Hot day, hot car, SHIT idle.
 

I know i've bugged you guys enough with this crap... but i haven't gotten any decent suggestions aside from the leaking injectors thing...

We had one of the warmest days this year yesterday in Ottawa... the car ran like SHIT at idle. On cold days its perfectly fine... anything 20 celcius or under its perfectly fine. but once it gets warmer than that, it seems to run like a bag of shit. accelerates hard and quick... but nonetheless... idle is CRAAAAAAAAP. Misfiring... too low... etc. When revved, its steady.

TPS has ben set, double, triple quadruple set...
BAC has been tested REPEATEDLY...
No vacuum leaks, used propane.
TID is not cracked...
Timing was fine last time i checked...
MPG is ASS. 300KM to a full tank. (about 180 miles)

S5 T2... PLS HELP!

no advice but check your PMs.

bump

welcome to the club... for me it's only on humid hot days.

Is leaky injectors a valid cause?

I don't think so...I'd check vaccum lines as when it's hotter out the line will expand and open any small cracks in the lines. leaky injectors on a hot car on a hot day would make for hard starts and fuel vapors and I don't know why they would leak on a hot day versus a cold one. also try opening the AFM and cleaning it out w/ some brake cleaner and an eraser on the metal contacts. your stock intake pipe could be a source of cracks and vacuum leaks when it's real hot, take a look.

Is it safe to open the AFM? I have the series 5 remember :)

ANd the stock intake pipe has been removed and VERY THOROUGHLY inspected... it wa sin mint shape.

hehe then no, don't open an S5 AFM. I bet if you remove the UIM you'll notice some of the vacuum lines in the rats nest are aged and cracked...I bet thats the problem.

well i wanna know what to do first... i mean... if its a leaky injector, i dont mind bringing it in to get cleaned... but i have no way of telling... which is why i was wondering if board members can shed some light ;)

mazda installed the previous UIM to LIM gasket... i imagine they didnt use any sealer. Would that cause the issue?

I never use sealant on intake gaskets. Just a little oil on each side to soften the paper. Plus next time when you pull it off it doesnt stick to the gasket surface ;)

hmmm alright then
any other ideas?

Ross, I have a little something that I bought off ebay to check codes, etc, etc... I dunno if it will work on a T2, but we can try it out! I was going to run it on the baby too.

already ran codes buddy :) but i'll help ya out with yours whenever the time comes. gimme a shout.

maybe check the exhaust ground. if you've got an aftermarket exhaust, sometimes the ground doesn't get connected back to the exhaust. when the O2 sensor isn't grounded (throught the exhaust) properly, the car can run rich and burn through fuel. maybe check that?

already ran codes buddy :) but i'll help ya out with yours whenever the time comes. gimme a shout.

Checked it yesterday, the ground is intact and still connected.

Have you checked the TPS when it was idling like crap? I had tested mine when cold a hundred times and it was within spec using the resistance method, but last weekend I checked it when warm and iding like ass and the narrow range sensor on the TPS was at 3.9 kohms (as opposed to the ~1 kohm it's supposed to be) and would not change regardless of how I moved the sensor or adjusted the set screw. Mines also an N/A so I don't know how different the TPS may be with a T2.

Just my .02

Well i adjusted the tps when really warm, but of course, not warm enough... there has to be specific conditions met when it runs like a bag of shit. I'm actually thinking of running two wires out of the TPS, and testing the voltage from inside the cabin.

I am almost positive it's a faulty tps, but i dont have a spare one to replace it with.

Oh yeah... symptoms that exist regardless of temperature:
-1000-2000RPM random misfire
-popping sounds (i guess raw fuel dumped into combustion chamber because the rpm changes when it pops) upon decelleration

Yeap its tps

I can relate to the random misfire and popping sounds. I also had the added benefit of when it got warm enough, the idle would drop so low that it would sputter, backfire and almost stall before jumping back up ~750 rpm. It was great fun, really turned heads. But when the engine is cool and the temperature outside is in the 60's to mid 70's it runs and idle's like a champ. Unfortunately I only get about 4 weeks of that kind of weather a year in NC.

I just found a replacement TPS for a reasonable price. EBay had them all over the place all of the time for next to nothing until I determined for sure that mine was bad.

you're decribing my exact symptoms.... idle would drop so low that it would sputter, backfire and almost stall before jumping back up ~750 rpm... that's EXACTLY what happened the entire Gatineau Hills cruise that i went on.

Was your random misfire/popping solved when you threw on the new tps?

It should be here today or tomorrow and I WILL have it on this weekend before I do anything else. I can't help but believe that will fix it. I mean the 3.9 kohm reading on that narrow range sensor and the fact that it didn't change when I moved it is as clear an indication as I have had that there was a problem on this car . I'll let you know on Monday or Tuesday if it fixes it though.

To get by though I waited until the car started that shit and adjusted the idle up to about 1K rpm's. It helped, but damn does it idle high when it's cold.

Sweet. Please let me know how it goes!!! I'm dying to hear.

Do you have a t2 as well?

'91 Vert. Couldn't find a T2 when I was looking (not many around here anymore apparently) and stumbled on a vert which was in pretty good shape with low miles and jumped on it.