Restrictor for MAP sensor

[drews240]

OK, if it is sheilded, then that is not the problem.

 

You are running EDIS? I would mount the trigger wheel to the solid part of the crank pully (not rubber isolated). Just in case at high rpms the damped pulley distorts, it could effect the gap between the sensor and the trigger wheel. I dought this is the problem as BRAAP has his mounted to the damped pulley and hasn't had problems. You have no more than 1mm between the VR sensor and the trigger wheel, right?

 

Yes, I can check your settings, send me a PM.

 

I sheilded the TPS myself just incase. The trigger sensor is more like 1.5mm from the wheel. I noticed tonight when i was reving the car no load the Throttle was never going more than 10% even at 5000RPM but when the motor is not running it goes from 2% to 100% on the guage. You will notice in the log that I send you the TPS is doing really crazy ♥♥♥♥.

 

Drew

[z-ya]

200sxBoY: I just took a TB off a 240SX yesterday, and the signal wire from the TPS WAS sheilded from the factory by Nissan. This is not the first sheilded TPS harness I've seen BTW. I've been an EE for 20+ years, and I know if you run a sensitive analog signal near 40,000V high tension leads, you will have interference problems. I've also had this same problem with installations of Megasquirts and other engine management systems where sheilding the TPS signal fixed the problem.

 

I don't want to make this into an argument, I'm just try to help drews240 get his problem fixed. Are you involved with this project?

[Guest 200sxBoY]

200sxBoY: I just took a TB off a 240SX yesterday, and the signal wire from the TPS WAS sheilded from the factory by Nissan. This is not the first sheilded TPS harness I've seen BTW. I've been an EE for 20+ years, and I know if you run a sensitive analog signal near 40,000V high tension leads, you will have interference problems. I've also had this same problem with installations of Megasquirts and other engine management systems where sheilding the TPS signal fixed the problem.

 

I don't want to make this into an argument, I'm just try to help drews240 get his problem fixed. Are you involved with this project?

 

I made the harness

This is the first time i get into this problem with MS. But i will believe that if you had similar problems which were fixed by shielding the tps, this could perhaps help. However, if the tps was having induction, it would apear on the datalogs .

I find this funny because i built other setups using MS and i had hightension wires run near the tps/coolant/iat and never had any problem.

[drews240]

I made the harness

This is the first time i get into this problem with MS. But i will believe that if you had similar problems which were fixed by shielding the tps, this could perhaps help. However, if the tps was having induction, it would apear on the datalogs .

I find this funny because i built other setups using MS and i had hightension wires run near the tps/coolant/iat and never had any problem.

 

It is a MS harness (connect the dots), I have now completly rewired the crank and TPS with sheilded wire down to wrapping them up to the connector, ?? I noticed that the TPS is grounded to the block Not sheilded (only the +5V and signal are sheilded) Is that OK?, Also the wire has been placed away from the plug wires. I revisited the crank pully situation and the ring piece is actually press fit into the center pully so it is actually connected directly to the crank itself and the balancing outer pully is still on its own so this should not be an issue. Although I will make it closer to the wheel.

 

thanks

 

Drew

[eec564]

The TPS should be grounded to the megasquirt signal ground, not the block. It should be isolated completely from the high-current/high-voltage systems in the ignition system. The alternator, fuel pump, and possibally radio/amp also contribute to noise in the system. Also, the VR sensor should have shieled wires. Those are the critical ones giving megasquirt crank position and rpm.

[z-ya]

Th VR sensor needs to be shielded, and the shield should only tie to the shield wire on the EDIS module. It should not be connected to the engine block or you could have ground loop problems. Same goes for the TPS. Both the +5V and TPS signal wires should be shielded with the shield tied to ground only at the Megasquirt. Do not tie it to ground at the engine block. Sometimes I will twist the 5V, TPS signal, and TPS GND together with an electric drill when I am making the harness. Sometimes this is good enough. Sometimes there is a lot of noise running through the harness or a round the engine compartment that requires a real shield.

[drews240]

Ok I understand. So I will redo the TPS WIRE with the three wires sheilded and isolated from engine ground and tied to the Mega ground.

 

the actual braid shield does not get tied to anything does it? if so what wire on the edis?

 

I have sent my settings to z-ya, once he looks them over and confirms everything is ok I will run her Monday night and see if all is well.

 

thanks

guys

 

Drew

[z-ya]

Pin 7 at the EDIS module should connect to shielding.

 

See below:

 

[drews240]

the 25uFcapacitor or condensor shown in the drawing goes from 12V + to body groung or Mega EDis ground?

 

Thanks

 

Drew

[drews240]

This was sent to me by 200sxBoy, the alternator thing is wierd.Originally Posted by MSEFI.COM

I had a similar issue. What do your spark plugs look like when you pull them? My car was being extremely picky with spark plugs after going to the EDIS setup. I had to source plugs 2 steps colder than stock to cure it. I went through a half dozen sets of plugs, each lasting 1 to 2 weeks, before I found the right ones. Now theyve been in there for a full year.

 

The problem was the plugs were arcing out against the block, not firing inside the cylinders at all. Try running your motor in pitch black and rev it up, check around the plugs to make sure they arent arcing out.

 

I've also experienced similar dropouts when my VR sensor wasnt quite close enough to the wheel. and also when the wiring plug for it started to fail. and again when the coilpack plug started to fail. The cure for those is to replace, clean, or tighten all the connectors and harness plugs, and if your motor vibrates alot, hotglue the suckers in place.

 

 

 

Upon looking at your log file, I think your problem is related to alternator disturbance. Have you tried to disconnect your alternator, and then take a test run?

I had similar disturbance, but got rid of it by installing a capasitor on the alternator, and a regular ice filter on the MS +12v

My log file is not anything like yours. All my parameters are nice and clean, exept that the rpm line drops much more than the actual rpm.

 

 

Problem solved in my case.

The drop in my case came from power drop to EDIS. Upon studying the log's I found that the drops came along with small drops of +12V. Connected EDIS directly to battery 12V, and everything ran smoothly. This resulted in a blown piston at 5500revs in fourth gear thoug. My engine didn't cope with 250hp, @ 1,2 Bar boost

[eec564]

That alternator thing isn't all that uncomon. Try running with it unhooked and get back to us. You may need to install a filter between the alternator and battery. Generally a good capacitor will do it. But test it out before throwing parts at it.

[z-ya]

Yes, the capacitor should connect from teh +12v at the coil pack, to a short wire to chassis ground. This acts as a low frequency filter. It's really there to surpress radio noise, but it can't hurt.

 

When you disconnect to alternator (remove belt) to test to see if it is the source of interference, make sure you put a battery charger on the battery so you have at least 13V in the system.

 

For plugs, I would use an NGK "6" heat range, gapped to 0.035". This should work find with the EDIS coil pack. For the track, you may want to go to a "7" heat range.

[drews240]

Yes, the capacitor should connect from teh +12v at the coil pack, to a short wire to chassis ground. This acts as a low frequency filter. It's really there to surpress radio noise, but it can't hurt.

 

When you disconnect to alternator (remove belt) to test to see if it is the source of interference, make sure you put a battery charger on the battery so you have at least 13V in the system.

 

For plugs, I would use an NGK "6" heat range, gapped to 0.035". This should work find with the EDIS coil pack. For the track, you may want to go to a "7" heat range.

 

Did you get a chance to look at the settings? are they ok? much appreciated.

 

Thanks

 

drew

[drews240]

I have some more questions,

 

temp sensor? the nissan VQ sensor is telling the Mega it is at 300 deg in the data sometimes although the car is never over 200 deg. does it make it glitch?

 

is there a way to calibrate the sensor?

 

I need exact specs for the ice filter on the battery line please?

 

Would the EDIS have a compatabilty issue with the plugs?

 

Thanks'

 

Drew

[z-ya]

You need to run EasyTherm to calibrate any OEM sensor that is not GM. You can find out how on the MSEFI.com website.

 

A 10uF 20V capacitor should work fine.

 

The EDIS module will fire any plug with the proper gap and heat range for the application.

[drews240]

You need to run EasyTherm to calibrate any OEM sensor that is not GM. You can find out how on the MSEFI.com website.

 

A 10uF 20V capacitor should work fine.

 

The EDIS module will fire any plug with the proper gap and heat range for the application.

 

Thanks, will do.

 

have you had time to look at the MS settings?

[z-ya]

I don't think I got your email. resend them to: psanders240@adelphia.net

[Tony D]

"The problem was the plugs were arcing out against the block, not firing inside the cylinders at all. Try running your motor in pitch black and rev it up, check around the plugs to make sure they arent arcing out."

 

This is common on Stationary Lean-Burn Turbocharged Engines.

This is a GREAT reason to install your plug boots with Dielectric Compound. Not only does it make the boots easy to get off, but it totally eliminates any air available to convert to O3 and give an easy arc-over path for errant high tension voltage.

[drews240]

Well boys at this point aside from the Capacitor I have put in new wires, rewired the TPS and the sensors with the shield done right, I have no arching in the cylinders with the wires, the Crank sensor could not be any closer, I have tried two different EDIS modules 2 different coil packs, we moved the MAP to the back of the throttle body so it os not near cylinder 1. Unplugged the alternator belt and all.

 

My battery "is" in back of the car and is grounded to the body in the rear (clean).

 

I know it is the Mega set up because I had the car running OK on the stock Maxima ECU, its just it cut me off at 6500 and was running too lean so it overheated. Same TPS, same temp sensor, same grounding.

 

 

 

 

HELP!!!!!

 

thanks again Drew

[z-ya]

What other grounds do you have? The MS needs at least 2 16 gauge ground wires to the chassis. The EDIS module should have a 14 gauge wire to ground. Do you have a 4 gauge ground wire from the engine to the chassis? Attach the MS ground wires where the engine block is grounded. I have the battery in the back of my race car, so that isn't the problem.