Joe Dirte

Hi i recently purchased an rx7 and have no idea what im looking at. after its warm my fd will almost die during idle, it hasnt actually died yet but its definately not right. If anyone can help point me towards the problem area thatd be great.

Damzil

iTrader: (1)

when I bought my 7 my idle regulator was fried and it had a similar problem (though different year, model, etc).

but I'm sure more questions need to be answered before anyone can truly help you.

gracer7-rx7

iTrader: (16)

Give us more details on your car - mileage, mods, details of who you bought it from etc. A video would also be great.

Sounds like it might be the throttle body and idle settings and/or maybe tuning.

GeenIdee

How much rpm does it make? under 750 ?

BOFHMike

My FC is performing similarly. Started it up last night, properly went to 2k RPM, dropped down after a few min to the 1k's, then as it continued to warm up would hesitate wildely every time it droped below 1k. Finally it dopped below 500 and lost it. I can restart it, but it's acting like the injectors are flooding/leaking too much fuel into the engine. I just recently baught the car, and I could tell durring the test drive that I scared the hell our of the seller when I got the engine over 2500 rpm. (he flipped, thought I was going to blow his engine.) My guess is the 2ndary injectors have not been used in the three years he's owned the car, and I opened them when I drove the car home... now they are not closeing. Your mileage may vary. I've dumped a bottle of gumout injector cleaner into the tank hopeing that will help until I can get the intake off and pull the injectors.

Joe Dirte

it has about 90,000 miles, cat back only, there is a hose plugged off where the IC piping connects to the manifold other than that nothing has been modded

GeenIdee

Lol, guy was flippin becaus u came over 2500 rpm? haha. The "shift buzzer" sounds somewere around 8000 rpm i belive

but if it drops under 500 rev's, it could be an adjustment.


I wil try to explain what happens if the engine warms up.

If u look at picture 1, the red circel indicates the lever that is connected to the throttle cable.

The lever on the left of it, blocks the other one from closing. When the engine gets warmer the thermowax expends and when the lever turns the other one will get able to close.

Dropping under 500 revs when the engine gets warm could mean that it is just a wrong adjustment of the idling speed.


pic 1

BOFHMike

Thanks, I'll take a look at that today. Would be nice if it was that easy.

GeenIdee

Only thing is, i belive there are 2 way's to ajust it. With a screw that blocks the lever, or with a screw on the BAC if im right.

Correct me if i'm wrong

BOFHMike

I didn't touch anything, started up the 7 and let her idel on her own. Hesitated a couple of times when it went to low idel, but recovered greacefully and continued to idel. I let her run for about an hour and found my coolant "leak". Not an actual leak. The straw in the coolant tank is too short. It's drawing air when it should be drawing back more coolant and the engine cools down. Anyone know how long the straw should be?

gracer7-rx7

iTrader: (16)

Post a pic of the engine bay and a close up near that hose.

It could just be the throttle body mechanical settings are incorrectly adjusted.

BOFHMike

I adjusted the TPS and didn't see the cam adjustment in the picture you provided. I'm guessing it's on the firewall side of the engine, so I'll have to find a mirror...

With the TPS adjusted as best I can 9see below) the higher idel speeds are smoother, but low idel is still lost and when drivin the car will most likely stall when I fully let off the pedel. (starts right up and then idels fine...).

Using the following diagram, and with the engine warm (1 hour from start, idel, drive, to test/adjust)

Idel A-B I set to 1k, A-C is properly between 4k and 6k.
At WOT A-B is between 4k and 6k, *BUT* A-C WOT is .5k NOT between 2k-3K mentioned in every article I can find that referances the resistance method of adjustment.
ALSO, when testing the A-C my meter jumps wildly high and low (kinda like my idel) I suspect I need to replace the TPS. I pulled it off, sprayed some contact cleaner around the plunger and worked it back and forth hopeing to get a little cleaner into the unit - No change. Retested the WOT resitance with the TPS removed, and same .5k (500 ohms).

Thought?

wayne harper

Forgive me for piggy-backing this thread. My 88 Turbo II is idling hi. Back in May 09 I had a fuel leak repaired (If you smell gas, check the Pulsation Dampener). Since then the car runs great; all my shift points sound and feel the same as always, and the turbo functions normally. But according to my tach, it now idles at about 1800-1900rpm standing still after warm up. It used to idle at about 900rpm. In 4th gear, cruising along at 60mph, the tach reads about 3000rpm -- about 800rpm higher. Is this a tuning problem or an issue with my tach, or both? At rest, I can hear the motor running faster (tho far from 'racing'). Comments?

gracer7-rx7

iTrader: (16)

^Check the throttle cable. Also check for vacuum leaks since you had everything apart.

Jay Efini

i actually had this happen recently with my FD and it turned out the idle was fine and vacuum was also but it ended up being the plugs, they were fouled but it would start and stay if you kept the revs up around 2500-3000..once you let off it would rev down to 350 and die..

when we looked at the plugs the leading were 7 and 9 and trailing 9 and 9..ended up the engine was flooded a bit so we deflooded changed the plugs started with jumpers and let it idle and everything was back to normal..a good drive also helped to

im new to FD's but this is what my problem was so maybe it will help you or im just dumb lucky

BOFHMike

Humbug, I've replaced my tps and when only using the resistance method everything was technically fine but still no low idle when the engine was warm so I tryed the lamp method. I used a screw driver to push the FIC open since I can't keep the engine idleing, both lamps were on, so I adjusted the TPS screw until only one lamp was on. I was about to unplug the TPS to backprobe it and check where the resistance was. As soon as I grabed the plug, both lights turned back on. HUH?????? let go of the plug and one lamp went off again.... Moved the plug back and forth a few times and the lamp would turn on and off....... yep, broken wire to the TPS. Since it was on the engine harness side of the connector I would have never caught it using only the resistance method. There is good reason to use both. Now I hope I have enough wire slack to put new spades and connector. Really don't want to replace the entire harness.

BOFHMike

Update - over a month since the last post.
After I repaired the broken wires to the TPS I decided to go on an electical gremlin hunt. Pulled the CPU, resolder it (fixed several issues there), pulled the lexicon, resolder its cold joints, now I have heat on full fan (better then no fan) and pulled the clock and resoldered a BUNCH of cold joints on it, now it works. I turned to pulling ground points in the engine bay, cleaned the contacts, cleaned the bolts, and used a LOT of dielectric. This brouht my voltage leak from +45mv at some points between battery negative post and various "grounded" locations in the engine bay to 0.00. figured I might as well check out the ECU while I was at it. Found a little mess (see my gallery) and cleaned that up w/ solid grounding. Now I have 0mV at every point I tested. Started up the 7, and idled like a champ for over 40 min. Low idel isn't quite right (800-1000) But left alone, idled great.

All that for the following....
Idles GREAT for 40 min. I'm trying to get the rpm at idel down to the 750 range, or at least 800. turn the screw on top of te Dynamic chamber clockwise, very* little effect (yes I had the jumper wire in place) Then suddenly it would drop idle and run really low (near 500) I would give the screw a turn CCW and recover. It was almost as if the ECU was waiting for me to step away before paying attention to the last adjustment....
I get the idle back to aprox 1000. Again, idles great. I jump in, give it a little (1700 RPM) throttle and let off. That's it, she spits in my face and stalls. Isn't the dashpot suposed to keep the throtle from returning too quickly leading to a stall? Or is this indicative of something more sinister?

gracer7-rx7

iTrader: (16)

The Factory Service Manual has details on checking and adjusting the throttle body settings. It could be the dash pot is slightly out of adjustment or it could be one of the other TB settings needs some adjustment.

This guy had some good threads on setting the idle on the FD if you want to read some of his threads on the topic.
https://www.rx7club.com/search.php?searchid=8244568
I'd piggy back on his threads rather than post here in the newbie section for such an advanced topic.

BOFHMike

Thanks for the link. I'll hit that next.
Tomorrow I'm trying to get an extra hand to see if I can adjust the dash-pot. I'm almost hopeing it's bad, I can replace it, and have a well running engine.

As for posting in the newbie section.. I've only been working on a 7 for three months... I'm full of questions I'm sure would get me flamed for posting in the tech forums.....

BOFHMike

Link is bad? Can we try that again?

gracer7-rx7

iTrader: (16)

Yeah, that link died.

Search for user name wstrohm using advanced Search
https://www.rx7club.com/search.php

There is also a thread in the 3rd gen FAQ for adjusting the Dashpot.

BOFHMike

Tonight I took a look at the dashpot. Never mind needing adjustment, it wasn't even touching the tab. I removed it, cleaned it up, it still actuates, so I tossed it back in. Found a friend to hold the RPM at 2800, and now I can let off the gas w/o a stall. My 7 is damn near ready for a road test. (now to find a good thread on dealing w/ the reverse lights.)

Thanks!
-=BOFHMike=-

FC3Superdrdrifto

iTrader: (3)

Why dont you just take it and have the ecu checked to see if its throwing a code, or codes for tps, afm, ect.