Kaiser_Damz

My car was having a few issue's with turbo switchover but has no stuck itself in constant limp mode. can't rev hard as engine just splutters, can rev high by gently pressing the gas. I disconnected the neg lead on the battery, waited about 30 odd seconds, press the brake pedal and held it down for a minute. put lead back on and still in limp mode.

I then connected the ten and gnd leads but nothing flashes on the dash so no code.

the car is a 1995 rx7 fd, stock ecu, pretty much stock all around apart from hks air filters.

Change spark plugs, oil and filter a month ago, changed fuel filter about 6 months ago.

Selbor

iTrader: (1)

By chance, when you attempt to drive it and above first gear does it repeatedly stick the rev's at 2.5k to 3.5k?

Sgtblue

iTrader: (16)

It sounds like limp mode. The ECU will not allow timing to advance and cuts fuel if vacuum isn't seen at the intake. If it bucks as soon as your boost gauge reaches zero, it's limp.
Since you're in Scotland, I'm assuming your's is a RHD car. IIRC, things are a bit different on those than our North American models which had a CEL on the dash. Here's a link to RHD specific manual (Aussie) that may be of some help. http://www.fdrx7.com/forum/manuals.php
Good luck.

Kaiser_Damz

yup, when moving it can't get more than 3kish when moving, only at a standstill.

one thing I noticedis the nipple on the charge relief valve appears to have snapped as I found a hose going from the uim that would connect to it. the nipple is still within the hose.

Selbor

iTrader: (1)

Ok so ill go into detail what happened to me when i first got my RX7 this sounds very similar to it(But there is a possibility that your problem may or may not be mine). the Symptoms was that it idled fine but after the car is on the road when in 2nd gear and above, if you were to depress the accelerator the cars would rev to a no greater then 3.5k-4k rpm. Then the ecu/engine would reduce the rpm to about 2.5k and try to rev up again. This is a repeating process that happens about every second. This was wayyy beyond my level so i took it to Kilo racing in florida (or a local rotary shop)

THE FIX- the oil metering pump that injects oil into the fuel mixture was shorting out ( uses a metal rod and a transformer for a sensor method) that was defined because of a hair line crack running down the shape of the transformer. ALSO the ECU had to be replaced in conjunction with the pump. (when a transformer shorts out it sends higher then normal voltage down circuit paths that cant handle it, and in my case blown two capacitors)

why it acting like that was because with the ecu being fried it couldnt read engine data and was constantly restarting that is where the rpm cutting out and back in came from. So there is the possibility that your ecu may be gone but there is no guarantees unless you swap it with a ecu from what car your generation is from.

Selbor

iTrader: (1)

I went through the forums and these links should help you out a great deal if you want to check the pump yourself. Also it doesn't hurt to read up and gain more understanding about it. the 4th link has the info about limp mode; I guess I was half wrong about my theory, my capacitors were blown so the ECU never could read the OMP signal so it limp modes the car :/ Now if you are new to electrical ohm checks if you find what connections the signal goes on you SHOULD NOT SEE either a low ohm reading (less then 50) or a Overloaded ohm reading where the multimeter cant even tell if there is a connection. from what the info from the links show looks like you should see a reading between 500-2k Ohms. Anything outside that means the pump is bad. you can refer to a wiring harness schematic to figure out where you can check on the connector but i know for a fact that you will first need to remove your air filter box and the intake channel that comes from the front of the hood to the filter so you can have room to see it.

https://www.rx7club.com/3rd-generati...sified-892750/
https://www.rx7club.com/3rd-generati...art-ii-895388/
https://www.rx7club.com/3rd-generati...mikuni-897507/
https://www.rx7club.com/3rd-generati...e-ends-978918/

if anyone else wants to look through and make sure my info is right please do, I make mistakes too

Sgtblue

iTrader: (16)

There are other things that will put a car in limp. He needs to find out the cause on his car. If it ends up being one of the three different codes (North American models) that point to the OMP, I can give him another link. But that's premature at this point.

Selbor

iTrader: (1)

and thats the fun in troubleshooting, you got to check the areas that can cause it to limp. I think I hit one area lol

Kaiser_Damz

don't think it's the omp. I had this happen before and managed to reset the ecu, worked fine and drove about. Then a few days later I started it up and was in limp mode. If i had fried the ecu it wouldn't get out of limp mode at all.

Selbor

iTrader: (1)

well thats all i got :/

Kaiser_Damz

managed to get it working, seems like some solenoids were being a bit odd, I fitted mbc's and bypassed the solenoids which go from turbo's into ratsnest and it works fine now.