The Semi-Unofficial Pistol-Forum Car geek, gearhead, hot rodder, and vehicle thread

[Welder]

The plot thickens. First, I looked up the firing order and I was wrong. It goes:

1 2 3
4 5 6

As viewed from the front of the car. Makes sense, I guess. So the plug I thought was #1 was #4.

While I had the plugs out, I did a compression test on the engine. It was dead cold, probably 45 degrees. Compression varied from 197 to 220 psi, which: 1) Is pretty good numbers, maybe even a little high, and 2) Is OK relative to each other, would probably be closer numbers if it got the valves adjusted.

Put plugs and oil in it, took it for a 40-mile drive to get some supper. The car ran smooth until the first time I went WOT and crossed the 3k RPM threshold, then it started missing on a few cylinders. I held it WOT after that to see what would happen, and it fuel cut at 4k RPM. The CEL was blinking and since I had my scanner with me, I plugged it in. Misfire codes for cyls 5 and 6 plus a P0300 random misfire code. It now had a continuous misfire at all RPM's. I hit the clutch and coasted, shut it off. Started it back up. Misfire was gone as long as I didn't get up over that approx 2500-3k RPM magic number. Crossed the magic number and it started misfiring and then fuel cutting again. Pulled the codes again and this time it was cyls 4, 5, and 6 along with the random code.

So I think I have two separate issues here.

1) I believe the timing belt has jumped a tooth on the front bank. I can't think of any other reason to be getting misfires on only those 3 cylinders, especially with new plugs. Too coincidental to be coil packs. Those were also the original codes I pulled from it when I bought it, before clearing them and running stuff through the oil to try and clean the rings. I'm assuming the computer is either pulling fuel or timing from those 3 cylinders once the misfires start, and that each time you restart the engine it's resetting and trying normal fuel / timing again, which is why those cyls run OK until you get the RPM's up and it puts itself into limp mode.

2) I know my compression gauge is good, so I think I might have some carbon buildup in the chambers / piston tops which is raising compression. I definitely need to run a little water or something through it to get that out of there. If I was getting misfire codes on all cyls, I'd assume my entire problem was that, actually, and that it was detecting knock and pulling timing or fuel. Which it might be as well.

All in all, I was tickled pink to see some 'good' compression numbers. I think my problem is confined to the oil control rings, and I think I can get them cleaned up with some more diesel fuel or just hours on the engine once I can get the timing belt replaced.

If I don't find a jumped tooth on the belt, then I'll start to worry more.

[OlongJohnson]

I've never seen a timing belt jump a tooth. Chains, yes - belts, no. I've only seen belts break. Doesn't mean it couldn't have been installed incorrectly.

I don't know anything about the details of these engines, but with misfires on all three cylinders on a bank, I'd at least think about the wiring supplying power to those coils.

Will it pull past that RPM smoothly at lighter throttle opening? I forgot whether it's AT or MT, might have to downshift the AT to get it to stay in a lower gear.

What RPM does VTEC activate?

[0ddl0t]

Does it have separate O2 sensors for each bank? I wouldn't think it would matter at WOT, but it might prematurely foul plugs...

Or maybe a large vacuum leak affecting only 1 bank? Bad ground on one bank?

[Welder]

I should be able to rig something up to test the coils for firing. I have a tachometer that runs off ignition pulse detection, so that should tell me if they're firing and if/when they stop.

Another thought I had along y'all's lines is fuel pressure, depending on if #6 is last in line for fuel. Then 5 and 6 throwing the CEL the first time would make sense, and so would adding in #4 on the second time. I should get a fuel filter for it. But that wouldn't explain why it resets itself and runs right if you kill it and then restart and keep the RPM's low. The ECU is either killing spark or fuel to these cylinders, or the signal is getting cut at a specific RPM.

Don't know the answer to whether it revs past 4k if done slowly. I'll know today because I think I've got some more time to work on this today.

It's a 6-speed manual.

VTEC engages at a point higher than 4k; on my 04 you can hear it engage around 4600. So VTEC never gets started on this car.

Separate O2 sensors and converters per bank. Front converter (the questionable bank) is new; somebody already tried that.

The car idles normally and the revs don't hang, so I don't think there's a vacuum leak. The vacuum leaks I've repaired in the past that were significant were also affecting both of those -- high idle RPM's and hanging revs if manual.

Checking for a bad ground is on my list.

[Welder]

I had to buy a new style of ignition tester at a pawn shop, but I was able to verify that all of the coils are firing, that they're all firing for approx the same amount of time, and putting out about the same amount of energy. The plugs are new. So not a spark problem.

I pulled the air filter (a new K&N panel filter in the original box) and looked over everything under and above it. No restrictions. So not an intake problem.

I'm working on checking fuel pressures. Honda didn't provide a schraeder valve like other manufacturers did, so it's not as easy even though I've got a Star Products test kit here. I just don't have the right adapters. Possible I've got a bad injector.

I sucked a can of Seafoam top end cleaner through the vacuum port behind the throttle body and then took it for a drive to try to get some carbon out. Now I have codes for 1, 3, 4, 5, and 6. I also got the VSA light which comes on as a result of a lot of misfires.

I also dumped 2 cans of fuel injector cleaner into the tank in the (distant) hopes that I can get that injector clean, if that's the problem.

I put a vacuum gauge on it which holds rock solid at 22 in/Hg at idle.

If I'm really gentle, I can get the engine up to 5500 RPM, maybe higher. This is sitting in N. Can't get it that high under load before it starts missing. New thing is that if I get it that high and get greedy and give it too much extra throttle, it goes into limp but also doesn't return to 750 RPM - it hangs at 1700 or so and won't come down the rest of the way until I shut it off and restart.

I'm going to pull the plugs now and see if there's any telltale evidence on any of them.

[OlongJohnson]

Have you checked freeze frame data for the codes? It might tell you something useful.

[Duelist]

Cool little car. 214k miles, 2200 engine.

I’ve always liked them, from way back when they were new and I worked at a Toyota dealership.

I should not buy this car. LOL.

[OlongJohnson]

I should not buy this car. LOL.

Correct. Find one with at least a sunroof, preferably a solid steel roof. Better handling for multiple reasons and no squeaks/leaks. That bit of wisdom will keep you from buying one for a long time, because the '80s and '90s were stupid in some ways, and that's one of them.

The only thing worse than a sunroof is a moonroof. The only thing worse than a moonroof is T-tops.

[BehindBlueI's]

Correct. Find one with at least a sunroof, preferably a solid steel roof. Better handling for multiple reasons and no squeaks/leaks. That bit of wisdom will keep you from buying one for a long time, because the '80s and '90s were stupid in some ways, and that's one of them.

The only thing worse than a sunroof is a moonroof. The only thing worse than a moonroof is T-tops.

I liked t-tops, having them on a Corvette and 2 Camaros. Lube the gaskets and that would eliminate squeaking and also help prevent leaks. Better than early sunroofs, IMO, but yes they do make the car less rigid.

[Bucky]

I liked t-tops, having them on a Corvette and 2 Camaros. Lube the gaskets and that would eliminate squeaking and also help prevent leaks. Better than early sunroofs, IMO, but yes they do make the car less rigid.

For the most part yes, especially in older cars. A GM engineer said the C7 Corvettes were designed to be a convertible from day 1 and roof is inconsequential to frame rigidity. That’s how they are able to offer all models with a convertible or targa top, including the 755 HP ZR1.