Tag Archives: ecotec

The New ECOTEC is Alive!

It has been quite some time since my last post.  The bowtie6 Ecotec project is alive and well:  this weekend we fired up the Ecotec for the first time!  Needless to say this was quite an awesome event!!

First, here is a quick recap:

  • The engine compartment has been fully wired up.  There is a new engine control fusebox containing circuit breakers, relays and the ECM.
  • Inside the car there is another small panel with relays and fuses controlling turn signals, park lights and main light circuits.  The dash is all back together along with all gauges.
  • In the trunk I have the battery mounted in a special enclosure.  Yet to be done is a separate set of relays and fuses to control the stop lights and fuel pump.

We hot-wired the fuel pump for this weekend’s engine start.  With the aid of my laptop and software, we disabled the VATS system by reflashing the ECM.  We removed the spark plugs, turned the engine a few times and sure enough after a few seconds we had oil pressure.  All good so far.

Next was fueling up and priming the pump.  After running the fuel pump for a few seconds it finally “primed” itself and started pumping fuel.  We attached a fuel pressure gauge and pressure looked very nice indeed.

The next step called for re-installing the spark plugs and re-installing the coilpacks.  Turned the key, and pushed the button.  It took a few tries but finally she fired up and ran.  I hooked up the laptop again, this time to check for DTC’s.  There were a few.  Not good.

Turns out we had a few “issues” with the wiring.  The 2.4 Ecotec has VVT on both the intake as well as the exhaust.  There are two cam sensors on the top of the engine and two more on the back of the engine.  The two on the back of the engine are identical to each other, and I had made the mistake of hooking up the wrong plug to the wrong sensor.  This is something very unusual for GM harnesses: all plugs are unique; in this case the camshaft sensors are identical and share the same plugs.  My bad.

We tried again.  This time the engine ran fine but the scanner on the laptop read we were having fuel delivery issues.  We tapped the throttle a few times.  Coolant temps started to normally go up and we let the engine run for a few more minutes.  Then things started to settle down.  The fuel delivery issue went away and the engine started running better.  We have encountered this issue before when re-starting an engine that has been sitting for a while and this can be attributed to an injector sticking.  Once it has fresh fuel flowing, it loosens up any gummed up fuel and all is good.

We let the engine cool down and this is where things got interesting.  On cold re-start the Ecotec sputtered and coughed.  We noticed we had quite a few more DTC’s.  This type of behaviour is to be expected.  Suffice to say, that after many hours of debugging, changing a few parts around and a lot of tracing of the wiring harness all checked out.  There is no issue with the ECM – we swapped the one in my cousin Jim’s TR4 and the engine behaved in the same way.  So we ruled out wiring, ECM and sensors.  We started looking closer…

As it turns out, the new fabricated intake had an issue.  No, not a leak!  We re-used the rubber intake from the donor Solstice.  However, the housing for the MAF sensor is all home-made in order to allow the low restriction air cleaner element to be mounted.  The size of the housing was the culprit.  This was giving some false readings and this caused the ECM to make erroneous calculations regarding the air flow into the engine.  After correcting the offending intake tube we fired the engine back up, and now it runs smooth as silk.

Next will be to start plugging in new values for engine run-time parameters.  We’ve done some of this on my cousin’s TR4 and this along with some other tweaks will enable my TR6 to finally be back on the road.

So what is next?  Now that the engine is fully operational, we are going to start hanging fenders and doors on the body shell.  We anticipate having to make some special shims for the body since the frame is all new.  However, the frame is perfectly level so we are hoping not to have to shim it too much!

I have some final wiring to do and once that is all complete the next step would be the maiden trip down the road.  Still a few weeks away from that, but the engine runs and this has been a great weekend!

Stay tuned…

Wiring Harness

Tonight I started working on the engine wiring harness.  Doing an engine swap requires some sort of engine harness to be used along with the computer (ECM) in order to make the engine work.  This is the part where “old school” hot-rodders shudder and panic about.  This is also the part the trips up many folks attempting to run electronic fuel injection (EFI).

I’ve worked with my cousin Jim for the past 15 years perfecting the fine art of transforming a stock wiring harness into something that can be used to fully run a modern EFI engine in a classic car.  At first we worked on “throttle body” engines – basically a glorified carburetor but with the advantage of electronics.  These were the early EFI setups that offered much better economy than a plain carburetor but had a long way to go.  Throttle bodies evolved into individual injectors feeding each cylinder and more sophisticated ECM’s.

Through the years, we were able to adapt the L98 Tuned Port v8 with it’s distinctive intake with eight runners going to each cylinder.  As the L98’s became scarce we moved to LT1’s and LT4’s.  During this time, we also mastered the L32 V6 as originally fitted to bowtie6.  The next step was the LSx family of engines.  Currently we’ve focused on the ECOTEC engine as fitted in Jim’s TR4 and now my TR6.

The throttle body harnesses were the simplest.  No much really to figure out.  When we started using L98’s and LTx’s in Jaguar XJ6 and XJS conversions, at first we sourced the harnesses.  They were not cheap, so we took a stab at using original GM harnesses and cleaning them up.  If done properly they make an excellent harness however it takes some effort to figure them out.

This photo shows the harness from a wrecked 2.4 ECOTEC powered HHR.  The harness is basically all there; however it must be modified to work with the ECM and placement in the engine fitted to bowtie6.  This photo shows the harness after I had removed all the plastic casings protecting the harness.  This is done for several reason, among them exposing all circuits and it is easier to trace the wires to decide what needs removal.

We don’t use the original GM fusebox.  We also remove redundant ground wires and hot feeds, thus allowing the harness to be much simpler and easier to deal with.  Depending on what donor harness you use, certain pinouts on the ECM connectors must be relocated.  This is all done by using original GM Factory Service Manuals.

I’ll have more as the process takes shape.  This is actually a lot of fun however it is a little time consuming.  At the end of the day, it is a very rewarding feeling when the harness allows the engine to run.

bowtie6‘s ECOTEC Custom Intake

Lots of new progress to report this weekend.

  • Solid axle & Posi-Traction differential – check
  • Disc brakes (on all four wheels) plumbed with hand-formed stainless lines – check
  • Handbrakes using original TR6 cables – check
  • Wilwood proportioning valve – check
  • ECOTEC using custom/factory mounts – check
  • Fourth Gen Camaro hydraulic clutch – check
  • AISIN 5 speed gearbox on custom mounts – check
  • Tilt steering on a Triumph TR6 (I’ll have more on this later) – check

And the pièce de résistance for today’s post:  a hand formed aluminium intake.

The factory ECOTEC comes with a very intricate and quite impressive composite intake manifold.  The thing has a very unique shape, with a convoluted “S” shaped intake that splits the aft of the throttle body into four runners feeding each intake port.  With the longer runners, lower torque is improved.  Too bad we could not use this intake.  Why?  In the TR6 the steering shaft is in the way and the front fender would just not allow the factory intake to fit.

So what is one to do?  Answer:

GM makes these cool plates for the exhaust and intake ports that are intended for exactly this type of application.  The exhaust plate has already been used to make the exhaust headers on bowtie6 (if you haven’t seen that, CLICK HERE).

Now the intake plate along with my cousin Jim’s serious welding and fabricating skillz yields the following:

The intake is fitted for a trial fit and the all-aluminium body is yet to be fully finished.  Here is another set of pictures:

The photo above shows the front section of the custom intake.  The fly-by-wire throttle body will bolt to the flange on the front.  Not shown on the picture above is the port for the MAP sensor as well as the bung for the vacuum line going to the brake booster on the right.  Which, by the way is from a Vette along with the mastery cylinder.  What are those blue thinggies on both of the brakes lines?  Hmmm…  Wonder what that is all about??

Last but not least, another view this time towards the front of the car.  Yes, that is an all aluminium radiator up front.  The fan is SPAL (the same kind used by the boys from Maranello) mounted on an aluminium shroud.  Why the shroud?  I covered that in my original explanation in my original website.  Want to read about that?  CLICK HERE.

Pretty cool, huh?


Today was  a milestone.

bowtie6 had a trial fit of body, new frame and ECOTEC engine.  The following pictures show what this all looks like.

Yes, there has been some “shaping” done to the body.  The area past the firewall was in need of change to make room for the oil filter (on the driver’s side) and the thermostat housing (on the passenger’s side).  For anyone thinking about doing this to a “stock” TR6:  beware.  There will be some work required on the firewall as well as the battery box tray on the stock TR6.  Since bowtie6’s firewall had already been modified, this was a small change.  Under the experts hands of my cousin Jim Thompson, there was some welding involved and voilà – the engine fits.

Once all that work was completed, I mixed up some of DuPont ChomaOne single stage urethane red paint and the bare areas were re-painted.  This took some doing but the result is awesome.  Tonight the new areas are drying and the plan is to bolt the new frame to the body permanently tomorrow.

Well… Here is what an ECOTEC looks like in a TR6 with a custom frame underneath it.  Note how far back the new engine sits.  This change is highly desirable in moving the weight back.  This is indeed a great day!


Ecotec Motor Mounts, Rear Suspension and Headers…

Oh yeah!  Today we have some really cool pictures.

The frame is starting to really take shape.  The front suspension is pretty much done.  The following picture shows how things are looking right now.  The front suspension towers are in place, coilovers and lower plates.  No more spring compressors, just the real deal:  coilovers.  The front sway bar has also been located as well as the steering rack.  The square stock bar in front of the pulley is not part of the build so don’t wonder what that is there for.  Finally, there are quite a few welds that need to be finalized – right now there is a lot of stuff that is tack-welded.  Oh…  And the Ecotec is now mounted on the table in order to finalize where it will be residing.

The next picture shows the driver’s side motor mount.  Since the frame is being made from scratch, we can use the original mounts.  Nothing wrong with them.  However, these are the ones that attach to the frame not the ones on the engine block.  Those would have been way too wide, so new plates have been made.  Look closely, and you will see the factory intake has been removed.  When fitting an Ecotec on a TR6 the original intake has to go – otherwise it will be in the way of the steering assembly.  There will be a custom-made intake so more room can be dedicated to the steering.

Next, let’s take a look at how the rear suspension is looking.  This is really trick.  Here we have a four point suspension also with coilovers.  They are not in place but they are identical to the fronts – however the spring rates are different.  The control arms are all finished with heim-ends; my cousin used polyurethane ends on the TR4 but they soon failed.  I’ll have a future article on that.  The diff is not in place yet nor the axles.  This will all be ordered soon.  The plan calls for a 3.80 to 1 axle with posi-traction.  This will give the car a great response at speed.  Special note must be taken:  this is not a drag car, instead it is being designed to excel at speed.  This is what the rear looks like:

Finally today’s real work of art:  the new headers for the Ecotec.  The headers have been hand-made, from stainless tubing.  The flange on the block is GM – they sell a special flange that gives an excellent base for the headers; there is also a GM flange similar to this, for the intake.  The header does not have a bung for a O2 sensor – that will be placed on the bottom tubing, after the flange.  These headers should flow very nicely and since they are very close to the block, it will prevent the body from having to be cut.  All this stuff is being built for a reason!

And finally, another shot of the lower part of the headers, showing the motor mount on the passenger’s side.  This mount has a special heat insulator – that is stock from the factory due to its close proximity to the header.  Cool, huh?

Like I said before, things are being tack-welded now.  Much easier to cut a tack-weld than if it were permanently welded in case we have to make adjustments when the body is fitted.

Comments?  Questions?  Drop me a line…