Limequat's 4.2l I6 Swap

[mobes]

Is it a low side trigger? PCM grounds the pin instead of putting 12V to it? Have you tried connecting the other side of the relay to +12 instead of ground?

I had a similar issue with my AEM, that turned out to be a bad connection on one of the ground lines.

 

[limequat]

So, to get this correct, PCM says the fans are activated, but the pin on the PCM itself is not activated?

Correct.

---------- Post added at 06:12 PM ---------- Previous post was at 06:07 PM ----------

Is it a low side trigger? PCM grounds the pin instead of putting 12V to it? Have you tried connecting the other side of the relay to +12 instead of ground?

I had a similar issue with my AEM, that turned out to be a bad connection on one of the ground lines.

Nope, PCM supplies 12V to the relay, the relay is always grounded. I've checked resistence between the relay ground and chassis ground - less than .1 ohm. I've jumped power directly from the battery to the high side of the relay and the fans run fine then.
Also, I checked resistence between the pcm pin when it should be on and battery and I get ~1000 ohms. Not sure what to think of that. Maybe the transister is toast and can't pull to 12 V? I guess the next step is to try a new PCM.

---------- Post added at 06:17 PM ---------- Previous post was at 06:12 PM ----------

Here's the trailblazer fan schematic. This is from a 2005 so the pinouts are different but the rest should be the same. Instead of driving a relay for an electro-viscous clutch, I'm using the relay for dual electric fans.

 

[DivMechDes]

Limequat...

Good job on the swap. I am happy to see and hear it running.

I too am very fond of these engines and am putting together some products to support them. I am currently installing one in a 1983 Jeep J10 pickup.

I would like to interest you in one of these: http://www.divmechdes.com/vortec_oil_pans.htm

The pan as shown is made from 3/16" sheet folded and welded to a 3/4" flange. It will require an "optional" bell housing inspection cover.

Let me know what you think. I am saying this because in an earlier post you mentioned having wished you'd have had one machined.

My website leaves alot to be desired, but I am going to make a point to change that.

Corey

 

[IJ.]

Very nice Corey, any pics of it finish welded?

 

[DivMechDes]

Very nice Corey, any pics of it finish welded?

Thanks. Actually, those pics were just taken. It is in process. I am a little anxious to get some exposure for the pan, so I grabbed some quick. I am still working on process for the welding and final machine. I need to finish machine the bungs for the drain and ream the bung for the oil level sensor.

My goal is to do a few configurations of the pan to fit various vehicles. After seeing Limequat's Supra, it looks like the current design is very close. I also have plans to do a dry sump for it to get it to fit just about anything.

I currently have material to machine up 10 flanges. In fact, I was thinking of making the flange by itself available if someone wanted to shape their own pan.

Corey

 

[IJ.]

Is there a reason the RTV channel intersects the bolt holes?
(My old magnesium Group A pan they looped behind the holes so the RTV became an o-ring)

 

[DivMechDes]

Limequat... Might it be possible that we need to supply a reference to the fan speed signal of some value other than nothing? The way the viscous clutch works is that is constantly turns on and off power to the solenoid to maintain a desired rpm. With that in mind, might it see an error if there is no speed signal? What if we tried feeding it a low reference voltage at the sensor?

---------- Post added at 07:30 PM ---------- Previous post was at 07:29 PM ----------

Is there a reason the RTV channel intersects the bolt holes?
(My old magnesium Group A pan they looped behind the holes so the RTV became an o-ring)

The grooves don't actually intersect the holes. They come up short. I mimicked the grooves from the stock pan.

 

[IJ.]

Thanks. Actually, those pics were just taken. It is in process. I am a little anxious to get some exposure for the pan, so I grabbed some quick. I am still working on process for the welding and final machine. I need to finish machine the bungs for the drain and ream the bung for the oil level sensor.

My goal is to do a few configurations of the pan to fit various vehicles. After seeing Limequat's Supra, it looks like the current design is very close. I also have plans to do a dry sump for it to get it to fit just about anything.

I currently have material to machine up 10 flanges. In fact, I was thinking of making the flange by itself available if someone wanted to shape their own pan.

Corey

Exposure is fine Corey, we have fairly strict forsale rules here so it would be worth your time reading them

On the grooves, cool was just curious.

Sorry to OT your thread a bit Lime, carry on!

 

[DivMechDes]

Exposure is fine Corey, we have fairly strict forsale rules here so it would be worth your time reading them

I understand... Just trying to help out. I know how hard it is to find stuff for these engines. As Limequat said, I'd like to see these engines come out of obscurity.

And it seems like the front-sump oil pan is the biggest turn-off.

 

[IJ.]

Won't take long to crank up 50 posts though, ever considered doing 7M pans in Al?
(rail is a bit of a pain though)

 

[limequat]

Limequat...

Good job on the swap. I am happy to see and hear it running.

I too am very fond of these engines and am putting together some products to support them. I am currently installing one in a 1983 Jeep J10 pickup.

I would like to interest you in one of these: http://divmechdes.com/PhotoAlbums/Vortec_4200/

The pan as shown is made from 3/16" sheet folded and welded to a 3/4" flange. It will require an "optional" bell housing inspection cover.

Let me know what you think. I am saying this because in an earlier post you mentioned having wished you'd have had one machined.

My website leaves alot to be desired, but I am going to make a point to change that.

Corey

Corey, nice looking pan. There's also a gent on inliners that is working on a cast pan, but competition is good

Will it have: Dipstick mount? AC Compressor mounts? Turbo oil drain?

---------- Post added at 08:46 PM ---------- Previous post was at 08:40 PM ----------

Limequat... Might it be possible that we need to supply a reference to the fan speed signal of some value other than nothing? The way the viscous clutch works is that is constantly turns on and off power to the solenoid to maintain a desired rpm. With that in mind, might it see an error if there is no speed signal? What if we tried feeding it a low reference voltage at the sensor?

I'd considered that as well. It doesn't make sense to me that they'd program the PCM that way, as it would be the opposite of fail-safe. If a sensor fails, it seems they'd run the fan all the time so as to save the engine.
I don't care to try to simulate the sensor, as the PCM may check for current on the power/ground too. Not to mention, that there are a variety of signals possible for Halls. If it comes to it though, I may try to find one in the junk yard.

 

[DivMechDes]

Won't take long to crank up 50 posts though, ever considered doing 7M pans in Al?
(rail is a bit of a pain though)

Yeah, that hump is a bit of an obstacle. It can be done by making separate flange pieces to go over the humps and welding them together into a single flange.

 

[IJ.]

Yeah, that hump is a bit of an obstacle. It can be done by making separate flange pieces to go over the humps and welding them together into a single flange.

Was going to digitise the rail in my CNC then generate a DXF but never got around to it as the Group A pan came on the market so I snapped it up.

 

[supra90turbo]

Lime: If you aren't getting power at the pin from the PCM, but adding power to that pin will switch the fans on, I'm afraid it's a PCM issue.
PM me if that's where you end up, I'll get you one cheap, but I'll need the core back. Part number is 19209820

I've looked through GM's Service Information online, followed the circuits, and checked the operations, and everything seems to be ok right up to the PCM....

 

[limequat]

I'm coming to the same conclusion as well. I just posted this on trailvoy:

Today I set the vs % ECT values to all 100%. This should make the fan run all the time and make diagnostics easier. Unfortunately, still no luck. I tried PWM EV, PWM electric, and discrete with no changes in the result. In pretty much all cases the output showed infinite resistance to battery and between 8k and 32k resistance to ground.

So in theory, if I connected the PCM control to the low side of the relay it would take ~0.4 mA of current. This is not enough to suck in a relay. I'm guessing that I'm actually measuring the impendence of a blown transistor.

Here's my operating theory: The GM manual is wrong and the PCM actually grounds the fan relay. Somehow in my testing, I fed power into a grounded transistor and blew it up.

I have a spare PCM I can test this theory on, but it would require me blowing 2 hptuners credits to reflash it first. Meh.

 

[supra90turbo]

Damn, they won't understand if you try to explain your situation?

 

[DivMechDes]

Will it have: Dipstick mount? AC Compressor mounts? Turbo oil drain?

Yes on the dipstick.
Not yet on the AC mounts. I have a couple ideas, though. I am not planning to use it for my Jeep.
I can add a turbo oil drain if needed.

The shape I have is basically the stock shape mirrored with the floor of the "front" of the pan raised up a bit. It may be necessary to do something different depending on the application. We would have to see what your requirement is. I think a sheetmetal pan is going to be alot easier to change for a given package. Casting the pan is going to lock you into a fixed shape, which may not work in some situations.

I also made up some really nice folded sheetmetal motor and transmission mounts. If you were interested in sending yours to me, I could digitize them and model some up and send you the CAD so you could get them laser cut and folded (I could help you with that if needed). I would be interested in helping out just to get the shape for my database in case you have inspired someone else to attempt the swap.

Corey

 

[limequat]

Nope, that's their policy.

---------- Post added at 08:29 AM ---------- Previous post was at 08:25 AM ----------

Yes on the dipstick.
Not yet on the AC mounts. I have a couple ideas, though. I am not planning to use it for my Jeep.
I can add a turbo oil drain if needed.

I would highly recommend the A/C mounts at least. Without them, you would have to relocate or remove the compressor altogether. And that has ramifications to the serpentine system.

I also made up some really nice folded sheetmetal motor and transmission mounts. If you were interested in sending yours to me, I could digitize them and model some up and send you the CAD so you could get them laser cut and folded (I could help you with that if needed). I would be interested in helping out just to get the shape for my database in case you have inspired someone else to attempt the swap.

I've taken some rough measurements to this end. I don't know if you've read through the entire thread, but my mounts incorporate subframe spacers as well. For a clean part, they'd have to be cast or billet.

 

[DivMechDes]

I have the part number for the belt if you want to eliminate the AC compressor. It only takes away a few degrees of wrap on the water pump and adds to the alternator. You just forget the fixed idler. I can take a pic to show you if you are interested. Unless you plan to keep AC anyway.

Also, the motor mounts look pretty straight forward to me. I have CNC's as well so there is no problem if that is necessary.

I'm here to help. Sorry I didn't catch your thread sooner.

 

[te72]

So, just finished up reading all 28 pages up to this point, and I'm in the same boat as everyone else so far. I like it man. Kinda makes me wanna go rip the LS1 out of the SS and toss it in the Mk2...