rx7r3

Bought 94 a/t rx7 Bogs,b/fires and won't accelerate. Idles well but can't drive over 10 mph. Does not smoke.
Things I've done...
1)Replaced all vacuum lines.
2)engine replaced b/4 i bought it.
3)leaky 2ndary inj. replaced.
4)boost sensor replaced.
5)fuel filter replaced
6)turbo's replaced b/4 I bought it.
7)pulls 10 on vac/boost gauge.
8)replaced plugs
9)fuel pressure test
10)replaced bad sensors
11)put on downpipe
12)cleaned fuel pump filter
13)replaced fuel pulsation dampner
STILL RUNS THE SAME!!! Soon as I press the gas it stumbles, spits and backfires...
Possibly TPS or Crank angle sensor or rest of injectors?

I'm stumped and $100.00 goes to the first to figure it out. Please no guess's and no amateurs.

Rob.

COLBALT

have you tryed yor ecu?

rx7r3

Yes I switched it out w/1 I bought used. The guy said it was to an a/t however when we installed it the hold light stuck on making us believe it was to a 5 speed. Car still ran the same so either way we deducted that it probably wasn't the ecu! Agree? Thanks, Rob.

user 84205

Coils? Grounding wires?

Switch back to the original ECU, and see what happens..

Jason
www.jt-imports.com

rx7r3

We switched back already and checked grounds and added Pettit ground wire setup also, (forgot to mention above,sorry) Coils seem fine, any way to test them?
Rob.

user 84205

Coils,
Mazda has a tester, I heard its kind of unreliable though. Also did you read the codes from the Original ECU? If you read the codes, it will tell you about the TPS and all the rest of that. Injectors shouldnt be fubar with the car running like that. They all would have to be broken, but then again it wouldnt run...

What about the turbos? They were changed? Did you see it happen?

Jason

SPOautos

Ok, here is my list in order

cloged cat (how many miles are on it?)
You vacume is low so you have a problem there, if you have a good idle its probably a leak which can also cause your car to run bad. Check all your upper and lower intake bolts and gaskets to make sure they are ok and tight. Look for any open nipples on the front and back of the uim and solenoid rack(there are supposed to be a couple open on the rack.

Test the coils, or at least pull the plug wires off the plug and turn the car over to see if you get spark, just do it for a second to make sure they have spark coming out.

Check to make sure the plug wires are not crossed. Replace plugs.

I would also suspect a bad wireing harness. Make sure all the connections were put back right when the motor was replaced, maybe look at things like the crank angle sensor connections and make sure they are not backwards.

Can you give us a little more info on the history of the car and problem? Did it start when the new motor was cranked up? Was this why the motor was replaced? Did it just start all the sudden? Were you guys doing anything or working on it around the time?

Another part that can cause big probs when it goes is the air temp sensor in the underside of the uim. Make sure its hooked up and tight, also if you know someone with a PFC you can install it and check to see what the temp says. If it shows a negative temp its bad. This will retard off you timing a ton and the car will barely run.

Hope this gets you started,
STEPHEN

jspecracer7

Just use the screwdriver trick to test if you've got spark or not...if you've got spark, then your coils should be good.

atpeak23

But ... You can make sure each part is tested and works that you replaced... When you replace something it doesn't mean it works.... Make sure the sparkplug wires are A OK... They caused me problems..didn't think they would fail but they did...

black99

Def. sounds like a vacum leak, fuel or ignition problem.. However it idles well with no smoke.. I'm lost on this one..

puma

iTrader: (2)

yeah, check it there ain't any cross spark plugs wires

jspecracer7

This may sound funny but have you checked your map sensor? Made sure that it's plugged up? Made sure that it's a good map sensor?

puma

iTrader: (2)

just do like me, find a friend with an FD and swap UIM, coils, ignitor and see what happens, if it does the same, the problem is not there.

just a thought, it ain't long if you are used to remove the UIM.

the MAP is a good idea too, i tried it, easy to swap from an other car.

rx7r3

I replaced the cat w/a downpipe.
The engine was replaced by a shop b/4 I bought it.
The turbos were also replaced by them.
Lots hoses and connecters backwards, it's amazing it ran at all.
Replaced the map sensor and then took it back to dealer for a refund, they did'nt like that so no more returns.
No wires crossed.
How can we tell if spark plug wires bad?
We replaced the plugs.
How do you do the screwdriver test?
What is a pfc tester?
I bought the car running this way to fix up.
Went right by the Mazda manuel. Tough when other hands been in the pie tho.
What is a UIM?
Thanks Rob.

rx7r3

GOTTA BLOWN CIRCUIT (mentally) so I'm going to fix it w/sleep. I've had 4 mkiv Supras and 2 94 rx7's and the 4 supras combined NEVER gave me one mechanical issue,EVER!

spooledUP7

UIM = upper intake manifold.
I would say that the coil (leading) is bad as well.

Wargasm

Where are you located in VA? If you're close to me, I'd like to come take a look in person.

Brian

SPOautos

I meant the main cat no the pre cat. The pre cat is replaced with a downpipe. The main cat is replaced with either another car, high flow car, or midpipe....depending on how legal you want to be haha

Tell ya what, crank it up and get someone to rev the engine with your hand by the tail pipe.....watch out though the exhaust can be very hot. It should blow out **** loads of exhaust. If it doesnt or if it feels weak I be the main cat is cloged. This really isnt a prove all test. A better way would be to drop the cat and drive down the road to see if its goes over 10mph.

STEPHEN

SPOautos

Also - was the turbos replaced before of after the motor poped....or at the same time?

If they were replaced then the motor poped they were probably trashed again.

STEPHEN

Mr rx-7 tt

iTrader: (5)

Might be the thermal sensor on back of the water pump housing...I believe the crossover number is tx4040 try your local auto parts store.

mazdaspeed00

iTrader: (6)

im guessing map sensor also. but you should be able to go faster then 10 mph with the map sensor disconected. try slowly applying pressure to the gas and see if you can go over 10 mph. if u can i think its the map sensor and your ecu is running in safe mode.

RAMotorsports

He said he replaced the "boost sensor". I'm sure he means he's replaced the map sensor already. However, if you haven't disconnected the battery to reset the ECU, it will stay in safe mode. Usually, the simplest of things ends up being the culprit, good luck.

GsrSol

First reset the ecu the correct way or leave the battery disconnected for a few days.

Your vacuum reading is low. Unplug the boost/map sensor and see if it acts any different. However it shouldn't idle very well with it disconnected or bad.

You can't go over 10mph. Can you sit in nuetral and rev it up? Im confused, is yours an automatic? If so it may be that safety switch.

With what you have told us, all we can do is guess.

DK

iTrader: (5)

You can test the plug wires and coils by pulling the plugs and putting the wire back on the plug, grounding anywhere on the metal base of the plug, and turning the ignition over (you might want to pull the fuel pump relay beside the battery +). There's no benchmark spark size for me to tell you to go by, so just look for a "decent" sized spark consistent between the L and T pairs.

This is the basic quick dummy test ... given the radical symptons that you are seeing, it would give you the idea of whether or not the wire or coil is the problem.

kkk93rex

one thing to check is is crank angle sensor it should 1mm away from the plate if its too far away gets a shitty singnal and runs like **** check it shright too.
Another issue with my car is it got really badly flooded to the point it atected like that there was gas in my exhaust manifold when i pulled the injectors. I ran it around for short distances then i just took the cat off it dorve arond and it slowly improved then it started somoking white and cleaned were talking like 30 miles throgh my neighboor hood never let it go to vacume. Just a thought Worth a try.

To check your wires hook em up to an ohm meter and make sure they have power.

Do the same with your coils they should have more than 4 ohms. restance.