum diapragm pull on this pick-up coil to advance the timing.

On the ECM/HEI's, the ECM gets a signal from the pick-up coil and electronically advances the timing. Thus the name Electronic Spark Timing, EST.

Originally posted by b4black
Still confused. Retarding timing should prevent detonation. (That's what an ESC does - retards when it senses knock) Maybe it's not retarding enough during shifts (or in other words leaving to much advance)?

Now I'm confused! Perhaps I had it backwards. (I thought one can get detonation in either exteme, too much advance, or too retarded). Oh well.....

Anyway, right after a shift change the engine knocks. I know it's the ECM. I disconnected the 4-pin connector to the EST and the knock stopped. Running it this way won't damage anything. It's called by-pass mode. It just throws a code, (EST).

It's not that the ECM is damaged. I think that there's something it does'nt like about the mods I got. The OTC Moniter 2000 checks everything out fine. So I just can't figure it out....I really have'nt given up, I just want to try something different....

 

[Freddie's Buick]

Not doing much of anything on my car lately my anal compulsive tendencies came back to haunt me.

I seemed to of solved the problem of the knock by changing the OEM timing from 15 degrees to 8. But how/why I asked myself?

Today as I was passing by the collection of stored stuff I have, I see my old cast iron dueljet intake. (Does anybody want it?). The OEM EGR is still attached to it.

Junk I say. The OEM EGR thing never really worked right anyway. I removed it and disected it completley. Wo' this thing is wierd.

Went to my manual and bingo! Not all EGR's are alike. In fact, the current EGR that I am using is for the OEM '82 aluminum Q-jet intake AND IT IS NOT COMPATIBLE!

The '81 ECM system for the N/A has low back pressure. It uses an EGR that utilizes this back pressure from within the intake and thru the EGR to open. That's it's opening signal. It's not from the carb! The Carb's EGR port is a timed vac source. It does'nt really open the EGR. This system is known as a modulated negative back pressure EGR .

The problem is that all our Regal's EGR's look alike. But they are not.

Knowing this I think this is the way it's suppose to work: The '81 EGR releases 'timed' flow into the combustion chamber thereby cooling combustion and preventing knock.

Flow is released, (timed), due to internal back pressure from within the EGR. This can only happen at peak combustion, (the shift changes).

The '82 EGR uses a thermal vaccum valve. It allows a constant flow of vacuum thru its port once it's activated. The valve is water temperature activated and the EGR gets it's opening signal direct from the carb. Very different!

Within the next few days I am going to put back it's original EGR and bring up the timing to OEM and see what happens.....