Cant Rev Past 4k
#1
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Cant Rev Past 4k
I turned my car on today 88 N/A and it idled fine let it warm up a bit went to go drive it and it was like driving a slug it has no power and i can get it past 4k rpm.
I was have a bog problem at 3800 for the past few months but it was drivable but now i cant even drive it. I recently changed the fuel pump but still has the same issue. I was thinkin it was the secondaries dumping fuel because takes a 1/2 tank of gas to go a few miles. Anyone else had this issue?
Stock 88 NA
I was have a bog problem at 3800 for the past few months but it was drivable but now i cant even drive it. I recently changed the fuel pump but still has the same issue. I was thinkin it was the secondaries dumping fuel because takes a 1/2 tank of gas to go a few miles. Anyone else had this issue?
Stock 88 NA
#2
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If you have the original exhaust on her, you've got a clogged pre-cat or secondary cat. My guess. 4K was my "magic" point also, and she ate the hell out of gas...
#4
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Speaking of clogged cats, I'm going to gut my cats this weekend before I put them back on. I know if you gut them completely you can have problems with the 5/6th ports opening (S4). What if I just partially gutted them, enough to allow airflow, but keep backpressure. Would this work or am I insane?
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Hermit- after I gutted my first two cats (long, long time ago) I THINK my ports were still working, can't really remember now. I DO remember feeling so much extra power with the first two cats out of there that I was wondering why I didn't gut 'em a lot sooner, lol...Which means the ports must have been working, huh?
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#10
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Originally Posted by WAYNE88N/A
Hermit- after I gutted my first two cats (long, long time ago) I THINK my ports were still working, can't really remember now. I DO remember feeling so much extra power with the first two cats out of there that I was wondering why I didn't gut 'em a lot sooner, lol...Which means the ports must have been working, huh? ![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
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#11
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Yes, by all means get her running again- more stuff will break just sitting there, lol...
All you really need to do is reroute your "vac" hose from the split air pipe to the air pump hose (between the air pump & ACV) and tap in there. Install a little "T" in the line so that you have a means of dumping excess air & regulating the activation pressure (by adjusting the size of the hole in the end of the "T"), and your set. I've been running with this setup for quite a while now with no probs...
All you really need to do is reroute your "vac" hose from the split air pipe to the air pump hose (between the air pump & ACV) and tap in there. Install a little "T" in the line so that you have a means of dumping excess air & regulating the activation pressure (by adjusting the size of the hole in the end of the "T"), and your set. I've been running with this setup for quite a while now with no probs...
#12
Wait................What?
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Originally Posted by TurboII2NV
check your compression
thats how my N/A sounded when I blew my motor
check the TPS and the MAP sensor
thats how my N/A sounded when I blew my motor
check the TPS and the MAP sensor
Just for ***** and giggles, check your coolant thermo sensor (under the alternator, green plug)
I've heard that S4s... if that sensor is bad/unplugged, it'll give the car a "limp mode" kind of feel. (S5s have a 'limp mode' if the MOP is bad)
#15
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Here's a fairly simple way to check for clogged cats- rev it in neutral, does everything seem normal? Now go have some fun, does everything seem normal until you hit about 3.5 to 4K? Are you using more gas than you were before the problem? Classic symptoms, man...
If you think it's your secondaries, just disconnect the connectors from the injectors, and take her for a spin. Anything change?
If she starts well and revs well in neutral, don't worry about blown motors just yet...
If you think it's your secondaries, just disconnect the connectors from the injectors, and take her for a spin. Anything change?
If she starts well and revs well in neutral, don't worry about blown motors just yet...
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In neutral it bogs really bad, I tried new injectors same problem, the exhaust seems to be flowing out the back but the garage fills with fumes after I shut it off, I will probably be trying the CPU later, The engine has 174k miles on it there is no smoke or sign of failure other than the bogging under 3k.
Reving it in neutral if i floor the pedal it rev's to 3500 then tracks down to 3000 and sits with the bogging sound. If i dont punch it It goes to 4000 and stays. The temo sensor is plugged in, tps is new, checked timing dead on, AFM is ok tried 2 car has new fuel pump only thing i havent tried is filter.
Reving it in neutral if i floor the pedal it rev's to 3500 then tracks down to 3000 and sits with the bogging sound. If i dont punch it It goes to 4000 and stays. The temo sensor is plugged in, tps is new, checked timing dead on, AFM is ok tried 2 car has new fuel pump only thing i havent tried is filter.
Last edited by MrFuzzy; 08-20-04 at 01:07 AM.
#17
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OK, well, why didn't you say all that in the first place, lol...So clogged cat is out, for now...Have you pulled any codes yet? Something's gotta be coming up with it running like that, I would think.
Clogged fuel filter will also rev fine in neutral, but bog under load, so don't think it's that, either. Do you know how to get to your ECU? You can pretty well troubleshoot the entire performance related systems from there using the FSM, fuel section...
How are your grounds?
Clogged fuel filter will also rev fine in neutral, but bog under load, so don't think it's that, either. Do you know how to get to your ECU? You can pretty well troubleshoot the entire performance related systems from there using the FSM, fuel section...
How are your grounds?
#19
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Man, if it's the cat, it's clogged BIG time, but usually with a clogged cat light loads (like revving in neutral) aren't affected as much. I'm not talking about replacing the ECU, I'm talking about testing all the relevent sensor inputs AT the ECU. Yes, you need to check codes also. And when you get to the ECU to check those inputs, check your 4 grounds at the pins too, especially the two on the small plug (#3) with all the injector wires. These two run to the rear rotor housing ground, which seems to give a lot of guys fits...
#21
Please tell me youve tried changing your spark plugs and leads!
Please tell me youve checked your fuel filter!
Please tell me youve checked your coil packs!
Its always little things that you overlook, these may not be the problem but could definately cause the problems you are having!
andy
Please tell me youve checked your fuel filter!
Please tell me youve checked your coil packs!
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Its always little things that you overlook, these may not be the problem but could definately cause the problems you are having!
andy
#23
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Well, if it's just as bad in neutral as all other loads, it MIGHT be the engine, but you're going to need to rule out everything else first...Just go over her system by system, fuel, ignition, etc...Have you done a compression check yet?
#25
If you've still got the charcoal can, check the vacumn line that goes to the engine.
Mine came off where it ends up under the BAC. Had most of the same symptoms you describe. They all disappeared after I stuck a new hose on it.
Good Luck, it'd be a real cheap fix.
Gerard
Mine came off where it ends up under the BAC. Had most of the same symptoms you describe. They all disappeared after I stuck a new hose on it.
Good Luck, it'd be a real cheap fix.
Gerard