Category Archives: Tech

Technical discussion and articles from the staff of Modern Performance.

Motor Mount inserts – using them with worn/broken motor mounts

Motor Mount inserts – using them with worn/broken motor mounts (pertains to 95-05 Neons and 03-05 SRT-4’s)

We get calls all the time from customers who state pretty much exactly the same story.

“Ive got a 1996/2000/2003 Dodge/Plymouth Neon and or 2003-2005 Dodge SRT-4 and Ive got a lot of movement from my engine. I think my motor mounts are shot, and I want to use the Prothane motor mount inserts with my factory motor mounts to prevent the engine movement.”

Now, it sounds like a good idea, but heres the problem.

Prothane motor mount inserts are meant to be used with new, or good condition motor mounts to prevent flexing of the engine. They are NOT designed to be used with worn out or failing motor mounts. Why ? Well, when the motor mounts are failing, they will have way too much movement, and a motor mount insert wont fix it.

It would be like using a band aid on a major cut on your arm (that really requires stitches). It might work for a little while, but its ultimately the wrong way of fixing the problem.

Bottom line :

If you have a failing set of motor mounts with your 95-05 Neon or 03-05 Neon SRT4, and you’d like to use motor mount inserts, REPLACE your motor mounts and then install the inserts at the same time. It will make a drastic difference, and the combo of solid motor mounts and new inserts will last a LONG time.

2008-2009 Dodge Caliber SRT4 owners who change their own oil, take notice!

Just a note for those of you Caliber SRT-4 owners who change your own oil..

About every 4,000-5,000 miles your Caliber SRT-4 will make a BING noise and your display will read CHANGE OIL SOON.

Now, for those of you who go to dealerships to change your oil, no problem, they will reset the message for you. BUT for those of you

who change your own oil, you may be wondering how to erase/reset this message.

Its actually quite easy to do and theres no special tools involved !

Put your key in the ignition, turn it to the ON position but dont start the car. Then, push the accelerator pedal to the floor and release 5 times.

Then, start your car, and the message will be reset ! PRESTO !

Change to the Eibach 00-05 Neon/SRT-4 Swaybar hardware kit.

Eibach has made a change to the Eibach 00-05 Neon/SRT-4 Swaybar hardware kit.

Here is the new hardware kit.
Eibach Swaybar Rear Installation hardware kit for 03-05 Neon SRT4

Now, what makes this hardware kit different than the previous hardware kit?

Well, if you have a 03-05 Neon SRT-4, it will bolt to your car just like before with no problems.

If you have a 00-05 Neon without a rear swaybar mounting bracket, then this revised kit is a serious problem. Why ? Well, the old rear swaybar mounting kit had a L shaped bracket that mounted to the strut, allowing you to install the swaybar kit onto your car. This new kit, is designed around the Neon SRT-4 which already has a mounting kit permanently attached.

So, if you have a 00-05 Neon without a rear swaybar on your car, then youll have to fabricate something to attach this swaybar to your struts.

At this time, we feel the easiest thing to do, is to get new endlinks like these:
Prothane Shorter Endlinks for the 00-05 Neon, 03-05 SRT4

and buy a set of used L shaped brackets from a 00-05 Neon in the junkyard, or off to install the rear swaybar onto your car.This would be the easiest, and cheapest way to install these Eibach swaybars onto your 00-05 Neon.

Photo installation instructions for Depo LED taillights for 2003-2005 Dodge SRT-4.

Bought a set of Depo LED Taillights for your 03-05 SRT-4 ? Well, this is a easy product to install, but due to the product not coming with installation instructions, some customers can be confused on how to install them. Many of our customers cant understand how these taillights will plug in like a bulb, and are expecting to find some sort of special electrical plug to connect to.

So, we’ve taken some photos, and have written up a installation instruction set on how to install these on your 03-05 Dodge SRT-4.

Heres the Depo Led Taillight in black on top, and the factory taillight on the bottom.

Depo LED Taillights for the 2003-2005 Dodge SRT-4

Heres a shot of the backside of the taillight. In this guide we arent going to cover how to remove the nuts that hold the taillight to the car. We’re going to cover

the part most customers of ours get in trouble with: installing the wiring for the taillights.  In order to access the taillight, you’ll need to remove the carpet that covers the taillight.

Depo LED Taillights for the 2003-2005 Dodge SRT-4

After locating the taillight, the next step is to remove the brake light/turn signal bulb and wiring, as well as the backup bulb. You remove both of these

from the taillight by turning the sockets counter clockwise. The large bulb is for the brake light/turn signal, and the smaller bulb is for the backup light.

Depo LED Taillights for the 2003-2005 Dodge SRT-4

Next, remove the brake light/turn signal bulb from the socket. This is what the socket will look like after removing the bulb.

Depo LED Taillights for the 2003-2005 Dodge SRT-4

This is the wiring from the taillight, and the bulb that we removed earlier from the socket. Notice how they are identical. The taillight wiring plugs into the factory wiring socket like a bulb normally would.

Depo LED Taillights for the 2003-2005 Dodge SRT-4

Now, plug the taillight wiring directly in ! Also, dont forget to screw the backup light into the taillight clockwise!

Depo LED Taillights for the 2003-2005 Dodge SRT-4

Presto! Your done ! Its that simple !

Depo LED Taillights for the 2003-2005 Dodge SRT-4

Link to Depo LED Taillights for 2003-2005 Dodge SRT-4.

Fitting Halo Projector Headlights on a 08-09 Cobalt – YES they work !

We had a customer call yesterday and state that the Halo Projector headlights he bought from us didnt fit his 2008-2009 Chevrolet Cobalt.The customer claimed that the wiring from the projectors wouldnt connect to his factory wiring.

The customer sent us this photo showing the projector light wiring on the left, and the factory wiring that he had on the right. Notice how the two connectors are shaped radically different.

Chevrolet Cobalt headlight wiring

So, just to make sure they fit, we took our project 2009 Chevrolet Cobalt SS Turbo and tested the connection.

Test fitting the Chevrolet Cobalt headlight wiring

Here you can see the factory male plug, plugged into the female projector wiring.

So what happened? Well, the Cobalt factory wiring is somewhat complicated. It is a large harness, that has a quick disconnect, and further down from the quick disconnect is the factory male plug for the headlight bulb. What this customer did, was disconnected his factory wiring harness at the quick disconnect, and assumed that he could connect the headlight wiring to his quick disconnect.

This is not the case. You simply connect the factory plug that connects into the headlight bulb, INTO the wiring of the Halo/Projector. The Halo Projector wiring plugs in just like a headlight bulb!

Its so simple, that most people overlook it !

03-05 SRT4 owners – Have Check Engine Codes P0121, P0122, P0123 ? Have weird idling/Throttle issues?

03-05 SRT4 owners – Have Check Engine Codes P0121, P0122, P0123 ? Have weird idling/Throttle issues?

If your 2004-2005 Neon SRT-4 has a weird idle that jumps up and down, or if youve ever noticed a weird surging issue when your holding the gas pedal steady while cruising, its very possible you need to do the TPS Rewire fix.

This is a common problem with 2003-2005 Neon SRT-4’s because of the way the wiring is run to the TPS sensor. Take a look at this photo we took of a 03-05 Neon SRT-4’s TPS wiring. The wiring runs from the bottom to the TPS sensor, and makes a sharp 90 turn back into the TPS sensor.

2003-2005 Dodge Neon SRT-4 TPS Wiring PO123, PO121, PO122

This puts strain on the wiring, and over time, the plastic outer sheathing looks fine, but the wiring inside breaks down and fails.

You can easily check to see if your wiring is failing, by jiggling the wiring going to the TPS sensor while your car is running. If your idle changes, or you can hear a change in tone of your motor, then more than likely its time to replace the wiring. Even if your car DOESNT have a change in tone or idle, we would still recommend changing the wiring.

Heres a photo of the Mopar TPS rewire kit. Its a very inexpensive and easy to install fix to the TPS sensor wiring issue and it includes much longer, reinforced wiring, and a new plastic connector.  With this kit, you remove the strain on the short, bent factory wiring that fails.
Mopar TPS wiring fix kit

Heres a link for more information and how to purchase the TPS wiring fix kit:

Click here to go to our website for more details on the TPS wiring fix kit.

Caliber SRT-4 owners – difference between Mopar stage 1 and Aem FIC packages.

Caliber SRT-4 owners – difference between Mopar stage 1 and Aem FIC packages.

We’ve gotten a good amount of questions from 08-09 Caliber SRT-4 owners asking us what the difference is between the Mopar stage 1 upgrade package and the AEM FIC.

The difference boils down to what your ultimate goal power wise.

If your happy with 320-330 horsepower at the engine, and a maximum of 15 psi, then the Mopar stage 1 kit is a great kit that improves throttle response and increases boost and power.

If you want more than 320-330 horsepower, and more than 15 psi of boost, then youll have to move to a AEM FIC kit. Why ? Well, it has to do with the PCM and the drive by wire system. The pcm will try to regulate boost level to limit torque steer and maintain smooth drivability. Therefore, if you are giving 100% throttle with the gas pedal, and you go over 15 psi, (or any boost level that the PCM is programmed to not allow the engine to exceed) then the pcm will cut back on the throttle to regulate the boost pressure.

Example: You have a boost controller on your 08 Caliber SRT-4, and want to do 18 psi. As soon as you floor the car, and are giving 100% throttle and exceed say 15 psi, the pcm will cut the throttle back to 60-70% to regulate the boost level to 15 psi.

The way to bypass this from happening, is to limit the voltage from the map sensor going to the pcm. The AEM FIC will do that for you, and then you can increase the boost level in your car to whatever you desire because the pcm thinks that your running at say 14 psi. The major problem with you running say, 20 psi, when the pcm is seeing 14 psi, is that the pcm will only deliver 14 psi worth of fuel, therefore making the car run excessively lean. The other major benefit of the FIC is that it will control fuel, so you can use the FIC to deliver extra fuel to make up for the pcm not putting out enough fuel.

Wiring up the FIC involves quite a bit of work. The FIC has MAP sensor inputs, and output (to modify the map sensor voltage), the FIC has input and outputs for the injector wiring, an more.

After the FIC is wired up, youll need to then use a laptop to program the FIC for the fuel curve as well.

So, as you can see, there is quite a bit of work involved. However, there is also QUITE A bit of power that can be made with the FIC as well!

More information on the AEM FIC here:

More information on the Caliber Mopar Stage 1 kit here:

95-99 Dodge/Plymouth Neon Check engine codes (CEL)

Check engine light on in  your 1995-1999 Dodge/Plymouth/Chrysler Neon ? Read further to find out how to check why the light is on.

1. Cycle the ignition key ON-OFF-ON-OFF-ON within 5 seconds.
2. Count the number of times the “check engine” lamp on the instrument panel flashes on and off. The number of flashes represents the code. There is a slight pause between the flashes representing the first and second digits of the code. Longer pauses separate individual codes. For example, flash-flash-flash [pause] flash-flash represents the code 32.

To cycle the ignition key ON means to turn it only as far as it takes to get the radio to come on. It does not mean to turn the
engine on.

CODE Description of Trouble Code
11 Timing belt skipped 1 tooth or more from initial learned value, Intermittent loss of either camshaft or crankshaft position sensor, No crank reference signal detected during engine cranking
12 Direct battery input to PCM was disconnected within the last 50 key-on cycles
13 No change in MAP from start to run
14 MAP sensor voltage too low
15 No vehicle speed sensor signal
17 Closed loop temp not reached or engine cold too long
21 02s sensor problem (oxygen sensor), upstream or down stream
22 Engine coolant temp sensor out of range
23 Intake air temp sensor out of range
24 Throttle Position sensor out of range
25 Idle air control motor circuits, target idle not reached (+/- 200),vacuum leak found
27 Injector control circuit
31 Evap purge flow monitor failure or evap solenoid circuit
32 EGR system failure
33 A/C clutch relay circuit
34 Speed control Solenoid circuits
35 Rad Fan control relay circuit
37 Torque converter clutch solenoid CKT or park/neutral switch failure
41 Generator field not switching properly
42 Fuel pump relay control ckt, Auto shutdown relay control ckt, No ASD relay output voltage at PCM, Fuel level sending unit volts out of range, Fuel level unit No change over miles
43 Multiple/ single cylinder misfire
44 Battery temp sensor volts out of range
46 Charging system voltage too low
51 Fuel system lean
52 Fuel system rich
53 Internal control failure
54 No Cam signal at PCM
55 End of error messages (If you get this only, no errors were found)
62 PCM failure SRI mile not stored
63 PCM Failure EEPROM write denied
64 Catalytic Converter Efficiency Failure
65 Power steering switch failure

Fluttering noise after installing a blow off valve on a Neon SRT-4, Caliber SRT-4 or Turbo Cobalt? Read further.

For those of you who hear a fluttering noise after installing a blow off valve in your Dodge Neon SRT-4, Caliber SRT-4, Turbo Cobalt, Turbo Neon, etc, read further.

The common perception of a blow off valve noise, is a solid WHOOSHING noise. In most scenarios, that is the case, HOWEVER, there are some important things to consider in the normal operation of a blow off valve.

First, lets give you a full background on a blow off valve. A blow off valve is a vacuum operated device, that seals the pressure piping when the car is in positive boost pressure, and at times of vacuum, opens and releases pressurized air. For those of you who may not know why a blow off valve does this, you have to consider a turbocharger, spinning at tens of thousands of rpm, being driven by the exhaust gases of the motor. When you shift gears, you release the throttle, and the throttle plate closes briefly. When your throttle plate closes briefly, the turbocharger is continuing to spin, and send pressurized air towards the throttle body. If there was no blow off valve to release the pressurized air when the throttle plate closes, then pressurized air would be sent towards the throttle plate, and either damage the throttle plate, OR worse, could damage the turbo by trying to spin the compressor side of the turbo backwards.

So, the blow off valve, is used to protect your turbocharger, and throttle body primarily, and as a side benefit it makes a cool whistling noise.

Now, back to first time turbo owners and how they assume the blow off valve makes a constant whoosh noise. Since the blow off valve is a vacuum operated device, its operation will be dependent on the boost level within the motor. If your motor has 15 psi when the throttle plate is closed, then the blow off valve will release a LOT of air, making a nice solid whoosh noise. If your motor has 2-3 psi when the throttle plate is closed, then the blow off valve wont make much of a noise, and it will actually make a fluttering noise as the blow off valve internal piston moves back and forth, not fully closing or opening.

So im summary, fluttering is very normal and nothing to worry about, AS LONG as the blow off valve functions correctly when your in higher boost levels. NOW if your blow off valve never makes a solid whoosh noise, more than likely you have a damaged vacuum line, or your car has a boost leak, or some other turbo related problem.

How to adjust a wastegate actuator on a 03-05 SRT-4 or 08+ Caliber SRT-4

We get a lot of calls from customers about wastegate actuators, how they work, and asking how to adjust them for different boost levels.

This post will be a explanation of how a wastegate actuator works, and then we will discuss how to adjust the wastegate actuator to your desired boost level.

First off, for those of you who may not be familiar with the inner workings of a turbo, a wastegate can be designed two ways. Most commonly found on factory turbos is the internal wastegate (what we will be discussing here) and the external wastegate. The internal wastegate is a bypass that allows exhaust gases to be routed past the turbo.  The sole purpose of the wastegate is to regulate the amount of exhaust flowing through the turbo, therefore controlling the boost pressure the turbo is putting out.

In this photo, youll see the wastegate flap on the left, and the fins on the exhaust side of the turbo. Normally the wastegate flap will be closed, therefore pushing the exhaust gases out through the exhaust side of the turbo, therefore building up boost.

The wastegate actuator, is a pressure device, that once it reaches a certain pressure (8, 10, 15 psi) will activate, and open the wastegate flap. When the wastegate flap opens, exhaust is routed around the turbo, therefore creating a consistent boost pressure output from the turbo.

So, now that we’ve explained all of that, lets get into more details of the wastegate actuator. Since the wastegate actuator controls the boost level, making adjustments to the wastegate will directly change the level of boost! If you want MORE boost pressure, then youll need to make it so that the wastegate actuator opens up later than normal, or shortening the wastegate rod so that it pulls on the wastegate flap harder.

If you want less boost, lengthen the rod so that it will open the wastegate sooner.

Heres a photo of a AGP Wastegate actuator for the 03-05 SRT-4. In this photo you can see that the end of the wastegate is adjustable, and you can make it longer or shorter to adjust the boost levels.

03-05 Dodge SRT-4 Wastegate Actuator

How To: Sealing headlights/taillights to prevent condensation/moisture buildup.

Sometimes, regardless of the manufacturer of headlights/taillights you buy, condensation or moisture can leak into your new lights.

With installation usually requiring 45 mins – 2 hours for headlights or taillights, its pretty frustrating to have a leak develop in  your new lights. This procedure will take about an extra 20-30 minutes to do, but will guarantee you wont have to remove the lights due to fogging/condensation buildup.

So, to properly demonstrate the procedure of how to seal the taillights/headlights, we decided to demonstrate on a set of 08+ Dodge Caliber headlights.

First off, heres the headlight we’ll be working with.

Dodge Caliber SRT-4 Depo Headlight

This headlight has a clear plastic outer shell on the front, and a black plastic basket surround. The two are sealed together with a heavy duty industrial glue/sealer. However, sometimes with extreme heat, the glue/sealer can come loose, and holes can form that will allow water to enter.

This is the sealer we are using. This is GE Silicone 2, a premium grade silicone sealant. This is a great all purpose silicone that can be used indoors/outdoors and it will never crack, and is permanently flexible so it will seal, but yet flex with heat/cold expansion/contraction. You can buy this in small tubes for about $4 at your local hardware store.

Heres what the initial bead of silicone looks like that we used to go around the headlight. We made sure to apply a consistent bead of silicone across the entire headlight.

The last step of sealing a headlight or taillight, is to make sure that the silicone has a good seal against the two surfaces its sealing. So, with our pointer finger, we ran our finger along the bead, pushing the silicone into the crack, and sealing the silicone to both the inner and outer casings. Notice how there are no globs, and how the silicone nicely fills the void.

Most silicone sealers will take about 1 hour to cure, and about 12-14 hours to fully cure, so be sure to allocate enough time for the silicone to fully dry and seal.

95-05 Neon Transmission Cross Reference Guide (for 3.94 / 3.55 trans identification)

This was already posted as a sticky on, but because its such a valuable reference to first gen Neon owners, I think its important to have several copies of it posted in different locations. This way in case someones computer fails, we wont lose this valuable cross reference guide.

This guide will be very useful for you guys out there trying to identify which gear sets and final drive you have in your Neon manual transmission.

In order to use this chart, you will need to read the identification tag on your transmission. Its attached to the transmission on the drivers side, behind the wheel, facing outwards.

Heres a small chart that you probably cant even read, just to show what it looks like.

95-99 Neon Manual Transmission Cross Reference guide 3.94 / 3.55

To see the actual chart, click on this link.

Installing a clutch into your Neon/SRT-4/Cobalt? For proper clutch life, break in the clutch smoothly for 500 miles..

We get a call everyonce in a while from a customer thats installed a clutch in their 95-05 Neon, Neon SRT-4, or Cobalt, about their clutch slipping that they just installed.

Even though paperwork is sent along with the clutch that states a 500 mile break in period is ABSOLUTELY neccesary, along with us telling customers on the phone of the 500 mile break in period at time of purchase, we get this type of call way more often than Id like.

So, to stress it here again, its very important to break in your new clutch properly for 500 miles.

Im not talking about hopping in your Neon/Neon SRT-4/Cobalt and driving to see your grandmother a few states over, Im talking about, good, daily driving, lots of clutch engagement/disengagement driving. You can slip the clutch, and shift it through all the gears as much as you want, but do not apply more than 35-40% throttle, and do NOT FLOOR the car.

If you dont, the friction material inside your clutch may not seat properly and you can have a slipping clutch. After youve spent good money on a clutch, and paid for someone to install it, or installing it yourself, nothing can be more frustrating.  I know it can be REALLY hard to not drive your car aggresively or floor your car on the highway on ramp, or when the Honda boy next to you wants to race, but its worth it in the long run to break in the clutch properly.

Melted SRT-4 Spark Plug due to lean mixture/detonation

Ok SRT-4 fans, here is a Neon SRT-4 spark plug that suffered from so much heat and detonation that it failed. This was from a local Neon SRT-4 owners car that looks to have been running too lean . (Modern Performance did not work on this customers car, nor did we dyno test, or tune this car)

This particular Neon SRT-4 had such high cylinder temperatures in the combustion chamber, and detonation, that not only did the spark plug melt, and the cermic insulation break off, but the piston partially melted. Pics of the melted piston later!

Melted 03-05 Neon SRT-4 spark plug

Heres a closeup of the spark plug. Notice how the electrode partially melted, causing a glob of electrode. Compare the melted spark plug on the left to a brand new spark plug on the right.
Melted 03-05 Neon SRT-4 Spark Plug

This is why its absolutely CRITICAL to check your Exhaust GAS TEMPERATURES, and to check your Air/Fuel mixture ratios when tuning.

Comparison between 03-05 Dodge SRT-4 stock throttle body and MPx 62mm with spacer.

I came across a factory stock throttle body from a 03-05 Dodge SRT-4 today. So, for kicks, I thought it would be neat to show a comparison between the factory throttle body and the MPx 62mm throttle body.

For those of you who are not familiar with the stock 03-05 SRT-4 throttle body, it consists of two pieces. a throttle body that looks like most throttle bodies, and in between the throttle body and the intake manifold is what we call a spacer. The spacer is a simple aluminum plate that the throttle body mounts to.

Heres a photo comparing the factory throttle body on the left, and the MPx 62mm throttle body on the right.
Neon SRT4 Throttle Body versus MPx 62mm Throttle Body

Closeup of the stock throttle body.
03-05 Neon SRT4 factory throttle body

Stock Dodge Neon SRT4 throttle body spacer versus MPx 62mm Throttle Body spacer

Neon SRT4 Throttle Body versus MPx 62mm Throttle Body

Look at the difference in inlet size. The factory throttle body inlet necks down to 52mm at its smallest size. The MPx throttle body inlet is 62mm. This difference in size allows a far improved throttle response, as well as more incoming air into the motor. The larger amount of air allows for an increase in power because the motor compensates for the additional air by adding more fuel. So, one part not only increases power by nearly 9-10 horsepower or more, but it also improves the acceleration/throttle response greatly!

More photos and details here (Click here)