GSL-SE surges between 1200 -1500 RPM
 

1984 GSL-SE sat for 15 years, Oil change, new fuel filters, new fuel injectors. Great compression. Starts right off and idles at about 1k. Then starts to surge. Drops to about 500 rpm then rises to about 1500 rpm, does it over and over. If I hold it at about 3 K RPM it evens out, but let off the gas and it surges again? Curious.

Thanks - Bob

Have you adjusted the TPS according to the Factory Service Manual?

Foxed.ca

Search on my username and "SE Idle Surging"; you'll get plenty of hits. Actually, scroll down a bit and endless scroll might have brought up the links for you.

Thanks, Did a search here and found a lot of really good information. I hadn't thought about the TPS but it sounds logical and seems to be a major trouble maker. I have checked for vacuum leaks. Major benefit here is that it's a mostly unmolested unmodifed SE.

Thanks - Bob

I swapped the TPS from my spare Throttle body/Dynamic chamber unit and while it didn't cure it completely it dropped the throttle surges from about a 1500 rpm span down to about 300 rpms. (1000 - 1300 rpm's.) Almost drivable. Still, there is something wrong. Perhaps could be another bad TPS.

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Did you try the two-light TPS adjustment?

It's on my to-do list. I just have to line up the hardware. Also the WD-40 around the vacuum lines. I hope something works the TPS's are not cheap, although Parts Geek has them at around $161.00. Others quite a bit more than that.

Bob

As you may have read from my past 20+ years of posts on this topic, the TPS setting is touchy, to say the least. Best bet is to set it using the "Two-Light" apparatus, and then go for a drive,... tinker with 1/8 turn one direction,... go for a drive,... 1/4 The other direction,... go for a drive. You see where this is going.

The root cause of this condition is that too many of these old and aged parts are trying to work together and the ECU is jumping in occasionally to get every one to play nicely together. Usually, I've found that you can find an ideal setup that works for awhile, and then a year later, it starts to crop up again - usually caused by something else going out of spec. Its a labor of love.

Your TPS is likely the culprit, though - I would NOT go firing the parts cannon at it yet. Keep at the TPS setting, and make sure you're not dinking with more than one sensor or adjustment at a time, complicating everything. There's also the Idle Speed and Idle Mixture (*factory sealed) adjustments as a last ditch effort.

Thanks, still gathering parts but a fresh day and thought I would try it again. Started it (cold) and without touching the throttle it idled nicely at about 1300k rpms for about two minutes,. Then it dropped to 1000k and cycled again between 1 and 3 k every couple of seconds. Took it for a little spin. Runs great otherwise.

I'll be 86 in October and have been at this restoration thing for about 40 years but never with anything newer than 1980 - American and British sports cars mostly which means no computers and less complexity. I'm a lost puppy at this newer stuff.

i don't have anything technical to add to this thread, but i just had to say you have my utmost respect. i've got over 30 years in with these cars (and this quirky engine) and i hope i can still love it like you do, and be on this forum, if/when i make it to your age.

as a total aside, it also kinda messes my head up when i saw you say "newer stuff" about an SE. :)

Newer = it's Fuel Injected!

Seriously, though - setting the TPS when engine cold is guaranteed NOT to be the right settings for engine hot. Let it warm up, drive it around a bit, and then set the TPS using the Two-Light method. I think you'll get it there. Good luck,

Thanks all. My son, pushing 60 is a lot more computer literate than I am and has sent me a bunch of information gleened from this site. Printed it out as my memory would not pass the two light system test. Eager to check it out.

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BTW, did a little more RX-7 this morning...............

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Debating whether to paint or not to paint.............

As received:

https://cimg8.ibsrv.net/gimg/www.rx7...58933cb419.jpg


Thanks all. - Bob

Ditch that krylon can and buy some SEM burgundy along with duplicolor adhesion promoter.

Where were you two weeks ago. :)

Too late now, and yes I'm not at all happy with that Krylon. Coverage is terrible. Thinking about redoing it. Thanks, looking into it.

But for now.

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