stumbles on acceleration, WHEN COLD, idles fine, usually

GRRR this is really pissing me off!

Okay, the car is a '89 SE-i with a K&N stock replacement air filter. Nothing fancy, except for the muffler, which will be getting a OEM replacement soon.

Stuff I've done/replaced:

cleaned the air filter.
replaced: plugs, plug wires, cap, rotor, PCV
The coolant has been flushed.
The timing has been checked and is OK.
The belts are tight. There are no obvious vacuum leaks, BUT I HAVEN'T CHECKED EVERY HOSE.
I've cleaned the IACV.
The EGR operates normally, afaik.
Fuel pressure is OK.
I do have a vacuum guage and compression tester, but haven't used them on the car yet.
The plugs look fine (indicate the car is running perfectly).
Grounding (cleaned and added a few grounds; didn't help).

The problem:
When cold (i.e. sitting for like 7 hours or more), the car starts fine, idles great, but at moderate rpms (up to 3000), it stumbles under acceleration, even cutting out sometimes. Since the engine mounts are shot, this REALLY jerks the car around. About three or four city blocks later, it quits and runs great. Gas mileage is normal, and there is no smell of unburnt gasoline when it runs rough.

I've pretty much narrowed it down to bad valve sleeves, a bad ignition coil, or some stupid vacuum leak I haven't found yet. The bad engine mounts will be replaced soon (as will the bad brakes and shocks), but those by themselves couldn't make the engine stumble, could they?

So, anyone ran across this problem before? Fixed it? Once it warms up just a tiny bit, the sucker runs like a champ, but I can't lick this problem (and it's REALLY annoying for those first few blocks). I'm going on a long (1000+ mile) trip soon, and I don't want to be stuck by the side of the road because these symptoms are indicating a bad ignition coil or something like that. GRRR....

HELP!

Yeah I was thinking coil.

I had similar problems with the car stumbling when cold on my EFI corolla. I swapped out the coil and everything was fine.

This thread detainls my coil swap... aftermarket coil install, and stock coil test proceedure.
https://www.3geez.com/forum/showthread.php?t=114



Also how close is the muffler & pipe to the fuel tank? Has any heat sheilding been removed?

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.
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have you replaced your O2 sensors? They are supposed to be changes every 100k miles. After running for a while the computer will override what the bad O2 sensors are saying and the car will stop hessitating. I had this problem before. Make sure you hook the wiring up to the right sensor. I got the two confused and ended up hooking the up backwards and boy did it run terribly. I switched the wiring around and it runs great! There are many things that could be wrong its just a process of elimination. Is the car throwing a code? Just because the check engine light doesn't come on doesn't mean it isn't throwing a code. I know people that disconnect the check engine light. Just a thought!

Muffler is a cheap flow-through glasspack. Plenty of clearance, stock heatshield untouched. After 40k that sucker is a straight-pipe.

I've got spare coils. I'll test and swap when I dig them out of my shed.

I've checked for codes before and founds none, but I'll check again. Disconnecting the battery did absolutely nothing to affect how it ran.

I'll look into the O2 sensors (I've got two of them).

A friend suggested doing a vacuum test; maybe the valve sleeves are leaking and warm up after ~45 seconds and expand; then work fine until the engine completely cools. THAT would be time-consuming to fix but at least they won't cause the thing to die on the side of the road.

Hi,
I have similar problem - but not as bad - my 86 LXI occasionally hesitates under acceleration when cold. I found the following in the newsgroups. Has anyone tried lubing the advance? Is it hard to disassemble the distributor?



Hesitation/Surge Problem 1989 Honda Accord LXI
All 2 messages in topic - view as tree
From: Suezee911 - view profile
Date: Sat, Aug 22 1998 12:00 am
Email: [email protected] (Suezee911)
Groups: rec.autos.makers.honda
Hi,
If anyone can help with this problem.
There is hesitation upon acceleration from a stop and then a quick surge.
Fuel injectors appear to be okay. New plugs, rotor, fuel filter, etc. EGR
valve okay. Centrifigal and vacuum advance okay BUT TIMING RETARDS BEFORE
ADVANCING.
Also, PCV valve okay.
(And it's not the transmission -- just had work done on that)
Thanks in advance,
Geri
E-mail or Post
([email protected])
Reply
From: Rob Relf - view profile
Date: Sat, Aug 22 1998 12:00 am
Email: "Rob Relf" <[email protected]>
Groups: rec.autos.makers.honda
The timing retards before advancing because that is the way it is designed.
The vacuum advance has manifold vacuum at all times. When you open the
throttle to accelerate, manifold vacuum falls (to zero at full throttle) and
so the timing is effectively retarded. At the same time, as rpm's climb the
centrifugal advance operates to bring the timing back up. Even though you
say the centrifugal advance is ok, I am betting that it is not. Now that
the '86-'89 Accords are getting older, (on TEC brand distributors) the
grease in the distributor shaft area is dried up and rust causes binding of
the centrifugal advance. If you take off the cap and twist the rotor, you
will find that the advance is stiff to move and does not return all the way
without assistance when you release it. You need to disassemble and clean
and lube the centrifugal advance parts (if in otherwise good condition) to
cure your problem. Our shop charges 1.5 hours to do this, including
replacing a leaking vacuum advance if needed.
Rob

Hrm I'll take some pictures for you of the centrifugal advance if I have not destroyed the last of my spare distributors.

Worth a shot. I can tear it apart tonight.

Well here is the inside of a Carbed "Hitatchi" Distributor, the "Tec" is a little different. But the mechanical advance is in the same place, you'll have to dig to get at it.
https://www.3geez.com/forum/showthread.php?t=53918

Okay, the rotor does not return easily, so I'm going to look into that.

I haven't torn apart the distrib because I'm swapping out the front shocks and replacing a torn CV boot. Not to point fingers, but I just got a front alignment at Les Shwab and they claimed the excessive toe out (causing major tire wear) was due to the shocks "going bad."

Yeah, right. And I'm the queen of England. New control rod ends, anyone?

Then the CV boot splits once I drive it about a hundred miles or so.

Again, not pointing fingers. So I'm swapping out the shocks anyway, and fixing the CV boot. The cap and rotor are off the distrib, but I want to clear one repair job before starting on another.

Turns out replacing the outer CV boot is "impossible." Parts stores around here don't sell it. Since the inner one was not in good shape, I just replaced the whole axle... and found the fork bolt was rusted tight. I mean TIGHT. Had to use a 5 foot improvised breaker bar to get her loose. Everything is lubbed up and back together now, at 10 pm.

how is it impossible?

There are easy repair boots that are split down one side so you don't have to remove anything to get the boot on.
You glue the ends together. I put my clamps on loose cause I found most of my CV breaks are at the clamps... I'd rather it slip off then tear.

I shoped around here and cound find exactly nobody that carried split boots. I needed the car to run errands today. Ergo, "impossible.":(

The boots on the other side aren't in hot shape. I have to make custom axles for my project car... so I'm thinkin' I'll get a set of boots for the driver's axle and keep them on hand in case it starts spewing grease too.

Distrib. isn't off, since I need the car today. This weekend I should be free to tackle it, along with new motor mounts. :)

I wonder if ceran wrap will work as a temporary fix

I was about to put on red RTV, but the tear was pretty bad.

Maybe some bike tube patch?

Quick update. Pulled the engine mounts and filled them with urethane window-weld. Found out the torque mount had come loose again. Put them back in (lock tite on the torque mount bolt!), and noticed a soggy coolant hose. I'll get her later. She shifts and engages much better now. You can literally tell that the engine isn't jumping around like a kangaroo in the engine compartment. The missing is less noticable now, but I noticed it doing this at idle occasionally, which is weird. It doesn't stumble at all when the A/C is running however.

Next weekend:
I will re-lube the distributor (finally), check the coil and wiring (again), and replace the vacuum hoses. We'll see if that helps any.

The temp sensor controls the amount of gas to the injectors.
This will cause problems starting and running too. If the sensor thinks the engine is warm(Low Resistance value) it will not put as much gas to the injectors and the engine will run rough until it get's warm.
If the sensor thinks the engine is cold(High resistance value) it will dump gas into the injectors and the engine will not start after a short trip because the engine is warm and the increased gas will flood the engine.
If you pull the green connector off and short the wires there on the connector and start the engine you will get a pgm light with a 6 code and the software will defaut to a pre-programed gas feed, because it will think the sensor is bad. I run my car like this cause I don't want to hand over the fifty dollars for the sensor, and mine runs fine, but is a little hard to start when cold because there isn't enough gas being sent to the injectors, but it wams up fine and accelerates fine now that I have replaced my plugs yet again(they go bad A LOT, like 5-10 thousand miles).
It won't cost you anything to try it...
To test the sensor you don't have to pull it, just take a ohm meter and put it on the two leads on the top of the sensor below the green connector, take the connector off, of course.
When the engine is cold the sensor should read something above 20000 ohms, as it gets warmer the value should come down to somewhere around 500 or less ohms.

When was the last time you replaced the plugs? Did you see an improvement when you replaced them, and later it the problem resurfaced? If so the plugs are bad again, they go bad a lot.

Whew. Okay, I'm back from vacation!

The trip went good, but the car is running rough all the time when cold. Before we left, I started it up (been sitting for two days) and stomped on the throttle. Big smoke cloud for about 30~40 seconds. After this, she ran great, no hesitation, stumbling AT ALL. Also, no oil burning smells.

Checked the brand-new plugs and wires after a 20-mile drive. Clean as a whistle. No indication of bad connections. No stumbling when warmed up. No hesitation or missing once warmed up. In fact, she's running great... unless she's cold.

Hmm... oil leaking into combustion chambers? Compression test! I'll try to get it done this weekend, but I'm betting that after 140k of abuse from the previous owners, this motor is on its last leg.

finally got the distrib apart. TEC type, apprently. The plate that the vacuum advance turns was almost stuck--claeaned and greased it. The centrig. adv. I can't get out of there, but it's very sticky too. All the grease has the consistency of hard plastic. See if it runs good on my 600-mil trip coming up... tomorrow.