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-   -   This is weird!! (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/weird-913624/)

twan 07-18-10 02:20 PM

This is weird!!
 
Having prob with power and a/f ratio so to isolate the prom i Pull the codes. i get a long 4.
I assume its 40 but thats purge control. Ok, so thats another issue but doubt it has any affect on A/F ratio. So thats with the o2 sensor connected, Well, no o2 code, maybe thats not the problem right; but when I disconnected the o2 plug from the line to double check, I get a steady on "CEL". it doesnt blink at all. I sat and watched for like 2 minutes and no blink at all. Thats not supposed to happen right!!! Maybe my ecu is shot?

twan 07-18-10 08:36 PM

c'mon guys, i need opinions! Anybody have any experiences with this?

oo7arkman 07-18-10 09:43 PM

I do not think you are getting much help b/c your tittle is not very descriptive and your description of the issue you have does not make much sense. I am not trying to be a jerk, just my thoughts on why you are not getting much help.

I will try and help as much as I can or possibly try and foster help from other members..

How do you know the a/f ratio is off? Do you have a wideband O2 sensor? If so, what are the current O2 readings?

The factory O2 sensor is a narrow band sensor and will be little (if any) use to you.

Unfortunately I cannot help you with any of the codes, I have never used the factory ecu. Maybe someone will be able to chime in on that but there are also MANY threads on here on how to pull and interpret the factory ecu codes, all you need to do is search. I even think there is one in the 3rd gen FAQ section.

It is doubtful the ecu is shot. Not impossible, but very unlikely.

twan 07-19-10 05:51 AM

I kinda thought the title would get more views due to that but whatever, to late to change it now. Thanks for replying though appreciate any help at all. I 've been building this car for some time now and she ready to hit the road but I got this problen after loop transition. when engine is cold, she drives, moves, can drive around for a while, And ABS light is on. But, when all warms up, no power, no move, like shes bogging out or fuel cut. Why? TPS and Air bleed are reset, Compression in high 90's all around, new plugs, wires, and 2nd gen coil for leading. Idles great and starts everytime. LIMP MODE? NO codes besides 40 which is purge control and ABS light is off now. so thought O2 (stock, narrow). but i checked Only 40. so then i disconnect the sensor and "CEL" freezes. Doesn't go out till I remove jumper. She does run a little different when the O2 is disconnected but not much. pops in exhaust. No difference in power issue either. Maybe coolant thermosensor? did make sure that fuel and coolant weren't switched and fuel pressure is 35-40, filter new and pump is new wahlpro. Simplified seq with resistors and blockoff plates except for ICS. Any ideas welcome

oo7arkman 07-19-10 09:00 PM

Kinda sounds like limp mode, but I have no personal experience with that. I have only used the PFC.

The CEL is going to stay on with the O2 disconnected b/c it wants to see it. It is expecting feedback. Try resetting the ecu (instructions should be on here somewhere) and see if that helps.

But the ecu is not liking something. Possibly recheck all plugs making sure they are right and also go over all vac lines. They may be mixed up, it is easy to do. Does the car boost at all? If so what is the boost pattern?

twan 07-20-10 04:34 AM

When shes cold, i do get boost. trying not to hit it to hard cause the engine hasn't broken in yet but I do feel and hear it. Haven't actually watched the guage that hard yet. And limp Mode,Thats what I thought but once again, no codes??????? makes no sense unless bad O2, ICS, or Coolant temp.
Lastnight i started her up, the idle was low so I gave her some throttle, The LED's I have wired into the injectors are telling me primaries and secondaries are firing, so I can move her without problem. But after warmup, she tries to die out like fuel cut when i give her gas. cant get the secondaries to fire either. I can feel the change not easy to describe though

oo7arkman 07-20-10 04:38 PM

Secondaries should not fire until later. 4500rpm (I could be a lil off there but I am close) with the stock ecu I believe. They are linked with the initialization of the second turbo that also comes online around 4500rpm.

If you believe those sensors are bad they are very easy to test with an ohmmeter. Correct ohm readings are available in the FSM and related electrical diagram. If you have not downloaded them they can be found here in post #10 and are invaluable.

If they are out of the listed range then they are bad. Contact Ray Crowe at Malloy Mazda for replacement parts. He gives us a great discount on oem parts. Search on here for his phone number. If those check out, it has to be something else.

Edit**One more thought. When is the last time you changed the fuel filter? This sounds like it could also be possibly clogged...

twan 07-20-10 08:12 PM

I changed the fuel filter a little ways back but the car hasn't been really running. It's been since i have had the motor back in. Thanks for your thoughts. I believe the secondaries come on line when the primaries hit 40% duty cycle, and they are doing just that when the engine is cold. But the change from one loop md to the other. It did it again today. She drove great for lite 10 to 15 min; and i watched the boost gauge this time. I hit about 5 psi but my street aren't long enough to do more before I have to break. And scared to go too far from home cause dont know how long i have. I will replace those sensors. I've already changed everything else. I'll do the resistor mod to the ICS to take that out of the equation. The its just the Coolant thermosensor and the O2 sensor.

twan 07-22-10 01:59 PM

Update!!! took the ecu out and marked it where the input from a few sensors like the Fuel thermo, coolant thermo, tps, map and O2, goes into the ecu and found out that at the connection 1U, i'm getting a strong 12 volts. the FSM says that it should be 1.5 to 3.0 v which is the Fuel thermosensor. Could that be the problem, the ecu is being overloaded or something from the extra voltage or maybe it's responding to that voltage and doing something to the fuel curve? Im guessing here but im definitely getting 12 volts at connector 1U. The coolant thermo was about 3 volts so I assume thats ok. gonig to test the map after i finish my way too strong black medallion and coke!!! Dont hate!!

twan 07-22-10 03:52 PM

OOPS!!! scratch that. That was not the connector for the fuel thermo. I was wrong, The correct connector was showing within spec for both the fuel and coolant sensors. The MAP sensor however is definitely shot or at least its not seeing any change in vacuum vs pressure. I hooked my VOM to connector 1O and its reading the voltage at idle just about right but when I give it throttle, theres no change in voltage at the ecu connector. Checked contunity so I'm at the right wire. gonna also do a bench test with a guage.

twan 07-22-10 05:49 PM

Could I substitute a gm 2 bar for the stock map sensor? friend of mine says he has one!
Would it be plug and play with the stock ecu?

REVIT93RX7 07-22-10 07:30 PM

Weird
 
I would get everything healthy before I started changing MAP sensors etc. As one poster asked how do you know your AFRs' are bad? Just a suggestion can you reverse your NS changes and put everything back?

twan 07-22-10 10:20 PM

I agree with getting everything healthy first thats why I am looking for a stock sensor but I just thought if I could get one for nothing, it might be something like a God Send. Plus I could have gotten it within the next 12 hours but that plans been changed for the weekend anyway. I actually wasn't 100% sure about the A/F ratio but the symptoms were similar. Really, i just assumed that there was too much air vs fuel; which is actually true. My understanding is that the MAP isnt seein or at least transmitting the change from vacuum to pressure, via voltage increase, to the ecu. Therefore the duty cycle inst increasing and secondary injectors are sleeping soundly when I need them to work. This is just my theory but based on the VOM, it makes sense. Too late to put anything back on but it's only simplified sequential not NS besides the runs great until the ecu begins to look for inputs to run the engine/ fuel curve.

twan 07-29-10 12:36 PM

You guys are lucky that I cant leave voice messages on this forum cause if I could, your ears would bleed from me shouting HOORAY!!!!!!!! All issues seem to be fixed. Replacement MAP is on and my baby is running like a champ!!!!! COLD AND AFTER WARM-UP. Dont worry, not boosting hard yet. Plus i have a boost leak anyway; which is actually good. I know exactly where it's coming from and will fix after break in period!!!!!!! Thank you all for all your help!


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