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87 rx7 turbo No Power 30K original miles

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Old 08-18-10, 01:46 PM
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87 rx7 turbo No Power 30K original miles

I own an auto repair shop and one of my new customers has a 1987 RX7 turbo II with 30K original miles (mint). The car came in after they stored it all winter as a no run condition. First things first I checked the air box and of course it was a mess, full of mice "stuff" so upon further examination I found that the MAF sensor door was frozen and full of "mouse stuff". So I replaced MAF and vehicle still has very little power, I can bring up the RPM's very slowly and it will "R" out, but if you wack the throttle there is no response, kinda dies out. I checked all the throttle butterflies and they all seem to be good and free, so I checked the fuel pressure and have found a couple of posts w/people saying I should have around 71-90 psi. I hooked up fuel pressure gauge inline and w/vehicle running I have 30 psi. I also jumped fuel test plug w/key on to see if it changed (without vacuum to fuel pressure regulator) and only came up w/36 psi. One of the test I read about does not specify if test is a "deadhead" test or not and if it is not, what is operating fuel pressure supposed to be? New to "forums" and any help would be much appriciated.
Old 08-18-10, 02:00 PM
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71-90 sounds like the deadheading fuel pressure spec. With the engine off, they key to 'ON', and the test connector jumped, you should see approx. 38 psi. 36 psi should be within the given range listed in the FSM (Factory Service Manual). There are links to the manual here: https://www.rx7club.com/showthread.p...18#post5131218.

If mice were in the car, I'd suspect they ate some wiring.
Old 08-19-10, 12:38 PM
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Will not rev up

Pulled alot of interior apart yesterday, NO evidence of critters being inside of car, had alot of jute carpet backing in air box and when pulling up carpet inside of car all the carpet backing appears to be more of a foam not jute. Major wiring harness appears to be coming down driver's side floorboard, up under drivers footwell I can see the main harness and I can't see any evidence of mice inside car. (jute may have come from different car stored in garage) Anyway, I pulled the main cat off right behind turbo (p.i.t.a.) and fired it up just to confirm not plugged cat and still no power, car will run but as soon as you try to rev it it just dies out, if you feather the throttle slowly you can get the rpm's up, almost seems like a throttle position sensor in a newer geny car but from what I can see there is no tps as far as one that would be a potentiometer. Anyhelp appriciated.
Old 08-19-10, 12:42 PM
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Not sure how much it will help but if you want to simulate load you can disconnect the vacuum hose from the pressure sensor and plug the hose and then disconnect the TPS connector plug and see if the car still bogs down.
Old 08-19-10, 12:47 PM
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whats the purpose of simulating a load? I'snt the tps in this car a throttle open switch?
Old 08-19-10, 01:01 PM
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It's probably worth checking trouble codes too: http://www.teamfc3s.org/info/article...odes/main.html. The method is crude, and there aren't many codes, but it could save you some time. Just make sure the LEDs aren't hooked up backwards.

The car does have a TPS (throttle position sensor), but you'll have to take the intercooler off to see it. It's located on the front of the throttle body. The resistance sweep can be tested per the FSM specs, and just look for dead spots in the range or values that are way off. The car can actually be driven with the TPS disconnected, but there will likely be some hesitations and drive-ability issues. But power at WOT will not be affected if the TPS is unplugged, which could point you in the right direction.

EDIT: posted before I saw your reply. The TPS is very simple on an S4 RX7, and is used at idle and low throttle situations only. Once you go past around 25% throttle it's fully extended.
Old 08-19-10, 01:12 PM
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Checked codes

I use a Snap on Solus w/multi II adaptor, checked codes last nite w/scanner and I was unable to retreive any codes (almost seemed like something wrong w/scanner, did not come up as no codes present but menu for retrieving codes sat on screen for 3 mins. and nothing came up) might have to try retrieving w/other method.
Old 08-28-10, 10:02 PM
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clogged fuel filter?

if there was mice crap everywhere....they prolly chewed on something to make that mice stuff
Old 08-28-10, 10:18 PM
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if there was carpeting in the airbox, did the customer drive the car there? likely stuff (meese included) could have gotten sucked into the intake or the turbo?
Old 08-29-10, 07:52 PM
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This is an 87, most codes weren't standardized until after 94 95. A lot of these 'early model' ecus (generally speaking) have either built in lights or contacts to clip an LED to. the light will flash in a pattern that will convey the error code.
Old 09-02-10, 09:04 AM
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RX7 poor run

I checked under the carpet and most of the backing on the carpet is foam, not jute. Pulled intercooler, checked all tubes and no debris of any kind, customer did run car with the mouse **** in the MAF but checked the turbo, no damage. All the turbines spin very nice, no bent vanes. Even pulled Cat off back of turbo and no change. Runs (barely idles and will run if you feather the throttle), just won't rev at all, almost acts like MAF isn't plugged in checked new MAF and it's working properly, even tried another MAF just to verify and still no rev.
Old 09-02-10, 09:39 AM
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Have you ruled out the Boost sensor yet?
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