I recently picked up a 1990 dx for use as a dd.

For some reason the car has a slight misfire or sputter at lower rpms. ( I can't specify the rpm range as it doesnt have a tach, its automatic) Once you put the throttle past 1/4 or so, it runs fine. Not sure if its something throttle related or what. I already replaced spark plugs, wires, dizzy cap and rotor. No difference with any of those changes. Any ideas?

 

My 1989 CRX HF is having the almost identical issue. I've also noticed that when I go down a hill it does the same thing at the 1/4 throttle and then when I mash on the accelerator it has the same hesitation and then it kind of like catches up and then accelerates what seems to be normal. I'll also be in 5th gear or any gear for this matter at just below 1k rpm with the 1/4 throttle and it does the same thing until it catches up it seems like it's a little less than 1/4 throttle for me though. On top of what you've done, I've also replaced the TPS switch checked and double checked the timing checked compression a little while back, cleaned the piece right by the tps behind the throttle (the name of the part slips my mind know this doesn't help) and replaced the fuel filter. Can't figure it out. It's like it's not getting enough/ too much fuel or there's no spark or it's not hot enough. There was some carbon build up in my distributor (I think this might be normal though) And my battery light will some times flash on and off almost with the firing of the engine when it's around the 1k rpm mark. My check engine light will come on when I'm downhill and off the gas (just idling downhill), I don't know if it comes on because it's lean or too rich. I'd like to think all these symptoms are related, but that would make it to easy I hope!! I had auto zone check the alternator and they said it's "ok" and the battery is less than a year old. The battery light comes on sporadically at the 1k rpm. What gives anyone, are there any tests I or Thapimpfromchi can do to narrow it down?????? Thapimpfromchi, You might want to try the TPS and fuel filter if you haven't already and see if that helps, albeit being a grenade they're cheap fixes.

 

I'll take a look. It could be fuel related. Didn't think of that. Thanks.

 

Do you have any of the symptoms I listed??

 

nope. Just what I stated. And mine is automatic.

 

Did you check the gap on the plugs and use NGK?

 

Some autos had a tach FYI - my LX did.

This could be so many different things.
Ignition timing set wrong (common if you don't disable electronic adavance with service connector)
Weak spark - weak coil, cheap/incorrect plug wires, wrong spark plug gap (hope you don't have platinum tips... better spark with basic copper)
Air filter
Dirty throttle body/intake
Dirty valves
Dirty injectors
Restricted fuel filter
Lazy O2 sensor
Low compression
Other sensor getting lazy

I'm sure there are more things to add.

 

I'm gonna go over the car pretty thoroughly tomorrow. I actually had the chance to sit in it today without being in a rush to get anywhere, and I noticed i have a jumpy idle, like fiacv (or whatever you call it) was iffy, so i'm gonna start there. Plugs are new, basic NGK coppers, i always get those. Wires are just brand new cheap pep boys wires. no name brand, but I tried the set from my EK, similar length and whatnot, same problem. Air filter is like new.

I haven't really had an opportunity to really do anything to it, so everything i say is just an assumption. I'll post more up on here tomorrow once I actually wrench on it. Thanks guys.

as for the other guy, no, i did not check to see if they were properly gapped, I don't have a gapper (lost it), but i dont think it'd make THAT big of a difference? could it?

and, i knew somes auto's came with tachs. Thanks guys.

 

Check the distributors rotor shaft -- if it has play this could be the problem. At low rpms the engine will sputter, misfire. As the rpms climb things even out. Thanks physics.

 

i put my money on low compresion,,,my care runs rouugh at idle and smoths out ,thought the inj....nope bad rings

 

Played with it a little more today. Figured out that rpms don't matter, just throttle positioning. Vaccum issue??

Video, i replaced the rotor and cap the other day, everything else seemed fine.

 

I have the same problem only my misfire doesnt happen unless i drive over approximately 40 miles. It'll just start misfiring at a really low throttle opening and at any rpm's. As soon as you open the throttle more than a hair the misfire goes away...

 

Ya, same here, except the 40 mile part. lol. Did you ever resolve the issue? Its annoying. I want to get it fixed.


I just picked up an o2 sensor for her, i'm gonna swap that out, change the oil, and check the gap on the plugs. if that doesn't work I have a few distributors laying around, if any of them fit i'll swap them and see if they help, otherwise i am at a loss. Anyone have any more suggestions?

 

Hey, you solve the mystery? Interested cuz my ride has the same prob, but worse... So far I've taken off the throttle body and cleaned the crap out of it. All vac lines look good. Took off the TPS but looked good so put it back on. (Tps is still in the back of my mind.) After the TB I replaced the PCV and that actually cleared up the issue... For one short ride. That's when things went from bad to worse. Ran super rough next startup. So I checked the plugs, which looked healthy and were gapped correctly. Next time out the car died, the engine just quit cruising down the highway. Fun. Got it home, checked for file and spark. No spark. Tested the coil, returned 12. Took a gamble and replaced the ignitor. Ouch, still no love.

 

Wow this is pretty common it seems. Had this sort of issue on my D16A6 and still goes on with my D16Y7. Replaced intake manifold and TB, dizzy components, ECU, MAP sensor, fuel filter, air filter, added DC header... What remains? The rest of the exhaust, fuel pump, plug wires..

 

My next step is resoldering the main relay. By the way I'm dealing with a d16a6.

Everyone, please post up how you fixed your problem... as you fix it.

 

i have the same problem, i think.. but sometimes, and i mean rarely, it jerks real hard then when you put a bit more gas, its all good.. can't find what else is wrong with it so i'll be cleaning the IAC valve..

 

It is the distributor. 100%. The sensor inside the distributor is on it's way out. You can replace the ignitor and coil, but in the end, it is the sensor. I went through this before, swapped out MAP, IACV (was leaking), and AIT sensor (was original). My symptoms were bogging and sputtering off the line until 2500 rpm, then all was ok. This happened when the engine is hot. When cold it was fine. The crank sensor is subjected to a great amount of heat over time. This will take it's toll on electrics. Pick up a good rebuilt unit and call it a day.

 

I checked out my main relay and all the solder points looked fine, so i put it back together. And today my new distributor came in but still no love. I dont have a second person to check to see if I'm getting spark but I'm definitely getting gas. No ECU faults and to make sure it's working I disconnected my therm sensor and cranked the engine. The ECU instantly threw an error. So I know the ECU is healthy.

Anyone have advice? Way bummed.

On a side note, I discovered something puzzling while inspecting the timing belt. I put the front on jack stands and with the timing belt cover removed I rotated the wheels with the transmission in first gear but the timing belt pulley would not rotate. Why did the pulley not move??

 

I figured it out. My friend had an extra obd1 b16 dizzy which was kinda random cuz they really rare. I threw it on and i been drivin it for a while with no problems...

 

I have a feeling mine is TPS. I'm gonna start there. Unfortunately they arent that easy to come by. anyone have a TPS for a DPFI motor for sale?

 

swapped out the tps. No change. However, i keep hearing about "adjusting" the tps, i've never done that. they usually either worked or didnt. what exactly do i do to adjust it?

and, assuming that isnt the issue, any other ideas? Map? Dizzy? i cant think of anything else.

 

I don't understand the purpose of your post.
You have a slew of suggestions in the replies above that you haven't tried.
I don't think anybody even suggested TPS and you replaced it anyway.
...and with all that you are bothering to ask for more suggestions?

 

throttle body needs some adjusting.. well, worked on mine..

 

4dref - I've already checked compression, plugs, wires, cap rotor, swapped the complete throttle body (including tps), air filter is fine, and replaced o2 sensor. Hence, any other ideas? only 2 remaining that i dont think i have tried would be dizzy and the soldering of the main relay someone mentioned. Don't have to be a smart ***, but yo should read the whole thread instead of jumping down my throat.