Car Bogs Out before 4k RPMS - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


ECUs and Tuning Discuss Engine Management, Tuning, & Programming

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 01-10-2012, 10:04 PM   #21
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

Hornet I cant thank you enough. PLEASE Excuse this HORRIBLE Video. But I tried to take it while driving. You can see how when I try and give it fuel...how the AFR just goes full lean. when it goes full lean the car just doesnt do anything and im barely moving. As you can see when I go past 4k rpms...the afr is around 13 I know I did not hold the video steady...but it was around 13-14 when I was above 4k rpms. If I drive above 4k...the car runs great... Let me know what you think. Thanks!

daytona675 is offline   Reply With Quote
Old 01-10-2012, 10:47 PM   #22
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

My other reason to think that it could be the Fuel pump could be that the ECU is trying to add too much fuel and the fuel pump just cant handle it? Then when it gets to 4k rpms it is revering to its fuel curves and is then not dumping fuel like it should be below 4krpms?
daytona675 is offline   Reply With Quote
Old 01-10-2012, 11:15 PM   #23
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

Disconnect your o2 input into the stock ecu to force it into open loop mode.
See if it still goes lean with stock ecu running open loop.
Techsalvager is offline   Reply With Quote
Old 01-10-2012, 11:17 PM   #24
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

Tried that. Still seemed to run the same. I think I only disconnected I at an idle though while reviving. But saw no improvement.
daytona675 is offline   Reply With Quote
Old 01-10-2012, 11:19 PM   #25
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

you need to keep it disconnected and go for a drive with in open loop

if it has two disconnect both, maybe you disconnected the one after the cat. I'm not sure what a 96 has
Techsalvager is offline   Reply With Quote
Old 01-10-2012, 11:25 PM   #26
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

My miata is a 91 and it only has one. I also have an o2 clamp on the wire signal going to the Ecuador. I have tested this while driving and even did a test where I had a buddy blow in a tube to make sure a lean signal was going to the ecu and it did not make a difference. I thought the of clamp was going to fix my issue but no go.any other thoughts ?
daytona675 is offline   Reply With Quote
Old 01-10-2012, 11:29 PM   #27
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

disconnect the clamp and o2 to get into open loop, may want to disconnect tps as well.
Techsalvager is offline   Reply With Quote
Old 01-10-2012, 11:31 PM   #28
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,315
Total Cats: 1,913
Default

Quote:
Originally Posted by daytona675 View Post
My other reason to think that it could be the Fuel pump could be that the ECU is trying to add too much fuel and the fuel pump just cant handle it? Then when it gets to 4k rpms it is revering to its fuel curves and is then not dumping fuel like it should be below 4krpms?
It's not the fuel pump or the filter.

Inadequacies in the fuel delivery system become worse as the demand for fuel flow through the injectors increases. Fuel demand (in units of volume per unit of time) increases as RPM increases. Thus, the problem would be worse at high RPM.

I'll be honest, to me, this just sounds like business as usual for a 1.6 engine running on the stock electronics. These suckers are 20+ years old at this point, and they're starting to degrade. My '90 isn't quite that bad, but it does nearly the same thing.
Joe Perez is offline   Reply With Quote
Old 01-10-2012, 11:36 PM   #29
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

Wish I could agree with you about it just being old but I have driven other ones and trust me there is something going on here. I have to crawl o accelerate or shift to get the rims past 4k. Its almost underivable. Its not slow, it stops. Like wont move unless I let off the gas then get on it slowly. If I get on I slowly it is ok. I still wonder if it could be a bad ground and it not allowing the ignition two work right? Just so weird how it doesn't do it above 4k.
daytona675 is offline   Reply With Quote
Old 01-10-2012, 11:39 PM   #30
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

is it anywhere near boost when you normally trying to go past 4k?
And by crawl you mean staying out of boost?
Techsalvager is offline   Reply With Quote
Old 01-10-2012, 11:44 PM   #31
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

Yea its going into boost. Like 1 psi it'd more load. If the cars under load. It just hesitates.
daytona675 is offline   Reply With Quote
Old 01-10-2012, 11:52 PM   #32
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

try to get it out of closed loop, once out the wideband shouldn't be going back and foth aroudn 14.x to 15.x and should be steady around some number instead iirc
Techsalvager is offline   Reply With Quote
Old 01-11-2012, 10:14 AM   #33
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,008
Total Cats: 583
Default

From the video, it looks like the repeatable pattern is you go full rich, snuff out and the resulting misfire makes the WBO2 read full lean (although you are actually so rich you can't fire). Can you pull the plugs to confirm? If you are really this rich, those plugs should be completely black and might even be wet.

The other thing that would help is a COMPLETE description of your setup. Is it a 100% stock Greddy install? When you tried the MSPNP, did you do anything with the AFM? Are the fuel injectors stock? etc. etc. In the process of making this list, you might actually stumble onto the cause.

Sounds like there has been enough fiddling with the car that there is some basic thing not right -- like a wire cut on the AFM. Your shotgun troubleshooting approach (like adding a garbage E-bay O2 clamp) is not helping.

What the heck is an Ecuador?
hornetball is offline   Reply With Quote
Old 01-11-2012, 12:17 PM   #34
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

From the video, it looks like the repeatable pattern is you go full rich, snuff out and the resulting misfire makes the WBO2 read full lean (although you are actually so rich you can't fire). Can you pull the plugs to confirm? If you are really this rich, those plugs should be completely black and might even be wet.

I will check this when I get home to confirm. But if that was the case then I would think it wouldnt happen or would not be as bad when I remove the Vortech FPR. But with the FPR removed it was still doing the same thing.

The other thing that would help is a COMPLETE description of your setup. Is it a 100% stock Greddy install? When you tried the MSPNP, did you do anything with the AFM? Are the fuel injectors stock? etc. etc. In the process of making this list, you might actually stumble onto the cause.

Car is a 91 Miata with manual transmission. It is Greddy kit, with a front mount intercooler and BOV. (Nothing Fancy) When I did try the MSPNP I tried it with a brand new AFM, as well as with an IAT sensor and both did not work no matter what I did. In the process of trying to get the ecu working I killed 3 ignitors. I dont know if that tells you something, but it is like my car eats them. The car has the blue FPR from Vortech that comes with the Greddy Kit. The Injectors have a blue top on them and from my research that means that they are the stock 1.6 injectors? The previous owner said they were RX7 injectors but I am not sure if he was mistaken as he was not the one that installed them on the car. The car has an full turbo back exhaust, aftermarket clutch. I think that is everything I can think of that has to do with the setup of the car and everything I can determine. I have checked the timing, no change. etc.

Sounds like there has been enough fiddling with the car that there is some basic thing not right -- like a wire cut on the AFM. Your shotgun troubleshooting approach (like adding a garbage E-bay O2 clamp) is not helping.

I am using an "olderguy" o2 clamp that I got from him on this forum. It should help with lean tip in, and as I thought my car was going lean I thought this was something good to test. It could be a wire to the AFM that is causing this, but what is odd is that I was having this issue prior to getting a brand new AFM. I could get a new harness that goes to the AFM and try that?

Maybe it is something as simple as that?

What the heck is an Ecuador?

Ahh, the Ecuador. You havent heard of it? Its the most important part on a miata.... j/k Seems my tablet does not like "ecu" very much and was autocorrecting it to "ecuador" Sorry for the confusion...
daytona675 is offline   Reply With Quote
Old 01-11-2012, 02:12 PM   #35
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

as you guys have suggested I am going to check the grounds to the AFM. If they are bad it could be getting a very bad signal back to the ECU and then causing the car to pull fuel or maybe just be dumping too much fuel, but I think it may be pulling fuel. I still may replace the fuel filter this weekend as it is cheap and does not look too hard to do but it is also just not a bad idea given how old the car is. I have been searching for any threads about the AFM ground wires but have not been able to find any except that there is something under the brake booster that I should be looking for? Any other suggestions on the grounds that go to the AFM?
daytona675 is offline   Reply With Quote
Old 01-11-2012, 02:14 PM   #36
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,008
Total Cats: 583
Default

The normal Greddy theory of operation is that the stock engine management (consisting of stock ECU, stock 19550-1970 212cc fuel injectors, stock AFM, stock FPR) handles fueling when not in boost. In boost, the fuel injector pulsewidth will be maxed, and the only way to get more fuel into the engine is to increase fuel pressure. That is the job of the Vortech FPR. The Vortech FPR should have no effect before spool up.

Significantly, RX-7 fuel injectors MUST NOT be used with this setup unless you have a programmable ECU to control them. Otherwise, you will just flood the engine when running open loop, such as when you stomp on it at low RPM. The RX-7 19550-5740 440cc fuel injector has a blue top. If you've got those in your car, it would be bad. 440cc >> 212cc.

Here's a website that might help you out: http://miataturbo.wikidot.com/fuel-injectors.

So, your task is to make sure that everything is stock and functional (preferably by diagnosis rather than parts replacement) to handle the sub-4K region:
1. Fuel injectors good and correct part number?
2. ECU good (only way to determine is to swap -- do you have a friend with a Miata)?
3. AFM and wiring good (check with multimeter)?
4. FPR good (check with fuel pressure gauge)?
5. NBO2 and wiring good (check by comparison to WBO2 in steady state closed-loop conditions out of boost)?
6. MSPNP uninstalled correctly. For example, was the IAT sensor removed and stock wiring 100% restored to the AFM? Was the 10A ST SIGN fuse put back in? etc.

Keep in mind that the 1.6 is naturally low on torque below 4K. This is exacerbated by the following:
1. Your engine may be tired.
2. With the Greddy install, you are supposed to retard your timing 4 degrees to 6BTDC. This kills the low end.
3. If your timing belt is off a tooth or two, the "peakiness" of the engine can become really exaggerated.

I was happily running an MSPNP with large injectors and no AFM long before I ever installed my turbo. There is no way I would run bandaids like the Vortech FPR, a high pressure fuel pump or an O2 clamp. Too imprecise. The only parts of the Greddy kit I used were the turbo, exhaust manifold and downpipe. The only part of the Greddy kit I used without modification was the turbo.

If you do ever re-install an MSPNP, you must permanently remove the ST SIGN fuse and you must unplug the ignitor anytime you flash new software. Otherwise, you will kill the MSPNP and/or the ignitor.
hornetball is offline   Reply With Quote
Old 01-11-2012, 02:18 PM   #37
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,008
Total Cats: 583
Default

Ooops

Last edited by hornetball; 01-11-2012 at 04:04 PM. Reason: Double Posted
hornetball is offline   Reply With Quote
Old 01-11-2012, 03:34 PM   #38
Junior Member
Thread Starter
 
Join Date: Aug 2011
Posts: 113
Total Cats: 5
Default

is there an easy way to know exactly what injectors they Are without pulling them out? I will check this and I am positive the mspnp was fully removed. Etc.
daytona675 is offline   Reply With Quote
Old 01-11-2012, 04:03 PM   #39
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,008
Total Cats: 583
Default

I guess you could try getting an inspection mirror in there. But pulling the injectors is really easy. Two bolts hold the fuel rail on (12mm IIRC). You may also need to pull the air valve off the intake manifold for a bit of clearance (7mm IIRC).
hornetball is offline   Reply With Quote
Old 01-11-2012, 06:30 PM   #40
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,624
Total Cats: 1,559
Default

Disconnect the wastegate arm so that the wategate flops open and try accelerating. Does the bog remain at higher rpms or still go away at 4k?

Is the stock fuel pressure regulator still on the fuel rail? If so, is the vacuum hose still connected to it?
sixshooter is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM
The "other" spool question stefanst DIY Turbo Discussion 44 09-28-2015 08:16 PM
ME221 Now has Autotune and Long Term Fuel Trim Tables Motorsport-Electronics ECUs and Tuning 0 09-05-2015 09:02 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:42 PM.