Hesitation Problem - NOT a ground problem I don't think

 
 
 
 
Old 10-27-01, 01:15 AM
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Free Stuff for Help - Hesitation Problem - NOT a ground problem I don't think

This is more complicated, and to anyone that helps me figure out why my baby is not running well, I will get A Gift Certificate for 50-100.00 to some RX7 related site, or any part in that range that you would like me to buy you.

YES this is bribery plain and simple

For anyone that just wants to help and doesn't need the bribe that would also be VERY much appreciated.

Ok here goes:

48k original miles 3rd Gen TT

Mods: Mid pipe, K&N Intake, 3" Exhaust all the way back, ported.

Problem: The problem is a hesitation that is NOT fuel injector specific like the ground problem it does not care what rpm I am at, but it DOES happen RIGHT when the secondaries open up, I can feel the spring in the pedal for the secondaries how its a little stiffer right when you depress at that point, and that is RIGHT where it does it, it makes the car bog to no end it will not even make power to keep its own wheight moving, its like fuel cut but with enough fuel to keep it running, but bogged.

Tested: Tested good ECU, Tested another Boost Sensor, pulled vacuum line for secondary valve, Tested ohms on TP sensor and it LOOKS ok but kind of funky sometimes can't tell if its perfectly smooth or the little bit of shake is normal its not all over the band but was hard to hold meter, lines and do throttle to check if it wigged at the secondaries opening or not, not sure if this would cause that problem or not tho.

History: Did this while blown motor before AND now with brand new motor.


Thanks in advance for the help!
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Old 10-27-01, 11:42 PM
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on the passenger side, where the engine harness goes just under the plenum is your fuel pressure reg, remove the vacumn line from it and plug it off. this will raise your fuel pressure - see if problem is gone for normal driving (while line is off do not drive under extreme boost levels)

also, did you check the resistance of the injectors? They should be approximately 13.8 ohms.

have you checked the fuel lines for splits where fuel might be leaking?
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Old 10-28-01, 05:54 AM
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Have not checked these things, the rear injectors are newly flowed and such, but today I found something interesting.

I was driving and thinking about the different grounding problems I have seen and the peoples fixes for them so I decided to see if I could get the secondaries to engage BEFORE 3k and see what it did, wouldn't you know it boosted 10psi no bucking and went up to 3k and BOGGGGGGGGGGGGGED bad...


WTF is going on ??????????


Ill check the ohm on the injectors and the fuel press test, its got the hi flow ND cosmo pump in it, so unless thats bad I think it would be good fuel press.
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Old 10-28-01, 06:28 AM
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the secondaries don't come on exactly at 3K. secondaries come on based on load and rpm. so it changes. also, reset your computer when testing different things. for example, when you check the fuel regulator, reset the computer prior to driving. ECUs in general "learn", so you want to clear the memory. to reset the ECU, disconnect the negative terminal, and hold the brake down for 15 seconds (maybe 60 sec, i can;t recall, so i just hold it for 60 sec).

remember, in the fuel systems of injected cars, just a strong, high flowing pump is not enough. you must have good and consistent flow through the fuel lines, injector rails, etc...

let me know what you find, cause i am going through the same thing you are.
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Old 10-28-01, 10:28 AM
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What are the condition to ur plugs??? Maybee one fouled out. Maybee ur wires are loose leading to the plugs. Have u checked the tps? Maybee needs adjustment. Also, why dont u have an aftermarket ecu? With those mods, i suggest u get one. These are just thoughts to what might be ur problem. For a minute, it sounded like the hose blew off to ur boost sensor.
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Old 10-28-01, 11:27 AM
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Can you accelerate to higher RPMs as long as you stay under light throttle? Does it only bog when you really put the peddel down? If you can accelerate to higher rpms, say 4-6k, with light throttle and it bogs as soon as you floor it and will not make power again till you let up then I may know your fix.

Last edited by broke3rdgen; 10-28-01 at 12:09 PM.
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Old 10-28-01, 02:48 PM
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I can get on it a little bit before 3k and does "ok" but after that it bogs, also LIGHT throttle, runs JUST fine until about 4-6k like you said but it BUCKS under light throttle at that point and under medium to HEAVY accel after 4k same bogging and won't go back to normal until I left off the gas, just like your saying.


;?
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Old 10-28-01, 03:35 PM
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yea Broke3rdgen, let us know what the fix is. I may need to know someday.
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Old 10-29-01, 07:58 AM
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This is exactly what was happening to mine about 5-6 months ago. I think it's gonna be your fuel pressure regulator. It's kind of a pain to change out but it can be done (I did it myself in about 3 hours). Also you can bypass it before you change it to make sure that's your problem. I ran mine with it bypassed for about 2 months before I actually changed it out. And from what I've been told it doesn't cause any problems to bypass it. If you need any help changing or by-passing let me know and I'll help you out all that I can.
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Old 10-29-01, 09:08 AM
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If you by-pass it is there a solinoid that you must remove?
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Old 10-29-01, 10:04 AM
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Not necessarily remove, but by-pass yes.
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Old 10-30-01, 05:51 AM
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how do you bypass it?

Is it anything more than pulling the vac. line off and plugging it?
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Old 10-30-01, 11:22 AM
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Look on the bottom side of the hood, there is a diagram of solinoids. Look for the one marked presure regulator (I believe it's the one closest to the fire wall) just pull both lines from it and conect them with a small piece of copper tubing. Done.
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Old 10-30-01, 12:30 PM
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i have done that but i have still the same problem.

would the fuel pressure be bad if that was it?

how hard is it to change the pressure regulator?

If you do the by-pass you are saying, should it stop doing it?

i have eactly the same problem and i have been working on it all summer.

my fuel pressure is good though so is it because that is not my problem?

please, tell us more.

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Old 10-30-01, 01:54 PM
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I had a similar problem but not as bad, I had my plugs (NGK)changed and ended up one of them was bad, easy fix since it wasn't doing it before.

Has your fuel filter been changed recently?

Has it alwasy done this since the new motor was put in?
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Old 10-30-01, 02:17 PM
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First of all if this is your problem fuel pressure should still be good. Changing the presure regulator is not that hard except that the screws that hold it in are phillips heads and right up against the fire wall. You should have just enough room to get one of those little stumpy screw drivers in there. I then used a pair of vice grips to turn the screw driver while a friend held it in place. The next problem is actually getting the regulator out. The little rubber o-ring really holds it in there tight. Hopefully you know of a way to get the fuel pressure out of there before hand because I got a face (and eyes) full of gas when it finally popped out. Putting the new one in there is a tight fit but not too bad. Put the two screws back in it. Be extra carefull, as always, to put you vacuum lines back on correctly. Bolt everything up and you're done. If I remember correctly the part was around $175 from Mazda. Total job took me about 3 hours.
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Old 10-30-01, 02:55 PM
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"First of all if this is your problem fuel pressure should still be good"

you mean that even if my fuel regulator is bad, i should be reading the right fuel pressure?

How come it doesn't affect the pressure?

thanks a lot

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Old 10-30-01, 09:45 PM
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Your pressure regulator is in line right before you get to the injectors. The spot that you (or at least I) check fuel pressure at is in line before you get to the regulator. I don't know of any way to test presure after the regulator, or for that matter test the regulator itself other that to by-pass and see if it fixes you problem.
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Old 10-30-01, 10:23 PM
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i'm trying to find the solenoid for the regulator -
i don;t have the diagram under the hood, and can't seem to find it in the manual -

i know where the regulator itself is - is it near this? a pic perhaps?
thanks
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Old 10-31-01, 06:45 AM
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solenoid rack, orange one, closest to the firewall.
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Old 10-31-01, 12:03 PM
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ok here is an other one

is it possible to test it by plugging both hoses?

what would happen?

i by-passed the solenoid but it still does it.

puma
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Old 10-31-01, 01:11 PM
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hesitation

have you checked everything everyone else told you to check?
blahh
blahh
blahhh
blahhhh

if none of those applied here may be your answer but you have to promise to tell me if it was or not due to the fact that i had this happen to me on a second gen 89+ gxl

here goes you start the car take of normal. once you get on it it buggs like cracy it almost feels like someone hit you from behind
i tryed grounds i tryed cleaning injectors none worked

the finaly came to someone smart enough that told me to check the oil meter pump and computer( on a second gen if the oil meter pump goes bad the computer will do the same . do not replace the computer first or you will burn it . IF OIL METER PUMP IS BAD THE COMPUTER SENDS A SIGNAL TO MAKE YOUR CAR RUN IN A LIMP MODE ( ITS A WAY THE CAR TRYES TO GO IN A SAFE MODE)

I KNOW EVERY ONE IS GOING TO SAY **** OIL METER PUMP IS VERY EXPENSIVE . $ 1200 FOR THE SECOND GEN NEW. USED WAS LIKE 700 I WENT TO A PICK A PART AND GOT IT OUT MY SELF TOOK IT TO THE COUNTER THEY THOUGHT IT WAS AN OIL PUMP SO THEY ONLY CHARGED ME 10$

SORRY FOR THE LONG POST HOPE THIS HELPS
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Old 10-31-01, 02:23 PM
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and how do you know it is the trouble?

should there be a code on the ECU for that?

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Old 10-31-01, 08:07 PM
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as i said before

this is what happened to me on my second gen 89 gxl. and dont know much about 3rd gens at all. but they are descrbing exactly what happened to me.

but it only happens on 89+ rx7 do to the fact that 88 rx7 had a manual oil meter pump and 89+ came with electric oil meter pump

yes i did replace the compuetr first and burnt it then i got another computer and oil meter pump

i installed the oil meter pump first then the computer
and walllllaaaa it worked like a charm but
scince it took me so long to figure it out and kept driving the car like that the engine died after 3 months from it due to no oil mix

and yes i tryed everything else before i got the this point . but hey the good news is this happend to me and may be might just fix u up too

i could give you the name of the person who told me about it
his name is Brian and he works for maz-max in houston
you could give him a call there if you had like . i dont have the # right of hand . and ask him if this even apply for the 3rd gens

sorry guys like said it was just a thoought.

i dont know for sure.

please dont flame me im just someone trying to help


sorry for long post
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Old 11-01-01, 04:54 AM
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I have not had a chance to try this but I am hoping to try the bypass method this weekend, unfortuneately my car has a MazdaSpeed Carbon Fiber hood on it, so there is NO solenoid diagram that I can refer to, can you give me another method of finding it ?
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