When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello there, i hope this is the right way to post a question. Feel free to tell me if not. I have snd gen s5 NA and have been rebuilding it for several years. ADHD lol. It runs and recently i finally got the idle to stop surging with a different tps.but the idle still wont drip below 1200 or so. Cleaned thermowax and coolant lines but the fast idle cam even when manually manipulated doesnt do anything. She runs but if i give it throttle she misses and the catalytic converter gets cherry red. Used a timing gun and the leading mark on the pully (yellow) is about 2 inches to the left of the indicator and the red mark is off as well. I have good compression 100 or better. My next thought is to adjust timing but with idle higher than 850 im not sure if that will work. And then was thinking of dismantling the UIM and cleaning and checking internals and then possibly pulling injectors and having them cleaned and tested. Used propane and carb cleaner and cant locate any vac leaks either. And finally then engine shakes at idle as in runs chunky and rough. Sorry this jumps around a bit. Ive never even driven her with the current engine other than to move her around the garage so i dont know what she is like underload. With the cat getting that hot i havnt wanted to go driving. Any help would be so welcome. Thanks in advance!
Ive done some more research and found that retarded timing can cause the exhaust to run hot and misfires. So i checked the cas and it isnt located dead center but is a bit twisted back towards the engine so its a bit retarded. Made the adjustment after spending most of the night getting it unstuck and free moving. Cant start it up till tomorrow so ill update when i do.
Have you played with the idle screw?
Are you absolutely certain you have no vacuum leaks?
I'll share my experience with aftermarket cats. My cat would get red hot during idle even being timed perfectly. I blame it on the aftermarket cat. Cats are EXPENSIVE and I wasn't prepared to waste needless money on finding a cat that will probably just help blow my engine anyway haha. If you can get away with it I would delete it if you're planning to drive it like and rx7. An OEM cat for an rx7 seems to be quite specialized and many owners have been hard pressed to find an aftermarket option that works well for their car.
I would agree that it's going to be hard to time it with a high idle.
Are your throttle settings set properly?
And when you timed it did you ground the green wire next to the coil?<--- very important.
One thing that would help me help you is this:
Backprobe G/R wire on TPS with a paperclip.
Start the car. Let it warm up.
Use positive voltmeter probe on paperclip and then run the negative probe to a good ground.
Record value and post results(set meter 2v if possible to get a value with 2 decimal places).
This might shed light on what is causing the high idle.
Last edited by Rotary Alkymist; 07-10-22 at 10:49 AM.
Thanks for the reply! Are you talking about grounding out the BAC single connector green plug next to the coil? I did not. I havnt actually started the car w the new timing setting so ill set it back to were it was before i start the car and then ground out the plug before making adjustments.
as to throttle settings, ive adjusted throttle screw on top of intake to 3/4 turn out…..adjusted throttle stop? On front of the intake above and to the right of the TPS. I ohmed and calibrated the TPS 1K to 5K. I havnt messed with any settings on the back of the intake.
To the cat…it is aftermarket but had the same exhaust on a previous engine and it ran well tho the previous engine was an s4 and this is an S5. All components were swapped…harness..ecu…etc its a magnaflow made for an rx7 with both pre cat and main cat.
I will back probe the wire you specified when i get home tonight and post results. Thanks!
That's what I'm here for haha. Too many rx7s not running right for my liking haha. Yeah, the voltage reading will be much more precise and much more valuable.
As to vac leaks….i used the propane method and the carb cleaner method and no idle changes. Under intake…over intake….to all sides and any other vac line i could find.
I forgot to mention she doesnt start right up. She takes 2 or 3 attempts and she tries for sure but dies and then kinda chunks to life slowly. Even harder to start on a warmed up engine. Which kinda had me convinced i had a vac leak but cant find any.
All right so i got home and started her up and now the idle surge is back and it wont go away. I propes the green w/ red wore and the voltage is all over the place staying mainly in the mv range .436mv and bounces for a second to 1 volt and for a min climbed to 7volts and dropped back down. I grounded the bac and turned the cas to center and it had absolutely no effect. Im truly and well stumped.
Have you made any progress with the car? I've been pretty busy and my main laptop is on the bum so I haven't been here lots.
~0.4 volts is a very bad reading.
Let's try this:
1. Locate the throttle stop screw.
2. Get a mirror and a light, back the throttle screw up until you can see in isn't engaged in the mirror(screw end isn't butting up).
3. Turn stop in until it touches and go about 1/16" to 1/8" further(don't go more than 1/8")
4.Start your car and warm it up.
5. Back probe G/R wire on TPS and set the meter up with clips so you can use your hands.
NOW THE PAIN IN THE *** PART. This is a very touchy and finicky procedure so don't overlook any of this info below.
6. You need the longest biggest flat head you can find and you have to tape it with electrical tape all the way down to avoid arcing to the alternator(trust me, if you arc you will fry your MAIN fuse(80AMP or 100?)
There is a screw on the TPS that sits perpendicular to the drivetrain. You can access it by standing behind the driver's fender facing towards the passenger side.
You'll see the screw behind the alternator. If you get it right you shouldn't even have to hold the screwdriver, it will sit right in place.
7. NOW, CAREFULLY turn counterclockwise until you see 1.00V. By carefully I mean DON"T PUSH on the screwdriver when turning. If you do move the trottle you will see the readings go out of wack. To complicate things even more is, when this happens(push to hard on screwdriver) you must slap your throttle by hand to reset the mechanisms to take up the slack when this This can very very tedious.
8. If you've gotten this far your TPS is now set to 1.00V but don't get too happy just yet.
9. Now you have to go for a drive and do a few pulls.
10. Come back and set your meter like last time(No Hands).
11. Take a reading. It will almost guaranteed be off and you will have to adjust accordingly and repeat step 9,10,11 until you see 1.00v.
Notes:
This is procedure can be very tedious and will eat up a bit of gas to get it set properly. What makes this frustrating is how sensitive the sensor is.
Anecdote:
You set to 1.00. When you come back it's at 1.15v. So you turn it clockwise to lower to 1.00v. But when you get back it's at .92v. So you increase to 1.00v etc.
SO
When you set it DON"T SET to 1.00v... try setting it to .95v.
I hope this makes sense to you, because it's really the only way to set it. I'm trying to keep this as simple as possible but the fact is it isn't a simple process. It's the biggest pain in the *** and I'm a mechanic. One of the problems is corrosion on the butt where the stop screw and tps adjustment screw meet. Sometimes there is corrosion on the screw, on the stopper or both. That minute amount of corrosion is enough to create a varying distance therefore the sensor varies. PITA. This process can actually get too in depth for a regular guy.
If you ever have it apart clean those two areas and both screws really well to help maintain a perfect setting.
I'll tell you now I adjust mine EVERY YEAR and it's off every time lol!
Last edited by Rotary Alkymist; 10-21-22 at 06:43 PM.
Sinse i last posted i took the upper middle and lower intake iff and replaced w a different one and new gaskets. Some things were seized so i replaced them. And replaced all vac lines. It runs a lil better, no more throttle surge, but its still hard to start and i have to floor the gas pedal to get it to fire and the idle wont go below 1500. I replaced injectors and seals as well. A friend says i need to take it out and run it. On top if that while burping the coolant system a black residue was consistently flowing into the burp funnel. No water in oil so apparently i could have seal leak on the exhaust side of the engine…yaay. I tried adjusting the timing but doesnt really seem to affect anything. Im guessing because i cant get the idle down. At one point i did get her to idle at 800 but she ran sooooooo ruff and shook like she was having a seizure. I re stabbed the cas several times releasing if i stab and turn the engine over once it will be 180 off the mark so that was fun lol. Have to turn it twice to get back to “stab aligned”
Concerning the tps. The only screw i can find is the one right at the tbs connected to the throttle and i dont need a long screw driver to reach it its right on top so im not sure what your referring to.
Hmm, well you definitely should have black residue in there. Did you do a fresh oil change and coolant change? Are you seeing any bubbles(constant) while running?
The coolant was completely flushed and the bubbles stopped after the system was burped. Oil was changed as well.
timing procedure: align leading mark on pulley with pin, pull cas make sure arrow is aligned with divot and not role pin, reinsert. Start car, put timing light on leading coil wire and point at pulley. No timing marks visible except every so often one appears for a second about 3 inches away from the pointer. Assumed that was because the idle wont go below 1500?
There is a one pin connector on the s5, it's an orange wire. This must be grounded when adjusting the timing. Was this done?
I'm not sure if you've done it yet but maybe we should rule out sensors.
With that same orange wire grounded, get into your car and turn ignition ON. Your check engine light will begin to flash out codes. Once all the codes have been displayed it will cycle through them again in numerical order.
Long Flash=value of tens position Short Flash=value of ones position.
Example:
Code 12= one long flash, 2 short flashes
Code 27= 2 long flashes, 7 short flashes.
If you could do this it would be very helpful. Jot down any codes and maybe we'll have something to work with. Even knowing that you don't have any codes would help point us in the right direction.
Having said all of that, I was wondering if you adjusted your throttle resting position as explained in an above post. I was also wondering if you're actually warming up the block to operating temperature. It takes a good drive to really warm it up. You might be surprised that it will idle at a lower rpm for you(backing off the screw as described). Go for a 15 minute drive and see if you can get that to idle lower for you. Remember that these settings are touchy. Make adjustments slowly and listen.
Last edited by Rotary Alkymist; 10-24-22 at 03:31 PM.
By orange wire are you talking about the single green connecter down by the batter on the drivers side? I have done that previously but may have not done it this time around. Ill recheck and redo. I should also mention that the bac makes noise and the valve moves but if i unplug it while she is running it doesnt change anything. I have gotten her up to operating temp. Ran her for an hour the other night but just sitting still. I had looked at codes before i did the intake work but dont remember what they were but ill go thru that process tonight and report what i find. I havnt messed with any throttle screws behind the intake just the one up front and on top and the tps and the thermo wax. Ill do the throttle screw procedure outlined above tonight as well. I Forgot that had been a suggestion.
Update: I found that my brake booster is leaking internally! Every time i pump the brakes the engine dies. I just havnt ever gotten this far to try the brakes so now the swap will commence and hopfully that will solve this issue. Its always felt like vac issue but even a fog test didnt show it. Fingers crossed.
New brake booster didnt fix the problem. It fixed the brakes but the engine till runs like ****. Its hard to start when cold but next to impossible to start after the engine has warmed up. And i apparently have tps and cas codes in the system i didnt know about. So i checked continuity between the input devices and the ecu and they checked out fine as well as checking resistance on the cas and tps so the fsm says its the ecu so im looking for one to replace it and then im going to do a compression test with engine warmed up. I had the done one w the engine cold and the back rotor was only 95 so i may have a compression issue once the engine had warmed up and the metal has done its expansion thing. Ill post the updates.
So i should mention I havnt actually driven the car in years only ran it in place and moved it from drive way to garage. Maybe thats part of the issue and my apex seals are sticking? I just got done doing the compression test warmed up and it doesnt look good. Im posting pics of my chicken scratch. He reason i havnt driven it is i live on a mountain all dirt roads and to get to the main road is about a mile which isnt a big deal usually but with it not runnin quite right im worried ide get stuck comin back up the steeeeeeep dirt mountain road.
Well i found i had very low compression. I pulled the exhaust manifold and pushed on each apex seal w a wooden stick and all but one either dont move at all or barely move. So i started cleaning the seal with carb cleaner and pointing each seal down into a puddle of the cleaner inside the housing. An slowly they are starting to loosen up more and more. Probably not the right way to do things, should probably rebuild it, but i cant afford a rebuild kit atm so i figured not much to lose as long as i make sure all the cleaner is cleared out and everything is relubed and the oil changed before i go to crank it over for a compression check.
Sorry to hear about the stuck seals, but the carb cleaner method is what I would do. It has a decent chance of working. Don't use the ATF method, ATF may (may) eat at the rubber seals.
I would put some MMO or other oil in before starting though. Both for lubrication and to build compression.
07-09-22, 09:08 PM
