SimRX-7

having a problem when car is warmed up.
rpm is not determining factor.
i will be driving and try to accelerate and car bucks, coughs, and runs out of breatha nd dies.
now its ok if i barely touch accelerator but any more and this occurs.
if i shut car down and restart it goes away shortly.

i did change fuel filter, and take to a dealer(couldnt help me any)
dealer said;
-cats dead
-could be 2ndary injectors but then i asked tech and he said they come on about 2800-3k...and this problem is at any and all rpm.

dad thinks it might be a bad ground to ecm(will wire direct ground in morning)
also wants me to try to blow out fuel lines(maybe crap in line? but restart cures temp.)


ANY SUGGESTIONS OR OWNERS IN AREA WITH PARTS TO TRY(test-swap) WOULD BE APPRECIATED!!!

Anex 570

Longduck ! heh your the man. Anyway GSL-SE only has 2 injectors. Could be trouble with the TPS or even the throttle body. Hold tight someone smarter then me on the SE should chime in!

PT Ray

I say fuel delivery, primarely the pump. It was over a year ago when mine started to act up. The symptons it started out with was when you got it above 4k rpms it you have a loss in power. It would also just choke out while pulling away from a parking spot but ypu could crank back up as if nothing happened. The problems just got more frequent until one night it just made some awful noise while I rolled it into a gas station and did not crank back up until I replaced the pump.

Rx-7Doctor

iTrader: (13)

When this happens, pull over and remove the fuel pressure hose and see if there is any fuel coming out when you start to crank. If there is not then you need to test the fuel pump for pump pressure then system pressure and volume. If you crank it and fuel starts to come out and you reattach the hose then it starts and runs ok for awhile then starts over again the fuel pump is cavitating. which means it is failing or there is air getting into the fuel system.
The other setting is making sure the TPS is good and set correctly.
The AFM meter may be failing and have a dead spot on it. Can be tested per haynes manual for general idea of what is going on.
As far as the computer to test you will need to do a back probe test at the computer terminals to match values as set in the haynes manual.
When was the last time the distributor rotor was replaced? rx7doctor

LongDuck

RX7Doctor has repeatedly earned this title, and I think he's on the right track with TPS and fuel pump issues (as others have pointed out).

I would suggest adjusting the TPS first using a 2-light setup (search), since it is simple, free, and might fix the problem. Beyond that, you'll need to start looking into whether the fuel pump could be the problem, or if it's the fuel filter.

Filters are much cheaper than pumps, so I'd actually start there, and then move on the pump if the problem still persists. The FF is located under the rear axle on the driver's side and is easily accessible from under the car with jacks (and stands). The filter is a cheap part to replace, and should be done about every 2-3 years depending on fuel quality and how many miles you drive. You'll need the EFI type FF, however, and this is a very specific (and more expensive) part to replace. It looks like this;


Takes less than 30 minutes to change, but since it's fuel related, you'll need some rags and expect to smell like gas when you get done!

On the Fuel Pump, it is $389 from Mazdatrix (factory part), and looks like this;


I would hold off on replacing the expensive pump until you've done the other troubleshooting first. Start off with TPS and then go from there.

I'm in Phoenix, as well, so reply back if you'd like to get together and have a look at it - I could meet you somewhere. Take care, (and check out www.rccaz.com for the Phoenix area Rotary Club of AZ),

SimRX-7

well longduck i am open and available to all help!!!
i did replace the FF last monday...to no avail.
tried with multimeter to set the tps... probably same thing(i dont have the lights)
just checked rotor and cap...looked like normal age and condition so i cleaned the contacts.
its just strange that(i went out last night with it) when it acts up i restart car(even while going down the 101) and the problem goes away for a time

if your free today or tomorrow (315)529-4119 -dave

SimRX-7

is it possiable that the in-tank filter could be clogged? what type is it and how hard to get to?

LongDuck

The in-tank filter is part of the pickup assembly and is just a screen that filters out rough media as fuel is drawn out of the tank by the pump. This pickup floats on the top of the fuel level, so it should never pick up the crap at the bottom of the tank as long as you don't run it empty.

In that regard, as soon as the fuel flow stops, any crap caught at the pickup gate should fall off. Does this occur when you have a full tank of gas?

I'll give you a call tomorrow and see if we can get together,

Kentetsu

I had an old datsun hatchback and the PO had stuffed a paper bag into the gas opening when he lost his gas cap. Just stuffed it in far enough so that stray children wouldn't fall in or something, I guess. Anyway, tank built suction and the bag got pulled all the way in.

He sold it to me cheap...

Well, that paper floated on the gas and just like LongDuck said, it would get sucked up onto the intake screen. Once I stalled out and stopped pulling gas, it would slosh off. Turn the key and go, until next time...

This had my mechanic (hey, I was like 16 at the time) scratching his head for the longest time, because it was so inconsistent. Didn't even matter how full the tank was, it could happen at any time.

Of course, there's an excellent chance that this has nothing at all to do with your situation. Except, you didn't happen to buy your car from a man called Sid, did you? Good luck man...

LongDuck

Dude, that is a funny story!

Proof that strange things happen that result in odd vehicular behavior. Tried to give you a call just now, SimRX7, but the message said:

"sorry, but your organization has restricted this type of call. Message 42-610."

Don't know what that means, but reply back with a PHX number and I'll give you another call. Take care,

Kentetsu

SimRX7....

I hope you know how lucky you are to live in the right town. I couldn't imagine being able to just have an expert "drop by"!

You make me feel like I'm living on the North Pole, and I wish I had your luck.

SimRX-7

may be the right town but my allergies keep causing nosebleeds...i miss the east coast humidity!
1(315)529-4119 i dont have a phx # its my cell
you could email me your # at sim4runner@yahoo.com

Rx-7Doctor

iTrader: (13)

I have seen in vary rare cases the Dist rotor grounding thru the shaft and causing a crossfire situation that can give your exact symptons. The symptons would start off as yours then go to hard restart after sitting for 10minutes or so when the weather was warm. I had this happen to me with a 3 month old Bosch rotor.
Talk about testing my di
agnostic skills!!!! The problem got so bad that it just shut off on the freeway and would not restart. While doing a compression test over on the motor i had left in the front plugs and the ignition was hooked up. I was cranking and the vehicle started. So i did the same thing with the rear plugs and left the front out, it started again. Hooked up all plugs and would not start with no signal to either ignitor. Put in new rotor and ran, all previous symptons went away.
Recommend that you replace just as PM, if you have more than 15k would not be waste of money. But still don't forget to do all previous diagnostics if problem is not fixed by rotor. PM me anytime with questions.More than happy to help and had
addressed just about every problem on the SE. Good luck, rx7doctor

LongDuck

E-mail sent. Talk to you soon,

SimRX-7

i am curious about the temp sensor. car seems to act up when warmed up. also we are thinking afm. and fuel pump pressure?
as for the temp sensor...where is it and how to test.

and LongDuck... thank you for your help so far!!!

LongDuck

Some things we found with the car last night (so others can post suggestions);

1) TPS adjusted using 2-lights, was slightly off, but didn't fix the problem,
2) Timed perfectly, Leading and Trailing are dead-on and no stumbling/missing at idle - probably not ignition related,
3) Revs like crazy sitting still, hits a wall at 3k-3500rpm on the street, cuts-out
4) AFM tested okay - engine off, AFM door opening starts FP as expected. At idle, opening AFM door kills engine - as expected.
5) Heater return hose under oil filter tower is oil-soaked and will need to be replaced very soon,
6) Backfiring frequently between shifts and on deceleration,
7) '6'-ports are inoperable.

Some things to check;

1) Look at the pump connections and make sure the wiring has no frays or abrasions which may be shorting out,

2) Verify that the Thermowax system and diaphragm for choke are moving freely. At cold start (if you remove the airpipe to the TB when cold), the 'secondary throttle' butterflies (in front) should be open - behind them are the secondaries and those should be closed. If the vacuum system is working, the choke plates will close under vacuum on cold start, causing a rich mixture which aids in cold engine operation. If the vacuum diaphragm isn't working correctly, it may be choking the engine all the time, which would explain the backfiring and hitting the wall at 3k rpm.

3) I'm still not convinced that it's not a bad TPS. I have a spare that we can swap out, but I have some errands to run today and may not be able to get together today. That may be adding to the problem.

4) Check your gas cap to ensure that it's sealing correctly. When removed after running, it should give a 'hiss' as it releases the vacuum in the tank.

For those following along; if bad Cats, will they allow the engine to rev like crazy in the driveway, but bog down on the street?

TIA and HTH,

Also, your question about temp sensors - there are 2 of them, one in the AFM, and the other at the bottom of the Dynamic Effect Intake chamber. The DEI chamber registers manifold air temp, while the AFM registers ambient air temp. These signals are used by the ECU to determine whether the car is hot and also changes the fuel map a bit. Heat-soaking on hot restart will register as a bigger difference between the two signals, telling the ECU to run a slightly leaner mixture to help in hot-start. I've never seen these fail, but maybe someone else has.

NewRXr

Guys it could be the cat. I've seen many cases where the catalyst was busted up and the pieces were loose but trapped in the shell. It could always cause a restricted exhaust (yes it will rev like crazy without a load but die when really working) but after any period of time and especially with heavy throttle the pieces will pack together and cause a total loss of power even dieing. Then the pieces can fall back down, like with a tow or a lot of cranking, and it will start all over again.

Tap on the convertor with a mallet and listen for rattles. Or remove the O2 temporarily and take it around the block and see if the power is there.

Vernon

Rx-7Doctor

iTrader: (13)

Vernon is correct about cats but i thought you guys already addresed that problem? I don't see any testing on the fuel system yet though. A engine will rev perfectly at idle but when there is a load it will not. It has to have adequate fuel to keep the motor going and has to breathe. Taking the O'2 sensor out is a simple test. Fuel system/pressure test is not difficult either. You guys are driving me nuts,
wish i could be ther to diagnose,lol. Even thought the AFM passes the initial test it is not conclusive. rx7doctor

SimRX-7

so by taking the O2 sensor out that would bypass the restriction???
(now mind you that i dont have ramps or jack stands...etc. so just getting my 6'3" body near the underside of that car is an issue!)

SimRX-7

i am going to try the afm(after lunch) and see if there are electrical flat spots.

as for fuel system pressure... no gauge to test with.

where is the O2 sensor...after the cats near rear of car or before?

and the dealer already said cats were junk...so its a question of taking the pipe off and visual inspect. once again the issue of getting under the car.

NewRXr

The O2 is between the exhaust manifold and the catalyst. You can see it clearly from under the hood looking down the exhaust pipe. By temporarily removing it you will by-pass any restriction and it will run a heck of a lot better if that is the problem. Not that you would but don't go to far or hold WOT too long as it could start a fire.

Vernon

NewRXr

Hey guys I just thought of another odd ball problem I've stumbled across in many years of this junk. I went back and reread the post and it could be it.

Soft air intake tubing? I've seen rubber air intake tubing degrade over the years for one reason or another to the point that a fair amount of throttle will collapse the tubing. This usually happens once it's warm and flexible and your cruising down the hiway at a good speed for a while. Sometimes it is not detected until it happens everytime you go past 3/4 throttle. Once the tube gives it just keeps closing until it sucks together and chokes the engine. Little or no air is allowed past. Once the engine stalls or is shut off for a little while the tubing rebounds into shape. This usually occurs way before you pull over, pop the hood, get out, open the hood, and look. Then it starts and runs fine until you go again. Much to the insanity of all concerned.

Check the condition and rigity of the tube.

Vernon

LongDuck

SimRX7 - I'm back at home now if you want to give me a call to discuss.

While thinking on this further, you might want to have some one rev the engine (standing still) and go around to the back of the car. The exhaust volume should be enough that it will bend a rolled-up newspaper section at about 4k-5k rpm. If you're barely getting a trickle of exhaust volume out of the exhaust, it could be that the cats are clogged up preventing exhaust gas flow. (use the newspaper to avoid possibly burning your hand...)

Removing the O2 sensor will open up a hole about 1/2" in diameter - I don't know if that's going to be enough to diagnose a clogged cat, but it couldn't hurt. Problem is that the O2 sensor tends to weld itself to the exhaust fitting over time and can be very difficult to get out of there. Once out, you have the concern that it's going to be blowing very hot (~1800F at WOT) exhaust out of that hole... Risky, if you drive it anywhere at all to see if it's helped.

TPS swap is a 5 minute job plus reset; that may be a better direction to go and at least rules that out as being a simple solution. I'll be home - give me a call.

SimRX-7

a note to start...all 3 cats are completely empty!!! there may be a plug in muffler but i doubt it.

so the car died after leaving Wendy's for dinner(and after having just gotten off the phone with longduck) acting like there is no fuel. but i still have a 1/4 tank of fuel.

so lets find a fuel pump... then test the pressure regulator.

and we will be switching to 87 octane... my neighbors and the local mexicans dont like the "gunfire" that shoots from my tailpipe.

Rx-7Doctor

iTrader: (13)

When it does this you still need to pull off the pressure hose and see if it is pumping fuel when you attempt to start.
As far as the Tps there is no need to replace to test, just unplug it. If the vehicle starts to run fine there is a problem there if not then go onto other mentioned steps.
If you are popping thru the exhaust then you have unburned fuel which means flooding. When you turn the key to the on posistion do you hear the fuel pump coming on. If so there is a problem with the AFM. Should not come on until you start to crank. Running too rich or dumping fuel could be attibuted to the coolant temp sensor for the ECu which is located at the back of the waterpump housing.
rx7doctor