kingmaximo

I own a 1998 Acura Integra LS 4-door 1.8L and it is missing badly during acceleration and is idling rough.

A little backstory:
i was assuming this had to do with the fuel delivery system and I have changed the following parts:
New Fuel Pump
New Main Fuel Relay
New Pressure Regulator
New Fuel Filter
New MAP Sensor
New PCV Valve

New Parts last summer:
New Distributer Cap
New Plug Wires
New Spark Plugs
New Cold Air Filter
New Exhuast System with headers (This was a cheap exhaust system from eBay, the car first started doing this not long after the exhaust system was replaced last summer)

After changing these parts I got it started and it was running and idling alright until the engine gets to operating temperature. But then under acceleration it starts missing or misfiring very badly. It's almost as if it's not getting fuel, but the whole fuel system has been replaced and I know it's getting fuel cause fuel will squirt out of the fuel filter when you loosen the banjo bolt on the top of the fuel filter. You can mash the gas pedal down and it will accelerate and then miss, it's like it's getting fuel then cuts out and get fuel and cuts out, on and on like this. Once the engine is running at operating temperature it doesn't want to idle properly either. But when I step on the gas, it goes and then jerks and then goes and jerks, just like the fuel is cutting out. I even purchased an Acura Performance Stage 3 chip that is suppose to auto-tune the ECU but it's almost as if the chip has made it worse.

I would think it may be the plugs or wires but it's not even been a year since they were changed. I'm at a lose here and don't know what else could be the problem. I'm not sure if this could have anything to do with the cheap eBay headers and exhaust since it no longer has O2 sensors. Any ideas or help would be greatly appreciated.

CyborgGT

Were the plugs gapped?

kingmaximo

No, I didn't gap the plugs, but it ran fine for months after I changed the plugs and plug wires. It started doing this a few months after the headers and exhaust system was changed and then it started doing this missing during acceleration. I thought about the gapping but like I said, it ran fine after changing the plugs for months, so I don't see how that could be the problem. Sometimes when I try to start it, it makes a noise that sounds like it's coming from the intake.

It would seem to me if it had anything to do with the gapping of the plugs then it should've started doing this last summer as soon as I changed the plugs and plug wires.

kingmaximo

Does anyone have any suggestions on what could be causing this?

kingmaximo

No one? Anyone at all ever had this problem before? I'm really just at a lose on this, I can't think of anything else to do, the whole fuel system is brand new except for the fuel rail and injectors.

K7-1Ktrevor

It's hard to say without being able to throw a wideband o2 in your exhaust and see what afrs your getting. Have you tried running it on a stock ecu? Even if it's throwing o2 codes If it runs better the chip you got is probably garbage, either that or possibly your new injectors are a different cc size. I've done basemaps for guys who put d15 190cc injectors in a ls or b20 and it will run super lean and miss and be very hesistant. I bet if you were to find someone local who could tune it for you they could alleviate your issue.

Misfires most of the time are from weak spark as well as a way out of wack afr. If the afrs are good then I go through the ignition system and usually find the culprit pretty quickly.

K7-1Ktrevor

Oh one more idea just popped in my mind, depending on which style fuel rail you have if it feeds from the end then you need to make sure you have the right large washer on the end that the fuel rail cap thing screws on. If you have the smaller one on that end it will block fuel flow.

kingmaximo

The fuel rail and the injectors are stock, that's the only 2 things I haven't changed on the fuel system. So, in your opinion, I just need to get some tuning software and learn how to use it cause their is no one in my area that does import tuning.

Can anyone recommend a good tuning software program for beginners to use? I've never tuned a car before, so this would be my first time. I do have a programming degree, so I'm pretty sure I could figure it out with a little help.

kingmaximo

Also, does anyone think it could be the ignition coil?

CyborgGT

But suppose the gap is wrong, and you've got carbon or something built up (you know, that thing that happens over time???)? Weak spark. Clean the plugs, gap them, then check back. Don't ask for help if you're just going to brush it off because you're fishing for a specific answer that you want to hear. Stop throwing parts at it and diagnose. A Haynes/Chilton manual is a good, cheap place to start.

kingmaximo

I'm not fishing for any certain answer, I'm all out of answers, that's why I'm asking. The reason I don't see how it could be the plugs is that when it first starts and runs it runs really good, it's just when it gets to operating temps that it starts the missing so bad under acceleration. Now, I'm not a mechicanical engineer but if the plugs are bad, they're always going to be bad, but changing the exhaust manifold for a header and losing O2 sensors that only work when the vehicle reaches operating temps leads one to think it almost has to lie in the tuning just like the above poster said. And I would like to diagnose somethings if anyone has any recommendations, and I do have the Haynes manual for this vehicle but everything it's suggested hasn't been the problem and it doesn't tell me how to tune the car, if anyone else has any informative information that could help me please respond. Pretty much everything the manual say that can cause this problem isn't the problem, it's just leading me to believe the tuning is just off cause of the headers. But, I'll take any suggestions at this point.

But, I wasn't just throwing parts at something, changing the parts I've changed in the fuel system helped the car cause it wouldn't start until I changed out those parts, so it's gotten farther than when I started, it starts and runs now, it just has that miss under acceleration when it gets to operating temps.

But, I will take the plugs out today and see what they look like and check the gap. Just to be sure.

kingmaximo

Now, correct me if I'm wrong here, but the cylinder misfires the gapping of the plugs this is talking about is saying it should always misfire like this, not just when you reach normal operating temps. Please throughly read what I've written before just throwing out a solution to a problem.

By the way, I just checked the product description for the spark plugs I put in my car and it plainly says do not gap, the gap is preset, that's why I didn't gap the plugs.

CyborgGT

I did read thoroughly, it's you that is only just now mentioning that the plugs are the type that aren't to be gapped. Not only that, but it sounds like you didn't even know that at first and are just now finding out. And I quote:

^ To me, that says you knew but chose not to.


You've got to know that it's incredibly difficult to diagnose over the internet when all we can see is this laundry list of "new" parts you've thrown at the car. I use quotes because the only new parts I trust are OEM; anything else, especially if it's refurbished from a parts store and not actually brand new, runs the risk of simply not being reliable. It just happens, I've been there. A basic service manual will have steps you can take to troubleshoot an issue. If you're having trouble with something there, hopefully one of us can help, but it's hard when we don't have the car in front of us.

Thinking on it, I remember the ignitor inside the distributor being a common wear item in '90s Hondas. That part is worth testing when both cold and hot. Maybe like with the fuel pump relay, there's internal soldering that's cracked and separates when hot. All we can do from here is guess at different things as you say yes/no, though...

wunfstgsr

Do you have a check engine code? use the stock ECU to retrieve your codes, try resetting the ECU or unplug the neg battery terminal to clear any codes after. Put a proper exhaust manifold that has a O2 sensor and plug it in the harness.

kingmaximo

No, at first I didn't remember the plugs were pre-gapped, that was last summer. I was just thinking back on why I didn't gap the plugs and then I remembered and checked the product info for them. But, something with the plugs should give problems all the time, not just at operating temps. And all the parts I've put on the car have been brand new parts, they didn't come from the Acura dealership cause I can't afford parts that are 300% higher than normal OEM replacement parts.

I'm thinking you are right about the problem laying in the distributor cap/ignition coil though, that's about the only things I haven't checked yet. I will test these things and see what I can fInd.

I know the car could use a tune, but I really doubt it'd be giving me that much problems without something actually going bad or is failing.

And no, the Check Engin Light is not on, that's why I can't hook it up to a reader cause it won't show any codes with the light off.

I will post the results of the tests of the ignition system, thanks for everyone's suggestions.