2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

WOT bogging

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Old Jun 17, 2019 | 02:58 PM
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WOT bogging

I recently bought an FC that had a known bad OMP. Replaced it and the lines, as well as the vacuum hoses under the UIM. the car starts great, idles great, but bogs down under anything more than a 10% gas pedal load. if i keep the pedal extremely light, I can get through the gears without the engine bogging. As soon as i try to give it more gas than the 10% it bogs down, sputs and backfires. I let off the gas after the bogging and goes back to the perfect idle.

I have checked the ohms for the full Range TPS and it is in spec, Gas is good, fuel pump and filter are good and I cleaned the engine bay grounds. Could it be my injectors?

I have searched the forum, but all have fallen short. I am stumped and need help on what could possibly be causing this issue?
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Old Jun 18, 2019 | 02:07 AM
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what year is the car? is it throwing a CEL? if not the MOP is likely not your issue, you may have the secondary injectors not firing, cause a severe lean condition at WOT at around 4k+ revs.
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Old Jun 18, 2019 | 01:30 PM
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According to this post in this thread the OMP takes the ECU with it much of the time when it goes bad.

https://www.rx7club.com/2nd-generati...7/#post7028866
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Old Jun 18, 2019 | 05:24 PM
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Originally Posted by SpikeDerailed
what year is the car? is it throwing a CEL? if not the MOP is likely not your issue, you may have the secondary injectors not firing, cause a severe lean condition at WOT at around 4k+ revs.
It is a 1990 GXL NA. My idiot lights appear to not be working so I dont know if it is throwing a code.
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Old Jun 18, 2019 | 05:25 PM
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Originally Posted by Dak
According to this post in this thread the OMP takes the ECU with it much of the time when it goes bad.

https://www.rx7club.com/2nd-generati...7/#post7028866
I pulled the ECU this past weekend, things looked like they were good inside. What are symptoms of a bad ECU?

edit* will pull again and recheck to see if any resistors are burnt up.

Last edited by RotardedNooby; Jun 18, 2019 at 05:30 PM.
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Old Jun 19, 2019 | 10:26 AM
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Find a local buddy with a s5 fc. Try his ecu. Have had this problem happen to a lot of buddies s5 fc’s when the omp went out. Might want to look towards getting a rtek ecu and just going premix.
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Old Jul 21, 2019 | 08:07 PM
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I finally found a working idiot cluster and got it hooked up. Tried to pull codes and it gave the solid check engine light. After doing some research that seems to indicate a a bad ecu, as some of you said earlier. I have an new ecu in the mail and will be back with results when it arrives.
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Old Jul 23, 2019 | 02:52 PM
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My car has the same problem after an injector change. I bought new ones from ebay (denso), the car starts fine (cold and hot) and idles perfectly at 900 rpm. Two or three times it boosted up fine until red line and but after that I changed gears and it started bogging and backfiring.
I tried to adjust my TPS and it has a fine 1 kOhm on idle but has a reading of 6.3 kOhm on WOT. Also the mazda error code tester throws a TPS error and an intake air temp switch. The intake air switch cables and harness got ripped after all these years and I used solder to fix them.

Any suggestions? Is this a bad TPS or intake air temp switch? Could it be something else?

Grounds maybe? I had many grounds and I don't know if the mechanic placed them back after the injector replacement.

Fuel pump? I have a halmeter on board and when it bogs the reading goes to full red (lean).

RotardedNooby did you found solution to your problem?
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Old Jul 26, 2019 | 07:01 PM
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Originally Posted by erevos
My car has the same problem after an injector change. I bought new ones from ebay (denso), the car starts fine (cold and hot) and idles perfectly at 900 rpm. Two or three times it boosted up fine until red line and but after that I changed gears and it started bogging and backfiring.
I tried to adjust my TPS and it has a fine 1 kOhm on idle but has a reading of 6.3 kOhm on WOT. Also the mazda error code tester throws a TPS error and an intake air temp switch. The intake air switch cables and harness got ripped after all these years and I used solder to fix them.

Any suggestions? Is this a bad TPS or intake air temp switch? Could it be something else?

Grounds maybe? I had many grounds and I don't know if the mechanic placed them back after the injector replacement.

Fuel pump? I have a halmeter on board and when it bogs the reading goes to full red (lean).

RotardedNooby did you found solution to your problem?
We have two different problems Erevos, I would suggest starting a new thread. These guys will help you figure it out.
Mine ended up being that the OMP took out the ECU when the stepper motor went bad. This is a common occurrence according to the forum.

Last edited by RotardedNooby; Jul 26, 2019 at 07:04 PM.
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Old Jul 26, 2019 | 07:02 PM
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Originally Posted by RotardedNooby
I finally found a working idiot cluster and got it hooked up. Tried to pull codes and it gave the solid check engine light. After doing some research that seems to indicate a a bad ecu, as some of you said earlier. I have an new ecu in the mail and will be back with results when it arrives.
So the ECU ended up being the culprit the whole time. The 7 is now running healthy and feels good! thank you guys for the tips and suggestions!
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