I have a 89 CRX HF with a 1st generation B16 converted to OBD1.

Last week, I notice my CRX was lagging once I go over 50 MPH on the freeway… I first thought my suspension was vibrating but when my Check Engine light pop on, I knew something was wrong. It was code 3 (MAP sensor) so I unplugged the MAP sensor and the battery to reset my ECU. After that, the Check Engine light went away but the motor continue to lag once I go over 50 mph… I already replace the MAP sensor twice but nothing seems to fix it… I’m planning to change my IAT and the temperature sensor to see if that will fix it but I was wondering if someone had a similar issue…

I also replace the fuel filter this summer.
Spark plug and distributor was also replaced when I did the swap in 2008 Summer...

 

We need more info. 50 period? try 3rd 4th 5th, different rpm's will help troubleshoot. you need to find out if it is like a flat spot in the pedal or what. In 3rd will it pull past 50? in 4th? in 5th? same spot in the pedal? of just 50 mph period?

Faulty speed sence input to the ecu, or tps is my random guess.

 

You might want to take a look at your fuel pump. The higher the gear, the more load that is put on the engine. If the fuel pump can't keep up you want have much power on the freeway.

 

Sorry for not describing the situation accurately ... It's really hard to explain but I can accelerate in all my gears. When I try to keep my speed/RPM steady anything over 50mph, the car has a constant light shaking (bogging) which feels like an earthquake...

For the fuel pump, I might want to replace that since I never replace it...

 

It seems like bad fuel pump usually cause difficult start up but my motor starts every time without any problem...

 

so it only does it when you are at a cruising speed above 50 or cruising in any gear? where throttle is very light?

 

how is mechanical timing? TPS calibration?

 

thats what i was thinking possibly tps is bad or needs calibration. why i ask if it does it when your cruising and have the throttle barely pressed or at a steady speed

 

possibly but mines not converted to obd I and has a code 7 (tps) and it runs just fine

 

I'm going to change my IAT, coolant temperature sensor, use seafoam to clean the intake system, check my timing and recalibrate the TPS after Thanksgiving. Thanks for all the info guys.

It happens in 1-3rd gear if I punch the throttle hard or at 4-5th gear at constant speed over 50+ mph... It's really noticeable when I'm going about 70-80 mph.

 

sounds like tps is bad or uncalibrated...
singlecamsaint if your tps is totally dead then it wont act up like he is having issues with.
formula 91 try unplugging the TPS and then driving it down the road and see if it does it if it doesn't then tps needs to be calibrated or a new one

 

sounds like tps is bad or uncalibrated...
singlecamsaint if your tps is totally dead then it wont act up like he is having issues with.
formula 91 try unplugging the TPS and then driving it down the road and see if it does it if it doesn't then tps needs to be calibrated or a new one

 

Figure out the problem. The distributor was going bad and it actually die out after I replaced all the sensor...