Poindexter10thae

iTrader: (2)

Does anyone have the instructions or a link to how to make the TPS checker lamp? I remember seeing them somewhere

khoney

That and other info are located at:

http://home.rmci.net/panther/tech.htm

Have fun,
Kevin

Mykl

The TPS check lamp is a good way to fry your ECU. Use a multimeter.

turboconv

WTF?? I never heard that there was any problem using a couple of light bulbs as a checker lamp. What is your logic behind your statement that it can damage the ECU?

Thanks.

HAILERS

TURBOCONV.....Read this post https://www.rx7club.com/vforums/show...threadid=17974 Its step six in his post that relates to you. A proper lite assy probably works ok but if your making one beware. Never made one myself. I bought one from Mazdatrix and it gathers dust. I found a better way, in my opinion,( there are lots of those out here{opinions}). So I'm writing this to more or less confirm the above post. The post by RXSTER is worth reading all the way thru. Shoulda given it four stars.

RXTASY1

That's it! I'm getting a Haltech!

Mykl

I don't have a technical explanation for it, but you can damage your ECU if something goes wrong. Something about drawing current through it to power the light bulbs, not sure.

You can set it just as accurately with a multi-meter, although it takes a bit more experimentation. If you'd like me to write up the proceedure real quicklike just ask. What year/model is your car? I know that my method works with the '89-'91 n/a models with the six prong plug, I'm not sure about the others.

turboconv

Thanks for the heads up about the checker lamp. I can see that there may be a current issue with the ECU, but I find it odd that there are so many places on the net that show how to make a checker lamp with the bulbs. Seeing that I would rather not take a chance and damage the ECU I would appreciate a quick note on the multimeter method. I have an 88 convertible, na engine with TO4 turbo but all stock emissions, sensors, ecu, etc are intact.

Thanks.

Mykl

Well, since the method is so popular more likely than not you'll have no troubles going that route, I just wanted to give you a word of warning.

Alrighty, here's how it goes on the six pin TPS units.

Looking at the pins like this...

[1][2][3]
[4][5][6]

Set the meter to check resistance, I think it has the little horseshoe lookin' symbol next to the settings.

Touch pins [1] and [4] at closed throttle and check the reading. Now touch pins [3] and [6] at WOT. I've found that if the throttle body is correctly adjusted these two numbers should match, if they don't, adjust them until they do. If the car is still acting funny, or develops a popping in the exhaust or bucks at low speeds then tweak it a bit.

One thing I recommend that you do while adjusting the throttle body is that you disconnect the spring for the fast idle cam on the back of the throttle body. This way it doesn't matter if the car is warm or cold, you're still going to get an accurate reading. That and if your thermovalve system is malfunctioning somewhere there's no way you'll get an accurate TPS reading.

I hope this helps.

Poindexter10thae

iTrader: (2)

I THINK the TPS may be malfunctioning on my 86n/a(daily driver no mods) since it is the only fuel injected rex I have

HAILERS

BigWoogie, do you have a digital multimeter???? If you do write back and we'll try something with your tps.

Poindexter10thae

iTrader: (2)

I'll just go ahead and post all of the symtoms right here. After the car runs for about 20 mins(either idling or driving) the engine will buck violently, in all gears, does not do this while the clutch is in(of course) but when reving the engine in neutral you can watch the RPMS and it still does it. When it bucks the RPMS do not drop but hold steady and the car just jerks violently and will not accelerate no matter how much gas I give it. I have already checked the entire driveline(clutch components, tranny, U-joints and rear-end) they are all good. The problem is either the fuel or ignition systems. I have checked the fuel pressure(both inline and deadhead pressure) it is good, checked the pressure regulator and it is good as well. I checked the codes and did not have any, so I went to the troubleshooter in my snap-on scanner and it mentions an article about a bad ground, looked up the article and checked the ground, I have good ground(the strap that goes from the block to the firewall and provides ground to the ECU). I know there has been some talk of ECU grounding, if you want to check this you need to measure the resistance of terminal 3a and 2R on the ECM, there should be 0 ohms resistance for each(just thought id throw that in). So far the only things I have found to be bad are
1. solenoid resistor
2.Spark plugs are Extremely fouled

Now here is the list of components that I have checked so far and have found to be good, no problems with this stuff
1. BAC valve
2. clutch switch
3. all 4 injectors
4. A/f meter
5. driveline(clutch components,tranny, rear-end)
6.plug wires(2 weeks old)
7. chassis and ECU ground
8. fuel pump
9 fuel pressure regulator
10. water thermo sensor
11. intake air temp sensor

I am stumped. I am replacing the spark plugs as soon as I am through typing, but I dont think that will help. This is my daily driver and I depend on this car, I cant drive my carb'd N/A anymore because of blown water and oil seals on the intermediate housings. Please help me out

Jahoo88

Try the car with the TPS disconnected, it should run fune just a bit rich on cruise and backfiring a bit.

HAILERS

Whoops! I just re-read your last thread. You say the solenoid resistor is bad? Like the solenoid resistsor under the mass air flow meter that controls the fuel injectors? What is bad about it? Thats a biggie if you ask me, and you did by posting.

Poindexter10thae

iTrader: (2)

Yes the variable resistor(sorry wrong component) that sits on the passenger side behind the A/F meter, it has a small adjustment screw in it, which is covered by this gel stuff. It is not within the specified resistance range, it should be from 500-4,500 ohms. The resistance changes when the screw is turned. At first it read 0 ohms, ok something was wrong, the I turned the screw and got some really low numbers, it turned out that if I adjusted it just right I could get it to 391 ohms exactly, if I adjusted the screw any farther it would drop out to 0 ohms again. 391 ohms is far from the 500 ohm MINIMUM. its on page 4a-77 of the svc manual if you wanna check it out(and I have followed all of the testing and adjustment procedures about 50 times by now)

Poindexter10thae

iTrader: (2)

I drove it with the TPS disconnected for about 40 yards and it bucked worse than it ever has. I could not rev the engine past 2500 RPM in any gear(including neutral).

Keith

That variable resistor only affects idle.

Irv, Keith's dad.

HAILERS

Oh, variable resistor. I was thinking solenoid resistor for the fuel injectors. I notice on the seccond gen tech you also have a post on the subject that Irv has addressed in an orderly manner. It sounds promising. Hurrumph! Using logic again, eh, Irv? Say, what year car is this? I seem to have forgotten or it wasn't posted.

Six Rotors

iTrader: (17)

"When analysis stops everything else is hunch"
Thought I would just throw in a few comments:
1-Regarding the opinion that checker lamps are dangerous to your ecu--well yes anything which is hooked to the ecu can be dangerous if it creates a short circuit.In this regard the multi-meter is more dangerous than a properly constructed TPS lamp!I use the Mazda factory lamp and have never had a problem with it on my own cars.I know that the most accurate way to set the TPS is by checking the TPS output voltage to the ecu,but have rarely found this necessary.
2-The strap to the firewall does not provide the ground for the ecu.The motor is grounded directly from the battery--follow the negative strap it goes to the bolt above the top bolt on the starter motor.The ecu is grounded to the motor through wire(s) bolted under the support for the vacuum assemblies(drivers side).
3-The fact that you have a good ground at terminals 3A and 2R means that the ecu has a good ground BUT it does not mean that the sensors,such as AFM,TPS,temperature sensors etc are getting a good ground.If they do not get a good ground the signal to the ecu from those sensors will be DEFECTIVE and you will have a crappy running motor.You can only confirm the ground at the sensors by MEASURING it at the sensor or by measuring the voltage input from the sensor at the ecu.If the voltage input is OK you can infer that the sensor has a good ground.
4-Bad grounds at the AFM,boost sensor and the TPS are known,by Mazda, to create the symptoms you describe because they have produced TSBs describing the conditions.
5-The fact that you have no codes only means that the circuits are complete(ie not open).You do not get codes for any conditon other than open circuit.
6-Fix your plugs now--bad plugs are in the top 5
engine killers.
I am not familiar with the Snap-On Scanner,can you get ecu inputs and output signals on it? If you can it should be a piece of cake finding your problem.If not find a friend who has access to the Mazda Engine Signal Monitor.

Poindexter10thae

iTrader: (2)

Looks like I am going to have to make some friends that
1. ACTUALLY OWN 2ND GEN AND LIVE IN AUSTIN TEXAS(yeah right)
2. find someone other than the mazda dealership that has a engine signal monitor and would lend me the use of it.


The snap on scanner does not have that feature, to date mazda is the only manufacturer of a engine signal monitor for the Rx7

khoney

Big Woogie,
you and I are chasing the exact same problem. My problem seems worse when its hot outside, and it is intermittent (been nonexistent for a few days now). I've gotten some recent advice that I'm gonna follow up on this weekend (search for "violent hesitation" to find my post). I have a question for the group, though.

I mentioned earlier that I've been monitoring the TPS check connector output while driving, and when I get a bad lurch, it registers the 'idle' state on the LEDs. I looked at the wiring diagram, and this connector is not directly related to TPS position. It shows the state of the Switching and Relief Solenoid Valves. These are apparently switched by the ECU on the basis of a number of sensor readings, including the TPS (or maybe it is just the TPS?). Anyway, my question is: could a faulty relief or switching solenoid valve cause the bucking problems? They are responsible for controlling the state of the air control valve.

Another thing I noted. If you look at the inspection criteria for the Relief and Switching valves, there is only ONE proper setting at idle. The Relief valve should be on and the switching valve off. Reading the TPS adjustment procedure, it makes it sound like its OK as long as only 1 lamp is lit. That's not what I gather from reading sections 4B-43 and 4B-44 of the shop manual. Can someone shed some light on this for me?

Thirdly, the relief solenoid/air control valve have a switching point at 3750 RPM. Is the improper operation of this subsystem related to the infamous 3800RPM hesitation?

HAILERS

BigWoogie......I'm up here in Foat Wurth , and if you pay the postage I'll lend you my lamps that I bought from Mazdatrix. I also have a code checker (read the mazdatrix.com site) that I'll lend you, you pay the postage. Personally neither is worth the postage. Set the tps with a digital meter with a FULLY warmed up engine. Put the meter on the green with a red stripe wire at the tps connector. Do not disconnect, just turn the key on. The reading should be one (1) volt. If not turn the screw until it is one volt. Done. Thru. No more to be done. Nada. Fini. Go get a beer and rest. Unless of course you think the tps is defective. Then do like Irv, Six Rotors or someone else said and monitor the voltage thru its full range (1-4.65 on mine) and look for glitches. Or ohm the sucker thru its full range looking for gllitches. Make a ECU code breaker by http://home.rmci.net/panther/ecu_codes.htm doing that. If you want to buy my Mazdatrix Self-Diagnosis Checker, I'll sell it at half price to you. You'll have to wipe the dust off it though. Check Mazdatrix site for price. If you'd like to buy their lite checker, its yours for half price. Check the above site for price. You get a guarantee with the sale. The guarantee is that you'll kick yourself in the behind for ever buying them in four weeks time> KHONEY, ain't no way the acv is causing the stumble. Acv mixes air from the air pump into the rear exaust port or to the cat thru the split air pipe. Does not mix that air with the intake air. The 3800 rpm hesitation is attributed to bad grounds. The fix by MAZDA was to add a ground at the boost sensor. Splices into the ground at the boost sensor and attaches to a bolt on the engine. The boost sensor, airflow sensor, atp sensor, intake air temp sensor, water thermo sensor, tps, and variable resistor all share a common ground. They are spliced all together. If You ground one of these items, it seems you would ensure that the rest are now grounded better also. Reference the wiring diagram Bb=2. In case someone actually reads this post to the end, I have for sale a intake manifold for a six port motor. Just waiting for a holley carb. Made by Jay-Tech. A steal at 100 smackers. Does not get much better than this. Some intended humor in the above post. Shotgunning is more fun. Just cost more.

Blowtus

I'm also experiencing violent, intermittent hesitations all through the rev range, occuring almost always during my work commute, and not when belting round the mountains. I've found this thread most useful, thanks anyone... gives me a bunch more things to try

Charlie

peacekeeper

Hey Big woggie!
I haven't seen you in awhile. If you want I'll come help you work on your car. I only live in South Austin. I got that $300 rex running by the way. Give me a holler if you ever need anything. I'm willing to help.
Charles

Piranha

I made the lights... the ones you use for the ECU. As long as you put resistors and diodes in, I don't see what there is to worry about. Drawing too much current? Thats why you have the resistors.....