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Car Forum / Honda Cars / July 2005'90 Civic: Extremely sluggish low-end acceleration, poor fuel economy
A few more issues from my poor little car for anyone who can shed some light... My '90 5-spd Civic Ex has been bogging down at low RPMs since I bought it last fall. When I accelerate from a dead stop I have to goose it to about 2500rpm and then pop the clutch a bit to get it to take off as quick as I think it should. Especially in an up-hill situation. (no AC) If I drive it like other small manual 4-bangers I've owned (Corollas, etc), it will literally take 5-10 secs to get to the point where I think I should shift to 2nd. Gas pedal down half way or floored makes no difference. Also, doesn't matter if the car is at temp or just started. After 1st gear and I'm moving a bit, there's no problem. I seem to remember reading about a potentiometer (maybe in the throttle? can't remember the details) that, if the contacts were dirty, would cause this type of thing. Maybe I'm just crazy and I dreamed this.... I'm also getting only about 15-18mpg in town and 20-23mpg hwy this summer... seems incredibly low. Was getting the same last winter, but wrote it off to cold weather. Spark plugs are about a year old, newish air filter, and OEM O2 sensor's only 6 months old. ECU's not throwing any codes. -Back pressure too low/high? (bad catalytic converter?) -Bad plug wires? (I'm sure they're not Honda OEM wires, but I think they're only about a year old) -Clogged EFI? -Timing out of adjustment? I didn't fool with the dist. when I changed the timing belt, mostly because I couldn't find a damn marking anywhere on the crankshaft pully to save my life. Ran like a top after the belt change, so I'm confident it's not a tooth off... HELP! Any advice would be greatly appreciated... Regards, -Bruce That mileage is pathetic. When's the last time you replaced the PCV valve? I replaced mine on my 91 Civic for the first time (way overdue) two years ago, and the mileage shot up. The plug wires? Fuel filter? Air filter? All of these are easy to do, inexpensive, and could be a part of, if not the, problem. > A few more issues from my poor little car for anyone who can shed some > light... [quoted text clipped - 35 lines] > Regards, > -Bruce Do Honda plug wires make that much of a difference? What about brands of plugs? The wires I have now are the most expensive ones at Autozone and the plugs were about $2 each IIRC. Air filter is only a few months old, doesn't look dirty at all. I've heard the fuel filter is an easy job, but I've never done one before. Where is it located and what does it look like? I guess if I just buy one it will help me find it. I think my Haynes manual says it's on the firewall, but it also states that the fuel pressure must be released to do this, and it's pretty vague about that procedure. Thanks I checked the PCV valve a few weeks ago... I was told if the bead inside is loose, it's ok. I blew some degreaser through it just to be sure, but there is no moisture build-up in the crank case. I guess for a $3 part I might as well get a new one, but I don't think it's the problem. Do Honda plug wires make that much of a difference? What about brands of plugs? The wires I have now are the most expensive ones at Autozone and the plugs were about $2 each IIRC. Air filter is only a few months old, doesn't look dirty at all. I've heard the fuel filter is an easy job, but I've never done one before. Where is it located and what does it look like? I guess if I just buy one it will help me find it. I think my Haynes manual says it's on the firewall, but it also states that the fuel pressure must be released to do this, and it's pretty vague about that procedure. Thanks > I checked the PCV valve a few weeks ago... I was told if the bead > inside is loose, it's ok. I don't buy this. There's a spring in there and it will lose its optimum effectiveness over time, despite the little test one can do to hear the bead operate the valve. The valve is a control valve, meaning it often operates somewhere between fully open and fully shut, so the spring's integrity should be vital. Particularly if it's the original PCV valve, I would replace it. Just one easy thing to eliminate. > I blew some degreaser through it just to be > sure, but there is no moisture build-up in the crank case. Now I fully remove my Civic's PCV valve once a year and spray PB Blaster into it. > I guess for > a $3 part I might as well get a new one, but I don't think it's the > problem. Buy the OEM PCV valve for around $20 at your dealer's. Word on the street is that the non-OEM versions are not good. > Do Honda plug wires make that much of a difference? My understanding is yes. Buy the OEM plug wires. (I am frugal, by the way, but over the years I've learned my lesson on certain Honda engine parts and find the extra bucks laid out now saves me trouble later.) > What about brands > of plugs? Buy what the owner's manual recommends. My 91 Civic manual lists the exact plugs for three different manufacturers (NGK, ND, and Champion). I don't think platinum makes any noticeable difference, so don't let the salesperson at Autozone or wherever talk you into the platinum version unless you think it's cost-effective and/or improves performance. I think NGK is popular and a safe bet among people here. > The wires I have now are the most expensive ones at Autozone Lose these. > and the plugs were about $2 each IIRC. > > Air filter is only a few months old, doesn't look dirty at all. Sounds good. > I've heard the fuel filter is an easy job, but I've never done one > before. Where is it located and what does it look like? I guess if I > just buy one it will help me find it. Yes. > I think my Haynes manual says > it's on the firewall, That's where it is on my 1991 Civic. > but it also states that the fuel pressure must be > > released to do this, and it's pretty vague about that procedure. Autozone should have a free online repair guide for your Civic that matches Chilton's. The Chilton manuals are better than Haynes, in my experience. Or go to http://www.honda.co.uk/owner/ConcertoManual/index.html. Go to the "Fuel and Emissions" sections, and click on "fuel filter." There's a drawing there that may help. The Concerto engine is very similar, if not identical, to the early 1990s Civic engines. The torque specs vary, though, so you should go to Autozone or get a Chilton's to get the exact torque specs for your fuel filter. Many years ago during the first time I replaced the filter, I found getting the bolts loose a little tricky. I had to find ways to brace wrenches etc. I also didn't have the best wrenches for the job. Now I do. Having done this four or five times, it's now a piece of cake. It's not hard nor particularly dangerous to release the fuel pressure. One just slowly loosens what is called the service bolt on the top of the filter, holding a rag around it, so some gasoline leaks out and relieves pressure. As I trust you can imagine, these are all regular maintenance items, so by doing them, you haven't really wasted money, and you've narrowed down what's behind your Civic's problems. >> I checked the PCV valve a few weeks ago... I was told if the bead >> inside is loose, it's ok. [quoted text clipped - 7 lines] > Particularly if it's the original PCV valve, I would replace it. Just > one easy thing to eliminate. I fianlly replaced my original a few weeks ago. It had 14 years and 248,000 miles on it. Didn't make a bit of difference to gas consumption or engine running. New FAQ page on that saga: http://www.tegger.com/hondafaq/pcv-replace/index.html Pics are part-way down.  SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ "TeGGeR®" <tegger@tegger.c0m> wrote Elle > > Particularly if it's the original PCV valve, I would replace it. Just > > one easy thing to eliminate. > > I fianlly replaced my original a few weeks ago. It had 14 years and 248,000 > miles on it. Didn't make a bit of difference to gas consumption or engine > running. By your own admission, you totally baby your car. > New FAQ page on that saga: > http://www.tegger.com/hondafaq/pcv-replace/index.html Needs work. You and I continue to disagree on this. A guzillion web sites back up my (along with like every other regular's) position on this. > "TeGGeR®" <tegger@tegger.c0m> wrote > Elle [quoted text clipped - 7 lines] > > By your own admission, you totally baby your car. That is my point. Cars that are not taken care of are the ones that suffer from this. >> New FAQ page on that saga: >> http://www.tegger.com/hondafaq/pcv-replace/index.html [quoted text clipped - 3 lines] > You and I continue to disagree on this. A guzillion web sites back up > my (along with like every other regular's) position on this. And every working mechanic I have ever spoken to about this says exactly what I put up on that page. SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ Well, I'm going to change the PCV just because I kind of doubt the previous owner put in an OEM Valve, IF he changed it at all. One less thing that could be causing my mileage problems, and it probably needs done anyway. But, I'd also like to check the timing... any advice on finding the timing mark on the crank pulley? I assume it's just a little dab of paint and that I'll have to put some white-out on it to make it visible with the timing light, but I can't see ANY mark on the pulley. Nada. And I need to short the contacts under the kick plate in the passenger compartment to disable the auto-timing adjustment too, right? That sounds easy enough, but if I can't find the mark on the pulley it's a moot point. Thanks guys. -Bruce > Well, I'm going to change the PCV just because I kind of doubt the > previous owner put in an OEM Valve, IF he changed it at all. One less [quoted text clipped - 5 lines] > paint and that I'll have to put some white-out on it to make it visible > with the timing light, but I can't see ANY mark on the pulley. Nada. Like Jim said, it is hard to see. You should go at it from the top, and with a flashlight, using the directions he gave. That degreaser you applied may have helped shorten the life of the pulley's timing paint marks. The marks are mechanically etched into the pulley, though, so they should still be somewhat visible. You do realize it's four marks, all within about 10 degrees (too lazy to think about the exact degrees apart they are), right? There was a photo online of the c. 90 Civic's timing marks at a certain site that I'm trying to pull up now. My Chilton's has a drawing and photo, so Autzone.com and probably the UK site should have at least the drawings, too, under "ignition timing." I'll post a link if I find it. > And I need to short the contacts under the kick plate in the passenger > compartment to disable the auto-timing adjustment too, right? Yes. > There was a photo online of the c. 90 Civic's timing marks at a certain site > that I'm trying to pull up now. My Chilton's has a drawing and photo, so > Autzone.com and probably the UK site should have at least the drawings, too, > under "ignition timing." I'll post a link if I find it. FWIW, go to http://www.honda.co.uk/owner/ConcertoManual/index.html , and click on Engine Tune-Up, then "Ignition Timing... " at the bottom for some drawings of the engine and its timing marks. Check out the CRX manual's drawings, too, at the UK site. They are slightly different. www.autozone.com has the drawings and photo (under its free repair guides; "engine performance and tune-up"; "ignition timing") too. I have been having error messages when I accessing some of Autozone's sites from home, but I found that repeatedly refreshing usually clears this up. > > And I need to short the contacts under the kick plate in the passenger > > compartment to disable the auto-timing adjustment too, right? > > Yes. Ignore the UK site's steps on this. The c. 1990 Concerto and CRX have a different set up for disabling the automatic ignition timing adjustment. >>Well, I'm going to change the PCV just because I kind of doubt the >>previous owner put in an OEM Valve, IF he changed it at all. One less [quoted text clipped - 15 lines] > You do realize it's four marks, all within about 10 degrees (too lazy to > think about the exact degrees apart they are), right? i'm not sure the 90's do. my 89 does, but my 91 crx didn't - it just had a single mark - and i did check! i think this is because at about this time, the newer timing lights came out with adjustable advance angle. just set the degrees you want on the timing light and adjust the tdc mark accordingly. with the 4-mark system, you can use an older style non-advance timing light. > There was a photo online of the c. 90 Civic's timing marks at a certain site > that I'm trying to pull up now. My Chilton's has a drawing and photo, so [quoted text clipped - 5 lines] > > Yes. > Elle wrote: magnificent snipping, something some people, whom I will not name but whose initials are J.B., should try ;-) > > You do realize it's four marks, all within about 10 degrees (too lazy to > > think about the exact degrees apart they are), right? > > i'm not sure the 90's do. My 1991 Civic does. The UK manual for the CRX, claimed to cover 1988-1991 but also in places indicating it may be just for 1988, also shows four marks. The UK manual for 1995-97 Civics shows four marks. > my 89 does, but my 91 crx didn't - it just > had a single mark - and i did check! Sure. I believe you. A few perhaps pertinent observations: The CRX is not identical to the Civic. (I assume you know this, but I wanted to clarify for the original poster.) For example, on the CRX, the "ignition timing adjusting connector" that needs to be jumpered is in the engine compartment on the CRX. It's in the passenger footwell on my Civic. My Chilton's manual has two drawings, covering the 1984-1991 Civic/CRX/del Sols, showing four marks. But it also has a photo showing one mark. The online UK manual for 1990-1994 Concertos shows five marks... I'm betting the OP's 1990 Civic crank pulley has four timing marks. > magnificent snipping, something some people, whom I will not name but whose > initials are J.B., should try ;-) [quoted text clipped - 17 lines] > > The CRX is not identical to the Civic. it is mechanically and electrically. > (I assume you know this, but I wanted > to clarify for the original poster.) For example, on the CRX, the "ignition > timing adjusting connector" that needs to be jumpered is in the engine > compartment on the CRX. It's in the passenger footwell on my Civic. it's in the passenger footwell of the 91 crx. > My Chilton's manual has two drawings, covering the 1984-1991 Civic/CRX/del > Sols, showing four marks. But it also has a photo showing one mark. > > The online UK manual for 1990-1994 Concertos shows five marks... > > I'm betting the OP's 1990 Civic crank pulley has four timing marks. maybe it's a peculiarity of japanese imports vs. canadian imports? the only difference at the end of the day is $20 - the difference between sears' standard "fixed" timing light & their angle advance model. > You and I continue to disagree on this. A guzillion web sites back up > my (along with like every other regular's) position on this. I just tried two experiments on my own 1991 Integra just now. ----------------------------- Firstly, I tried plugging the PCV hose shut. The idle dropped momentarily, then climbed smoothly back up to 750 and remained there. When I let go of the hose, the idle surged briefly, then settled back to 750rpm. As expected, the engine management system was adjusting air flow to achieve correct idle speed. ----------------------------- Secondly, with the car fully warm, I unplugged the PCV valve hose at the pipe where it enters the intake manifold, so the PCV intake was completely open as a massive air leak into the intake downstream from throttle plate. The idle dropped momentarily, then began smoothly surging between 1,000rpm and 2,500 rpm. As expected, the engine management system, crude as it is, was attempting to adjust the mixture to be correct. The air leak being too great, however, it was unsuccessful in doing so. (Interestingly, air flow from the PCV valve itself stopped dead, suggesting that ambient air pressure was keeping the valve shut. IOW, crankcase pressure was lower than ambient.) I then plugged the PCV intake pipe with my thumb, mimicking a plugged PCV valve. The idle returned to a smooth 750rpm and stayed there. I discovered that I could uncover up to a quarter of the PCV intake pipe before the idle began surging again, the severity of the surging directly related to the amount of exposed intake pipe. ------------------------- Conclusion: Cars with engine management systems do not suffer noticeable problems from a plugged or stuck-open PCV valve unless an extremely unusual situation is present. History: I once had a 1975 Toyota Corolla with a carburetor and no feedback system. This car would not idle at all with the PCV valve removed. Unlike the Integras's feedback system, the carburetor was unable to compensate for the excess air. I discovered this quite by accident when an aftermarket PCV valve came apart on me. SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ >>You and I continue to disagree on this. A guzillion web sites back up >>my (along with like every other regular's) position on this. [quoted text clipped - 44 lines] > excess air. I discovered this quite by accident when an aftermarket PCV > valve came apart on me. plugged pcv can be compensated, just as you describe, but under load, especially under heavy load, you /really/ want that thing working properly. experiment with a hose clamp if you want to test. > plugged pcv can be compensated, just as you describe, but under load, > especially under heavy load, you /really/ want that thing working > properly. experiment with a hose clamp if you want to test. Absolutely, for preventing the pumping of junk into the intake, the PCV valve is 100% essential. At WOT is when you stand the greatest chance of oil getting pumped into the intake even with a correctly-functioning PCV valve. At WOT and high revs, blowby is going BOTH ways, both through the PCV AND through the breather. But for simple air/fuel management, it's not a big factor at any pressure differential. Especially OBD-II cars are more than capable of compensating for PCV problems, both leaks and restrictions. By the way, I just tried the same thing on our '99 Tercel: 1): The hose-plug test was identical to the Integra, except that the idle never dropped. It appears that the Tercel's engine management system is faster than the Integra's, and responded too quickly for the idle to drop. Idle remained the same. 2) When I pulled the hose off the intake, creating the same massive air leak I had subjected the Integra to, again the idle did not drop, but immediately began a surge cycle. The Tercel has no tach, but it did not seem to rev nearly as high as the Integra, and its cycle time was about a half-second instead of the Integra's full second. The idle settled down immediately once the pipe was plugged with my thumb. I discovered I could uncover fully half the exposed intake pipe before cycling began. Slowly uncovering the pipe resulted in a steadily INCREASING idle until surging began. Half of the intake pipe appears to be roughly what would be admitted by the PCV valve itself at full-flow. SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ > I checked the PCV valve a few weeks ago... I was told if the bead > inside is loose, it's ok. I blew some degreaser through it just to be > sure, but there is no moisture build-up in the crank case. I guess for > a $3 part I might as well get a new one, but I don't think it's the > problem. It's not. And unless it's aftermarket, there's no "bead", just a plunger and spring. SignatureTeGGeR® The Unofficial Honda/Acura FAQ www.tegger.com/hondafaq/ > A few more issues from my poor little car for anyone who can shed some > light... [quoted text clipped - 28 lines] > on the crankshaft pully to save my life. Ran like a top after the belt > change, so I'm confident it's not a tooth off... this is confusing - it's run bad since you got it? but it ran great after you changed the belt, now runs bad again? if that's true, check your timing belt, it's probably skipped a tooth. > HELP! > > Any advice would be greatly appreciated... > > Regards, > -Bruce Sorry.... that was kind of vague. What I meant is that it runs great except for this 1st gear hesitation, but that it's done it since day one. There was no difference what-so-ever after the T-belt job. It starts on the first crank every time, idles great and drives very smoothly (always has) except for the sluggishness in 1st gear in low RPMs. > Sorry.... that was kind of vague. > [quoted text clipped - 3 lines] > time, idles great and drives very smoothly (always has) except for the > sluggishness in 1st gear in low RPMs. automatic or stick? if automatic, ensure the timing is correct, clean out the egr valve and replace the thermostat. 5-spd...I've been thinking about checking the timing for a while, but last time I had the engine torn apart I studied the crank pulley for a good 10 minutes in fairly good light looking for a timing mark and found nothing. Is it a paint mark? or a metal nub? I cleaned it off with some degreaser when I changed my timing belt and still couldn't find any mark. What gives? Maybe this is just related to late-80s/early-90s Civics... My 88 Toyota PU has a very obvious orange mark on the pulley and it's really easy to see. > 5-spd...I've been thinking about checking the timing for a while, but > last time I had the engine torn apart I studied the crank pulley for a [quoted text clipped - 8 lines] > My 88 Toyota PU has a very obvious orange mark on the pulley and it's > really easy to see. if the pulley is rusted, it's not so easy to see, but it's a tiny cut between the alternator & a/c bands. should be painted too. you can't see it from the side - you have to look down the gap between motor & body near the l/h motor mount. Gotcha... should have considered that as I know you have to look down and line up those two little pointy things on the timing belt cover to check it. A little white-out will help me see it w/ the timing light while the pulley's turning. Thanks > Gotcha... should have considered that as I know you have to look down > and line up those two little pointy things on the timing belt cover to > check it. A little white-out will help me see it indeed, but don't make the mark too big - even 2 degrees out made my 91 crx hesitate. > w/ the timing light > while the pulley's turning. > > Thanks |
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