theory

iTrader: (5)

Last night I was driving and monitering my RTek on my S4 NA. The temp gauge was about 1/4-1/3 most of the trip, but the Rtek varied from 185(lowest) to 214(highest) during the trip while the temp guage didn't move much.

ALSO, when it is cold in the mornings, car will not idle on its own until 30 seconds or else it will die when I come to a stop and I don't keep the idle up. AFter about 30secs-1min it's warm enough to run on its own perfectly fine.

I have even read on here in some threads that this can also cause problems with the 3800 hesiation after a search. I have re-grounded the main grounds I have had access to and I have grounded the ECU to the chassis as read in threads by Hailers, yet the hesitation remains.

Not sure if this is the thermo sensor malfunctioning? What's the best way to tell if the water thermo sensor is not working right? Isn't there also a water temperature sensor elsewhere? ( I think on the rad itself?) I thought maybe the water temp sensor controlled the gauge, while maybe the RTek reads of the water thermo sensor, which may explain the variances?

theory

iTrader: (5)

Well I found some info in the FSM. I checked the resistance and I got 2.20 when the car was cold (RTek read approx 71 degrees) which is JUST out of facory spec (2.45 +- .24)

I don`t think that would cause a problem being 0.01 out of spec?

The TPS is 1.00 at the ecu (.96 back probed at the sensor itself)

HAILERS

Maybe you have a open in the circuit that's intermittant?

The gauge works off the sensor next to the oil pressure sensor. The water thermo sensor is strictly for a ECU input. IF disconnected the ECU defaults to 185*F. Defaults to what is a normal temp for a RX when fully heated up.

If you go out to the car in the morning, the water temp should be real close to air temp, don't you thinK? Really depends how long the engine has sat overnight.

Just go out and start it up in the morning. Watch the temperature on the Palm and see how/if it rises from air temp up to whatever your thermostat is in the car. Like 185* for a 185* thermostart.

But if the air temp in the morning is 77 degrees,and you start the Palm and engine and the Palm says approx 77*F, and rises as the engine warms up, then I's say the sensor is good.

You might have someone wiggle the wires at the sensor while you look at the Palm reading, to see if you have a intermittent at the plug.

In fact I'd say pull the sensors plug off to see if one of it's contacts is loose in the connector. As in pushed back, or not.

I'd say it's close to zippity for the water thermosensor to cause 3800 rpm hesitation. Makes no sense whatsoever.

TPS.............IF the Palm reads 20 when the engine is fully HOT, then that's good. It means the TPS output is approx 1vdc which is...............20% of the five volts ref voltage input to the TPS.

HAILERS

I thought the RTEK 2.1 eliminated the hesitation at 3800rpm.

TPS........you can fully heat the engine up. Then look at the TPS reading on the PALM. Turn the engine off, key ON. Slowly step on the pedal. The TPS should rise number wise as you slowly step on the pedal. You should be able to see anything *peculiar* till it goes fully open or 100*. Goes fully open just about the same time the secondary throttle plates start to open.

theory

iTrader: (5)

Thanks Hailers.

This morning I started the car, the palm read the coolant temp about 71-77 degrees (can't remember exact number). It was very close to the temp at the afm and intake according to my palm.

I let it sit and watched it slowly reach 183 degrees. Nothing seemed out of whack. I checked the plug and it didnt seem to have anythin wrong with the contacts (nothing seemed strange when I looked at it, other then parts of the plastic connector were in rough shape, which may not be holding it as tight as it should be come to think of it...)

Now as far as the TPS goes, this is strange, I warmed up the car to 183 degrees, at the ECU I read 1.00, .96 backprobed at the connector... BUT the palm only read 14%? It should read 20% according to you/FSM?

Also, after a test drive, if i was about 1500 rpm and just puched the clutch pedal in, it held idle at ~1200 rpm (not normal). If I let the car sow down to below 1000 rpm before pushing in my clutch it idled at my set idle of 850 rpm.

Something isn't right somewhere...

HAILERS

The 14* is odd to me. Tell you what. I'll warm my car up tomorrow morning and let it get hot. Just the other day it read 20* so I'll backprobe the green/red wire at 2G (memory)and see if it's approx one volt dc.....or not.

What does the TPS read if you sit there with a hot engine, key just to ON, engine OFF, and hold the pedal all the way down? Should be approx 100* or close. And as you slowly press the pedal to the floor, the reading should rise and go up to close to 100%. I see something. I should have been using the % sign instead of the * asterik (sp?) sign. Opppps.

Water temp. IF you wiggle the sensors plug, does the reading for water change much at all? Should't. Maybe a touch. Never done that myself.

The clutch pedal thing is an oddity for me. I think I've seen that once on one of my cars and it was a sticking BAC. Mabe remove it's two attach nuts and spray some injector cleaner????or???in it and have the elect plug on it and the key to ON. It should vibrate to self clean itself. Dump the fluid and repeat acouple of times.

EDIT: I not the FSM says the Palm ought to read 20 for the TPS and at the same time the backprobe of the TPS signal at the ECU should read approx one volt. Like 0.95vdc or 1.05vdc is approx to ME.

FSM says the output of the TPS at idle should be approx one volt dc. See Control Unit pages in the Fuel and Emissions section of the FSM. Pin 2G if memory is right. Series four.

theory

iTrader: (5)

I will check out what you said in the am.

I'll check the vdc instead of resistance with the TPS (I've been probing for resistance up to now).

I'll also pull the palm into the engine bay and see what happens when wires are moved around. I recall hearing a clicking noise sometimes when I move the harness that the TPS plug comes out of around.

3800 rpm hesitation update:
Previously I had grounded pins 3A 3G 2R accordding to directions I found on here (from wires to ecu studs), that didn't fix my 3800 hesiation. Today I added pin 2C to the list. The car pulled like crazy and didn't hesitate once at 3800 noticeably until this evening after it sat and cooled down, then it hesitated only in 4th noiceably?

This car has some gremlins somewhere. It even hesitated at ~2800 (not a typo) rpm a few times tonight.

Thanks for the help. I'll make a checklist of things to do in the am and report back with results.

HAILERS

Yeah. 2C is connected to all the ground side of the sensors in the engine bay, like the AFM, boost sensor, tps, water thermosensor etc.

The ohms reading of a TPS should only be done with the tps connector off the harness and is designed to check for *open*problems in the TPS itself when it's moved from fully extended to fully depressed (idle positon...not quite fully depressed).

The Control Unit page of the FSM gives values for what the individual wires on the ECU plugs should read at idle.

Never check for resistance with the key to ON. That will save you some headaches

HAILERS

EDIT: I keep forgetting you have the Palm and RTEK. If the engine is fully hot, like you see 185 degrees for the water temp, and you go look at the TPS and see ANYTHING under or above 20, then just go turn the TPS screw til you see 20 instead of what ever you were seeing. Done. No need to check for voltage/ohms/other.

Also try the SET IDLE feature on the Palm/RTEK. It leads you step by step to set the idle speed/tps etc.

theory

iTrader: (5)

Updated info:

2800 and 3800 hesitations seem intermittent. Sometimes they happen, sometimes they don't. Most sensors I check seem to be very close to the outer range of factory spec. Maybe it`s time to invest in a bunch of sensors.

Set TPS to 20%, reaches max of 95% according to RTek while driving WOT. I tried 2 TPS's and both reached a max of 95%.

When ignition set to ON, the TPS goes from 20%-95% and then any further it drops to 74%? Not sure why it does this when the car isn't running...

Checked air intake sensor: a ~ 20 degrees it was 36.2 kOhms which is out of factory spec by 1.2kOhms. Not sure if this will help with the cold sart issue. I checked the Palm in the morning, after the car sat all night, and the coolant temp differed from the air intake temp by about 8-9 degrees.

Atmosphere Pressure sensor read 3.47 volts which seems alright.

BAC read at 12.2 ohms cold, need to check warm tosee if that is within spec.

The wires for the ground from the engine to the firewall seem pretty black in colour. So I`m going to re-wire some grounds with fresh 10G wire and ring terminals with di-electric grease

All in all, still hesitates and still has an issue starting in cold.

HAILERS

Cold start problem...............air intake sensor has zip to do with starting. See the attached chart.

The ECU uses water thermosensor input, engine speed under 500 and CAS inputs only for Start.

Seeing as how the water thermosensor is working (you see a temps close to the outside air temp and your diff is reasonable) then I suggest your problem MIGHT be the ECU not seeing the START signal from the starting circuit. That is easy to prove. Take the small plug off the ECU. Pin 3D is the wire the ECU Recieves the start signal on. A black/blue wire. So you put your meters positve lead on it and the meters negative lead on a good ground point. I use the ECU brackets studs.

Then, car out of gear and turn the key to start. As soon as you go to Start, you should see, oh......9-12vdc on the black/blue wire of the ECU. IF not you need to find out why not. The plug does not have to be on the ECU to see this signal. Engine won't start of course but that's not what your looking for.

IF the ECU does not see the start signal, then it will not use the internal ECU start map. It instead will use the afm. Using the afm for fuel will give you a much too lean amount of fuel during a COLD start. Makes it a bitch to start unless you live in a very warm climate.

HAILERS

If you have the START signal, then you might take a look at the CRANKING MAP on the RTEK/Palm. I'm pretty sure the na has this feature. You might try adding fuel for a cold start with that map.

You do have the ability to set the idle using the na RTEK? Or not?

HAILERS

It's possible your hesitation is caused by a lack of an orifice in the pressure sensors line. Take a look. OR search for ORIFICE and HAILERS or ORIFICE and NZCONVERTIBLE.

theory

iTrader: (5)

My S4 RTek/ECU doesn't support adjustments of cranking fuel, I'm not sure if that's for S5's maybe.

I SHOULD have the ability to adjust idle via my RTek/Palm, however mine is glitching and no matter how many times I try it won't provide me with current data(ie when it says it has to be a min. of 164 degrees, it wont give my current temp, and it wont give my current tps setting, etc...)

I will search orifice threads, and I will check the start signal!

Your help is greatly appreciated. All this hunting will be worthwhile once it runs like it's suppose to and I can start tuning.

I will report back with results of course once those steps are complete.

HAILERS

That seems to be a PROBLEM, the lower than 164 degrees thing. I found out about that last week. I had to go in/out of that function of the RTEK several times til it did right by me. Frankly I don't use it much at all. No need here.

Yeah. I have the n/a RTEK and the Turbo RTEK 2.1 and evidently it's the Turbo one that has the cranking feature. Kinda sorry 'bout that. I need to drive and mess with the na more.

Pull the pressure line off. Look in both ends to see if one end has an obstruction in it. It should. It's nothing but a small, oval (hence the pill designation) that has a tiny hole in it. It's to prevent spikes by the pressure sensor. Dampens the signal. NZCONVERTIBLE tells how and what size drill to use. Or I gave the MAZDA part number in one of my ORIFICE threads. Gotta be a cheap thing. A buck????

And as an aside, I've messed with starting problems on a car and found that with HOT starting difficulties, that if the START signal on 3D is interuppeted, the engine will start better during HOT starts. But removing that signal resulted in harder starts during cold engine starts. I kinda know what I'm talking about when the START game is played.

Problems with cold starts can occur if the stock starting wiring is bypassed. If done wrong, the signal to the ECU is out of the circuit and the ECU never knows the engine is starting, even if it is cranking over in real life. Lack of that signal means the ECU will use the afm for starts and NEVER the Start map inside the ECU as in normal.

theory

iTrader: (5)

Yeah I found the thread. It's a 0.5mm hole (0.020" inches) or you can fill it with epoxy and use a sewing needle ~0.025" with vaseline to create your own orifice. I'll probably try that as I don't want to wait the 1 business day to try it from mazda haha.

The threads are a bit confusing, I'm just making sure, for an NA I'm looking to check for the orifice in the "Boost Sensor" vacuum hose, in which case the boost sensor is on the passenger side shock tower? I'm getting confused between the atmospheric pressure sensor and the boost sensor as I only have 1 sensor on the shock tower with a vacuum hose attached to it.

So if the orifice doesn't work I'll jsut move to the next course of action.

As for he starting, I still have to check the start signal tomorrow after work.

HAILERS

Boost sensor or pressure sensor is the one on the right front strut tower.

Atmospheric pressure sensor on a series four is in the passengers foot well up and to the right and has no hose at all going to it. Not a player in the orifice game.

ON my 87na, when it was a na and not a turbo, I replaced the vacuum lines and went for a ride. It bucked on me, something it had never done before. So I discovered the orifice in the origianl vacuum hose and installed it in my new hose. Ran normal after that. By the way, it bucked not a block from home. Lower rpms and not the 3800rpm hesitation thing.

theory

iTrader: (5)

There is defiently no pill in the vacuum line leading up to the pressure sensor. I'll have to add that.

I wiggled the water thermo sensor while watching my RTek and there were no changes. SO I think that rules out the sensor or connector in this starting problem completely.

I need to still check the start signal.

My fault here, I have one ground I haven't fixed. It's the ecu ground on the rear housing. If I haven't fixed this one, but have grounded all the grounds at the ECU could that still be the cause of the hesitation?

theory

iTrader: (5)

Update: I just got back from checking my ecu.

I checked pin 3B insead of 3D. 3B was the black and blue wire, and the FSM said it was the starter switch. I assumed that was what you were talking about.

It gave me a consistent 8.10v during cranking.

HAILERS

Yeah. 3B. I should have known better.

IF your talking about the ring terminal on the rear housing, just left of centerline of the rotor housing, well that two wire outfit is the ground for the ECU.

If you talking about the gnd wire that runs from the wiper motor area to the rear of the engine.........I doubt that does much of anything. I ran for yrs without it.

I stole the jpg attached from someone on this site. The red line points to the ring terminal that is the ECU ground for series FOUR.

theory

iTrader: (5)

Yeah that ECU ground was the only one I haven't re-done yet. But If I grounded the pins at the ECU I wasn't sure if that one is necessary to re-ground?

That ground, cleaning the BAC, and the orifice are my last two options it seems.