Occasionally stalling at idle and hesitating when accelerator pressed.

dibls

New Member
1990 Acura Integra RS Automatic.

Girlfriend complained that when she was sitting at a light, sometimes, and pressed the accelerator to go, the car did nothing for a moment before it began accelerating. Driving the car, myself, I noticed there were times when it would feel like a deadspot, and I could press the accelerator and let it out slightly with no response from the engine (RPMs remained steady, no acceleration obviously) and would have to give it a disproportionately high level of pressure to get a response form the engine, at which point would be a large jump in RPMs when it finally responded, since I had pressed the accelerator so much. This was not, however, a dead spot with the accelerator, because at other times the same amount of pressure on the pedal would illicit response from the engine. I wasn't sure if the car was refusing to shift or what, but it definitely felt more like it was simply not feeding more gas into the engine.

One day she calls me because the car won't start, I'm not sure if she understands the questions I'm asking her, but she says it will turn over then die. I recreated the problem myself and the engine turned over and revved, revs shot up to over 1k then dropped down as if to catch at idle, but just kept dropping as if the ignition had been turned off. Tried to start it again, second time it hardly revved at all, hitting about 500, dying about as fast as it started.

Next I tried it while giving it some gas by applying slight pressure on the accelerator; this worked as I hoped and the car started fine and jumped up to about 1500-2k RPMs, which was about it should considering where I was holding the accelerator. I believe when I slowly let off the accelerator, that time, it idled alright, but at various times the idle would drop low, like 450 or so, and the engine would start shaking, right on the verge of stalling. I had asked her previously if she had experienced the same thing, with the engine almost stalling, and she said she had.

I tried adjusting the idle screw on the throttle body, and was unable to get the car to idle above 500 RPMs, which proved problematic as this is a fine idle level when the car is in park, but when I shifted to reverse or drive, the RPMs would drop to around 400, threatening to stall. This was while my foot was on the brake, it almost seemed as if I were letting the clutch out, maybe. I suppose I'm wondering if there could be a clutching issue going on here.

The other possibility I'm considering is that there is a fuel delivery problem, since I was unable to get the car to idle above 500 RPMs (I was hoping a temporary fix, until I could diagnose the krux of the issue, would be to just up the idle so it wouldn't stall on her, going to work and back). I was able to adjust the idle lower, almost stalling the car, but as I unscrewed the idle screw it would always stop increasing the idle level around the same point. I suppose this causes me to think it's more likely a fuel delivery issue than a clutch-transmission issue...

It's an old car 1990, and from what I've gathered in my little experience working on cars, people rarely ever change fuel filters on cars. So I have assumed in the life of this car it has never seen a new fuel filter, but I do not know this for sure. I've looked through the old receipts my girlfriend kept of past work done on the car, but they only go back to around 1999 or so, and may not be exhaustive even in the time since then.

Is this a sensible place to start looking for a fuel delivery issue? Should the fuel filter be my first suspect? What about fuel injectors? The Haynes manual did not mention that as a possible source for trouble with a car starting and dying immediately, but there are other symptoms here as well...

Does this sound like a fuel delivery issue to you? What else may be going on here? Haynes manual also suggested vacuum leak, but the hoses show surprisingly little stiffness/dry-rotting, I briefly tried spraying some carb-cleaner around the throttlebody-intake gasket to see if it improved RPMs, and saw no response, but did not check it all around, just on top.

Any suggestions appreciated :D
 

dibls

New Member
When I say:
"it almost seemed as if I were letting the clutch out, maybe. I suppose I'm wondering if there could be a clutching issue going on here."
I mean the response from the engine seemed the way it would in a manual car if I was letting the clutch out, while holding the brake. This car is not a manual, therefor there is no clutch, but I'm just thinking about what I know about cars, and trying to relate the problem to other phenomenon I've experienced.
In the second sentence I mention I wonder if there's a clutching issue, because I assume that automatic cars have some sort of clutch system that is automatically engaged when shifting or when the car comes to a complete stop.
 

Detman101

Da9 newbie
Yikes, sounds like what was happening with my old sunbird.
Crappy pedal response and wouldn't start right at all. cylinder 2 was not working properly for some reason.
I didn't have the know-how or money to fix it and donated the car as it was.
Wish I''d have taken my sound system out of it...now that I have a DA I could use it.


But I digress...
On my old car it had the same problems you've explained. I believe it was clogged injectors combined with a plugged CAT. I could never get the cat off to replace it (no lift) and I didn't know jack about fuel injectors so...it never got fixed and consequently only got driven in the summer when the outside temps seemed to negate the NO-START below 32 degrees condition.

good luck, I'm sure it's something fixable. These cars are so much better built...

EDIT: Oh yeah, automatic transmissions have multiple clutches...

Dm
 

Alvi84

New Member
Could be a variety of things. I'd check for vacuum hose leaks, fuel delivery (filter or check pressure at the rail to ensure your fuel pump is still working to spec), and a weakened ignition coil in the distributor can cause the car to not maintain enough spark to keep her going.

On some hot days I have problems starting my teg and have to hold down the gas to start and keep the gas lightly pressed for a minute or so. My problem is related to the main relay that I'm just too lazy to fix cause it only happens once in a while.
 


emd513

New Member
The fuel filter is suppose to be replace every 15,000 miles so it needs one then check pressure and use a fuel system cleaner reccomend Lucas. Has worked awesome for me
 

dibls

New Member
I appreciate the responses!

I'm definitely going to replace the fuel filter, since I'm sure it's overdue for one anyway.

I believe the distributor wouldn't be a problem, it was replaced a year or so ago. But if I'm not finding anything, I'll keep it in mind to check it out.

I also believe the injectors were replaced in the past 5 years or so, but I will also check them out, worth looking at.

Vacuum leaks was one of the first things I considered (well just an issue with air in general), so I will look at the vacuum hoses.

When you say clogged CAT I assume that is the Catalyitic converter? I also considered, briefly, that it may be clogged exhaust, but not sure if the symptoms really point in that direction... There's an easy way to check if exhaust is a problem, I guess... disconnect it and see how the car runs. Although I'm sure you always get improved engine response with back pressure from the exhaust system... So I don't know if that would be indicative of the problem being in the exhaust.

Anyway, Fuel Filters are cheap, so I'll go ahead and replace that.
I'll also check the fuel injectors, and the fuel pressure.
I will check for vacuum leaks.
Fuel System Cleaner sounds like a good idea, too.

Thanks guys.
 
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