How are your diagnostic skills?

I looked at a car for sale yesterday. Used car lot, consignment sale. Clean, one owner, low mileage (60k miles) 99 Suzuki Swift. It starts, and idles fine. Rev it up, and it sounds boggy. Try to drive it, and unless you keep the revs high, it won't go. Foot to the floor, and it won't move until you hit the mid 2000 RPM range.

It warmed up very quickly. A few drips of coolant were coming out of the rad cap, once warm. No smoke, or steam out the exhaust, at all. I checked this 6 times. The exhaust was unusually hot. No indication of anything wrong under the hood, like leaks, or previous repairs, except that the timing cover was missing a few bolts.

I'm pretty sure I know what it is, but there are some grade A mechanics on this board, and I'm curious if I missed something.

Clogged intake and/or exhaust ?

Lack of power, hot exhaust and missing timing cover bolts make me think it's not timed correctly.

Plugged catalytic convertor.

iceracer wrote: Plugged catalytic convertor.

+1

Combination of carzan and iceracer's diag. Stick a vacuum gauge on it and fire it up and let it idle, if the vacuum starts good (around 17 inches or up) and drops back as the engine idles the exhaust is plugged (catalyst). If the vacuum starts off crappy (12 inches or so) and gets no better I'd look at the cam timing.

Jensenman wrote: Combination of carzan and iceracer's diag. Stick a vacuum gauge on it and fire it up and let it idle, if the vacuum starts good (around 17 inches or up) and drops back as the engine idles the exhaust is plugged (catalyst). If the vacuum starts off crappy (12 inches or so) and gets no better I'd look at the cam timing.

I would've given more thought to the cat if he said it came off the line with at or near-normal power, but felt weak as the revs/load went up. He says it gets power above 2000rpm. Doesn't fit my experience with a plugged cat.

plugged converter, clogged fuel filter, bad timing depending on symptoms. It's hard to see what you mean, do you mean you have to go above 2 grand to make it move, or that above 2 grand it acts normal? I am guessing the former, and hence my attempts.

I am not sure how that engine works, but lots of 80s Cadillacs were warrantied because the cams had worn so badly that the engine didn't produce any power, yet had fantastic idle quality.

-Brian

carzan wrote:

Jensenman wrote: Combination of carzan and iceracer's diag. Stick a vacuum gauge on it and fire it up and let it idle, if the vacuum starts good (around 17 inches or up) and drops back as the engine idles the exhaust is plugged (catalyst). If the vacuum starts off crappy (12 inches or so) and gets no better I'd look at the cam timing.

I would've given more thought to the cat if he said it came off the line with at or near-normal power, but felt weak as the revs/load went up. He says it gets power above 2000rpm. Doesn't fit my experience with a plugged cat.

A mostly (but not fully) plugged cat will do this but only under load. At idle the demands of the engine to get burnt gases out isn't as important. Since the partially plugged exhaust will only hinder flow at higher velocities, the idle vacuum (dependent on how much can be shoved out as well as pulled in) will start off good then drop. The engine may or may not idle well but you really got to get on it to get any power. In severe cases, there will be a loud 'hiss' on acceleration as the exhaust gases try to get out any way they can. Otherwise, there may not be a lot of indication that there's a problem other than power loss and MIL (generally a P0420 catalyst efficiency code). No mention of MIL in the OP's post but that is not really surprising, if someone cleared it and the PCM hasn't seen it enough times it may not light the MIL.

The missing T/C bolts tell me somebody had the bad timing/jumped belt idea already but that didn't fix the problem unless the timing marks were improperly aligned during checking/assembly (don't laugh, it happened to me on a 1.8 Subaru) so I lean toward partially plugged exhaust. That would scare me worse than a bad cat, as in why would the engine have jumped time in the first place? Possible answers (none good): momentary camshaft seizure (lubrication related), reassembly of an interference motor with partially tweaked valves, all kinds of stuff.

If it has less than 80K miles the 8/80 Fed emissions warranty would cover a bad cat. The OP did not mention mileage so I'm going to SWAG (Scientific Wild Assed Guess) that it's over 80K miles.

Loooonnggg shot: improperly adjusted valves (too tight) but I kinda doubt it. IIRC the 'Zook engines have HLA's (hydraulic lash adjusters) so I don't think human stupidity in that department is to blame. Although I have learned over the years NEVER to rule out stupidity as a proximate cause.

Jensenman wrote: If it has less than 80K miles the 8/80 Fed emissions warranty would cover a bad cat. The OP did not mention mileage so I'm going to SWAG (Scientific Wild Assed Guess) that it's over 80K miles.

But that's just it. He DID mention mileage. He said it has 60K miles on it. Somebody tried to replace a timing belt, botched it, and gave up? Funny you should mention a 1.8 Subaru. I got one for $200 because the owner's (used car dealer) "mechanic" botched the timing belt job (got the passenger side 180 out). I fixed it on his lot and drove it home. At any rate, probably more information is needed, but I've owned and been around owners of Swifts/Metros and never seen a plugged cat/exhaust at all, let alone at 60K.

In reply to suprf1y: Check the air filter?

Bad fuel pressure regulator or leaking injectors?

carzan wrote:

Jensenman wrote: If it has less than 80K miles the 8/80 Fed emissions warranty would cover a bad cat. The OP did not mention mileage so I'm going to SWAG (Scientific Wild Assed Guess) that it's over 80K miles.

But that's just it. He DID mention mileage. He said it has 60K miles on it. Somebody tried to replace a timing belt, botched it, and gave up? Funny you should mention a 1.8 Subaru. I got one for $200 because the owner's (used car dealer) "mechanic" botched the timing belt job (got the passenger side 180 out). I fixed it on his lot and drove it home. At any rate, probably more information is needed, but I've owned and been around owners of Swifts/Metros and never seen a plugged cat/exhaust at all, let alone at 60K.

Woops. :embarrased: Case of the raging dumbass here. Still seems odd that someone's been fiddling with the TB (I assume that from missing cover bolts) and then appears to have given up, at that point I assume (yeah I know about ass/u/me ) whatever they were doing had no positive effect. Also, the 8/80 emissions warranty on a '99 would have expired in '07 (assuming the car was sold in '99).

The Subie that I goofed on had two sets of timing marks, one set was for ignition timing which included a TDC mark. About 20 or so degrees away were three hash marks with no degree marks or anything else to indicate what they were for. Turned out THOSE were the cam timing marks. Another weirdo: 2.3 and 2.6 Isuzus have the ignition timing done with the #4, not #1, cylinder and THAT will drive you bonkers trying to reinstall the dizzy.

I also saw a Pinto motor many moons ago where the crank key was left out, the crank pulleys had migrated on the crank meaning NOTHING lined up.

Low fuel pressure can cause similar symptoms but generally is accompanied by black smoke (yeah weird for it to have symptoms of running rich but I've seen it before) and come to think of it if the fuel lines are reversed (easily done on some cars) it will run but runs like ASS. That's assuming (there's that word again) that this is not a non-return FI system.

In my years at the shop I've learned one thing. Sometimes computerized cars tell you opposite symptoms. We just did a Mazda Protege for exactly what you describe; no power until 2000 rpms, then it was normal. It ended up being the fuel filter. A fuel filter should start restricting at WOT up high in the RPMs only, but in this case, something about the fuel mapping/closed loop operation meant that low RPMs were more sensitive to leaning out. The restriction showed up first in the low RPM map. New filter cured it.

I would assume a cat could do the same thing if its on the verge of being plugged. Full throttle at low RPMs tend to be richer than high RPMs. The extra HC going through a hot converter makes it really hot which can swell up the catalyst.

Jensenman wrote: < Still seems odd that someone's been fiddling with the TB (I assume that from missing cover bolts) and then appears to have given up, at that point I assume (yeah I know about ass/u/me ) whatever they were doing had no positive effect.

You're thinking what I'm thinking when you mention the TB cover. Why were they screwing with it? The 60K mileage figure sorta raised a red flag with me because I know that is a common number for people to change the belt...even if that interval is not necessarily valid on that particular vehicle. Many people will be scared to let a belt go as long as what is recommended despite the 1.3 Suzuki not being an interference engine, Hell, I'm afraid to let our Subie go to the recommended interval (over 100K) because I know what will happen if it pops. I'm thinking someone got it in their head that the belt needed to be changed and a) attempted it themself b) got a friend/relative/drunk guy down the street to do it.
Sooo, taking in account the symptoms, conditions,visual defects, past experience as well as some deductive reasoning, I concluded with what I felt was the MOST LIKELY cause. BUT, it's only as good as the original post's information. With that in mind, I hope the OP realizes that he MUST, according to (unwritten) Grassroots law, purchase this vehicle, solve, or have the problem solved, and report back the results. If I'm wrong, I'm ok with that. That's part of the fun of playing "Stump The Chumps". There's no way to truly, 100% accurately diagnose a problem over the internet. You can only make a judgement based on the information you have. No one should ever be upset if they are wrong...and I've had plenty of opportunities to be upset.

I've had good luck with my vehicles over the years- I'm not a fantastic mechanic, by any means, but for some reason about 80% of the time I know about what's wrong with it before I take it to the shop. :p

My first thought was plugged cat (due to hot exhaust), but since somebody's been into the timing gear, who knows. Guesses: Trash in the tank that clogs the pickup on acceleration/ bad fuel filter/ collapsed fuel line?

Did anybody guess "timing belt jumped a tooth or so/ reinstalled incorrectly" yet? Maybe close enough to idle/run/with heavy ECU help, but not close enough to run well.

When all else fails, replace the blinker fluid and muffler bearings.

No codes?

My dad's Escort did all the things you described and threw no codes. It also wouldn't start below 40 degrees outside. The timing belt had jumped a couple teeth.

Been away for a few weeks, but I think that car is still on the lot. My call would be the valve timing. It's easy to screw up on the Suzuki motors. Being the 16V it probably is interference, but compression seemed good, and there was no misfire. I offered him $500, and he came back with $600. I may go back leter this week. The body is almost perfect. Something you don't usually see on those up here.

According to the Gates belt site, it is not an interference engine...of course that doesn't necessarily mean the valves didn't get damaged by other means.

If this motor uses a CKP using the flexplate as the trigger wheel, you will end up with the same symptoms as a plugged cat when the flexplate cracks the center out.

Just another possibility.

I would suggest that you drop the exhaust first, and then drive it to see how it feels. A clogged CAT will destroy your power down low.