Required noobi intro....

[95 honda delsol]

Recently bought a 95 Del Sol w a JDM b18c, cold air intake, headers, 3" exhaust, stage III racing clutch and some ground effects, agressive new nose and tail. Although I've been asked if this is my mid-life crisis car, it's my daily commuter (1 hr in the morning and 1.5 hrs in the evening.) Anyway, it's been fun so far. The car has developed a problem with the VTEC -- "engages" for just a second or so and drops out; doesn't have the power it did before when it kicked in. Noise level is much lower too. Any thoughts? Sure would appreciate some help. Tried searching for a thread about this but didn't find one. (Not saying it's not there, I just didn't find one.) Thanks!

[jae8908]

Welcome to SHO. solenoid maybe? Idk.

[legacyo13]

It's either the solenoid, or check your plugs at it. might be loose.

[95 honda delsol]

Thanks guys. I kept searching (after I posted) and found two threads addressing this problem. The oil level was low but has been changed and is the correct weight and volume. Since the VTEC engages, but not as well as it did, can we eliminate the solenoid as a problem? I'm guessing that if it works at all it's going to work, period. That leaves the spark plugs. Prior to the VTEC quitting, I used an octane booster (Lucas Oil product) because I bought a tank of fuel that was knocking. Booster helped! But did I foul the plugs? And if they're fouled, wouldn't it run rough at lower speeds (i.e. 4,000 rpm and less) too? It still runs smoothly and sounds good, just doesn't seem quite the same though.

[legacyo13]

What octane did you use?

And a fouled up plug that isn't firing right, will effect the whole range.

[95 honda delsol]

Not sure what octane I ended up with; Added per the directions on the bottle, so it should have been 104 +/- I think. Thanks for confirming what I was thinking - the entire RPM range would be affected. So, that eliminates the plugs. Takes us back to oil pressure (oil pick up screen or is there some input to the ECM/ECU (whatever its called) that if its low or absent, would cause the VTEC to not operate or operate very poorly? i.e. bad oil pressure sensor - reads higher or lower than it really is; or speed input reads hi or lo; or no input as to what gear its in; engine load input is incorrect (where does that come from? a vacuum sensor?) Through the "normal" driving range up to 4,000 RPM, the engine runs very smoothly, sounds great (but quieter than before), doesn't seem to have the same power, but I'm not sure if that's my paranoid imagination or an accurate assessment.

[legacyo13]

Most octane boosters were proven to be a myth. Some lost octane, others got a slight bump (1-3 octane higher). None have ever given what the bottles promised.

Oil pressure can be tricky. If it doesn't give the proper pressure, you can cause a rod knock. Do you know how many miles are on the motor? Or is it unknown? You shouldn't buy into the whole, "the motor has 80k miles on it." Without a cluster from a front clip, there is no proof. Plus look through all the ads for motors and see how many have 30k, 65k, or 80k miles on them. Hell I saw an 88 EF sedan with 280k miles, and the guy said he swapped in a D16A6 with 45k miles on from an 88 Si. I mean seriously, how often do you find a 23 year old DD car that's beat to hell with it's motor having 45k miles on it. Lol

[RedWabbit]

oil pressure sensor or the solenoid. I would still suspect the solenoid first, imo.

[95 honda delsol]

Update: Not oil pressure; not plugs; not screen -it's clean; replacing solenoid tomorrow. Not sure about the number of miles on the engine - best guess is 36K-46k.

[RedWabbit]

if you put a 12v source to the solenoid and it clicks its good, if it doesn't its bad.

[95 honda delsol]

Replaced the solenoid. It worked 50% of the time when 12v was applied to it. VTEC engages each and every time at 5400 rpm now. That's good. What's bad is that it doesn't have the power it did before. Used to throw your head back against the head restraint. Now just gets a little louder and seems to have just a little more power. (My mother would probably approve now; that's not what I want!) And not as much exhaust noise. Used to engage 4300-4800 rpm depending on the variables. i.e. rpm, gear, engine load, etc.

Honda VTEC experts: I need your help! Thanks.

[91EGGURA]

i've been following this and i just don't understand if you're correcting every possible problem then why the hell won't the son of a bitch get going again? did you unplug the battery when you did the solenoid? cause i don't know wtf to tell you other than go to honda directly and dish out the bucks.

[91EGGURA]

call me a quitter but just reading this thread gets me all pissed off at the car, it ain't even my car and i want to kick it seriously kick very hard, it just sounds frustrating as hell

[95 honda delsol]

Just saw 91EGGURA's reply -- thanks. I saw in another thread that someone had a "3x3" obstruction in their catalytic converter that caused a similar loss of power. I actually had that same thought earlier in the process and thought I might be half nuts; but now I'm thinking that might be the next thing I check. Also for your valued consideration: What about speed and rpm sensors sending bad data to the computer? And where is the computer? Under the passenger seat? If the previous owner chipped it so the VTEC would engage in the 4000 range instead of the standard 5300/5400 from honda, wouldn't it still do that? Would it if the input data was bad? Are there any other "inputs" i.e. vacuum for instance, that would cause the apparent loss of power across the board? I can't stop thinking about a partial block in the exhaust somewhere. The gas mileage hasn't dropped at all.

[95 honda delsol]

Ok, so let's "consider the following" (Bill Nuy, The Science Guy). Oil pressure sensor, speed sensor, rpm sensor, Temperature sensor (there is one, isn't there?), partially obstructed (sounds medical doesn't it?) exhaust. (Come to think of it, that causes a loss of power in people too.) Hmmm....