[Sak123]

Help! I have a 1990 Prelude SR (same as the Si in the US market but mine was built for Canada).
Automatic transmission, with the B21A1 engine. I am the second owner and have just put over 7k in parts into this vehicle but am at a standstill. Here is the issue. Speedo and odometer haven't worked for years which is fine. Recently fixed a hard-start problem by replacing the coolant temp sensor and replacing plugs and wires. Car now starts fine, but is undriveable due to power loss. Here is the sequence:

• car starts fine
• runs fine for 2-3 min, then the S3 shift indicator starts to flash
• 2-3 min later, the engine reaches operating temp
• then, as I am driving comfortably at 70 KPH and 2000 RMP the power starts to slowly drop: loss of power and revs
• pushing slowly on the gas pedal does nothing: it's as if the pedal is no longer connected to the throttle
• pumping on the gas will keep the car lurching along
• flooring the gas pedal will (almost) redline the tach, and the car will grab 2'nd gear for a few seconds, then lose poser again

As stated, car has new wiring and plugs, and fuel filter was also cleaned
Also, the tech used a camera to look behind the instrument cluster (which I replaced a few years ago), and stated that there is a big scratch across the circuit board.

WHERE DO I GO FROM HERE?

• Replace the cluster?
• VSS?
• MAP sensor?
• plugged cat convertor?

Please help. I LOVE this car and need to get it running again.
Thanks in advance for any/all advice you can provide.

 

[Hammbone]

Help! I have a 1990 Prelude SR (same as the Si in the US market but mine was built for Canada).
Automatic transmission, with the B21A1 engine. I am the second owner and have just put over 7k in parts into this vehicle but am at a standstill. Here is the issue. Speedo and odometer haven't worked for years which is fine. Recently fixed a hard-start problem by replacing the coolant temp sensor and replacing plugs and wires. Car now starts fine, but is undriveable due to power loss. Here is the sequence:

• car starts fine
• runs fine for 2-3 min, then the S3 shift indicator starts to flash
• 2-3 min later, the engine reaches operating temp
• then, as I am driving comfortably at 70 KPH and 2000 RMP the power starts to slowly drop: loss of power and revs
• pushing slowly on the gas pedal does nothing: it's as if the pedal is no longer connected to the throttle
• pumping on the gas will keep the car lurching along
• flooring the gas pedal will (almost) redline the tach, and the car will grab 2'nd gear for a few seconds, then lose poser again

As stated, car has new wiring and plugs, and fuel filter was also cleaned
Also, the tech used a camera to look behind the instrument cluster (which I replaced a few years ago), and stated that there is a big scratch across the circuit board.

WHERE DO I GO FROM HERE?

• Replace the cluster?
• VSS?
• MAP sensor?
• plugged cat convertor?

Please help. I LOVE this car and need to get it running again.
Thanks in advance for any/all advice you can provide.

speedo not working could be a bad vss.
S3 flashing is like a “check engine” light for the transmission.
It has been many years since my 3rd gens, and I never had an automatic Prelude, but from what I have read, if your S3 indicator is flashing, your Transmission Control module/unit should be flashing a red LED at you… under the carpet at the passenger side footwell. Long flash is first digit, short flash is second digit of two digit trouble code. That should help to diagnose the problem before throwing random parts and money at it.

 

[Sak123]

speedo not working could be a bad vss.
S3 flashing is like a “check engine” light for the transmission.
It has been many years since my 3rd gens, and I never had an automatic Prelude, but from what I have read, if your S3 indicator is flashing, your Transmission Control module/unit should be flashing a red LED at you… under the carpet at the passenger side footwell. Long flash is first digit, short flash is second digit of two digit trouble code. That should help to diagnose the problem before throwing random parts and money at it.

THanks for the reply. The controle module in the passenger footwell has two red lights flashing. Is one light for the tranny and one for the engine? The RHS is flashing code 4 (Crank Angle Sensor) and the LHS is flashing one code for VSS and one for O2 sensor

 

[Sak123]

speedo not working could be a bad vss.
S3 flashing is like a “check engine” light for the transmission.
It has been many years since my 3rd gens, and I never had an automatic Prelude, but from what I have read, if your S3 indicator is flashing, your Transmission Control module/unit should be flashing a red LED at you… under the carpet at the passenger side footwell. Long flash is first digit, short flash is second digit of two digit trouble code. That should help to diagnose the problem before throwing random parts and money at it.

THanks for the reply. The controle module in the passenger footwell has two red lights flashing. Is one light for the tranny and one for the engine? The RHS is flashing code 4 (Crank Angle Sensor) and the LHS is flashing one code for VSS and one for O2 sensor

 

[Sak123]

THat is backwards. It is the left light that is flashing for MAP sensor and the light on the right is flashing VSS and O2 sensor

 

[Sak123]

ANd once again, i cannot type. LHS is flashing for Crank Angle Sensor, not MAP sensor

 

[Sak123]

ONe other weird thing to note: Sometimes when i am lurching along losing power, the CEL in my cluster illuminates and after that the engine runs fine, although there is a distinct overheating/burning smell once i stop.

 

[Hammbone]

THat is backwards. It is the left light that is flashing for MAP sensor and the light on the right is flashing VSS and O2 sensor

The one flashing the code for the VSS should be the transmission. Check to be sure it is connected and that none of the wires are cut or melted.

I had a car with a clogged Catalytic Converter that would cause the exhaust to get RED hot and lose power after the car warmed up... on my way to the dealership at night, I gunned it to get more power up a hill and i heard a load "BANG!" and saw a large flaming ball bouncing down the road behind me... I had apparently blew out the honeycombs in the cat in a fireball which got rid of the obstruction (all the way through the muffler) and made it run awesome again lol
A dealership should hopefully be able to diagnose a clogged or broken cat before that happens lol
An O2 sensor COULD cause lack of power and hot exhaust if it is incorrectly telling the ECU to add/subtract fuel... once the ECU realizes something is wrong and basically "bypasses" the O2 sensor, the fuel mixture could be correcting itself and giving you back your power.
Not being there, I unfortunately cannot help in a better capacity...
Knowing what a b*tch the O2 sensors can sometimes be to remove (I have yet to have success on my older cars), I tend to buy the Catalytic Converters and the pipes and replace both O2 sensors at the same time.