5th Gen (’97-’01) Honda Prelude Issues

A running blog of common (and maybe not so common) issues with my Prelude.

Vehicle: 1999 Honda Prelude (Non-SH) Coupe, BB6
Engine: H22A4
Miles: 128,500 
Transmission: Automatic M6HA
Color: Crystal Blue Metallic

A Brief History

I picked up this Prelude for a song last month, the seller believed the engine needed replacement (thanks to one or two local mechanics diagnosing an issue he had with overheating), even to go as far as saying the engine failed a block test (whereas another shop said it passed).

The car was clean otherwise, and in great shape so I took the risk of buying it, knowing the possibility of having to replace the head gasket, machine the head, or very worst, replace the engine.  But from what I learned, it wasn’t ran very long when it started to overheat.

Block Test

You can get an inexpensive combustion leak detection kit from Amazon.  You place it in the radiator fill opening, and let the coolant push up into the sampling tube once the engine has warmed up.  Then remove it from the radiator (put the cap back on!) and pour the test fluid into the tube.  If it changes color according to the instructions, you have exhaust gasses mixing with the coolant.   This would indicate a bad head gasket.

Mine actually passed the block test.  Next on to the compression test.

Compression Test

Again, I picked up an inexpensive compression tester from Amazon.  For this test you will need to unplug the harness from the ignition coil so the engine doesn’t during the test.  You’ll also need a helping hand to turn the engine over while you watch the gauge.

You’ll do this for each of the 4 cylinders

  • Disable the ignition coil by unplugging the power connecter from the bottom and set it aside
  • Remove the spark plug
  • Thread in the compression tester by hand so it’s snug
  • Have a friend turn the engine by turning the key to Start and keep it cranking.  The cranking will force pressure from the compression stroke into the gauge, stop turning the engine over when the needle stops moving
  • Write down the reading and continue with the next 3 cylinders, write down the result for each one
  • Reconnect the spark plug wires and don’t forget to plug the ignition coil back in!

In my case the PSI readings from Cylinders 1 thru 4 were 205-200-205-205, respectively.  Which impressed me for being a 20+ year old car.  Typical values should be in the 180 to 210 range.

What’s important is not having high numbers as much as it is similar numbers.  You want to see even compression across all cylinders.  The rule of thumb I learned in high school auto shop is that the lowest cylinder shouldn’t be more than 10% to 15% (at the very most) of the highest reading cylinder.

For instance, (and I’ll use 100 PSI as the max value, for ease of math) say your numbers were 100-100-85-90.  Cylinders 1 and 2 look good, cylinder 3 is 15% of the highest (100 PSI) and Cylinder 4 is 10% (90 PSI) of the highest cylinder.   So Cylinder 3 has the lowest compression.  That’s not to say the engine is bad, the piston rings might be worn more than the others, or the valves may not be seating correctly due to damage or carbon buildup.

But if one (or more) cylinders is substantially lower than the others, you have an issue that needs to be addressed.

Overheating Condition

With the two previous tests out of the way, I was fairly confident the head gasket and engine block were intact.  After topping off the radiator for the block test, engine warmed up, I noticed coolant dripping underneath the passenger side of the car.  After having rebuilt the entire engine bay of my CB7 Accord, I knew this was likely from the heater hose.  Sure enough, it was dripping from a tiny hole on the underside of the heater hose coming off the cylinder head beneath the distributor. I cut off about 1″ to get rid of the pin hole and reattached.

Why did this happen?  I could see the distributor had been replaced with a new one.  My guess is that the distributor oil seal failed (common issue) and leaked oil into the distributor, and down the side of the cylinder head onto the heater hose.  Eventually contact with oil will cause the rubber hose to get spongy, swell, and in this case, leak.  So replacing the heater hose is in order.

Electrical Issues

I was told the car would stall when coming to a stop.  When I got it running, I didn’t have that issue at first, until my fuel level dropped below quarter tank.  At first I thought, fuel pump – they lose the ability to pump fuel when the tank gets low because it doesn’t have the pressure buildup behind it from the weight of the fuel bearing down on it.  Once you get to quarter tank, the weight of the fuel is less than if you were to have a full tank.

But it turned out that wasn’t the problem.  (Or it was part of the problem)

After I replaced the fuel pump (and pick-up strainer), it didn’t stall anymore, but when coming to a stop, my battery light would come on, as well as the emergency brake indicator light. (video below)

Likely culprit was the cheap alternator that was recently installed, voltage regulator couldn’t compensate for the drop in RPM’s when coming to a stop and then trip the computer into thinking the engine was off.  Within a few seconds the lights would turn off, no stall.  The drop in voltage could also have attributed to the old fuel pump not delivering consistent fuel pressure, thus causing the stall.

So don’t cheap out on an alternator, get an OEM one, or at least a remanufactured OEM for reduced cost.  Aftermarket alternators usually don’t play well with the cars electronics.

Door Lock Actuators

The driver and passenger side door locks won’t operate (or operate poorly) when using the key fob, or using the lock switch on the doors. The door lock actuators were tired and worn out, needing replacement.  I picked these up (again, Amazon) to replace the bad ones.  There are quite a few videos on YouTube for door actuators, but the symptoms include

  • locking or unlocking once, then it won’t lock/unlock again for several minutes/hours (which was my issue)
  • sluggish lock/unlock
  • no lock movement at all (verify your fuses are good, and you have voltage at the connector when the lock is activated)

These were nice because they included the plastic keepers that snap into the door to keep the wires secured.

Power Steering Pump

Another issue was the power steering pump – it made a horrific noise worthy of my toddler when she wants to scream her head off.

Take a look at the power steering fluid reservoir – mine was bubbling.  Also evident underneath it was that it overflowed from all the bubbling given the amount of oily residue I found.

Most likely cause: leaking gasket(s) in the power steering pump, sucking air into the system.

Solution: Get the rebuild kit, takes about 30 to 45 minutes and it’s not hard to do.  Just take your time.

Coming up…

Automatic Transmission: Shift flare from 1st to 2nd gear when cold.  New dual-linear shift solenoid currently on order.

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