1990 CRX HF with 160k.

Cap, Rotor, Plugs, Wires all within 1 year. Also clutch, transmission rebuild, timing belt, waterpump, all new brake system, o2 sensor, exhaust, fuel filter, etc within 1.5 years.


So, it seems I get a shaking/hesitation at partial throttle. Idles, fine, 30%+ or WOT acceleration is fine (for an HF, heh), coasts fine, revs down in gear fine... it's just under partial throttle.

I'm thinking (hoping really) something like a mount of some kind, worried it could be something like the TPS (I actually have a replacement, but I do not have a voltmeter, and I know you have to 'slash' the rivets with a dremel, back the 'screws' out, and replace, which is within my mechanic abilities).

I do want to run some fuel injector cleaner (Techron) through it, just in case! Next empty tank, it goes in.

Input welcome. No CELs, all original.

 

are you talking about when the car is completely warmed up and is sitting idling? Cause my HF does the same thing. I cannot figure out why it shakes so much at idle.

 

sounds like a bad or uncalibrated TPS if its bad or not calibrated correctly when u barely press the throttle at 5% it could be reading incorrect or bad and thinking your pressing it 20% and it will cause it to buck all over the place and shake unplug your TPS and see if it does it then

 

vg_Ace,

Car is fine at idle. I will pay attention this morning to see if it makes a difference is if the car is warm or cold.

1990hondacrx,
You can just unplug the TPS and drive? This only happens when driving, not idling and pressing the throttle. I may try this later today.

 

it shouldn't do it as bad just be hesitant when u press pedal and not go right away and yes take it for a small drive plugged in and then unplug it to see how it drivers unplugged im 95% sure the issue is bad or uncalibrated TPS

 

Well, I paid close attention today. Didn't do it when cold, but I was also really only able to 'do it' in 5th gear on the highway (Already warmed up by then). But once at work, there are some straight stretches (stayed in 2nd) and it did not seem to do it.

I am not lugging the engine, I know what that feels like (a lot... it's an HF). So it really seems to be best/easier to reproduce in 5th gear.

When I unplug the TPS, what should I notice? I'm still amazing because I thought it needed the TPS to drive properly/at all...

 

Happens warm or cold, 3rd, 4th, 5th gears, partial throttle (those are the gears I was able to use on the highway to demonstrate).

Going to do a techron treatment soon, another 80 miles to go before fill up!

It's either fuel delivery or TPS. Have not had the stones to disconnect the TPS and drive… how does it work if it doesn't need the TPS? The ECU uses the TPS position to adjust fuel map?

 

Disconnecting the TPS, going a few blocks, then going home from work. Will report when I get back.

When it comes to replacing the TPS, how do you 'calibrate' the new one? I know the original is held on with rivets that must be slashed, backed out with a screwdriver, and then the replacement put in. Is that? How do I calibrate the new one? I already have it (from another project)? Do I just swap it, or could that be worse?

 

1990hondacrx,

Nailed it. Unplugged TPS (CEL is on of course), drives perfect (in terms of not doing the bucking/badness at partial throttle).

Sooo...

Can I drive with the TPS unplugged? Bad for MPG? I didn't really have any hesitation or problems driving it like this on back roads.

I have a replacement TPS.... do I just do what I said above and install it, or how do I check/calibrate it once installed? Should I bring it to an indy shop to do, or to Honda? Would they even do it (Honda)?

p3

 

before you remove the tps, hook an ohmmeter up and read the values as you go from closed to wide open throttle with the car off.

 

pimpwagon,

Any instructions on how to do this? I know how to pull the throttle cable from closed to open, but
1) What do I set the Ohm meter to (don't have one, will borrow one)
2) where do I put each probe (Black and Red)?


*Edit* From random internet searching, I think the following makes sense


Black Probe to Ground. Set Multimeter to 20v. Key to on, engine not started. Make a tap from a paperclip, go to red wire on TPS



like so. Start reinstall of TPS. TPS turned left or right changes the voltage out. Should read 0.00 close and .45 Wide-Open-Throttle? Is that right?

 

- Clean the IACV. Spray carb cleaner down the inlet port in the throttle body until the engine stalls. Let it soak for 15 mins and restart it. Spray 5-10 bursts of cleaner down the port so the engine bogs down but doesn't stall. Repeat until you feel satisfied that it's clean, you run out of carb cleaner, or the fumes get to you.

- Check for vacuum leaks. Spray carb cleaner on various hoses, seals and such in the engine bay, listening for changes in the idle (bogging, stuttering and such). Try pinching off each vacuum hose one at a time at the manifold... If the idle drops, that hose or component is leaking.

- Check the TPS. Pick up a digital multi-meter if you don't already have one. A model with a bar graph helps. Switch the ignition on and measure the voltage across the wires. You should see between .45 and .5 volts with the throttle closed, and around 4.5 volts with it fully open. You should see a smooth (no voltage spikes - this is where the bar graph comes in handy) transition between the two as you slowly open and close the throttle.

- Unbolt the EGR valve and see if the ports look clogged or the valve looks worn or damaged. If you have a vacuum pump, check that the valve moves smoothly and isn't leaking. Go ahead and soak the ports down with carb cleaner while you're in there.

 

im not sure of thre wire colors for testing the tps.

 

Thanks pimpwagon,

I've replaced the EGR in the last year, so shouldn't be clogged.

The IACV, is that the one you can unbolt off the back, and has the little screen, and 'figure 8' o-ring? I took that off last summer and cleaned it really well previously (wasn't very dirty).

I think it's the TPS.


Again, what's the bad part about driving with the TPS disconnected (At least temporarily, like a week?)

 

why do all of this when u can replace the tps and calibrate it properly and call it a day.. its a common thing for the tps to go out on these now days i mean really its a 20 year old moving sensor. unplugging the tps and seeing it clearing up clearly shows its a bad tps

 

refer to this for calibration
http://www.d-series.org/forums/diy-f...djustment.html
there are several u can look up i believe b series is calibrated exactly the same

 

Running a stock D-series, thanks 1990hondacrx.

Going to check the existing TPS readings at lunch. Got a multimeter from work.

 

These are all things that can contribute to the OP's prob. It's just being thorough, which the OP apparently is.

 

So thorough I was measuring resistance (Ohms) instead of voltage like a dumbass...

I ended up having to poke probes (made thin ones) past the two o-rings to the three different wires (because I was measuring resistance... because I didn't remember wth I was measuring from the time I left my desk and got to my car)...

So yeah, I will be removing the TB so I can slash the rivets, back them out, and replace. Question: Driving without the TPS plugged in means less MPG, but that's it, right? Computer uses some sort of ideal map and just isn't as efficient?

Will post final results. Oh, and after probing each line, the problem seems less pronounced. I didn't go to the parking lot to confirm, on my (somewhat traffic-y today) way home, it was significantly reduced... which makes me wonder if I should use electric cleaner spray and spray the hell out of everything...

 

if you really wanna get cute with it, use dialectric grease on the plug's terminals too!

 

I replaced the TPS. It seemed to help for a few days, but now it seems to be back (though maybe not as severe). Since the CRX is my only car at the moment, I haven't tried to exacerbate it (though it did happen harshly a few times). Anything else it could be? I suppose if I disconnect the TPS and I cannot make it occur, I 'know' it's the (replacement) TPS. Is that correct?

p3