87 Civic 1.5 runability during load - Honda Civic Forum

Mechanical Problems/Vehicle Issues and Fix-it Forum If you've got a problem you just can't figure out, a noise you can't diagnose, or a Check Engine Light that won't go away, ask about it here!

87 Civic 1.5 runability during load

Reply

 
 
 
Old 03-12-2013
  #1  
Registered!!
Thread Starter
 
Join Date: Sep 2009
Location: NW Oregon
Posts: 39
Rep Power: 0
iim1rmg is an unknown quantity at this point
87 Civic 1.5 runability during load

Car is an 87 Civic 1.5 Base Model 5-speed manual with the Hitachi distributer and 3-barrel carb.

Problem: Car runs great except: Only at higher speeds (65+) and only in top two gears, and only while under load (like floorboarded going up a steep grade) the car will suddenly loose power, begin stumbling and missing, and almost feel like it lost a cylinder). Once this starts, it pesists until - release the thottle completely for about 3 seconds and problem is gone. Releasing part way or slowing down does not change the symptom, only coasting for a few seconds. The problem is repeatable, but not consistent. Pulling hills at lower throttle settings will not bring it on.

Recently done: Plugs (NGK set at .044), replaced distributor, replaced ignition wires, timing set at 20 degrees BTDC with vacuum lines removed and plugged per DEQ sticker.

I'm at a loss, but, heavy load at full throttle may be affecting the mixture and the exhaust, so...

Is it possible that this could be caused by the O2 sensor causing an improper timing advance? Coasting for a few seconds clearing the problem may allow recovery from the overly rich condition.

If not the O2 sensor, what else?

When not misbehaving as described the car runs great, gets 38 mpg pretty reliably, and uses about a quart of oil every 2500-3000 miles (mostly leaked).

I guess a sticky valve could do it, but somehow I don't think thats my problem.

Thanks for any suggestions or help.
iim1rmg is offline  
Reply With Quote
Old 05-14-2013
  #2  
Registered!!
Thread Starter
 
Join Date: Sep 2009
Location: NW Oregon
Posts: 39
Rep Power: 0
iim1rmg is an unknown quantity at this point
Re: 87 Civic 1.5 runability during load

OK- I think I finally got a handle on what is going on. I fell victim to convincing myself it had to do with the last thing I did (replaced distributer).

I tried changing the O2 senser - no change.

Then I thought about it a while - what could cause a problem like this, but once it starts, it keeps doing untill one lets off the gas for about 4 seconds, then the car runs OK until the next heavy load situation?

It must be a fuel problem.

What is happening is that the float bowl is getting emptied and it isn't getting enough fuel. Letting off the gas for a few seconds lets it catch up and refill the float bowl.

Changed fuel pump (which showed some diaphram leakage) and the fuel filter and... Problem got much less severe, but did not go away.

Dumped a can of Chevron Techron into the tank (one of only two automotive additives I have ever had actually work sometimes) and syptoms got better still, but did not completely go away. I can still make it do it a little, but I have to really try.

I can live with it the way it is, but I have another carb I could install and my guess is that would completely cure the problem.

Changing the carb is a miserable job due to all the vacuum lines and sensors attached and the close clearance to the firewall, so I am going to put off changing the carb for a while at least, and the car runs great almost all the time, so I can live with an occassional uphill bauble that I know how to clear.

I've seen a few similar symptoms discribed in the forum for the older carbureted models. On mine, it was a combination of carb and weak mechanical fuel pump.
iim1rmg is offline  
Reply With Quote
Old 05-14-2013
  #3  
If you think a good mechanic is expensive, try hiring a bad one
 
ezone's Avatar
 
Join Date: Dec 2011
Location: Midwest, aiming about mid-chest
Posts: 30,399
Rep Power: 409
ezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond repute
Re: 87 Civic 1.5 runability during load

It must be a fuel problem.

What is happening is that the float bowl is getting emptied and it isn't getting enough fuel. Letting off the gas for a few seconds lets it catch up and refill the float bowl.
Hmmm. I wonder where I have heard this before.....I wonder.....



Did you ever check into the second fuel filter between the pump and the carb?
ezone is offline  
Reply With Quote
Old 05-15-2013
  #4  
Registered!!
Thread Starter
 
Join Date: Sep 2009
Location: NW Oregon
Posts: 39
Rep Power: 0
iim1rmg is an unknown quantity at this point
Re: 87 Civic 1.5 runability during load

Yes, changed it when I changed the fuel pump. Old one did not seem plugged and according to my log book, it had been in service less than 10K miles.

Biggest problem was marginal fuel pump. Still working but weeping, so it had to have a hole in the diaphram. It was likely the original and had well over 200K miles of service.

We have a requirement to have 10% ethanol in our fuel. Doesn't seem to matter to injected vehicles, but it plays havoc with carbs, and the carb on my little civic is probably one or two years after carbs should have gone away, and one of the most complicated carbs ever made. It is plastered with vacuum hoses and sensors, and is controlled by an ECM. It works great when everything works, but there is a lot to go wrong.

I have a friend with a chain saw shop. He is months behind on repairs and is running out of places to store all the two-cycle and small engines he has in, all with gunked up carbs.

Most marine engine and PWC shops have the same thing going on.

There are a few places we can get non-ethanol for off road use only, and it goes for about $5.00/gallon.
iim1rmg is offline  
Reply With Quote
Old 05-15-2013
  #5  
If you think a good mechanic is expensive, try hiring a bad one
 
ezone's Avatar
 
Join Date: Dec 2011
Location: Midwest, aiming about mid-chest
Posts: 30,399
Rep Power: 409
ezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond reputeezone has a reputation beyond repute
Re: 87 Civic 1.5 runability during load

Most marine engine and PWC shops have the same thing going on.
Funny, I'd think marine is one place to get alky-free fuel. Maybe these are the folks with the boat on a trailer gassing it up at a local gas station?

We have a requirement to have 10% ethanol in our fuel. Doesn't seem to matter to injected vehicles, but it plays havoc with carbs,
Now that you mention that, I remember back in the 80s when ethanol was first introduced and it was hugely popular here (corn belt ya know!), and how within a short few years it seemed like almost every car on the road developed carb problems, like sunk floats and rotten diaphragms. I rebuilt a crapton of them on what seemed like all makes and models at one of my early jobs.
I grew up with carbs, no big deal.

I worked in a Honda dealer for a short while (mid 80s) as a rookie mechanic and got to see some of this in Hondas of the day. The cars from the 70s just dropped like flies. Even better was all the cars showing up with "Pro-Gasohol" bumper stickers in for carb work.


My ex-brother in law also works with small engines, he tells the same stories about the carbs. I have been getting new kits for my 2 cycle yard stuff about every 3 years.

Notice how it's called Ethanol (and E-10, E-15, etc.) fuel now, and not Gasohol? Too many people still remember what the crap did to their cars in the early 80s......so the powers-that-be decided to give the same old crap a brand new name and hope nobody figures out the difference.
ezone is offline  
Reply With Quote
Reply
 
 
 
Related Topics
Thread
Thread Starter
Honda Civic Forum
Replies
Last Post
mattdoc
Mechanical Problems/Vehicle Issues and Fix-it Forum
9
03-14-2017 12:10 PM
rcolosi
Mechanical Problems/Vehicle Issues and Fix-it Forum
4
04-29-2015 07:48 PM
BREADFAN
Mechanical Problems/Vehicle Issues and Fix-it Forum
0
04-15-2015 08:58 AM
EvilTwin
General Automotive Discussion
4
11-08-2001 12:17 PM


Thread Tools
Search this Thread