So I have a 95 Integra GSR giving me a heck of a problem that I can't solve.

Sooooo.. i've searched and have tried just about everything (I think) and don't really want to shotgun another part.

The symptoms:

At cold start-up, car runs perfect
No CEL
When fully warmed up (which can take 20-30 minutes) the engine feels like half-power.
No apparent misfiring, just really weak when warmed up
Problem worstens with AC running
VTEC does not seem to kick on

Everything i've replaced:

TPS
MAP
Engine Coolant Temp Sensor (yes the two prong one)
Spark plugs
Plug wires
Distributor ignition module
Double checked the grounds

Only mod is a short-ram intake.



Anyone have any ideas or insight to whats causing this?

 

Do a compression test. That will tell you the health of the engine.

 

What does it rev to after it warms up? Sounds like thermostat is bad.

 

happened to me same year, same car
If engine coolant temp does not pass a certain threshold, vtec engadgement wont occur.

 

After it warms up it will rev to red, just sloooooowly. I'm gonna replace the t-stat and see how it does.

 

The rev limit in the ecu remains the same,
It's just running on the low cam and the high cam profiles are needed to promote the healthy correct rev to 8000rpm,
Report back after replacement if T-stadt

 

I have noticed the same problem with my 94 RS non-vtec. Maybe not half power, but an obvious loss of power when warmed up. Only mod is short ram AI...Could it be the hot engine bay air robbing that much power?

 

No it's that you have a tired non-vtec car probably,
Op's gsr needs the vtec system to function properly to promote the rev/power characteristics of the b18c engine,
If your engine is reaching proper operating temperature and there is no other ailments to your car, it is probably just regular loss of power due to wear ect.

 

That's kind of what I was thinking, and I wasn't too concerned about it cuz I will be doing the b18c swap by the end of the year. Just ran across this thread and was curious. Thanks.

 

My question is did you replace the ECT sensor or the ECT switch, both are "two prong", the sensor has red/white and green/blue leads and the switch has green and black leads.

What does the temp. gauge indicate engine temp. is, once warmed up?

Does the rad fan turn on, [cycle on off] once engine temp up? 94

 

^^
This.

Also, once you confirm that the fan is cycling you may want to look into fuel pressure issues. Do you have a fuel gauge in the car?
When was the last time that the fuel filter was replaced?
You might have a fuel pump on its way out.

 

Replaced the T-stat and it warms right up now. Though the half-power thing is still a mystery and didn't fix it. The power problem is prevalent through all gears and all speeds. The fan seems to be cycling as well.

Still don't have VTEC.

I replaced the ECT sensor under the distributor. Should I have replaced the one on the t-stat housing? Temp at steady state is a hair below half when its warmed up.

I'll shotgun a fuel filter.. I don't mind shotgunning maintenance scheduled parts.

 

That's perfect temperature.
No CEL's right?
When cold, you have normal low cam power, right?
But, once warm, VTEC won't engage, right?
When was your last oil change?
Maybe your oil filter might be collapsed. Any oil light flickering?
Do you have access to tools?
I can help you do a test on the hydraulic system to see if the rockers are working properly.

 

No CEL's right? Correct.
When cold, you have normal low cam power, right? Correct.
But, once warm, VTEC won't engage, right? Correct.
When was your last oil change? 500 miles ago.
Maybe your oil filter might be collapsed. Any oil light flickering? Nope, checked the oil pressure sensor too and that is fine. Its normally closed right? then when it sees proper pressure it opens the switch?
Do you have access to tools? Yes.
I can help you do a test on the hydraulic system to see if the rockers are working properly.
Are the rods in the rockers not sliding a typical vtec problem?

 

Use a known good spool valve assy.
I just got done troubleshooting one that was stuck open which is rare and this locked us in high cam setting.
You won't net an engine light if the unit is simply not switching over, at least not all the time.
You would need an open circuit to net the light.
It's worth a try.

 

It's really time to start crushing the flow charts for the vtec system as this will be the factory trained way of eliminating the problems or culprits that can inhibit your vtec system from functioning properly

In the manual I think it will be under fuel and emissions, codes 20,21,22 I think.
You will be needing an oil pressure tester used at the service port of the cylinder head near the spool valve assy.

 

Nice

 

https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

I guess this flowchart is a good place to start

 

my man!

 

Found the problem to the running weak problem. It was the coil in the distributor. Replaced it and it is running good so far in 100 degree New Mexico heat.

... now onto the vtec problem. I pulled off the spool assy and cleaned out the entire assembly with alcohol. The screen was clean and cleaned it anyway.

Still no vtec.

 

^^^^^^^
Not clean it
If the spool valve assy. was defective or not working condition the flow chart would have determined that.

 

Im having the same problem with my 94 gsr car runs good cold but then sluggish and vtec will not engage when car warms up and my rpms will start jumping

 

do you have access to a multimeter?

 

pull valve cover and check your cams at tdc.

 

Yea check your timing marks first, your loss of power is cause theres no vtec. I would of changed the thermostate switch as well. But if the fans come on during idle then the fan switch is still working. If your oil level is good then look into other factors to why vtec won't engage. Try reseting the ecu unplug it and plug it back in after a few mins. maybe your vtec solenoid is not working. But i think i read that you cleaned it out..