MSnSE MSI Getting Resets at higher speeds, car won't go past ~3400 rpm

[FlatBlack]

I'm running a MSI V3.57 PCB using a 83 ZXT Dizzy for spark on a turbo F54/P79 L28E, Intercooled, L28ET 260cc injectors.

 

I didn't bring my laptop to work today so I can't upload the MSQs or datalogs yet.

 

Problem #1:

 

On surface roads, the car will run fine, the Fuel maps still need a bit of work but it will rev fine up to 4500. [i didn't want to go above that because my wideband is acting up, see Problem #2].

 

My problem is on the interstate, of if I am going over 60 MPH, so in 4th or 5th, When I try to give it gas it will start to sputter and when my wideband was still reading it would go lean. Occasionally if I give it enough throttle, it would sputter so hard MS would reset. On the datalog you can see the MAP go from ~ 3400 RPM and a little over 100 KPA immediately drop down to ~30 KPA when it would reset.

 

I'm fairly sure it's not my fuel maps, it'll run rich at the same RPM and MAP at lower speeds, it's only when I'm at the higher speeds.

 

My injectors only had a 60% duty cycle when this was happening, and I've got 36 psi fuel pressure at the fuel rail gauge at idle.

 

I tried jiggling the wire harness around when it was idling to see if anything was loose but nothing happened.

 

I'm confused. I'll upload the Datalog and MSQ when I get home tonight.

 

 

Problem #2:

 

My LC-1 Wideband was working fine until I got the resets on the interstate last night. Very soon after that happened my wideband settled on 16 to 17 AFR.

 

I pulled over immediately and checked the wiring, nothing was loose or disconnected.

 

I pulled the fuel up so far at idle the car almost died and the AFRs did not change a bit in MegaTune.

 

I have my 12V+ going to switched 12 Volts for Megasquirt, I have the Brown Analogue Out 2 connected to the O2 spot on the MS Relay Board.

I have all of the other wires going to the same chassis ground that MS uses. I have the Brown Analogue Out 2 connected to the O2 spot on the MS Relay Board.

 

I'll pull it out of the DP and re-calibrate it to see if that is the issue, but I calibrated it two days ago.

 

I guess my O2 sensor could be going bad [i bought the LC-1 and sensor used], any other ideas?

 

I checked my Config settings and it is still on the LC-1 Lambda Settings. I was worried the resets made it go to Narrowband or something.

 

Thanks for the help, gentlemen.

[softopz]

Do you have auto tune on? If you do with enough authority and if the wideband gets wacky it could be giving you this symptom. Are your ignition inputs shielded?

[trwebb26]

what plug wires do you have? (no, I'm not crazy).

 

http://forums.hybridz.org/showthread.php?t=120033 may help...

[letitsnow]

Post up the datalog, or look specifically at the batt v graph in MLV, I'd bet it's really rough, kind like this one. This one specifically was cured by doing away with PWM and installing dropping resistors.

 

[FlatBlack]

what plug wires do you have? (no, I'm not crazy).

 

http://forums.hybridz.org/showthread.php?t=120033 may help...

 

I'm using the N/A Spark plug wires...

 

I'll be getting some Turbo ones this week now. Thanks for the suggestion.

 

I'll have to read that thread more thoroughly later in the week when I'm not swamped with school work but I think my timing is right with the Dizzy/MS

 

Post up the datalog, or look specifically at the batt v graph in MLV, I'd bet it's really rough, kind like this one. This one specifically was cured by doing away with PWM and installing dropping resistors.[/Quote]

 

Hmm that is very probable. What did you do exactly with the dropping resistors?

 

Here's a screen shot at the time of the resets.

 

[letitsnow]

You're definitely getting some resets because of voltage spikes, I can't say if they're all because of them though.

 

With dropping resistors, you basically just put some high wattage resistors inline with the injectors and turn PWM off. What is the resistance of your injectors? You probably need 1 for each bank, around 25w and 3.5ohms, it depends on the resistance of your injectors.

 

Where are you getting power for the MS/relay board? If it's on the alternator, I'd move it to the battery.

[FlatBlack]

You're definitely getting some resets because of voltage spikes, I can't say if they're all because of them though.

 

With dropping resistors, you basically just put some high wattage resistors inline with the injectors and turn PWM off. What is the resistance of your injectors? You probably need 1 for each bank, around 25w and 3.5ohms, it depends on the resistance of your injectors.

 

Where are you getting power for the MS/relay board? If it's on the alternator, I'd move it to the battery.

 

Alright. Which dropping resistors did you use?

 

I've got switched 12V and straight 12V running directly to the battery.

 

I've got the turbo injectors for now. I'll be upgrading to 35# Ford SVO injectors soon.

[letitsnow]

The graph I posted was a TBI 305 in a firebird, it only has 2 very low resistance injectors which changes the required resistance.

 

If you have 3 4 ohm injectors per bank use a 25w 3.5-4ohm resistor per bank.

 

I like this one if you mount it to a heat sink(like the case of the MS or something). It's pretty big, I doubt you could fit it in the case, so you'd have to put it on the outside or mount it to something else.

 

 

Or this one if you don't want to mount it to a heatsink, but it's about twice as long.

 

Either will work for turbo injectors, I'm not sure about the ford injectors, if they have a resistance lower than ~2 ohms each, use the latter one and mount it to a heatsink.

 

Even if it doesn't completely cure it, it's about the cheapest thing to try at under $10. Just be warned, mouser will send you multiple catalogs that are at least 4" thick.

[FlatBlack]

The graph I posted was a TBI 305 in a firebird, it only has 2 very low resistance injectors which changes the required resistance.

 

If you have 3 4 ohm injectors per bank use a 25w 3.5-4ohm resistor per bank.

 

I like this one if you mount it to a heat sink(like the case of the MS or something). It's pretty big, I doubt you could fit it in the case, so you'd have to put it on the outside or mount it to something else.

 

 

Or this one if you don't want to mount it to a heatsink, but it's about twice as long.

 

Either will work for turbo injectors, I'm not sure about the ford injectors, if they have a resistance lower than ~2 ohms each, use the latter one and mount it to a heatsink.

 

Even if it doesn't completely cure it, it's about the cheapest thing to try at under $10. Just be warned, mouser will send you multiple catalogs that are at least 4" thick.

 

Cool! Thanks for the info. I guess I should track down the source of the nasty voltage first but it can't hurt to order those, they are cheap.

[trwebb26]

Please do yourself a favor and buy magnecor wires... I had SO many problems with resets until BRAAP got me straightened out by getting some new wires. Magnecor wires are a 100% must for a Z megasquirt install IMO.

[letitsnow]

Some of that nasty voltage is because of the PWM, dropping resistors would cure some of it up. Notice how it gets worse when you get on the throttle, it's because the injectors are at a higher DC and the pwm circuit has to deal with more current/emf.

[FlatBlack]

Please do yourself a favor and buy magnecor wires... I had SO many problems with resets until BRAAP got me straightened out by getting some new wires. Magnecor wires are a 100% must for a Z megasquirt install IMO.

 

I'll get in touch with Paul tomorrow about some for my S30, my N/A wires are crappy and old and I'm sure are causing some problems.

 

Some of that nasty voltage is because of the PWM, dropping resistors would cure some of it up. Notice how it gets worse when you get on the throttle, it's because the injectors are at a higher DC and the pwm circuit has to deal with more current/emf.

 

Where are yours mounted? I'll order two of the 25s tomorrow. I've got a busy week ahead...

[letitsnow]

I don't have any in my s30(yet), my uncle mounted them to something under the dash in his firebird(it was his car that had the issue, not mine), really any cool piece of metal that has a flat spot big enough to mount them will work, bare metal with some heatsink compound is preferred, but painted would be alright. The MS case is pretty ideal, but I think they'd make it look slightly too 'mad scientist' for me, especially if it's visible, like mine is.

 

The only time these have a chance to heat up is under extended high duty cycles, like a track day or top speed run.

[FlatBlack]

Alright, I just ordered the 50W 4.0 OHM dropping resistors. I'm seeing if BRAAP can get me some magnecor wires and see where that gets me.

 

Anyone care to look at my wideband issue in the first post? Anyone think the sensor crapped out?

 

I had a steady 20.0 AFR on the way to school this morning and I know I'm running really really rich.

[trwebb26]

Does your wideband reset every time your megasquirt does? Did you do the free air calibration? Where is the sensor in relationship to your turbo, wastegate, downpipe, tailpipe, etc? Is the sensor pointed up like it is supposed to be? Did you properly set up the guage using the Innovative software to be a 0-5V signal (mine came as something different 'from the factory')- and then verify that it is set up properly in the megasquirt setup file?

[FlatBlack]

Does your wideband reset every time your megasquirt does? Did you do the free air calibration? Where is the sensor in relationship to your turbo, wastegate, downpipe, tailpipe, etc? Is the sensor pointed up like it is supposed to be? Did you properly set up the guage using the Innovative software to be a 0-5V signal (mine came as something different 'from the factory')- and then verify that it is set up properly in the megasquirt setup file?

 

The wideband was working fine for a couple of days. On a night run, shortly after a few resets, the wideband got locked up and started giving me the "stuck-lean" readings.

 

The sensor is located about 1 and a half to 2 feet after the turbo, as far to the edge of the MSA 2.5" DP I could get it.

 

It is "pointing down" I guess, on the top of the DP tube. I'm not really sure what you are talking about. If you pulled the wires straight up out of the sensor to make a straight line, the sensor metal end is pointing directly to the ground.

 

I haven't had the time to play with Megalog Viewer, or re-calibrate it, but I recalibrated it in open air about 2 days before it started

[bradyzq]

Alright, I just ordered the 50W 4.0 OHM dropping resistors. I'm seeing if BRAAP can get me some magnecor wires and see where that gets me.

 

Anyone care to look at my wideband issue in the first post? Anyone think the sensor crapped out?

 

I had a steady 20.0 AFR on the way to school this morning and I know I'm running really really rich.

 

When a wideband is exposed to reaaaallly rich exhaust, it can show a false lean reading sometimes.

[FlatBlack]

When a wideband is exposed to reaaaallly rich exhaust, it can show a false lean reading sometimes.

 

My friend Dan was telling me he was tuning his buddy's GTP and the sensor started showing a 15:1 AFR, switched sensors and it was actually 8:1

 

If that is the case, is my sensor done for? This is the first wideband I've ever owned and I don't know much about them.

 

Hopefully going to get time to work on the car/wideband tomorrow, It was sunny and warm today so I drove the S30. It's running really well, cranks right up with MS, but I can tell it's absurdly rich up top.

[Flexicoker]

sorry, I only skimmed through most of this post, but I was having similar problems. Magnecore wires didn't cure it, redoing all the grounds didn't help...

 

Problem 1

 

I turned PWM off and drove around for a bit and it seemed like it helped with the voltage spikes, so I installed dropping resistors... problem completely solved. Unfortunately i don't remember what resistors I used at the moment, but that is my first recommendation before you spend $100 on plug wires. You can turn off PWM and drive around for a bit, as long as you keep the duty cycle low, and should not have a problem with overheating the injectors.

 

Problem 2

 

My LC-1 was throwing a bunch of different error codes, most of them about the sensor overheating. A bunch of people on the LC-1 forum were having this problem as well. I reflashed the firmware to the older version, and it fixed the problem (mine shipped with the new firmware. Supposedly if the sensor gets to hot, you start getting erroneous readings. The new firmware has a tighter temperature range and throws a code if it exceeds this. The older firmware is more tolerant to overheating, and thus will give slightly erroneous readings if that happens, but it will no longer stop working and throw a code if it happens briefly.

[FlatBlack]

sorry, I only skimmed through most of this post, but I was having similar problems. Magnecore wires didn't cure it, redoing all the grounds didn't help...

 

Problem 1

 

I turned PWM off and drove around for a bit and it seemed like it helped with the voltage spikes, so I installed dropping resistors... problem completely solved. Unfortunately i don't remember what resistors I used at the moment, but that is my first recommendation before you spend $100 on plug wires. You can turn off PWM and drive around for a bit, as long as you keep the duty cycle low, and should not have a problem with overheating the injectors.

 

Problem 2

 

My LC-1 was throwing a bunch of different error codes, most of them about the sensor overheating. A bunch of people on the LC-1 forum were having this problem as well. I reflashed the firmware to the older version, and it fixed the problem (mine shipped with the new firmware. Supposedly if the sensor gets to hot, you start getting erroneous readings. The new firmware has a tighter temperature range and throws a code if it exceeds this. The older firmware is more tolerant to overheating, and thus will give slightly erroneous readings if that happens, but it will no longer stop working and throw a code if it happens briefly.

 

 

Sweet, thanks so much - I got the dropping resistors Let it snow recommended, I'm going to try out the PWM off thing tonight. The car runs fine otherwise.