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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.


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Old 01-28-2009, 12:15 PM   #16
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Have you checked your injectors yet? They may be old and leaking...






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Old 01-28-2009, 12:24 PM   #17
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Are you running all leadings? or all trailings? Never tried all 7's in a boosted (even stock boosted) 13B before....interesting.
Wait, I can't remember now. Been a while since I changed them!
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Old 01-28-2009, 12:34 PM   #18
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Have you checked your injectors yet? They may be old and leaking...
They were cleaned awhile ago. I don't think an old and leaky set of injectors would only misbehave when operating temps were reached. could be mistaken though.
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Old 01-28-2009, 07:43 PM   #19
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Are you sure its the engine and not electrical issues? Weak alt, etc?

If the idel is not lopy (like 1500 to 3000, back to 3000, etc) its probably not a vac leak. Pull the new plugs out now and see what they're like just after running for a while. Also, check the fuel filter...
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Old 01-29-2009, 11:16 AM   #20
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Are you sure its the engine and not electrical issues? Weak alt, etc?

If the idel is not lopy (like 1500 to 3000, back to 3000, etc) its probably not a vac leak. Pull the new plugs out now and see what they're like just after running for a while. Also, check the fuel filter...
I'm pretty sure I found a vac leak. I checked the vac too on the RTek and it was only pulling in 5inHG. Normally I pull in 11+inhg at idle. The rear securing bolt on the LIM had sheared, and while running it condensation had developed on the engine. The condensation got sucked into it, and that opened up the passage way. Forcing me to cool the engine back off which developed more condensaiton in the vac leak which froze again blocking off the vac leak. Repeat until vac leak was found.

At least that's my theory. I really won't know until I replace the UIM and test out the idle again.
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Old 01-29-2009, 01:05 PM   #21
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Don't take this the wrong way, but 11 inches of mercury is LOW for an N/A engine especially.

My 1/2 bridge with monster exhaust ports would pull 13in/hg idling!!
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Old 01-29-2009, 04:52 PM   #22
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Don't take this the wrong way, but 11 inches of mercury is LOW for an N/A engine especially.

My 1/2 bridge with monster exhaust ports would pull 13in/hg idling!!
(I don't know if the ports have been ported on this engine or not. So they might, they might not) I'm of the thought that I have alot of little vacuum leaks going on. When I rid myself of the emissions crap I imagine that I'll eliminate alot of the vac leaks. I'll have to double check the actual numbers when I idle again.
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Old 01-30-2009, 05:22 PM   #23
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alright, i put it all back together and it idled fine until it warmed up to operating temperature.

I'm still only pulling 5.8inhg according to the RTek. It's got to be quite a big vac leak as I've checked compression and both rotors are fine. The only thing i've changed would be the egr block off plate though i'm hesitant to mess with it until I remove the emissions (Or it warms up).

Anything else I should check?

I checked the condition of the new spark plugs, still look good. Rear rotor tends to flood when the vac leak presents itself.
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Old 01-30-2009, 08:20 PM   #24
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Honestly, vac leaks are either there or they arent, cold or hot. The vac numbers sound low, which isnt good. Its hard to get accurate compression checks with a piston tester, but I'm thinking you may want to do another comprsesion test when the engine is hot and see...
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Old 01-30-2009, 11:05 PM   #25
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Honestly, vac leaks are either there or they arent, cold or hot. The vac numbers sound low, which isnt good. Its hard to get accurate compression checks with a piston tester, but I'm thinking you may want to do another comprsesion test when the engine is hot and see...
I did it when the engine was hot. It had just been shut down from operating temp to get the readings.
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Old 01-31-2009, 02:16 AM   #26
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Just out of curiosity, is there a test I can do to see if I have a coolant seal going? Maybe what I'm seeing in the rear rotor isn't fuel but leaking coolant... Is there any test I could do to see without breaking open the engine?
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Old 02-01-2009, 01:28 AM   #27
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I"m leaning more and more everyday to my coolant seal letting go. It makes sense as the car dives fine one minute and as soon as it warms up it runs like it's on one rotor. I think the rear coolant seal is letting go, hence why the plugs are continually soaked when I check them when the problem occurs. I also have a rather large plum of smoke when I start the car when it sits and feels like it needs to clear it's throat.

Does that fit the symptoms pretty accurately?
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Old 02-01-2009, 02:13 PM   #28
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Quote:
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I"m leaning more and more everyday to my coolant seal letting go. It makes sense as the car dives fine one minute and as soon as it warms up it runs like it's on one rotor. I think the rear coolant seal is letting go, hence why the plugs are continually soaked when I check them when the problem occurs. I also have a rather large plum of smoke when I start the car when it sits and feels like it needs to clear it's throat.

Does that fit the symptoms pretty accurately?
It's a possibility. You could possibly have an injector that's getting stuck open, too, but I haven't witnessed that before, I'm not exactly sure how it would manifest itself.
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Old 02-01-2009, 02:25 PM   #29
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I think I may just go ahead and pull the engine and order an overhaul kit. I'm fairly certain that the apex seals, oil rings, and other seals are fine on the car, just my rear coolant seal has gone to crap.

I think the only sure way to check to see if I have a seal failure (without taking it to a shop and pressurizing the system) would be to check it with a bore scope through the exhaust ports. I should be able to see a majority of the engine through that. At least from the locations of when the full cycle of the rotor.
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Old 02-02-2009, 06:57 PM   #30
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what kind of temperature are we talking
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