TPI OBDII - Thoughts/Opinions
 

Any thoughts/opinions about an OBDII TPI engine?

Are you considering this for the sequnetial injection? Would you try to incorporate individual spark timing, too? Would you use both the MAF and MAP? I can see no other benefits to changing to an OBD II PCM, and either would require a cam and crank position sensor, and possibly a higher resolution crank sensor depending upon the system used.

Individual spark timing: no
MAF and MAP: possibly, maybe just MAP

Benefits as I see them:

• Sequential Fire
• 4L60E/4L80E Control
• VSS Sensor Control
• Custom Operating Systems for Forced Induction (EFILive)
• Auto VE Correction (EFILive)

I was surprised to recenty learn that the 01-02 LS1 PCM 12200411 was used in the 01-02 Express Van that still uses the Gen 1 small block (L31) with cam sensor (distributor) and crank sensor with external igniton module and coil (like the LT1).

Currently EFILive supports this PCM and offers some pretty cool features (auto VE correction, custom OS, etc).

Possibly next weekend I'm going to convert a L98 to work with the 01-02 LS1 12200411 PCM on my test stand. I almost have all the parts. Since I've been rewiring my S-10, I'm going to begin building a new engine harness for these newer electronics. I really like the idea of using the 4L80E with my truck.

:hmmm: I for one find the idea a bit intriguing... I'd appreciate it if you'd keep us apprised of what you learn.

Sure...

Here's a list of parts (this will be revised until the engine is running and I know the list is complete):

• 12200411 PCM (LS1, Truck, S-10, Blazer, Express, others)
• Wiring Harness for 12200411 (must follow Vortec L31 schematics)
• Vortec 305/350 Distributor (has camshaft sensor in it)
• Vortec 305/350 Harmonic Balancer
• Vortec 305/350 Timing Cover
• Vortec Timing Reluctor Ring (goes behind timing cover)
• Vortec Crank Position Sensor
• Vortec Ignition Module
• Vortec Coil
• Knock Sensor (2001 Express Van w/ 5.7 engine)
• 01-02 Express Van HO2 Sensors

Let me suggest that the O2 sensors from the Camaro/Firebird will probably work, but they use different connectors (but wired the same to the PCM). The Corvette sensors use the same connector as the Express Van. Please look beyond what vehicle the sensors were used with. The O2 sensor simply returns a voltage to the PCM that represents the air/fuel mixture. Zero volts being lean, 1.0 volts being rich. The Corvette sensor is no better than the Express Van sensor.

I just installed the Vortec distributor into my TPI engine. It completely clears the runners, but will require relocating the coil. The distributor is offset just like the runners are (bank two is set further forward than bank one).

S10Wildside can do it!
He has also built the same harness for my streetrod project.
It looks great, and I'm installing it next week. He made the injector harness to work with Ramjet instead of TPI. Either should work great.

I was always wondering about this. I'd like to see how it turns out. I think with MAF would be better in the long run for future mods. Would it be possible to convert a factory TPI harness to OBDII?

I've already done the swap with a TPI 305 van (1994 G10 w/ 4L60E). I used the OBDII SFI PCM from a 1998 Express Van.

Sounds interesting but I have to pass smog in Kalifornia. Will the smog technicians know there is a different computer in the car than what is supposed to be there?

There are a few snags in doing this.

PCM Location
The LS1 PCM will not fit under the 3rd gen dash.

Passenger Side Harness Bulkhead
The molded bulkhead ECM harness connector in the passenger side pillar does not pass enough wires through it for the LS1 PCM. You can not easily add more wires. The extra wires are for injectors, transmission, and the individual sensor ground wires from the PCM to the TPS, CTS, IAT, and MAP. (The TPI ECM has these shared...paired for speed density, shared for mass air.)

I could build a plug and play third gen harness (not quite 100% plug and play), but have no intentions of doing this anytime soon. There would be a lot of hours into it until a template is made.

Why would the PCM not fit? I have an LT1 PCM under my dash and they are about the same size.

You're using the computer on the left (96-99 Vortec Truck/Van), and I'll be using the computer on the right (01-02 LS1/Truck/Van/S10).

http://www.eficonnection.com/temp/pcms.jpg

It's my understanding that there are a few annoying limitations with the early Vortec computer (no way to get around the 5800rpm fuel cut-off). Someone correct me if I'm wrong...I can't even back that up with supporting documentation...but I know there's a discussion at Monodax Homepage - TunerCat OBDII Scanner and Data Logger - MXScan Info- about it.

Currently, EFILive is making the 01-02 PCM a very powerful piece of equipment. With custom operating systems available, you won't need to consider aftermarket PCMs for high horsepower applications. And these used PCMs are available in yards for under $40.00!

Good to know. I guess you'd need a custom mounting bracket then. The LT1 PCM is pretty much the same size as the LS1 PCM.

I'm not sure what they're testing for exactly, but I suppose you could still run smog equipment. I don't know if the smog techs care about the engine computer being used.

I'm still on track for making this happen this upcoming weekend. I'll have the camera with me to show what's involved.

All I'm waiting on is a crankshaft timing ring and EFILive. They should both be here this week.

I also need to find documentation about installing the new distributor (crankshaft and camshaft positions). I did a little reading at AllDataDiy.com, for the 2001 Express Van, but it wasn't as specific as I had hoped.

I am using the old black PCM with the 5,800 rpm limit. I am also limited by the stock LTR TPI intake, so I am not that worried about it. This is for mid-range torque and mileage, not HP.

As far as dropping in the distributer, it is easy. Just turn the crankshaft over until you get to TDC on number 1, then look at the distributer cap to find where the number 1 position will be, turn the rotor about 30-40* counterclockwise from number 1 and drop it on in, it should now line up with the number 1 wire on the cap. You can tell pretty easily which contact goes to number 1 by looking at the top of the cap. My vortec distributer had a white line that faced the rear of the engine when properly installed. When I started the engine and looked at the cam/crank correlation I have been within +/-1* on all 3 Vortec engines that I have built.

PS- It is in my plans to re-pin the existing harness into a 2001-2002 Vortec Van silver PCM, but I haven't gotten around to it yet. The old style PCM isn't all that bad, just the rev limiter thing.

Easy enough. Thanks!

Did you have to perform the crankshaft relearn procedure?

I never had to do the crankshaft relearn procedure, but I have never used the 2001-2002 PCM either. I have done this 3 times with the older 97-98 PCM and never had an issue.

I know that the guys that get PCM "TUNES" over on Fullsizechevy have to get them done.

In that case the bulkhead would have to be cut out and removed and just use a big grommet or something like that to pass all the new wiring through.

I had said not easily because the connector can be carefully disassembled using a heat gun.

Well it runs...

..and what a long day. The crank reluctor ring is no big deal to install...and it can only go on one way without slipping. It's obvious that the Vortec balancer has a slightly different height (from end of balancer toward crank) because of the extra distance the reluctor ring takes. So, the Vortec balancer is required when doing this conversion.

I like the way the wires lay with this distributor.

http://www.eficonnection.com/12200411/stand02.jpg

The engine started right up and threw the following (expected) codes:

http://www.eficonnection.com/12200411/ckp_problems.jpg

I was unable to successfully perform the crank relearn procedure. I initially had a transmission code P1810 that was preventing the relearn procedure, but after disabling that code, I still can't perform the relearn. I'm stumped. So I'll try disabling all the tranny codes and see if the relearn procedure will cooperate.

It's still a great start. The engine fires up immediately and runs great on the LS1 PCM (considering the relearn issue).

This setup would be sequential wouldn't it. Is that a new model MAS I see in the pic?

Yes, it is.

S10Wildside- too bad you don't grab a 4L60E case and stuff it with your 700r4 guts.

Sequential - yes
GM 85mm MAF - yes

http://www.eficonnection.com/12200411/stand04.jpg

The 85mm MAF is a great alternative to the original one used with the Vortec and LS1 applications. It's a 5 wire sensor where three wires are used for the MAF and two are used for the IAT sensor. This is desirable if NOT swapping to speed density (and not deleting the MAF) because the IAT is built in and doesn't need to be mounted somewhere. It does require a change to the MAF table values. I swapped in the values from my 2003 Silverado SS. It's actually a very common MAF sensor. It's sometimes referred to as the Z06 MAF, but it's found in 99 and newer full size trucks, too.

Some wires are extra long because I built this harness to go in my S-10, but am using it on the test engine at the moment.

I am about to do a TPI swap on my Grand Prix and this idea is very interesting. I know the newer PCMs are superior to the older ECMs, but what would this cost? I have all my parts, but this would be a nice upgrade later.

The cost could completely vary. I purchased many of the Vortec parts on ebay for a very low price. The knock sensor for the 01 Express Van (5.7L)was a different part number than the 90-92 TPI (5.7L) knock sensor, so I added that to the list above. The crank sensor and ignition module are very pricey new, so I'd either pull one from a yard or watch ebay. The PCM is very common and can be easily had for less than $40.00.

Consider a TPI ECM:
- about $40.00 for used 1227730 ECM
- about $70.00 for a new memcal
- about $35.00 for the Moates adapter to get around the OTP proms

When you break down all the parts and compare to the cost of original TPI parts, sometimes you'll see that the OBDII setup is cheaper, and sometimes the original TPI parts are cheaper. Overall, the original TPI stuff is still cheaper...but that all depends on the transmission used, VSS used (12200411 PCM can work with more VSS signals), etc.) If you were set on a OBDI TPI with 4L60E/4L80E, aftermarket transmission controllers are currently very expensive (over $600.00).

I could go on and on...

I'm smiling from ear to ear right now. that's sweet.

I did mine so that I could have a MAF setup using a newer PCM to control my 1994 Chevy G10 vans moded 305/4L60E that I converted to TPI.

I already have the correct ECM for my car, so I wil run like that for a while. The ignition module looks like the same as my LT1(I have a spare), an LT1 MAS would also work(also have one), I know where a PCM is I can get cheap. I was mostly wondering about the harness and programing required.

I should explain the P1638 Generator F-Terminal Circuit diagnostic code mentioned above. The newer PCMs are controlling the charging of the generator. It used to be that that an ignition source was always tied to the alternator to charge when the engine was running...now the PCM controls this. I currently have the test engine wired to have the generator charge when the engine is running.

What MAF did you use?

This is probably unrelated, but I noticed the LT1 and LS1 MAF sensors had different part numbers...wonder what is different?

The one from the 1997 Vortec 305 G-Van that the PCM, harness, crank relucter, timing cover, etc came from.

I can build these harnesses, but I'm taking a short break this fall to work on my projects. I can't mention prices because I'm not a site sponsor...and I haven't thought through pricing for this sytem yet. I've been wrapped up in harness work for the past few years and not working on my own projects like I should. I recently found that some mice have claimed ownership of my S-10 while it's been sitting in the garage the past few years. That's gotta tell me something right there.

A mail order tune typically runs several hundred bucks. I recommend forgetting about the mail order tune and buying EFILive and do the tuning yourself. It's all done through the diagnostic port and doesn't require the several extras involved with the TPI programming. You'll also need some sort of bidirectional communication capability to perform the CKP relearn procedure (you'll have that code right from the start). EFILive does this...however I'm scratching my head because I couldn't get the relearn to work tonight...but I'll get it figured out.

One other cool diagnostic procedure you can do with EFILive is the injector balance test. The procedure raises the idle to about 1400rpm and tests the performance of each cylinder.

Another pic. This harness is going in my S-10 and the PCM will be mounted on the passenger side wheel well.

http://www.eficonnection.com/12200411/stand05.jpg

HAHA, that shot looks very familiar. It wasn't fun trying to assemble the TPI unit under the dog house of the 1994 G10. Pulling the oil pan, timing cover, balancer, and timing set was even less fun.

Which MAP sensor did you use? I used the original TBI piece.

Cool, its gotta perform really nice once all the bugs are worked out,

I used all TPI sensors.

The engine in the pic is a test motor (1989 350 TPI). The harness will eventually be used with the engine in my S-10 (see signature).

I tried disabling more transmission codes and fooling the system that it was in Park/Neutral. I still can't get the CKP relearn to work. The odd thing is, the system will leave CKP relearn mode before the 10 second execution is complete, but only after the engine revs high and comes back down. It may be that I just don't fully understand what needs to be disabled yet or what PCM inputs I still need to spoof.

Here's a video of the engine running.
http://www.eficonnection.com/12200411/12200411.mpg

I'm glad you got her running. I knew when I started on my project, it had to work.
I need to get crackin' and get my 41 pickup running also. I'm installing your harness right now. Started installation last Friday, off tomorrow, so I'll get back on it.
Thanks,
Ron

I just recently got a used 411 PCM with its 2-80 pin connectors. I have been undecided between this swap and using Megasquirt, but I really like the idea of using a GM PCM. My project is a 98 GMC twin turbo. I would really like to know if this PCM will properly operate the 98 instrument cluster. I just started today, making a jumper connector harness to hook my trucks stock harness into the 411.

The jumper harness won't be straight forward. The 4L60E, MAP, TPS, CTS, and IAT sensor ground wires are all independent with the 12200411, but several are combined on the earlier Vortec PCM. If I recall correctly, you'll also be running an additional battery wire to the 411. AND there's a transmission range switch that you may need to wire to the 411 (or disable the codes in the PCM).

I originally built a 97 Vortec harness for scuzz, then he sent it back for me to convert to the 12200411 PCM. It was not simply a repin at the PCM and took a bit of time to do.

Make sure you use a 12200411 diagram from a 01-02 Express van (or similar vehicle). Do not use an LS1 wiring diagram. The LS1 firing order is different than the 1st gen SBC engines.

Thank You, I am going over wiring diagrams right now.

Sorry it's been awhile since my last post. The CKP relearn issues seem to be because the transmission is not plugged in and I'm not properly spoofing the PCM to think it's in park and 1st gear. I reflashed the PCM recently and the CKP learn was not commanded. I did find a procedure that bypasses a Tech2 or other device to enable CKP relearn. It's a lengthly driving sequence that I don't have the documentation to at the moment.

I've now decided to install a 4L65E in my S-10 rather than the 4L80E because the 4L65E case is the same size as the 700R4 that's currently in there. This way I'll have no driveshaft or crossmember modifications to worry about (if I used the 4L80E). My 03 Silverado SS is holding up just fine with a 4L65E, so my S-10 should be okay with one, too.

I'm also finding that converting the 12200411 system to speed density only is not a big deal.

Well I hope to get my 98 GMC with the 12200411 running tonight. I have about 10 wires left to repin. I don't want to speak too soon, since it is not finished yet, but this swap has been a piece of cake---so far. Wish me luck, I will keep you posted. Jeff

Very nice write up! I would want speed density b/c you can max out a MAF where as you can't with a MAP sensor. How big of a deal is it to do? How do you think it will react to a HSR setup.

Got the truck running lastnight ( 98 GMC ) This swap was EXTREMELY easy, but you do need the wiring diagrams for the 01-02 Express Van. I still have to hookup the speedo. The 98 has 2 green wires that go into the truck that are speed sensor inputs, but the 12200411 PCM only has 1 speed sensor output. I am thinking that I could connect the 2 truck wires together into the 1 PCM output. There is also 1 A/C wire that has nowhere to go. I think that wire is not used as the 411 PCM cycles the A/C differently at heavy throttle. The gas gauge did not work at first. The 98 uses a splice with most sensor grounds and the fuel sensor ground went to that. That ground must be cut at the splice and get it's ground from the PCM--The same as most of the other engine sensors. CKP,CMP, and MAF are not altered, they are left wired as stock. To anyone that is contemplating this swap--I would highly recommend it. It was very straight forward and easy. I used Tunercat to disable P1638 Generator code, because I didn't change the Alternator wiring. I do have code P1336 Crank variation--So I need to do a relearn. Edit the 98 GMC has 3 speed inputs into the truck and the 411 PCM has 2 speed outputs.

Awesome!

I forgot to tell everyone that the 01-02 Express Van uses the SAME emission equipment as the 96-2000 Old body style Vortec truck engines. This means all emission equipment can remain intact and operate properly---If you want.
EDIT: 96-97 use a different charcoal canister setup. 98-2000 is the same.

I might make this upgrade next year for my 1989GTA. New motor going in this year. See signature. Where would one acquire the wiring diagrams for the 01-02 express vans? I will also convert to the 4L60E transmission so that I can program in the shift points. I have already converted to speed density. Also where do you find the plugs? If off a the van where do you find pins? Thanks guys looks like a good project.