Does a bad MAP sensor have long lasting effect on vehicle?

[PeeluckyDuckee]

If he's using percentages, this is a leakdown test. Your engine mildly worn the hell out, and the third cylinder has a major problem.

Bad cats don't cause codes, unless the parameters are met to set a catalyst efficient code.

Random guess on diagnosis- engine was running like shit. Possibly having random misfires on all cylinders due to a worn out distributor cap or something similarly simple. Excess fuel caused the 'honeycomb' of catalyst material inside the converter to begin to melt. Excessive exhaust backpressure caused a blown headgasket.

Correct, the distributor cap was worn to almost nothing and the car would sometimes start, sometimes not when I go to start the car previously about a year ago. The spark plugs were all black, with oil, but it maintained it's physical shape nothing was broken off.

The mechanic at ZR tested the TPS throttle position sensor and it registered throttle position from 6% all the way up to 90%, whatever that means exactly but he deemed it to be within operational limits and not a cause for concern for him.

I noticed that when I apply throttle, the vehicle would respond better and the car would slowly accelerate than if I forced throttle to 60-70% then it wouldn't get me any where at all until I eased up on the throttle.

My regular mechanic still leaning towards the clutch-to-transmission side of things and says something internal to the transmission may be at fault, but I feel that it's sensor related. He's hesitant to double check his own work on timing belt installation and insists that I am wasting our time.

Where should I go from here? I am almost at a point where I just want to give up and get me a beater for work instead. If it's transmission/engine related and requires major work and $$ I really don't want to throw any much more money into it.

As for video, I don't feel safe driving and recording with a handheld camera/cameraphone at the same time.

 

[lsd]

You have a bad #3 cylinder. Your mechanic should have told you why it's reading low (if he actually did a leak down test).
Before you do anything get that cylinder fixed.

IMO, I would just get a new long block.

 

[phucheneh]

Set the camera somewhere. I just want to hear it. If it can see the tach and speedo, that's a plus.

I do not see anything in this thread that indicates a clutch or driveline problem. I also don't see a sensor issue. You could possibly have something that is a little 'off' (but not wildly so), which can cause a fuel trim code. But it will not cause major running issues.

A valve timing issue (timing belt is not installed right) would probably set a CMP code and/or a VTEC code (manufacturer code, P1xxx). However, I didn't see you mention that the timing belt was recently done earlier. That may be the cause of your cylinder leakage. (bent valves if it broke, or if things were rotated too far during a routine belt change)

Again, I question your mechanic's abilities. A lot. If he did a leakdown test and found those numbers, he should have also attempted to locate where the leakage was. It's not hard. Open airbox as if replacing filter, and see if air can be heard coming through there (intake valve leakage). Then listen at the exhaust. Then take the oil cap off and listen for air escaping into the crankcase. It's going to be one of those.

If it does have a bad headgasket, it's not blown between cylinders. So it's probably between the cyl and a water jacket (so you could also possibly see coolant bubbling with compressed air hooked up to that #3 cyl). Or maybe an oil return.

It is not that hard to check for a plugged converter, also. The definitive check is to simply disconnect the exhaust and see if the engine runs normally. However, this can be harder to accomplish if there is a cat integrated into the exhaust manifold (not sure on that car). Can't exactly start the car with no manifold. But starting it with the pipe to the manifold disconnected won't hurt it.

I tried to respond to everything yesterday, since you're kind of all over the place on this. I may have just made it more confusing...again, I don't think this should be that hard a problem to diagnose for someone experienced with engine performance issues. Honda 4 cyls are just not that complicated.

Again, does the engine run bad at idle? If so, just record a startup...then walk around the car...pop the hood...rev the engine a bit (you can manipulate the throttle from the engine bay, it's a cable throttle). Build RPM's slowly...give it a couple quick revs...switch it up a little. Post results and I think I (and others) will have a better idea of what is occuring.

Right now it's hard to tell you where to go. If the leakdown test was done right, that's what needs to be investigated, I would say. It's not hard to pull plugs and you can rent a compression tester (or buy a half-decent one for like 25 bucks) if you're willing to do some diagnosis on your own. (edit: you need compressed air to definitively diagnose a belt valve, though.)

I'm happy to try and guide you down a proper diagnostic path. This forum has been devoid of good 'diagnose my car' threads recently and I'm bored...

 

[sontakke]

By a vacuum gauge for less than $20, hook it up to one of the vacuum line, go to youtube, search for EricTheCarGuy and get the instructions on how to interpret the results to see if you have blocked exhaust. It is literally less than 10 minutes job.

Since your mechanic does not seem to know this, ditch him. He really does NOT understand the engine performance issues.

It is unfortunate that you are not much mechanically inclined but in these days if you have any engineering background or work with the computers day in and day out, it is certainly not beyond your abilities to do little bit of diagnostic work yourself.

Bottom line is that finding a talented *and* trustworthy mechanic is very very hard. If youtube is any indication of the pool of those mechanics, there are probably handful of them in the entire USA. Some of them are instructors in automotive schools and do consulting work for local shops (e.g. Paul Danner aka ScannerDanner on youtube) Extremely smart mechanics end up not turning wrenches but end up in higher paying fields.

Your mechanic is NOT talented that is for sure. I am with the previous poster. He knows a lot but unless OP wants to get his hands at least little dirty, it will be very frustrating for anybody else. There could be some local guys who might be willing to help OP but he does have to take some initiative. From my perspective, when somebody is not willing to even get the <$20 code reader, I tend to give up on them.

 

[phucheneh]

Fuck, I forgot about the vac gauge test. I use them so little anymore.

OP, do what sontakke said. It's an easy, fairly conclusive way to check for exhaust restriction. Although a poorly-running engine will generate low vacuum in general...the gauge won't behave like it does with a blocked exhaust as you rev the engine, though.

 

[PeeluckyDuckee]

By a vacuum gauge for less than $20, hook it up to one of the vacuum line, go to youtube, search for EricTheCarGuy and get the instructions on how to interpret the results to see if you have blocked exhaust. It is literally less than 10 minutes job.

Since your mechanic does not seem to know this, ditch him. He really does NOT understand the engine performance issues.

It is unfortunate that you are not much mechanically inclined but in these days if you have any engineering background or work with the computers day in and day out, it is certainly not beyond your abilities to do little bit of diagnostic work yourself.

Bottom line is that finding a talented *and* trustworthy mechanic is very very hard. If youtube is any indication of the pool of those mechanics, there are probably handful of them in the entire USA. Some of them are instructors in automotive schools and do consulting work for local shops (e.g. Paul Danner aka ScannerDanner on youtube) Extremely smart mechanics end up not turning wrenches but end up in higher paying fields.

Your mechanic is NOT talented that is for sure. I am with the previous poster. He knows a lot but unless OP wants to get his hands at least little dirty, it will be very frustrating for anybody else. There could be some local guys who might be willing to help OP but he does have to take some initiative. From my perspective, when somebody is not willing to even get the <$20 code reader, I tend to give up on them.

I am willing to try this vacuum guage you speak of. What is roughly the normal vacuum at idle for a 4 cyclinder 2.2L vehicle? If the cat is clogged, then what number should one expect to see? This specific test relates only to the cat? I was told the cat can be dropped to check physically but because the car is so old, bolts may get too rusty and he'd have to cut the pipe and so I declined that diagnosis.

My dad has a multimeter, and I would like to test the TPS sensor myself. What voltages should one expect at idle and WOT? I was told by the mechanic at ZR at is within specs via OBD readings. Are readings from the computer more reliable than the multimeter method?

In neutral gear, I can revv the engine, the RPM goes up and down very fast according to my throttle input all the way up to 4k RPM but doesn't go further. When I come to a stop light and get myself out of gear and into neutral the RPM would drop to 200s, the car would shake but not stall out.

I brought it back to the mechanic who originally installed the timing belt for him to double check his work, but like I said he's hesitant to look over his own work and insists that's not a problem area. If it's not, check it, and eliminate that question mark. I most likely will pickup the car tomorrow and can probably record an audio of the vehicle, of how it sounds starting, at idle, revving at idle, posting a video of the RPM movement while the car is in gear I would need someone else to hold the camera while I drive.

 

[NutBucket]

If it only revs to 4k in neutral there's an obvious problem. ECU is definitely in limp mode to attempt to prevent you from grenading the engine. Please find a competent mechanic to figure out WTF is going on.

 

[sontakke]

Some ecu do prevent revving car to the redline at idle. I do not know if your Civic has that protection. Get MS509 free shipped from Amazon for $49. This will give a good scanner which will let you look at lot more engine parameter even without opening the hood.

If I remember correctly, 22 inch hg of vacuum at sea level for a good healthy engine but do look up the youtube video for real details on how to determine if the exhaust is clogged or not. A decent MightyVac gauge runs less than $50.

With the scanner, testing TPS is trivial. And if scanner shows TPS operating correctly, a multimeter is NOT going to give you more data and you don't need multimeter to verify TPS operation if scanner has done the verification. Remember, if the car's computer says TPS is good, then it is good regardless of what you may find via multimeter.

If you give your location, somebody local might be willing to help you.

 

[phucheneh]

Vacuum at idle can be as low as maybe 16 inHg, but 20ish is a good mark.

If his engine is missing, though, vac tests might go out the window. I would really like to hear how the thing is running.

A consistent miss on one cylinder, and you can still probably spot a bad converter (as engine revs, you'll lose most of your vacuum well below WOT). Random missing, who knows. Also, if he has a miss due to a bad intake valve, that's gonna act extra-funky.

Again, video would be awesome. I could evaluate a video of a vac gauge much better than I can instruct someone to interpret results. It's more than just looking for a number, especially in this case. It's reading the fluctuations and how the gauge responds to changes in throttle.

Oh, and yeah, cutting spark at 4k is pretty common...on autos. He has a manual, so there shouldn't be any idle rev limit. Only input for the computer would be the clutch switch. It's called 'neutral safety,' but there's not going to be an actual 'the shifter is in neutral' input, obviously. Maybe some cars limit revs when the VSS reads zero, but I haven't observed it.

 

[NutBucket]

Some ecu do prevent revving car to the redline at idle. I do not know if your Civic has that protection.

H22 ECU doesn't have that "feature"...unless it was added since mine was a '94 or so. It will not engage VTEC while in neutral though.

 

[DaTT]

I once had a plugged/melted cat on a car and it would not go over 2200 RPM, it was just so laboured.

 

[PeeluckyDuckee]

I once had a plugged/melted cat on a car and it would not go over 2200 RPM, it was just so laboured.

Did it throw any codes? Were you experiencing hesitations, jerkiness, and major loss of power?

 

[NutBucket]

My coworkers Saturn suffered a similar fate. Symptoms were random stalling (like on the freeway) and lack of power. I don't think it threw any codes.

 

[sontakke]

OK, it is a 2000 era Honda! Why didn't you say that before (I meant, why didn't I read that before?

You need one or more ignition coil! You are most likely running on 3 cylinder. You will have lots of engine vibration and it will tend to die or at least the rpm would go very low. You will be getting P030n codes. But one would think a mechanic would be smart enough to figure that out.

Now it is possible that because you ran the car like that you have now melted the catalytic converter and are running in to other issues too.

 

[DaTT]

Did it throw any codes? Were you experiencing hesitations, jerkiness, and major loss of power?

This was a 1987 Audi 4000. There were no codes thrown and there was an extreme loss of power due to the fact it would not go above 2500 rpm.

 

[PeeluckyDuckee]

So I brought it to a third mechanic, the one my dad normally goes to, supposedly they deal with imports a lot, and within an hour of bringing the car to them I got a call back detailing what the issues were.

It was the cat that was clogged. He said the cat and the oxygen sensors needed to be replaced, mainly due to my vehicle burning oil over time will clog up the cat. Besides that, the right rear wheel bearing needed changing as well, and that's the 3rd wheel bearing I've changed to date. Total damage for this is $1250, not including $250 for second mechanic's diagnosis, and $200 from the 1st mechanic for spark plug and wire change.

He says now my car roars back to life and is very peppy. As for my regular mechanic, yeah from his diagnosis he sounds pretty inexperienced. He said the problem may lie between the clutch and the transmission. Both myself and my brother in law look at each other thinking WTF is he on?? And he seems too proud to go over his own work that he did, saying we're wasting time. So yeah from now on I'm taking the work to my dad's mechanic instead. I had my clutch changed originally from my dad's mechanic, don't know why I didn't bring it to them prior to taking it to ZR Auto and getting dinged for $250 for nothing.

After $1800 and a week's worth of frustration I am glad this nightmare is finally over, and I've gained a little bit more insight into the mechanics of a vehicle. It's one of those things you learn as you go, and thank you very much guys for your time and input, MUCH appreciated!

 

[sontakke]

Usually it is the severe misfire which causes the cat to burn quickly. Many many cars drink oil without clogging the cat. Obviously it is not good for the health of the converter but blinking CEL (severe misfire) is extremely bad for the catalytic converter. If you had uncorrected misfire for a while then that is the explanation for the clogged cat not just the oil consumption.

 

[NutBucket]

OK, it is a 2000 era Honda! Why didn't you say that before (I meant, why didn't I read that before?

You need one or more ignition coil! You are most likely running on 3 cylinder. You will have lots of engine vibration and it will tend to die or at least the rpm would go very low. You will be getting P030n codes. But one would think a mechanic would be smart enough to figure that out.

Now it is possible that because you ran the car like that you have now melted the catalytic converter and are running in to other issues too.

Even though he solved his problem I'll just mention the the H22 never had coil packs, always a old school distributor.

 

[sontakke]

wow! even in 2001 they were still using distributor? I sure hope they had finally fixed the problem with the distributor bushing which used to wear out in the older Honda causing a lot of ignition related problems. Drove me crazy on 83 Prelude until I found the hidden TSB and the new bushing from a trusted dealer technician. Dealer wanted to replace the whole distributor.

 

[NutBucket]

They switched to a bearing but inevitably it still wore out. But if the only real trouble spot is the distributor bearing, I think you're doing well as a car designer/manufacturer

The thing that was worse than the bearing failing with when they had the coil under the cap. That failed a lot faster than the bearing/bushing.

Small design flaws aside the '91 Accord my family had was bulletproof. When I swapped out the engine after 150k miles the only mechanical failures were an ignition coil and an alternator. I only swapped it because I wanted more power.

 

[PeeluckyDuckee]

Had a look at the cat they took out and sure enough, as many here said, it melted away. Shining a trouble light through it I could not see the light on the other end at all. Shaking the cat the whole "beehive nest" would rattle and shake. The inside was deformed and melted away.

The distributor cap and rotor was reduced to almost nothing when my dad changed it out for me. That perhaps lead to the rounds of misfires, and couple that with an engine that burns oil constantly (about a litre once every two months) lead to where I am today.

The wheel hub bearing is another area I've been having issues with as well. First it was the front right wheel, then the rear left wheel, and now the rear right wheel. Are wheel hub bearings considered wear and tear items? When it gets louder and louder as I get up to speed I begin to think it's the wheel bearings again, and sucks to say it was contributing to the noisiness of the vehicle.

Good news is that my dad's mechanic cut me a $200 break from the bill.

I changed out the starter myself and that was a relatively easy process. Before when I had a garage I would do my own oil/filter change, lights, and even replaced the cold air intake. I would be more inclined to do/learn more if I had a garage, but alas I don't. The next thing I want to change is probably the alternator (still original) and the thermostat.

I've dumped so much money into this vehicle now that, short of transmission/engine failing, it would be a waste to let it go.

 

[PeeluckyDuckee]

Even though he solved his problem I'll just mention the the H22 never had coil packs, always a old school distributor.

Are coil packs superior to distributor? Less prone to failure?

 

[NutBucket]

I think it allows for more accurate timing control but I really can't tell you why its superior.

Also, OP, its perfectly normal for that engine to use a decent amount of oil assuming you're driving it into the upper rev range. I would easily use at least a quart between changes. Nothing abnormal there. Sounds like your issues started partially due to lack of maintenance (as you pointed out already).

Oh, and don't bother replacing anything unless it failed. Thermostat would probably be a good idea since its over 10 years old at this point. I'm a bit surprised the radiator hasn't sprung a leak yet...stupid plastic tanks.

 

[sontakke]

Preludes used to be better built cars. I drove mine (83) to the junkyard in 2000 after over 250K miles, original engine, original clutch, original transmission! I am almost certain that there would be quite a few Preludes still running with excess of 200K on them.

Honda is very conservative when it comes to latest technologies. They stuck with carburetors for many more years than other manufacturers. Similarly, they stayed with mechanical distributor and rotor far longer than others.

Starters, alternators, fuel pumps, wheel bearings etc are all wear items and as long as rest of the car is in good condition, should be replaced when needed. It is true that they can last 150-200K miles but by their very design, they will eventually wear out. What you want to do is to be able to recognize their impending failure before it happens and replace them at the first sign of trouble if you intend to keep the car.

Please contrast this with regular maintenance items such fluids, filters and belts ( and plugs rotor cap wires etc) which should be replaced on the schedule.