alritzer

I have searched and read but now its time to ask.

I have a 1990 GXL / T2 swap. The PO blew a rotor after the swap, so we swapped in another 1990 T2 motor. I can not get it to run correctly.

Compression is 90 psi
New plugs and wires
Vacuum is about 15 psi
Timing is dead on.
Idling is pretty good. It is about 900 rpm +/- 50 rpm. Bouncy.

The car will not accelerate unless the pedal is pressed very slowly. If the gas pedal is even tapped hard, the motor will completely cut out. Its very hard to get the car to even move if its not on a level surface. To start out on a small grade you have to slip the clutch while keeping the rpms up to 3000.

thanks guys

satch

iTrader: (1)

Take a voltage reading on the wires at the Boost Sensor w/key to on and see what you get. There are 4 wires with one of them being a ground.

alritzer

Also:

RTek 1.7
750 cc secondaries
Walbro 255 pump
Front inter-cooler

matt87FC

iTrader: (12)

Doubt this will help you much but i figured id throw it out there. My 87 n/a did something similar and it was because of tps adjustment. Setting it back to 1v corrected my issue. Dunno if this is.even relevant to you on a T2 with RTek but maybe worth the time to atleast rule it out?

alritzer

While adjusting the TPS I found that the plug for TPS and the plug for the OMP had been swapped. I have no idea how long it was like that. I was able to adjust the TPS using the led method so it must be OK.

Would swapping the plugs damage the TPS or the OMP? The plugs are almost identical except one of the male plugs is black and one is white.

Setting the TPS had no effect on the way it runs and it runs really bad. I took it for a short drive and I didn't think I was going to able to get back home.

ash

satch

iTrader: (1)

If you take a voltage reading on the wires at the Boost Sensor and find that two of the wires have 12 volts w/key to on then you will have found your problem. This would be caused by a Turbo emission harness being mated to a non turbo front harness and the appropriate changes not being accounted for as these two harnesses are not compatible thus requiring changes to be made to ratify the difference.

alritzer

OK, are you talking about the sensor on the right fender wall or the sensor that is on the left side of the motor, near the oil fill.
If they are 12 volts with key on, can you point me in the right direction to solve the problem. The engine harness that came with the car was not exactly like the harness that came with the swap motor. Maybe I should take the harness off the blown motor and swap it onto the motor that is in the 7. Or not. What a pain. This is my 5th 7 and I have never had a problem like this before.

The guy I bought the 7 from told me that it ran really great and had no problems until he blew the rear rotor seals.
The motor that I swapped in has a questionable past. The guy that sold it to my Dad said it had recently been rebuilt and was street ported and only had about 38000 miles on it. But, he told somebody else that he had NO idea how many miles were on it.

ash

satch

iTrader: (1)

The Boost Sensor is bolted to the passenger fender well via a bracket and also has a vacuum hose plugged into the bottom of it and features 4 wires to it.


Pic of Boost Sensor at the bottom of the page linked to.

http://www.mazdatrix.com/86-92Electrical-Engine.htm

alritzer

OK, I know which sensor you refer to. If they are 12v, how do I proceed?

satch

iTrader: (1)

There should be one wire with 12 volts w/key to on and not two. You're a little ahead of yourself here for if there isn't a problem then explaining the manner to how to correct it would be a bit counterproductive.

EDIT: Since you have an S5 there are only three wires to the sensor and not four like an S4 Boost Sensor.

alritzer

OK, great, thanks for the help. I will check the boost sensor in the am.

satch

iTrader: (1)

The three wires at the Boost Sensor should have the following voltage readings. Green/Yellow = 3.4 to 3.6 volts w/key to on and hose disconnected and capped. Brown/White = Approximately 5 volts w/key to on. Brown/Black = ground. Now the problem I spoke of occurs on an S4 turbo swap when the turbo emission harness is mated with a non turbo front harness. The problem is I am not sure the same problem exists on an S5 that had the same procedure done to it but check these three wires anyway and also check the number on the Boost Sensor to see if it is for a turbo and not a non turbo engine as they are not compatible.

alritzer

The wires are:
green/yellow 2.3 v
brown/black 5.0 v

The boost sensor is a NF01. I'm not sure if this is the correct part.

ash

satch

iTrader: (1)

Did you remove the vacuum hose and plug it when you took the voltage reading on the G/Y wire and was the plug connected to the sensor as it should be? Also, NFO1 is not the part # as I believe it should be something like N370.

satch

iTrader: (1)

I think you meant to say Brown/White is 5 volts and not Brown/Black as Br/B is the ground wire.

alritzer

I did and it was. I searched for the part #(NF01) and somebody said it was for a Cosmo and that it might be swappable.
Is the difference in voltage (2.3 v as to 3.4- -3.6) enough to cause my total lack of power?

The wiring harness that was in the car is not the same as the wiring harness that I am using now.
The wiring harness in use now: Immediately after coming through the firewall, it has a connection for the wipers, then it goes to the boost sensor, then to the injectors, OMP, water sensor and then to the left side of the motor.

The harness that is on the original motor: Immediately after coming through the firewall it goes to the left side of the motor, then to the injectors, OMP, water sensor, boost sensor and then back to the wipers.

It looks like the connectors are all the same but they are just laid out differently. But I can't tell what it looks like under all of the stuff on the left side of the motor. Both motors were supposedly from 1990 RX7 T2s. But, are they really? Could this be the problem?

satch

iTrader: (1)

I don't believe the voltage reading you got is acceptable.

HAILERS2

What kind of RTEK do you have on that series five turbo car?

Sounds a bit like someone who has the elect plugs for the primary and secondary crossed up..........or like a car with the sparkplug wires crossed up. Like lead on trail and vice versa.

Got a fuel pressure gauge? See what the fuel pressure is at the rails.

EDIT: It also has traits of a car whos throttle plates are a bit screwed up. Talking about the two sets of seccondary throttle plates. Maybe something is'n t quite right there. I'd make sure the inner set of secondarys are closed at idle. Theres a figure in the FSM where you check 'em. The primary has to be closed........and then as you open the throttle plates, the secondarys open when the primary is approx ????? 0.17 open. Real figures are in the FSM. I was just using memory here.

alritzer

It has the RTek 1.7. Plug wires are definitely attached correctly. I'll get a fuel pressure reading today and I'll pull the UIM to double check all of the wiring and hoses but I'll be totally surprised if I crossed the primary/secondary wiring.

The TPS and OMP wires were swapped. Could that mix-up have damaged the OMP? Could it be in "limp-home mode"?



thanks for the help guys........ ash

satch

iTrader: (1)

You can check codes for limp mode or other error codes. If need be take the Green single wire check connector located near the leading coil and ground it to the negative battery terminal then follow that up with the key to on and you should be fed the available error codes if present.

When you say the TPS and Oil Metering Pump plugs were swapped what do you mean "exactly?" Do you mean the wires and plug to the TPS were connected to the OMP and vice versa "or" the plug from the TPS was cut from its harness and used to connect to the wires for the OMP and then connected to the OMP in addition to the plug from the OMP being cut and then being used to connect the TPS wires to the TPS? If it was the former then yes, there is a chance you fouled up the OMP and ECU.

LunchboxCritter

iTrader: (9)

You most likely should replace that pressure sensor with a N370 one. Your AFM should also be a N370 model.

alritzer

Right, the plugs for the OMP and TPS are almost exactly alike. One of the male ends is black. That is the only difference. Somebody (I'm pretty sure my bf) plugged the connection for the OMP into the connection for the TPS and vice versa.

I just did a fuel pressure test. The fsm says the pressure is supposed to be able to hold above 57psi for 5 min but the pressure never reached 55 psi and within 10 secs had dropped to zero. The maximum pressure was about 52 psi but actually started to drop while the pump was still running.

Would the lack of fuel pressure be enough to cause the problems I'm having?

ash

alritzer

Thanks I'll look around and see if I can locate one or both.

ash

satch

iTrader: (1)

If the car wasn't run then it won't make a difference but on the otherhand................... An error code test as suggested above will tell you whether your friend screwed the pooch or not.

alritzer

OK, I'll check for errors.