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Old 10-29-07, 10:10 PM
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RPM problem

Hello, i just bought my 87 turbo 2 fc a few weeks ago, it has racing beat rev t2 exhaust and was running fine for a while, but recently sometimes after the car warms up, if i rev it up to about 4000rpms, it will start to cut off (like i took my foot off the peddle and then just kept slamming it to the floor). sometimes it backfires when it does this. help please.
Old 10-29-07, 10:33 PM
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Your secondaries are not coming on because of poor grounds. Search for "3800 RPM hesitation"
Old 10-30-07, 12:11 AM
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yup..... read the FAQ's
Old 10-30-07, 12:18 AM
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https://www.rx7club.com/showthread.p...55#post5131155
Old 10-30-07, 12:18 AM
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yeah you have some bad ground wires..do what i did just make your own custom ground kit its cheaper than replacing all of them
Old 10-30-07, 01:59 PM
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http://i17.photobucket.com/albums/b8...a/100_0433.jpg


i'm pretty sure this is my bad ground wire that i have. But i tried following it to the source, it goes to the back of the engiveand how would i go about changing this wire out?
Old 10-30-07, 02:43 PM
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yeah that looks like the culprit, basically all you need to do is unbolt it and swap it with another one
Old 10-30-07, 06:49 PM
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grounds/ wires/ Tps/ clog cats/ clog fuel filter
Old 10-30-07, 08:57 PM
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alright, i think i'm just dumb, but i found the one ground in that pic and changed the wire and it didn't fix my hesitation. What did that ground go to? i looked under the air filter area for the ground for the pressure sensor. i'm assuming that since i have an aftermarket boost guage and a hks bov my sensor is rigged differently. And i can not find the other main ground locations.

and what is tps?

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Old 10-30-07, 09:39 PM
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here are pics of my pressure sensor

http://i17.photobucket.com/albums/b8...a/100_0437.jpg
http://i17.photobucket.com/albums/b8...a/100_0435.jpg
http://i17.photobucket.com/albums/b8...a/100_0434.jpg
Old 10-30-07, 09:56 PM
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Originally Posted by RotaryCyphaX
and what is tps?
Throttle Position Sensor

Most acronyms are found on the Sticky Page.
https://www.rx7club.com/showthread.p...&highlight=tps
Old 10-31-07, 04:10 AM
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the SPECIFIC ground to look for is the ground for the ECU, under the UIM (upper intake manifold) bolted to the block. If it's not that, I highly doubt the TPS would cause the hesitation. Check your secondary injectors, make sure the connections are tight, they are seated right, and that the babies are clean.
Old 10-31-07, 10:21 AM
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just trace/replace all the grounds one by one
Old 10-31-07, 02:55 PM
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Hey whats that black box coming off the pressure sensor called?
Old 10-31-07, 08:09 PM
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no idea, i think it has something to do with my aftermarket boost guage i have installed near the dash
Old 10-31-07, 09:00 PM
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i was trying a few things and test drove it to see if it stopped, and found out, if i ease the gas up, it can go up to 4500 then stop, and if i floor it, it can go as low as 3500, is this usual for the infamous hesitation? could this still be an electrical problem?
Old 10-31-07, 09:06 PM
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Probably. Have you tried revving it neutral? The secondaries only come on under load. See if you can rev high in neutral. If you can't, then you may have some other problem.
Old 11-03-07, 02:15 PM
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i tried revving in neutral soon after the car warmed up and it was fine, then i tried to rev it after driving it for maybe 10-15 mins and it did the same thing....could this be a bad fuel pump or fuel filter?
Old 11-03-07, 10:16 PM
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did you fix that ground? i guess i could say some stuff about grounds but a very wise man already has it writen...http://www.aaroncake.net/RX-7/grounding.htm .. as for the fuel pump maybe take the hose off that goes to the rats nest from the fuel filter the feed line. and measure the output it should five you at leat 1.3 liter per min or .34 gal per min. i usually just fill see how much it buts out in 10 seconds and do the math, it would be better to do the entire min though... all of this info is easily accesable @ your local frequently asked questions section scope it out theres alot to learn
Old 11-05-07, 05:46 PM
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Bump. anyone know what that black box is, or does, on the boost sensor?
Old 11-07-07, 02:14 PM
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fuel cut defencer (FCD)
Old 11-07-07, 08:44 PM
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Nice so I guess my FC does have a FCD.
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