Hi. I recently swapped my 98 honda civic sedan for a 1991 240sx fastback...it previously had turbo and possibly nos. All the gaskets are permatex (hi-temp), the harnest is ghetto-rigged, and it boggs at 2500rpms when driven or revved.
Ive recently cleaned out the fuel injectors, fuel injector plugs, the maf sensor, changed the tps, and tried to tune the distributor and tps....still boggs. Ive also tried pulling the idle air control valve hose out (it didnt kill the engine) but it sucks in air properly..I think the ecu is being tricked into keeping it running but dont know where the trick is coming from.
Its has a moshimoto radiator fan.....but they eliminated the coolant temperature sensor, so to be on the safe side I went ahead and plugged it back in.
Ive tried possibly everything I could think of at this point. ..I am a female, so I dont mind asking for some advice...any input would be greatfully appreciated. Thanks in advance.
1991 240sx with bogg issues after 2500rpms
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- Car: '92 240sx Convertible
'94 F-150 - Location: Fredericksburg, VA
Re: 1991 240sx with bogg issues after 2500rpms
If someone slapped a turbo and nos on it, did they build the block or leave it stock? If it was left stock, I'd consider doing a compression test on it.
As for the bogging, is the car acting like it's hitting a fuel cut at 2500, or is it just falling flat on its face but still revving over 2500? Usually if it hits the cut off and refuses to rev over 2500 under load, the ECU is in limp mode. If the car is in limp mode and you've checked and verified the MAF, TPS, and coolant sensor are indeed in operating order, then it could be a malfunctioning ECU. Since you mention the harness has been messed with, and I'm assuming a shoddy job was done since you say it's ghetto rigged, consider getting a multimeter and confirming all the values of the TPS, MAF, and coolant sensor are performing per the FSM. You can get a copy of the FSM at our Service Manual Library.
As for the bogging, is the car acting like it's hitting a fuel cut at 2500, or is it just falling flat on its face but still revving over 2500? Usually if it hits the cut off and refuses to rev over 2500 under load, the ECU is in limp mode. If the car is in limp mode and you've checked and verified the MAF, TPS, and coolant sensor are indeed in operating order, then it could be a malfunctioning ECU. Since you mention the harness has been messed with, and I'm assuming a shoddy job was done since you say it's ghetto rigged, consider getting a multimeter and confirming all the values of the TPS, MAF, and coolant sensor are performing per the FSM. You can get a copy of the FSM at our Service Manual Library.
Re: 1991 240sx with bogg issues after 2500rpms
Ive done the compression test...everything is a-okay...
I pulled out the ecu and did a self diagnosis...it threw out the codes
34, 12, &, 21 which basically is the knock sensor...which has been eliminated, the ignition signal circuit...which is still okay probably needs a tune up, and the maf sensor...which had a faulty plug...fixed it but it is still doing the same thing...
We used a multi-meter and checked all the sensor plugs and sensors...
We cleaned the injectors...and its plugs. ...
Im not sure what the issue could be..
Note that when I pull out the Iacv hose the car does not kill....it keeps running...
Something is probably tricking rhe ecu into staying on...although I know im posistive when I say it cant be the tps...the ecu is working properly i know becauee i can reset it and it throws out codes...which seem to be related to the symtoms the vehicle is experiencing. Help please?!?!
I pulled out the ecu and did a self diagnosis...it threw out the codes
34, 12, &, 21 which basically is the knock sensor...which has been eliminated, the ignition signal circuit...which is still okay probably needs a tune up, and the maf sensor...which had a faulty plug...fixed it but it is still doing the same thing...
We used a multi-meter and checked all the sensor plugs and sensors...
We cleaned the injectors...and its plugs. ...
Im not sure what the issue could be..
Note that when I pull out the Iacv hose the car does not kill....it keeps running...
Something is probably tricking rhe ecu into staying on...although I know im posistive when I say it cant be the tps...the ecu is working properly i know becauee i can reset it and it throws out codes...which seem to be related to the symtoms the vehicle is experiencing. Help please?!?!
Re: 1991 240sx with bogg issues after 2500rpms
Past 2500rpms it tries to rev but will pulsate making and up and down rev like its redlining..
On drive as soon as the needle reaches 2500rpms it boggs...so I would have to keep down and up shifting to keep at a pace..it feels as if it is also loosing accelration...tune up needed?
On drive as soon as the needle reaches 2500rpms it boggs...so I would have to keep down and up shifting to keep at a pace..it feels as if it is also loosing accelration...tune up needed?