411 Swap

[oldguy44]

I am sure that this information is in here somewhere but I haven't been able to find it. I have a 97 savana van with the 4.3 V6 that is the sorriest running thing I have ever owned. A month of crawling around on the internet has convinced me that the 411 swap is the cure. I have some questions that I would like answered before I jump into the deep end because if there is a way to screw up something electronic I will find it.

I have the lextech pinout spreadsheet for a 97 V6 S10, Is this the correct pinout for my 97 savana?

Can I use any 411 ECM that I can find at Pic a part or does it need to be out of a V6?

Does the ECM need some benchwork first or can I just put it in and then get it tuned?

I am retired and use use this van for volunteer work so if it takes me a couple of weeks to get it running it is not the end of the world but I do need to eventually get it running without having to take it to someone and spend a fortune fixing what I might screw up.

Thanks in advance for any information you can offer.

Dwight

 

[Erik the Awful]

If it's already running poorly, doing a 411 swap just adds another level of complexity to the diagnosis, and it's not likely the problem.

Have you checked your O2 sensor output? What about your intake air temp sensor or coolant temp sensor? Are all six plugs firing?

 

[MrPink]

and No the pin out for the s10 won't be the same as your van.

 

[stutaeng]

The 0411 ECU swap is more for a performance application, tuning, and such (think radical cam swap, forced induction, etc.) In a stock application, I don't think there's really much gain, if any at all. Maybe slight idle improvement? As mentioned, it may likely introduce other problems if you get any wires mixed up (there's like 4 dozen wires to swap!?), then you will have a real mess on your hands.

If you have an underlying problem, which sounds like you do, it's not going to get fixed, most likely.

Perhaps you can start a thread (or continue here) on your van issue and and someone here can help you out...

 

[oldguy44]

I have been under the hood for over 65 years and the underlying problem is that it is late on the timing until about 2000 +. You can hear it in the engine sound. it is hitting on all 6 I replaced the spider with the newer style, new cap rotor wires and plugs no help. I will guarantee that it just needs more timing. If it did not have a computer controlled distributor I could easily fix it but tweaking and peaking computers is totally out of my wheelhouse. If there is an easier way to fix it I am all for it. The guy who does all my remote tuning can't do anything with the original ECM which is where the idea of a 411 swap started. If someone knows how I can get about 10 or so degrees into the timing from 0 to about 2000 it will fix my problem. It has no CEL so my assumption is that all sensors are within proper range
In a nutshell that is my underlying problem, poor programming from the factory which I assume was their quick fix to lowering the nitrous oxides coming out of the tailpipe. The catalytic converter took care of the rest but no catalyst to drop NOX. Back in the 90's as memory serves me their were still 49 state and California cars. This is a California engine which if I am correct explains a lot. Out here on the left coast in the Peoples Republic of California the popular opinion in Sacramento is that if it works correctly their must be something wrong with it so we will make it illegal.
Short version, if someone knows of an easier fix I am open to any suggestion.

 

[df2x4]

Do the Savana vans share the same black box PCMs as the GMT400s? If so, there are people out there who can tune the '97 PCMs. You will want to look for someone who has the JET Dynamic Spectrum Tuner software, that's the only software I'm aware of that is fully compatible with the '96-'97 black boxes.

Alternatively Black Bear Performance can do it by mail if you send them your PCM or pay a core charge for an extra.

EDIT - I just checked JET DST's supported vehicle list, I'm not seeing '97 Chevy Express or GMC Savana on the list. Looks like the PCMs might be different from the standard GMT400 offerings.

DOUBLE EDIT - BUT... Black Bear Performance's website says they do offer tunes for '96+ G platform vans, which would include the Express and Savana. So maybe JET DST will work for the vans even though they're not listed as compatible. Maybe shoot Black Bear Performance an email?

TRIPLE EDIT (That's gotta be some kind of a record...) - I just remembered that when I did the 4L80E swap in my red truck ('97 C1500 4.3L) Black Bear Performance tuned my PCM to control the 4L80E, and I believe they did so by segment swapping an OS from a Van. The vans were available from the factory with the 4.3L and 4L80E, trucks were not. So I would say that bodes well for the PCM compatibility between the vans and trucks.

 

[L31MaxExpress]

Do the Savana vans share the same black box PCMs as the GMT400s? If so, there are people out there who can tune the '97 PCMs. You will want to look for someone who has the JET Dynamic Spectrum Tuner software, that's the only software I'm aware of that is fully compatible with the '96-'97 black boxes.

Alternatively Black Bear Performance can do it by mail if you send them your PCM or pay a core charge for an extra.

EDIT - I just checked JET DST's supported vehicle list, I'm not seeing '97 Chevy Express or GMC Savana on the list. Looks like the PCMs might be different from the standard GMT400 offerings.

DOUBLE EDIT - BUT... Black Bear Performance's website says they do offer tunes for '96+ G platform vans, which would include the Express and Savana. So maybe JET DST will work for the vans even though they're not listed as compatible. Maybe shoot Black Bear Performance an email?

TRIPLE EDIT (That's gotta be some kind of a record...) - I just remembered that when I did the 4L80E swap in my red truck ('97 C1500 4.3L) Black Bear Performance tuned my PCM to control the 4L80E, and I believe they did so by segment swapping an OS from a Van. The vans were available from the factory with the 4.3L and 4L80E, trucks were not. So I would say that bodes well for the PCM compatibility between the vans and trucks.

I have tuned my 97 Express when it had the black box. Tunercats OBD2. I read the stock van tune, modified it and then wrote the new tune into a 97 Tahoe PCM.

That being said, I am not sure why he believes a big jump in timing will help. All it will cause is detonation and knock retard without better fuel. My 97 knocked on 87, so I ran 91 and added timing to make it run well on 91.

As small as the 4.3 is and as underpowered as it is in a big van, needs a deeper gear set to get the weight rolling.

 

[df2x4]

That being said, I am not sure why he believes a big jump in timing will help.

I am skeptical as well. I think there may be something else going on. Even without any codes or check engine light, I think doing some research and checking the data stream with a good scan tool would be worthwhile.

 

[oldguy44]

I am not talking a big jump in timing just around 10 degrees. If you drive something with a non computer controlled distributor back the base timing down 10 degrees and see how it runs, particularly under 12 to 1500 rpm. That is how my van runs. I am oooold school where we tuned to how it felt and ran. No one had dino's you tuned to spec and then tweaked and peaked. This was all seat of the pants tuning. I have been putzing with small blocks since they were introduced I know what they sound like when they are right and I know what they sound like when they are wrong. Based on years of this kind of experience I am telling you that this truck needs a little more timing to run properly. I am not going to discount that there is something wrong in the computer system that is causing it to fire late, all I am saying is that it is late. You can hear it in the engine and exhaust, or at least I can. The plugs are reading fine so it is not fat or lean it just does not have enough timing at low rpm. Next week I will have more time so I plan to pull #1 plug mark tdc on the damper and put a timing light on it and see where we are. I suspect that I will find conclusive evidence that I am correct.

Stay tuned.

Oh by the way I sent Black Bear a message, waiting to see what their response is.

 

[BeXtreme]

I am not talking a big jump in timing just around 10 degrees. If you drive something with a non computer controlled distributor back the base timing down 10 degrees and see how it runs, particularly under 12 to 1500 rpm. That is how my van runs. I am oooold school where we tuned to how it felt and ran. No one had dino's you tuned to spec and then tweaked and peaked. This was all seat of the pants tuning. I have been putzing with small blocks since they were introduced I know what they sound like when they are right and I know what they sound like when they are wrong. Based on years of this kind of experience I am telling you that this truck needs a little more timing to run properly. I am not going to discount that there is something wrong in the computer system that is causing it to fire late, all I am saying is that it is late. You can hear it in the engine and exhaust, or at least I can. The plugs are reading fine so it is not fat or lean it just does not have enough timing at low rpm. Next week I will have more time so I plan to pull #1 plug mark tdc on the damper and put a timing light on it and see where we are. I suspect that I will find conclusive evidence that I am correct.

Stay tuned.

Oh by the way I sent Black Bear a message, waiting to see what their response is.

That's just not how computer controlled engines work. The only way timing gets 10 degrees retarded is if the computer detects a major problem and pulls the timing to save the engine. That's what people are trying to tell you. You need to fix the problem first, whatever it might be.

I've seen people go down this path and then they come back onto a forum and go "I'm tuning it to have more timing and when I check the actual timing while running it is still showing the same low amount of timing.. what is going on?!?!"

What happens is they have an issue with the engine, whether that is an actual mechanical problem or a sensor/electrical issue and the PCM is pulling timing to try and protect the engine. Commanding more base timing doesn't do anything because the PCM just keeps pulling more timing until it reads that everything is "safe" or it hits the maximum amount of adjustment. Once it runs out of adjustment it MIGHT throw a code.... maybe.