NCharlebois

iTrader: (2)

Good idea, I'll try that before I unplug it. Let us know your result !

Ok, let's do the test : start the car when to top is on and another time when the top is down. Certain to find the problem !!!!

jjwalker

I will try it when I wake up. Didn't get a chance to do it today.

HAILERS

************************************************** ************************************************** ************************************************** **Why not get the engine fully hot and leave it idling. Then check the output of the TPS AT the ECU? Compare it to the FSM Control Unit page.

And once again, the water thermowax's fast idle cam and roll pin have to seperate completley before setting the TPS. You can use a inspection mirror to check it. Or you could just turn the screw that sits on top of the water thermowax fully clockwise. That will guarantee a fully seperated cam/roll pin.

This thread is starting to sound like a TPS that isn't set right. CAm and rollpin have to be fully seperated before setting the TPS.

NCharlebois

iTrader: (2)

I know that the cam roller is completely separated from the roller because my screw is almost fully screwed. I've test my TPS with the volts and the LED lamps, so I tought it is ok. And when my car is fully warm, I think it really runs pretty well.

My idea was that without the TPS, the ECU cannot try to "adjust" and so my idle doesn't bounce : it does not run smooth with my TPS unplug.

I've never check the outputs at the ECU, but I have a friend that knows how and he's going to show/help me.

Going to make a "To do list" !!! I'll come back with the results beginning if next week.

jjwalker

I set my TPS with a ohm meter to 0.95 ohm. I read all over the place that this was the way to do it without using the 2 test LED method.

jjwalker

Aw crap, I meant 0.95kohm. Sorry.

pfsantos

iTrader: (1)

Alright, I think some are missing a point Hailer's is trying to make.

I've screwed up the setting of the TPS before, and it's easy to do.

Just because the screw on the cam is all the way doesn't mean the cam is disengaging. If the cam is not disengaging, you may be setting the TPS _itself_ correctly (i.e. one l.e.d. light or correct resistance), but the throttle won't be against the idle stop.

This is what I do...before messing with any of the fast idle or thermowax cams and adjustment screws:

When setting the TPS (I use the l.e.d. method because you can leave the checker plugged in, and hold both screwdrivers - I will explain) I do the following... First of all, with my method, you don't have to have the engine warmed up completely. I plug in the checker, turn ign. on, and take one screwdriver and place it on the metal arm that the thermowax pushes on, near where the screw is threaded on that is pushed by the thermowax. Essentially, I'm making it as if the thermowax is extended and when I do this, I check to make sure the throttle closes a bit further. This verifies the fast idle cam is moved out.

The reason I do it this way is if you're unsure the thermowax is doing its job or is adjusted properly, you can take it out of the equation and still have the TPS adjusted properly, with the throttle completely closed (against the idle stop).


edit: Once I know the TPS is set correctly, I move on to the fast idle adjustment. When the engine is warmed up properly (**** kicking drive), I use my screwdriver method (I have a hard time seing if the cam is disengaged behind the TB) to check if the idle drops any further (it shouldn't). This confirms the cam is out of the way. Now you can adjust the idle (don't forget to jumper the initial set connector near the leading coil, wheels straight, A/C off, other accessories off).

jjwalker

Okay, so I did the BAC off on cold start thing and nope, same issue. I did however unplug the AWS solenoid. I cranked the car and to my amazement, AWS is working, unplugged. The engine went to 3000rpm for about 15 second and then dropped to the same old fuel cut type idle. I didn't get a check engine light or anything for the AWS.

Now uhm, why would the AWS work unplugged? Maybe it is stuck open? Maybe that air bypassing the stuck open AWS is causing the idle surging?

I am going to cap the dynamic chamber port and the AWS off and see what happens. That really doesn't make any sense.

I'll also adjust my TPS based on your method pfsantos.

My mind is just blown with the whole unplugged AWS but it still works thing.

HAILERS

The BAC and the AWS Both create the high revs during a cold start.

jjwalker

Well, yeah, it shouldn't go to 3500rpm on just BAC alone, or at least as far as I understand. BAC + AWS takes it to 3000+rpm right?

jjwalker

Woah, now that it is 72* with a bone cold car, it runs fine!!!???

I usually don't cold start it in this type of weather so I don't know if this is normal behavior. AWS kicked on for several second and then the idle stabilized at 1300rpm....unbelievable.

*cries*

NCharlebois

iTrader: (2)

pfsantos, I have adjusted my TPS with the TB in my hand and the cam roller off the cam and then check with the LED lamps when my car was warm. So I know my thermowax "open" and my TPS is well adjusted. I'll look at the ECU to see if the signal is ok.

Euhhhh what did you do precisely ???

Magpie57

Everything seems so inter related. I have this problem and wil be researching this along with yous guys. This stuff is part of why I love this site. 0nce in a while it really gets into the meat of things. Cool!

jjwalker

I didn't do anything, the ambient temperature just changed.

jjwalker

At idle I can't hear anything but if I lean over the hood of my car and slightly move the throttle linkage to raise the idle a tad, I can hear what sounds like a sucking over by the VDI, 6port solenoid spider. The vacuum lines look fine. I guess it could be a vacuum leak I suppose but my idle is fine when the engine is warm so who knows.

jjwalker

The car cooled down again and I started her up. Of course the iddle issue was there. I pushed on the throttle linkage to close them up slightly and idle problem disappeared until i took the pressure off. It could be a vacuum leak (see above post) or my thermo wax is cranked out too far.

SpikeDerailed

iTrader: (7)

I have the same problem...The car is a ATX to MTX also, and it didnt start having the problem till a bit after trying to properly adjust the TPS. I have a stage2 RTek(s5 n/a) and I watched it and looked at the logs, during the decel that you think is fuel cut the trailing plug timing drops to 20* atdc, injector pulse width it still shoing the same times(3.4ms). I dont know what the actual problem is but that is what I am seeing on the RTek.

jjwalker

Yeah, I was doing research last night and found out the same thing. Apparently, the timing retards by 8* and not cutting fuel. I am curious as to what the purpose of that is. I am also curious as to whether that is damaging to the motor.

Is there ANY way to adjust the thermowax screw without removing the throttle body? I am assuming no

jjwalker

Sorry for the double posts, but this is just effin freaky.

First time starting the car for the day. It is 44* outside and it idle like it should without the jumpy crap....!!!!

I go to the bank (about 6 miles away) and park it. Usually, if I don't restart the car within a minute or two of killing it warm, it takes 4-5 seconds of cranking to get it to start back up.

I am in the bank for ten minutes, come out, car cranks right up.

Now I am extremely confused.

I just got back and I am waiting a few minutes then going outside to start the car and see if it hot starts correctly. If it does....well....I don't know what the hell to think.

Edit: It took about 4 seconds to start, which is better than normal.

HAILERS

About the fuel cut.................that got me interested, so I went for a drive while watching the Palm (RTEK2.1). And if I let off the gas the pulse width did not go to zero (from say 4ms), it went in the range of 1.68ms to 1.7ms there abouts. Soon as I apply pressure to the pedal it goes normal, whatever that is for a given speed, like back to 4ms.

Soooo I carried it a bit futher. I backprobed the primary injector (I forget if it's front or rear) with a digital meter that also reads duty cycle % and ms.

Well if the meter is on volts, I might be seeing something like a voltage drop to 11.5vdc as I drive along. Let off the pedal and the voltage goes immediatley to alternator output which was in this case 14.22vdc. To me that verifys that the injector has shut off completley. If the meter is duty cycle and I let off the pedal, the reading freezes for two seconds and then goes to 0L meaning zippity in duty cycle. The meter lags a bit in that respect, like two seconds for a true reading. But the meter comes right back when the pedal is depressed once again. Like immediatley.

So to me, when the Palm reads 1.6ms when I let off the pedal, that is the same as it being shut off completley. You might address that issue to the Digital Tuning folk. Then again we know the car idles at say 3.2ms and there's no way on gods green earth that the car will idle at 1.65ms.

I've also noticed that the Battery reading on the Palm in general will be about a quarter volt lower than the real output AT the alternator itself. So if I'm driving along and see 14.22 on the Palm for Battery, I mentally add .25vdc to that figure. Trivia

arghx

iTrader: (3)

where did you get a meter that reads duty cycle? that must have been expensive.

the battery reading is going to be lower. it is the reading from the constant wire going to the ECU and of course there is going to be resistance as the current flows through the car. a .25V drop from the measured battery reading to the ECU is actually pretty good. mine was about .5 volts (measured on my Power FC commander) until i cleaned my grounds, and now it is around .25V.

HAILERS

FLUKE 88 can be had fairly cheap on EBAY (that's where my second one came from ) . New cost me a few bucks more. http://shop.ebay.com/?_from=R40&_trk...All-Categories

I'm used to working on airplanes where the voltage will be 28vdc at any relay, so I'm spoiled rotten.

I'm fairly sure Radio Shack sells a meter with duty cycle fairly cheap. That's from memory of something I saw several years ago on a RS site.

But, even if one backprobes the injector with a common digital meter, he will see the voltage jump up immediatley after he lets off the pedal, to approx alternator voltage, showing the injector is shut off (no voltage drop anymore from working).

http://www.testequipmentdepot.com/fluke/dmm/88.htm INFLATION AT IT'S BEST.

arghx

iTrader: (3)

remember that the fuel pressure solenoid cuts vacuum to the fuel pressure regulator under hot starts. The result is higher fuel pressure and more fuel injected. According to page 4-31 of the factory training manual, the solenoid is active for 90 seconds if water temperature is over 65 C (149 F) and most importantly, air temp is over 78 C (172 F). That air temp only occurs when the sensor heatsoaks badly--but your air temp sensor is probably not as accurate as it was from the factory. 78 C is a shitload, I moniter air temp all the time, at least on my turbo car which has a front mount intercooler. Interestingly enough, on the FD Mazda installed a fuel temperature sensor to control this function instead of just using the air temperature sensor.

The fact that it is taking you a long time to start the car, except on very hot starts when you may be getting extra fuel from the host start system, indicates to me that you may need a new water thermosensor. They are like $30 from the dealer. If the water temp is not read correctly, insufficient fuel will be injected for a fast cold start.

jjwalker

It starts fine cold. The issue arises when i start the car hot. If I get the engine warm, kill it, then immediately start back up it starts fine. If I get the engine warm then kill it, walk off for about 10 minutes and try to start it, it takes several seconds to turn over.

Now here is a kicker. I eventually lose vacuum to the brake booster, which to me, indicates a vacuum leak somewhere. Is it possible that lost reserve vacuum after shutdown is causing the regulator to not function properly? Based on your description, not having reserve vacuum on a hot start means the regulator is raising the pressure, which could be making it hard to start.

jjwalker

I am going to go crazy on replacing vacuum lines today. Might as well, they are 20yrs old and HARD. Don't seem to be cracked though, but you never know.