Turdbo Neon

Project log for the re-building of the 1997 Dodge Neon Sport

I’m going to go ahead and call the intake manifold swap completed.  There are still a few problems, of course, and some things left to be done, but the intake manifold is swapped and the car is running better than before.  It’s getting in to boost sooner and with more force and it’s holding 15-16 psi easily.  The fans seem to work okay, but I don’t think they’re as good as the previous ones and I’m a little bit concerned how the cooling system is going to hold up during competition in the heat of the summer.  Time will tell.


With the OEM ECU removed from the car, I’ve started to trim down the wiring harnesses.  I need to wait until I have the idle valve thing worked out before I can wrap up all the wires, but in the meantime, I’ve pulled some connectors and tightened things up a little bit.

With that cleaned up a little bit, I moved on to another small project.  At some point, the bumper cover got a tear in it, near where I had cut for clearance around the intercooler.

I found an epoxy from Bondo at Advance that I thought I would try:

It smells a lot like JB Weld, but there’s a black and a clear part, plus it’s supposed to be flexible, which this spot will need.  I went ahead and put a layer on last night and then clamped it.  I totally forgot about the repair and drove it to work today with the clamp still on.  Herpaderp!  When I got home, I took the clamp off and added a little more of the epoxy to cover the spot that had the clamp previously:

Overall, I’m happy with it so far, but I won’t know how well it really works until I get the car into the dirt.

I got another update from AMR Engineering in regards to my suspension – Current estimated ship date is Monday April 3rd, so hopefully it doesn’t slip again.


Catching Up

I’ve updated the build thread that I had at GRM, but I haven’t copied everything over here.  So here’s a mega-update from there:


Okay, so Megasquirt is hard when you’re using a 16 year old PCB…

I was hoping to add in a knock input and outputs for tach, PWM IAC, and fan control, plus an input for launch control/flat shifting. It looks like I get 5 pins I can use, X11, X12, X13, and X14 plus pin 36 on the DB37. 11 and 12 are already in use for ignition control, so I’m going to put knock on X13 and tach on X14. Pin 36 is orphaned, so if I want to use that I just need to wire directly to the pin. Pins 1-19 are all wired directly to ground.

Not ideal, but I think I can make it work. I did swap out Q5 last night for the PWM-capable transistor. Knock input looks pretty simple – if I connect a jumper from X13 to X6 on the 2.2 PCB, that should put knock input on what MS2 calls JS4.

The tach circuit still perplexes me due to a lack of any specific direction. I have a bunch of the 2N2222A transistors (cheaper to buy 20 than to buy 1…) so I believe that I can use JS5 by wiring to X7 on the 2.2 PCB. That should mean that the right lead of the transistor should go to ground, the center lead wires to a 1k resistor and then to X7, and the left lead wires to a 10k resistor and a jumper wire. The 10k resistor goes to a 12V source and the jumper wire goes to X14. I don’t really understand that, but let’s see if it works.

That will mean that on my harness, the 2A wire (green/white) should be knock input from KnockSense and the 2B wire (green/red) should be tach out.

So I did all that wiring stuff, but it doesn’t seem to work. I suspect that I’ve failed in picking up the +12V and the ground properly, but anything is possible.

I wired up the IAC and the tach connection to the megasquirt harness so I could wrap up the wiring. It’s looking a lot cleaner than before and it should be less prone to any kind of breakage or rubbing:

The throttle cable bracket is installed and the vacuum lines are all hooked up as well.

Next, I need to figure out what went wrong with Megasquirt and then see how my mods work. The knock sensor is still not hooked up – I need to run it back into the cabin of the car because the knock sensor controller isn’t weathertight. I’m thinking that I’ll use the wire that is for the knock input pin to run from the sensor into the cabin, then snip the wire near the MS box and use the part wire that goes back to the DB37 as the knocksense output connection. Then I should just need to find switched +12V and a ground inside.

Well, there was a minor setback tonight. When I wired up the new PWM transistor in place of the old FIDLE transistor on the 2.2 board, I think I literally had my wires crossed. Uncrossing them got it working a bit, but in an attempt to troubleshoot, I cut out the tach output circuit and tried reloading the firmware. On the stimulator it acts fine but it always wants to keep the fuel pump relay turned on, even when it’s reading 0 RPM. I’ve ordered up a new Q3 transistor for the fuel pump circuit so I’ll see if that clears the problem up.

If that works, then I’ll go ahead and rebuild the tach output circuit. I’ll also need to find some place under the hood to pick up +12V when the ignition is on, but that shouldn’t be too tough. Initially, I wired the IAC to the fuel pump relay control, but that’s all ground not +12V so I undid that. I’m not doing anything else, though, until I know if I’ve fried the MS box entirely. If I can’t get this squared away in short order, I’ll just have to order up a new kit. And then I’ll have to see how much I want to gamble — do I hope that my MSII daughterboard is okay and just buy the MS1 3.0 kit and use my current proc, or do I spend the extra 60 or 70 bucks and get the MS2 3.0 kit?

And here things were running so well before I just had to make them better….

Fun fact.

I’m retarded.

All that stuff I posted before – just ignore it.

The real problem is that I blew a fuse that feeds MegaSquirt and it was getting backfed from a sensor somewhere so it was acting like it had power but wasn’t working properly. It’s all good now.

Tonight, I went ahead and re-did all the stuff I undid last night. I gave it a test fire and it started right up! Sort of. It won’t stay running because the idle valve is closed and I need to find +12V for that. That’s a job for tomorrow night. For now, it starts! And the tach works! So I will celebrate with hard root beer and Buffalo Creek Bourbon Cream!


Fans are wired up and installed on the radiator with zip ties. I put a new hole in the core support so I could position the radiator forward a bit. They actually seem to blow a ton of air, so I’m cautiously optimistic.

Megasquirt is working okay. The car will start and idle but the IAC is not working so in order to start, the throttle has to be slightly pressed. The tach gets a signal but it is really jumpy. The IAC makes clicking sounds when I hook it straight to 12v, but MS isn’t sending any signal down the FIDLE wire. I did have the TIP 120 transistor miswired at one point so I’m going to try replacing that.

And I’ve cooked yet another TIP120. With the output connected to absolutely nothing and the FIDLE setting set to “Off”. Something is wrong on the input side of the equation.

The next attempt was to remove the TIP120 completely. No smoke, but the dash tach was very jumpy.

Next test was to remove the jumper wire that sent the +12V to the CPU stepper chip. The instructions don’t say that you NEED that wire if you’re not using a stepper, just that you “should”. With that wire removed, the tach isn’t perfect but it’s pretty close.

The coolant is pretty low from pulling the intake manifold and all that, so I need to top that off, but otherwise, I think it’s ready for a test drive!


This whole idle valve thing has got me pretty bummed out. Same with the tach out. It’s gone back to being super jumpy again, so basically worthless, and the IAC is completely non-functional. I suspect that there is something that isn’t wired correctly, but of course the assembly manual for the 2.2 PCB with MS2Extra is no longer in existence, having been purged from the msextra.com site. Sure, they’ve got a link that says it leads to the manual archive with the older 2.2 manuals, but it’s a dirty lie. I get that it’s an old board, but why eliminate all traces of the old manual?

Anyway, the car starts and runs without idle air, but it does require holding the throttle down a little for a few seconds before the idle settles down to around 600 RPM. I’ll take a drive tomorrow and see what it’s like with the new intake.

Oh, and I found this sitting next to the car:

Stock ECU is out of the car! There’s plenty of wiring that needs to be removed and cleaned up as a result, but at least I know that full standalone is functional now.

Holy E36 M3.

It’s raining today and the car is basically undrivable. The slightest blip of the throttle in gears 1-3 breaks the tires free and gets the car bouncing off the rev limiter. Boost comes on much faster and holds at 15-16psi. Cruising in fifth at 65mph rockets to 80+ with no hesitation when I push the accelerator about half-way. This thing is fast.

Cooling seems okay, but it’s hard to tell on a cool and rainy day. Sitting in the garage, idling after running for 30 minutes, I put the fans on and it did drop the temps pretty steadily, so I’m hopeful.

After a slight delay, more progress

After a little searching and trimming, I was able to fashion a section of the aforementioned PT Cruiser silicone charge piping to run between the intercooler and the throttle body. I got the IAT sensor installed in it and the fit is pretty nice. There’s going to be a much cleaner look in there now with a little more room.

The rest of my time was spent working on the throttle cable bracket. After spending about 45 minutes cleaning out a space to work, I got this grafted together:

It took a little adjustment with my 5 pound sledge, but I put a nice bend in it and the throttle travel seems to be about perfect.

I put a couple coats of paint on one side tonight and I’ll do the other side tomorrow. It doesn’t really need to be SUPER pretty, but I want it to look a little bit nice!

I checked out the closing RadioShack near me and they had a few things that are nice to keep on the shelf, but they lacked any 2N2222A transistors that I need for the tach output circuit. I ordered a hundred of them from eBay (because it was way cheaper to order 100 than 1…) so when that gets in it will be time to open up the MegaSquirt again and add the tach output, fan control, IAC control, and knock input.

Intake Manifold Installation, Day 6

Setting the fans aside for the time being, I went ahead and lengthened the TPS wiring and the IAT wiring (almost. I ran out of butt connectors with one splice left to go) and get that taped up along with the IAC wire. It makes a nice little branch of the harness and I’m pretty pleased with how the wiring is shaping up.

The Stratus throttle cable isn’t just a little bit longer — it’s nearly twice as long as the 1gn Neon cable. Getting it through the firewall was a bit difficult because the grommet is significantly larger as well. Shaving down the rubber allowed it to fit snugly and the little clip on the inside will make sure it doesn’t come loose. On the other side, I fiddled with the 1gn bracket for a bit and wound up cutting it up so that I’ve got a small square that has the keyed hole for the throttle cable to lock into place. I’ve got some small angle steel that I’ll weld to it, drill a couple holes in, and mount to the throttle body’s original bracket mount holes.

Intake Manifold Installation, Day 5

More solid progress today along with a slight disappointment.

The pair of slim-line cooling fans arrived. I was hoping to just use the zip-tie method to attach them directly to the radiator and then just deal with the wiring. Unfortunately, the little plastic parts are complete garbage and every single one of them broke through just the act of trying to push the zip tie through.

So instead of doing it that way, I’m working on fabricating mounting brackets from some leftover steel bits I’ve got laying about. The bottom of the radiator has slots for the fans to slide in to and then there are two bolt holes at the top of the radiator for each fan. I’m going to make four brackets like the one below and bolt them to the fans to hold the bottom in place. Then I’ll make a bracket that will go across the top with the fan bolted to the metal and then the bracket bolted to the radiator. It should work okay, but it’s just more work that I didn’t expect to have to do.

Here’s one of the fans with the one lower bracket attached.

I did a little more organizing and wrapping of the wiring harness and I’m really liking the way it’s turning out. The only way that it could look better is if it had that real tight protective weave sheath around it, but I’ll take what I’ve got:

The TPS and IAC are installed in the throttle body and the throttle body is installed on the manifold. It’s a tight fit, but it works:

One problem-that’s-not-really-a-problem is that the TPS pin outs are slightly different. Orange should be the +5VREF, the black-blue should be sensor ground, and the purple-white should be the signal. The connector on the left is the connector that came with the TPS while the one on the right is the original DOHC one. Pins 1 and 3 are swapped. Rather than try to swap the pins, I’m going to cut off the DOHC connector and wire in the pigtail from the Caravan that donated the TPS, and that works out well because with the new position, the old connector doesn’t quite reach.

With the new position of the throttle body comes a need for a new cold side pipe. The IAT sensor needs to be installed in that tube yet, but the old section of silicone piping that used to be on the air filter just happens to be a perfect fit! It’s actually a piece of the hot side pipe from a PT Cruiser – I tend to collect those when I see turbo PTs in junkyards since it’s the right size and material and super cheap.

The throttle cable is definitely not long enough so I’ll need to install the one from the Stratus. I’m working the wiring back and it’s starting to look much cleaner. The upper radiator hose is resting against the hump for the MAP sensor, so I need to do something about that still. Hopefully tomorrow night will be spent finishing up some brackets – I need to get the cooling fan brackets made as well as make a bracket for the throttle cable.

Intake Manifold Installation, Day 4

Before we get to this evening’s results, there are a couple other updates that I’ve been remiss in adding. First off, in addition to the suspension order, I’ve also placed my order to import some new dry weather tires. I have no idea how long that’s going to take, but I’ll keep an eye on that. I’ve also been shopping quick release steering wheel setups and new seats. I never plan to do anything that would require SFI or FIA certification/homologation with the car so I’m looking at some more budget one-piece options that would work for RallyCross and maybe an HPDE/PDX once in a while. I’ve found these seats on Amazon that ship as a pair with the appropriate bracketry for a Neon and then there are high-back seats from Jegs which I’d need to fabricate my own brackets for. I actually have no idea how easy or hard it would be to do that, so I need to dig in to that some more.

In an effort to tidy up the wiring, I picked up this self-fusing silicone tape and it’s just amazing stuff! There’s no adhesive on the tape, but once it touches itself it almost instantly fuses together. More on that in a bit.

This morning I got out the junkyard with eastsidemav and found a couple gems.

There’s a super long throttle cable from an 01 or 02 Stratus, an upper water neck from the same car, a lower water neck from an 01 or 02 PT Cruiser, and over there on the right, I got a new cover for the PDC since mine broke and fell off at some point. Trying to make it look a little nicer, remember?

Here’s the water neck bits all put together:

The PT upper is way too tall, the 2.0 upper doesn’t fit, so the one from a Stratus is perfect. I probably could have used the PT turbo lower and made it work, but for some reason Chrysler moved the various ports around over the years. Here’s the 05-06 lower that I already had next to the 01 lower that I got today:

You’re looking at them from the bottom up as they would be mounted. The one on the left is the newer style. You can see that all the bosses are there, but for different applications and different years, they’ve drilled them differently. On the newer style, the CLT sensor bung is drilled into the left side which on my car would be a difficult fit due to the low pressure power steering line. The 01 PT Cruiser lower on the right, however, has the heater core output in the right spot and has the CLT sensor bung pointed towards the front where the wiring won’t be rubbing against anything.

The CLT sensor itself was different since I believe the newer cars used a single sensor and then fed the gauge cluster as an output from the ECU while mine is set up to have two sensors in one so the ECU (now MegaSquirt) and the gauge can each get their own signal. I swapped out the sensors so everything should continue to work the way it did before.

Here it is, all bolted up:

With the water neck sorted, I went ahead and got the intake manifold bolted up. I’m loving the way it looks:

I trimmed down the radiator hose to prevent it from rubbing against the intake, and I went ahead and started wrapping the wires. I had to extend the CLT sensor wires since the sensor has moved a bit. I also pulled the little fuel line locking clip off of the old DOHC fuel rail and put it on the new chrome one. The silicone wrap for the wiring really comes out looking a lot nicer and cleaner than the old split loom that I was using before:

Compare that to how the old setup looked:

Intake Manifold Installation, Day 3

Hmm. The 1gn water filler neck has the wrong bolt holes and the PT turbo filler neck is too tall to fit under the hood. Looks like I have some research to do tonight and some hunting to do tomorrow morning at the junkyard.

The only other thing I accomplished was to clean up the bottom part of the water neck and bolt up the knock sensor to the block.

Intake Manifold Installation, Day 2

Long day. Super tired. Measured the radiator and ordered up 2 slim 10″ fans to replace the original ones. They’re the type that basically get zip-tied through the radiator and they should fit between the radiator and the intake manifold if I relocate the radiator forward just a hair.

Installation of the Manifold, Day 1

The order is placed for the new suspension. Front and rear adjustable dampers with 2.5″ diameter springs and camber top mounts for the front. He’s telling me it’ll be 2-3 weeks before they ship, so in the meantime, I’ve got other stuff to do.

Starting out tonight was this mess:

The 2.0 intake manifold came off and I cleaned up the RTV that was previously used to seal things up.

At this point, there are no gaskets in place, I just wanted to test-fit and see what problems I’m going to run in to. I like the way it looks, though:

I’ve got a lot of clearance problems, though. The radiator inlet is rather unfortunately positioned:

And with that manifold in place, I only have about 2.5″ of clearance behind the radiator so the original fans aren’t going to fit. I’ve mocked up leaning the radiator forward to get that 2.5″ of space and that gives me a somewhat suboptimal, but maybe passable amount of clearance for the radiator hose. I think that the original throttle cable just might be long enough, so that’s good news. There isn’t much clearance between the throttle lever and the transmission, but there is just enough to make it work.

What I need to figure out is moving the radiator forward, getting a slim fan to replace the existing ones, and then coming up with a new pipe to go from the intercooler to the throttle body. I’ll also take the opportunity to re-run and clean up the wiring a bit, since it’s an ugly mess.

Still needing suspension

Davenport Racing USA never accepted my PayPal payment, didn’t respond to email, and their phone number is disconnected. I’m assuming that they are no longer a going concern, and I’m not getting my HotBits so I cancelled my PayPal payment and appear to be out absolutely nothing except a week’s time of waiting.

I reached out to AMR Engineering last night and they seem to respond to email and actually know some things. I’ve heard some horror stories of people not getting product for really long amounts of time, but I’ve also heard that when the product does show up it’s a quality thing.

I will probably go ahead and order those up but first I need to figure out what spring sizes and rates I need.