VERY odd gsl-se thing
 

ok this is a friends -se and its got the devil in it. i sware to god. i drove it about 50 miles on sat. and the last 2 miles this thing went ape shit. reved up to 3k for idle and jerked and bitched and shit... then after he got in it it did the same thing on restart.... a few foot on floors and it went back to normal idle... it doesnt have to redline just upen the T.B 100% and it would calm down. then it started this weird ass rev/ idle thing ill get him to describe it and ill post it. I do know he said it seens to change when you push in the clutch or WOT im at a total loss. i would GUESS at a TPS or ECU? but i have no idea

That's a typical -SE idle surging/hunting problem caused (normally) by a bad vent-solenoid valve. Do a search on surging in the archives and I think you'll find plenty about it.

well this isnt the tipical idle surge... that i can deal with and so can he this is REALLY ODD! heres what he has described it as....

I'll let you chew on my idle problem, since it has started its new stuff.... You can think about what would cause this scenario:

When it idles at 2800rpm, and I put my foot lightly on the gas, it goes to 1900rpm.
Only way I know to get it off of the 1900rpm or 2800rpm idle is to redline it... after I shift, or put my foot on the clutch... when I hear the pop from afterburn it goes back to idling at 550rpm
Only goes into high idle mode when driving at low rpms, especially when using the clutch.

When its idle is at 1900rpm (with foot on the clutch), if you take the foot off the clutch and put it in neutral it will surge between 1000-1400rpm.

Sometimes I wonder if cruise control or warm up process has gone bad and causes this. All sensors and vacuum hoses (with exception TPS) I believe are original.

I hear you man, that -SE FI has a mind of it's own. sometimes my hi-idle,though set @ 1100 stays up. even when the engine reachs temp. the main idle is set @ 850
rpm's. I thought CPU too,replaced it with another one, does the same thing.I don't get a surge, but my -SE runs like crap when theres less then a 1/4 tank of gas.

Oh ya me too. My Se likes to wander into idling at 1500 sometimes, and when I tac it out it will drop it. I have a large vacuum leak from my ACV as well so its all theoretical. I want a HOLLEY 670

It could be the BAC valve, and 550 rpm's is too low of an idle for a stock car.

sounds like a crazy tps sending wrong signals?

This is actually pretty common. I'm not sure I would be trying to 'fix' it by redlining it, however. On a cold engine that could cause problems - most of the time when my SE surges, it's due to being cold and the computer is trying to find a combination of engine speed and throttle plat settings that will allow it to warm up.

Once warmed up, it returns to a standard 900-1000 rpm idle. When it does surge, it goes from 1000-1400 rpm over and over and over again - which is very common for SE's. Do a search to come up with the solution, which usually includes cleaning out the BACV, checking vacuum lines to the vent and vacuum solenoids, and occasionally lubing the throttle body plates and rods.

The other issue that you described about it idling at 3000 rpm is pretty common as well and is entirely due to the throttle plates and actuator rods sticking in the throttle body, again when cold - usually this problem goes away once warmed up because throttle body expands in all directions, resulting in slightly more clearance of the steel rods to the aluminum TB. What happens is referred to as 'spalling' when you put to dissimilar metals in rubbing contact with each other, in this case steel rods and aluminum housing. The effect is that the rod 'sticks' in the housing to a degree, which causes the idle to remain higher than it's supposed to be. Cleaning and lubing only fixes the problem for a short time, as sooner or later, that lube is gone and the spalling starts up again.

The fact that you're seeing these effects now is likely because of localized temperature changes as fall swings around. I've noticed that my SE has started surging again, and I'm going to have to do the whole cleaning routine to keep it running smoothly throughout the winter. Other things that I expect as it cools off are the high idle issue when cold (which I just deal with), and also the tachometer sticking at 0 until the interior warms up - this last is due to the grease that lubes the electrical mechanism, it gets almost solid at low temperatures and prevents the tach from reading correctly. HTH,

A simple expensive fix= go with a carb or Haltech:)

Sub93 Mazda EFI is crap.

LongDuck:

I have not noticed this issue in my two SEs, but I have read this and other general complaints about the GSL-SE EFI. At least among a few, it has a very bad reputation.

Invariably (as in this post), somebody suggest 'upgrading' [sic] to a carburator. Having worked on several OEM carbs in my life (granted, the aftermarket performance carbs are different)...I abhor them. I will die happy if I never have to work on another carburator in my life.

Anyway, what are the options for upgrading to a better EFI solution? Is the 86-92 non-turbo EFI better? Assuming you could get the ECU to work, couldn't you switch the intakes?

Or is that so much work you might as well put in a Turbo II?

Out of curiosity, does anybody know if the hp & torque numbers on the 86-92 non-turbo are any better than the GSL-SE?

In another thread, somebody mentioned an aftermarket EFI upgrade, but they were not specific other than to say it was cost-prohibitive.

I intend to keep the stock EFI on these two cars if they continue to operate, but I am curious about what options are out there.

Thanks,
Brian T. C.

I smell an archive. Thanks LongDuck.

Zachstylez

YEP.

The TPS is VERY sensitive, mine did almost the same thing I made the 2 light bulb gadget and adjusted the TPS, it got alot better but the idle would still hunt when cold. One day while messing around in the shop I turned the TPS adj. screw about a 1/4 turn more and it was cured. Good luck

Sounds like the fuel filter is clogged. Especially it it was running perfectly for 48 miles and then did this in the last 2 miles and on restart.

SRE is working on a MegaSquirt based upgraded kit for -SE's. It'll give you either a S4 or S5 upper intake manifold (with a custom lower to fit the SE ports), with the matching injectors, plus the MegaSquirt EFI sstem which lets you dump the crappy AFM...

Also, from what I recall S4 NA's made arount 160hp? I think...
They apparently breathe much bettter than the -SE, but don't have the "bulletproof" durability...

To answer some of the questions here, I know that some SE owners choose to go with an aftermarket EFI system, but that's really beyond my means for my car's use as a daily-driver sports car. While I'm willing to make small adjustments and modifications for performance, going hell bent on an aftermarket EFI system, installing it, then troubleshooting it for best performance is beyond my willingness to undertake.

As for the comment to add a carb, that's a step backward in technology. I'm comfortable working on the stock EFI system, and my 80LS SCCA Solo II racecar had the standard Mikuni that had to be rebuilt just about every year. One of the reasons why I like EFI is due to the better reliability and PERFORMANCE once you learn to tune them well. Going to carb is not a good solution, for power or simplicity.

Back to the task at hand, a long-term fix for the throttle plate and rod issue would be to remove the TB and bore out the rod holes for installation of bronze bushings that fit the rods, or better yet, ball bearings. This would prevent the problems associated with 'sticky' throttle plate rods, and likely also increase reliability of not having to mess with lubing the TB prior to every winter.

Also, as someone else mentioned, the TPS is a critical adjustment for proper idle and acceleration, and a poorly adjusted TPS will result in poor throttle response off idle, surging at stead-state driving speeds, and occasional 'lumpiness' when driving. Check out the FSM for how to build the '2-light' adjuster, as this should be a standard workbench item for SE owners.

I had even thought about hard-wiring this TPS Adjuster light assembly onto the passenger side strut tower to allow for on-the-fly tuning, but it doesn't need to be adjusted that regularly. HTH,

Thanks for the info!