Idle viiiiiibration!
4 Attachment(s)
Posting this to try to get some help tuning my gorramn idle.
Last night, I had it at a startup idle of ~12.20ish AFRs. Today, oh shiiiit...15s to 16s, wtf? Shut it off, turned it back on - now it idles 1 AFR lower? WB Sensor (NGK AFX) was calibrated yesterday morning. WB sensor reports everything correctly when I throw it in my RX7 and matches a LC-1's readings in the RX7. As it warms up, it always makes the vibration less worse, but it never goes away completely. And it doesn't matter WTF the AFRs claim to be at idle - low 10s to 16 does the same thing, with the lower the AFRs, the worse the vibration**. RX7 550ccs 94 1.8 COPs as per Brainy's writeup* Brainy(tm)-rebuilt MS2 Basemap was as per Brainy, who knows what I've fucked up in it? *: The COPs helped a ---- TON with idle vibration, it's gone from rattle your teeth out to a bit worse than a couch back massager. **: You think an old-school carbed big rig warmup idle was bad? Try my Miata at 10-11AFR. |
I can't really tell why it's rough.
Your fuel table is awful. I think you should go leaner in cruise up to 80kpa or so and your spark table should reflect that too. You said you have no idle valve, right? |
Originally Posted by hustler
(Post 860853)
I can't really tell why it's rough.
Your fuel table is awful. I think you should go leaner in cruise up to 80kpa or so and your spark table should reflect that too. You said you have no idle valve, right? |
Have you thought about switching-on sequential fuel? In order to eliminate variables, you might want to consider switching idle advance off for now.
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Originally Posted by hustler
(Post 860857)
Have you thought about switching-on sequential fuel?
In order to eliminate variables, you might want to consider switching idle advance off for now. |
1994 is sequential fuel from the factory. What's the problem?
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MS2 needs some work and a sequential fuel expansion board. DIYPNP still needs a board however the work is easier.
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Originally Posted by hustler
(Post 860864)
1994 is sequential fuel from the factory. What's the problem?
Originally Posted by Reverant
(Post 860865)
MS2 needs some work and a sequential fuel expansion board. DIYPNP still needs a board however the work is easier.
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Originally Posted by blaen99
(Post 860866)
I run a 91 with a 94 engine ;).
I don't know what's going on, but I assure you that my 1.6 car with the 99 engine and 550cc injectors idles wonderfully with and without the IAC. |
Originally Posted by hustler
(Post 860869)
Well that's different than what you posted.
I don't know what's going on, but I assure you that my 1.6 car with the 99 engine and 550cc injectors idles wonderfully with and without the IAC. |
I think one of the injectors is screwed up or something causing a lack of fuel on one cylinder but I'm not exactly an expert on trouble-shooting MSQs. I know just enough to be dangerous and help-out newbs.
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Originally Posted by hustler
(Post 860879)
I think one of the injectors is screwed up or something but I'm not exactly an expert on trouble-shooting MSQs. I know just enough to be dangerous and help-out newbs.
Easy enough to fix, but I'm gonna be throwing in injectors that are worth rewiring for if I pursue that. |
Yep, one injector's wiring is completely fucked.
New injector time. EV14 all the way. |
Okay bros.
As per what you've all recommended at various points, I've done the following to try to fix this: Replaced the timing belt and everything related on a 1.6, as well as had the timing double, triple, and quadruple checked to be 100% Done a 1.6 to 1.8 swap with a known good low-mileage 1.8 Used more sets of spark plugs then Fae could manage to sawzall in half. Used 2 different sets of Miata coil packs, then switched to COPs with a full custom built harness Used just-cleaned RX7 550ccs, then moved to brand new EV14 650ccs* with a full custom built harness Changed exhaust, downpipe, manifold, and turbo. I am running the Mazdaspeed motor mounts instead of stock. Modification to the above .msq is changing req_fuel from 6.0 to 5.7 with the 650s, and changing dead time from 1.2 to .85 I'm STILL GETTING THE GODDAMN VIBRATION. What the ----?!? Seriously, even with brand new EV14s and a new injector harness, I'm getting substantial vibration (Like a constant vibrator going on through the whole chassis - you can watch the rear window vibrate) no matter what AFRs I have it idle at. *: One thing I found weird with this is in going from 6.0 to 5.7 req_fuel, I had to add an absolute ---- ton of fuel to get it to idle at all. Additionally, with the EV14s, I had it idling at 18AFR!!!! Wow! And what makes it really, really bad is there is no goddamn difference between idling at 12AFR to 18AFR in vibration with the EV14s. |
Blaen first of all, take the mandingo buzzing dildo out of your ass.
Second. Widebands can be inaccurate at idle. Third. Check your battery voltage. A slipping or loose alternator belt can make your voltage crap out and that will indeed cause a variance in afr and idle feel. Fourth. Check your motor mounts. They are prob fuked. Fifth. When setting fuel for idle, start rich. If it is too rich, it will bog. Lean it up until it starts to "miss". Then richen it up until it is smooth again. Then richen it 10pct more. That will prob end up making it idle about a point an a half richer than a smooth lean idle. You want to idle a little rich so fucky bs like temp changes, humidity, batt voltage etc do not screw up your idle. Yes there are trim maps but sorry, they do not always work that well. Fact of life. Sixth. When you set up idle, ZERO OUT YOUR IDLE TRIMS. Seventh. Check your injector and plug wiring. Its prob fine but stupid shi like a loose plug wire or a frayed injector wire can make you sad. When i took brain for a ride in my car i had misfire over 20psi and that was fixed by just plugging in my loose wire all the way. Eighth. Suck my dingdong and bow down before your god. Me. Hope this helps. |
Originally Posted by Faeflora
(Post 864308)
Check your battery voltage. A slipping or loose alternator belt can make your voltage crap out and that will indeed cause a variance in afr and idle feel.
Check your motor mounts. They are prob fuked. When setting fuel for idle, start rich. If it is too rich, it will bog. Lean it up until it starts to "miss". Then richen it up until it is smooth again. Then richen it 10pct more. That will prob end up making it idle about a point an a half richer than a smooth lean idle. You want to idle a little rich so fucky bs like temp changes, humidity, batt voltage etc do not screw up your idle. Yes there are trim maps but sorry, they do not always work that well. Fact of life. When you set up idle, ZERO OUT YOUR IDLE TRIMS. (Edit) Wait, does MS2 even have idle trims Fae? Check your injector and plug wiring. Its prob fine but stupid shi like a loose plug wire or a frayed injector wire can make you sad. When i took brain for a ride in my car i had misfire over 20psi and that was fixed by just plugging in my loose wire all the way. |
Get us a video of the vibration
put a jack under the engine, start it, and see what happens. |
Originally Posted by hustler
(Post 864310)
Get us a video of the vibration
put a jack under the engine, start it, and see what happens. |
Enough to move the engine up by like a half inch or so. Hustly is trying to rule out driveline mounting issues.
dont tear motor mounts while doing this Also seriously, disregard wideband indicated AFR when fuckying with your idle. After a while you can even tune by smell. Serious. |
Roger, getting my hands on a video camera to take video of ALL OF IT.
Thanks guys, it's appreciated. I'll be back as soon as I get the requested video! |
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