it DIES......
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
it DIES......
Well, so it seems there is WAY too much fuel into the engine soon as t's warmed up....backfires through the exhaust...., and don't seem to be affected much by any program changes.....
anyone local here in Jax Florida that knows anything about Megasquirt???
anyone local here in Jax Florida that knows anything about Megasquirt???
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
NO, more gray than anything, strange I know,....but these FI systems seem to be finicky on that point....and the 02 sensor says WAY rich as in off the map, and after running for a minit, or so, the engine insists on dieing.....sometimes it will restart, if warm enough it will NOT....
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I don't pretend to know ANYTHING about the megasquirt, but have you tried to lean it out? Does the exhaust stink? Burn your eyes? Maybe just lean the beejeebers out of it and see what happens.
Burning Brakes
Joined: Nov 2003
Posts: 990
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From: North Texas
I don't know anything about the Megasquirt but be sure you are using the correct injector sizing for the fuel pressure you are running. That can thro the system way off because it "thinks" the injectors are smaller than they actually are.
Burning Brakes
Joined: Jul 2006
Posts: 1,108
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From: Sebastian Florida
My brother just bought an 87 firebird with a carb instead on FI. It's doing just what you decribed. Bad fumes that burn the eyes, and backfires with black smoke coming out of the exhaust (only when it backfires). Also runs hot. Do you think it's just running rich? It sat for a couple of years and the PO ran it about once a month. We drained what gas we could and added fresh, just to get it home. He just bought it two days ago.
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
With a carb, I bet the float has sunk. Become saturated with fuel and is too heavy for the needle and seat to overcome. especially if it sat for a while. Rebuild the carb, use Lars' recommendations and that thing will run like a turpentined cat.
Drifting
Joined: May 2005
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From: Somers CT
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Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
My brother just bought an 87 firebird with a carb instead on FI. It's doing just what you decribed. Bad fumes that burn the eyes, and backfires with black smoke coming out of the exhaust (only when it backfires). Also runs hot. Do you think it's just running rich? It sat for a couple of years and the PO ran it about once a month. We drained what gas we could and added fresh, just to get it home. He just bought it two days ago.
Melting Slicks
Joined: Dec 2005
Posts: 2,441
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NO, more gray than anything, strange I know,....but these FI systems seem to be finicky on that point....and the 02 sensor says WAY rich as in off the map, and after running for a minit, or so, the engine insists on dieing.....sometimes it will restart, if warm enough it will NOT....
Last edited by shafrs3; Feb 5, 2007 at 09:05 PM.
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
OK, I"m looking at the 02 from the MSQ programme on the PC, and that's what it sez.....but the nature of what happens is lke an electronic failure....I wonder about wether the computer is heating up??
think I will hand a DVM off the 5 volt line and see if it quits....
I didn't think much of it, but they make a stimulator board on loan to me from bb69, Ken, up in Michigan....and it's got a hot running little 1/2 watt resistor on it....I wonder...don't seem to affect anything in the test modes though...everyone seems happy...
it's not a fuel problem, the Dizzy is the same unit as stock, and any inputs/outputs are well buffered by the design....I wonder about maybe two diodes there also, maybe the opto isolator....I gotta hang a scope on it....
most chips have an internal temp shutdown these daze, meaning if it's not happy and gets hot, it's internal wiring make it shut down....
the way it quits, so cleanly, just up and dies....
think I will hand a DVM off the 5 volt line and see if it quits....
I didn't think much of it, but they make a stimulator board on loan to me from bb69, Ken, up in Michigan....and it's got a hot running little 1/2 watt resistor on it....I wonder...don't seem to affect anything in the test modes though...everyone seems happy...
it's not a fuel problem, the Dizzy is the same unit as stock, and any inputs/outputs are well buffered by the design....I wonder about maybe two diodes there also, maybe the opto isolator....I gotta hang a scope on it....
most chips have an internal temp shutdown these daze, meaning if it's not happy and gets hot, it's internal wiring make it shut down....
the way it quits, so cleanly, just up and dies....
Melting Slicks
Joined: Dec 2005
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Ok now we know it's not running rich, that's good because I had an experience with one of the older Holley ECU products (4DI) that ran so rich on first time start-up it ruined a set of piston rings in a very short time, your symptoms are not pointing at that.
Sounds like you've got access to some test equip., when it comes to component level electronics I'm out of my element. I'll take a WAG (wild arsed guess) about that test board, if it's simulating an operating engine I wouldn't think it could operate both simultaneously and remove it to see what happens.
Sounds like you've got access to some test equip., when it comes to component level electronics I'm out of my element. I'll take a WAG (wild arsed guess) about that test board, if it's simulating an operating engine I wouldn't think it could operate both simultaneously and remove it to see what happens.
Drifting
Joined: May 2001
Posts: 1,651
Likes: 13
From: Holly MI
Gene,
If your computer is getting hot, you have something seriously wrong. Do you know if you have high or low impedance injectors? Also, have you gone through all the basic setting in Megatune? How many injections per cycle are you using? You should probably post your Megatune file on the Megasquirt forum. I can't open it right now because I only have Megatune installed on my home laptop.
When you say it dies, how long after it starts does it die?
Ken
If your computer is getting hot, you have something seriously wrong. Do you know if you have high or low impedance injectors? Also, have you gone through all the basic setting in Megatune? How many injections per cycle are you using? You should probably post your Megatune file on the Megasquirt forum. I can't open it right now because I only have Megatune installed on my home laptop.
When you say it dies, how long after it starts does it die?
Ken
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
Gene,
If your computer is getting hot, you have something seriously wrong. Do you know if you have high or low impedance injectors? Also, have you gone through all the basic setting in Megatune? How many injections per cycle are you using? You should probably post your Megatune file on the Megasquirt forum. I can't open it right now because I only have Megatune installed on my home laptop.
When you say it dies, how long after it starts does it die?
Ken
If your computer is getting hot, you have something seriously wrong. Do you know if you have high or low impedance injectors? Also, have you gone through all the basic setting in Megatune? How many injections per cycle are you using? You should probably post your Megatune file on the Megasquirt forum. I can't open it right now because I only have Megatune installed on my home laptop.
When you say it dies, how long after it starts does it die?
Ken
I know i'ts 2 inj/cycle high imp injectors, 24 lbs I have lied to the table somewhere/somehow telling it they are much smaller, the req fuel is 15.4 I wonder at what point it changes from idle/cold start to the normal fuel maps?? if it's something like say 120 or 160f coolent, then maybe it's so lean it dies?? it dont even balk, just up and quits, restarts allmost instantly though....dies quicker then.....I wonder....
that resistor on the stim board is....R9, a 1/2 watt in the air above the card, centered right behind the 38 pin D connector....I dunno what he does....no schematic...he is unhappy, scoarched paint...been hot...
I THINK maybe he showed signs of heat when I got the board....and there is a reason he is in the air and not on the board.....
I going to hang a VM on the 5 volt line like I said to see....and feel really good for hot parts in the CPU....
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
OK, guys.....5 volts did NOT die, engine started immediately, temp overnight was a cold as hell 45f, and when it reached ~160f the thing just went from a somewhat high 1200 rpm raggedy idle to a couple of backfires with black smoke, and instantly died.....the exhaust is of course raunchy smelling but just gray when idling, not the least bit rich....funny how the temp gauge says it's still cold though on the computer readout gauge set, but it's obviously lots warmer than that....
something strange....I gotta check that....
something strange....I gotta check that....
Thread Starter
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Guys, I went from a computer set in the program of 19.1 or 19.4 for a 350 chebby, and manually adjusted it from 12 to 21 and the engine runs fine on the cold start stuff, but over 120f, it INSISTS on dieing....will not run on any tables for a warm engine....stumbles, puff of black smoke and dies....but it's not running rich on startup....
I gotta go make some money now, be back in a few hours...
I gotta go make some money now, be back in a few hours...