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-   -   New injectors and tach don't work, old injectors at 164%duty cycle? (https://www.miataturbo.net/megasquirt-18/new-injectors-tach-dont-work-old-injectors-164%25duty-cycle-12818/)

db84drteg 09-23-2007 05:49 PM

New injectors and tach don't work, old injectors at 164%duty cycle?
 
So, here's my setup:

1.6 with the standard greddy kit
front mount intercooler
mspnp
AFM delete
supra 305's
FM dual feed rail
stock fuel system

Here's the problem I'm having with this setup. I took a datalog today and at ~5.5 psi, I'm at 89.9 dutycycle1 and 164.3 dutycycle2. What is dutycycle2?

Anyways, on to the more pressing matters. I recently bought a set of 550 low-impedance injectors with some 10ohm/10watt resistors that I soldered inline. Anyways, I tried jacking around with the opening pulse width that I adjusted via megasquirt's instructions. I couldn't get it to start at all.

Long story short, I putz'd around for about an hour and a half and didn't get anywhere except pissing off the neighbors. I put the 305's back in and loaded up the old map and voila, it started right up ... but the tach didn't work. Any ideas on that?

Thanks for the help!

Braineack 09-23-2007 06:02 PM

dont look at duty cycle 2.

did you ever flash the firmware without inplugging the ignitor? sounds like you toasted the tach signal circuit in it.

Mach929 09-23-2007 06:02 PM

probably fried your ignitor like i did. not sure why it didn't start, mine started right up with my hi impedence 550cc with only a req_fuel change to 4.9

cjernigan 09-23-2007 06:06 PM

Why is everyone frying ignitors? I have a switch i installed between MS and my coils. When I want to reflash the entire map i just hit the switch, flash, turn the switch back on and go for it. The '99 coils are a real PITA to disconnect because they're right against the firewall and the connectors might as well be glued on they're so tight. Atleast on mine.

db84drteg 09-23-2007 06:13 PM

Nothing's wrong with the ignitors. The car is currently running with the 305's. I'm just curious to see if anybody had an idea why the 550's wouldn't even start. Here's another question. Anybody want to send me a 550cc msq file so I can see if my cranking pw's were even close?

Braineack 09-23-2007 07:53 PM

did you change the req_fuel?

if you tach is gone then your ignitor is to blame. it will still fire the car, but the tach output on it is dead. no way around that fact.

Mach929 09-23-2007 07:54 PM

i haven't even changed mine from the mspnp base map yet

db84drteg 09-24-2007 12:53 AM

Well, if the tach output is toast, would the MS still be able to get a signal? The data log I took this morning had the rpm output just fine.

Ben 09-24-2007 03:28 AM

MS gets tach signal from CAS
Tach on dash gets tach signal from ignitor

sounds like your putzing fried the tach output on the ignitor, and it's likely spark output failure will follow

can't tell you why the car didn't start. but if you didn't get the req fuel ballparked, then the cranking pw's aren't relevant.

db84drteg 09-24-2007 03:38 AM

Sounds good. I'll go get an igniter and see if it fixes the tach issue.

As far as the req fuel and cranking pw's, I set the req fuel to 4.9 (1600cc, 4x550cc injectors) and the cranking pw's to what the MSPnP guide said (original pw - injector opening time * new/old flow + opening time). Perhaps another go at the cranking pw's again will yield new results. In fact, I'll go send out the injectors to make sure they're working fine, then put them back in.

Matt Cramer 09-24-2007 09:31 AM

While the rules for cranking PW will get you in the ballpark, they can sometimes be off by a few msec. You may need to fine tune them a little bit to get the car to start.


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