Ran great, now missing like crazy

[nelly1]

I don't have a clue as to what is going on. My 95 started with a slight miss and progressed to a undriveable condition. I pulled the plugs and every cylinder is wet and plugs are black. Fuel pressure is down to nothing after siting for a while. I thought it might be the fifth injector leaking. Changed it and it made no difference. Why would I be getting excessive fuel in all cylinders?

[Steve in VC]

I assume undrivable means this is happening off boost.

Do you have an A/F meter? What does it show at idle, off boost - should be 14:1 to 15:1. Less than 10:1 is marginally drivable.

Have you tried pulling the connector to the 5th injector?

Do you have a volt meter? If so, you can measure the duty cycle of all 5 injectors (0% = 0V, 100% = 14V, linear in between) I got this from Tom a while back, it is for the main injectors:At idle, it should be a very low duty cycle. About 1 mS on with ~133mS off at 900 RPM. At WOT, it will be about 11-13 mS On vs. the off time for whatever RPM (40 mS at 3000, 24 mS at 5000 and 17 mS at 7000 RPM. About 30%, 50% and 70% respectively).

30% ~4.2V
50% ~7V
70% ~9.8V

This shows what wires on the PC Pro to measure (put a pin through the insulation into the wire, clip the meter to the pin, wrap with tape. The other meter lead goes to ground.

http://www.fastforwardsuperchargers.com/Install/PC-Pro_Wiring.pdf

The other possibility is the fuel pressure too high.

[Tom @ Fast Forward]

My first guess would be a bad O2 sensor up front. As it starts to go, it falsely reads a little lean. Then more lean and more lean. As it reads lean, the stock ECU adds fuel and more fuel and more fuel.

[nelly1]

I assume undrivable means this is happening off boost.

Do you have an A/F meter? What does it show at idle, off boost - should be 14:1 to 15:1. Less than 10:1 is marginally drivable.

Have you tried pulling the connector to the 5th injector?

Do you have a volt meter? If so, you can measure the duty cycle of all 5 injectors (0% = 0V, 100% = 14V, linear in between) I got this from Tom a while back, it is for the main injectors:At idle, it should be a very low duty cycle. About 1 mS on with ~133mS off at 900 RPM. At WOT, it will be about 11-13 mS On vs. the off time for whatever RPM (40 mS at 3000, 24 mS at 5000 and 17 mS at 7000 RPM. About 30%, 50% and 70% respectively).

30% ~4.2V
50% ~7V
70% ~9.8V

This shows what wires on the PC Pro to measure (put a pin through the insulation into the wire, clip the meter to the pin, wrap with tape. The other meter lead goes to ground.

http://www.fastforwardsuperchargers.com/Install/PC-Pro_Wiring.pdf

The other possibility is the fuel pressure too high.



A/f reads 14.8 at idle.

when I start it cold, it idles fine, about 5-10 min. later it stumbles and spits.

I changed the injector and also ran it unplugged, no deference.

Fuel pressure is @ 55 psi

So what you're telling me is that the PC pro may be at fault?
Why not just unplug it?

[Steve in VC]

A/f reads 14.8 at idle.

when I start it cold, it idles fine, about 5-10 min. later it stumbles and spits.

I changed the injector and also ran it unplugged, no deference.

Fuel pressure is @ 55 psi

So what you're telling me is that the PC pro may be at fault?
Why not just unplug it?
No, the PC Pro is just an easy place to access the injector signal.

What does the A/F read when it stumbles and spits?

[nelly1]

No, the PC Pro is just an easy place to access the injector signal.

What does the A/F read when it stumbles and spits?


The A/F reads a constant 14.8

The engine soothes out at around 5000 rpm, with a cloud of smoke from loading up with excessive fuel

Again the fuel pressure drops from 55 to 0 lb.. in an instant after the engine is shut down

[socal pat]

OK, I'm going to come at this from the opposite position. What else (other than too much fuel) will make the plugs look dark? How about weak spark? You may not be burning off the fuel your ECU is providing. Of course Tom's theory is also a good one.

[Tom @ Fast Forward]

Instant loss of fuel pressure is due to a defective check valve in the fuel pump. It would not effect this if the fuel pressure stays constant over a WOT run in 3rd gear. It will effect starting the engine as fuel pressure will have to build before it starts.


The A/F reads a constant 14.8

The engine soothes out at around 5000 rpm, with a cloud of smoke from loading up with excessive fuel

Again the fuel pressure drops from 55 to 0 lb.. in an instant after the engine is shut down

[Tom @ Fast Forward]

I agree Pat. Weak spark will deteriorate over time and could cause the problem.

[nelly1]

I agree Pat. Weak spark will deteriorate over time and could cause the problem.

I thought it was the coil (weak spark) It's been replaced, ran the same!

[Tom @ Fast Forward]

Take the belt off the blower and unplug the PC-Pro harness and see what happens. That will make it basically stock to drive.

[nelly1]

Take the belt off the blower and unplug the PC-Pro harness and see what happens. That will make it basically stock to drive.

I took the blower belt off and unplugged the PC-Pro.
I have to say it still ran like crap! Lots of black stuff came out the exhaust.
Winter is here in Minnesota. I will have time to sort this out.
I did take the fuel pressure regulator apart and found a small piece of rubber stuck in the diaphragm. I bought the regulator on ebay. Not sure if it is of any quality. Seems to hold pressure now.
So check the O2 sensor?

[Tom @ Fast Forward]

I wonder if you could have swapped two of the injector connections?

You didn't happen to swap the connectors to the two coils?

Look for a vacuum
leak.

[Steve in VC]

Have you checked your CAT(s)? I was running rich, the plugs were black, the power wasn't good, even after I removed the supercharger belt.

A quick test is to open the connection between the resonator and muffler behind the real axle. If the car is really loud, the CAT is probably OK. If it doesn't sound too bad, plugged CAT(s).

[nelly1]

Still working on this! I checked the O2 sensor with an ohm meter and it was in spec. Pulled the coolant sensor and checked that. At the low temp setting it was in spec. The upper end was off somewhat. I am going to replace it. I will check the cat next to make sure it is not plugged. The plugs are black and when you peer into the cylinders thy are wet. I was able to dab the tops of them and they are oily.

[Tom @ Fast Forward]

Do you see any smoke? Oily would not be a good sign. If you let the sparkplugs sit, do they dry off or stay oily?

[bogey]

If the fuel pressure drops to zero on shutoff, the fuel pressure regulator is BAD. This should not cause a rich condition, but will cause you to go lean on boost, and will require longer cranking time to start.

I have seen 3 NAs with bad FPR's. A used replacement can be found for $25-40.

[maggie]

Tom mentioned the O2 sensor. Have you replaced it? I had a similar problem with the Volvo recently. O2 sensor fixed it.

[Tom @ Fast Forward]

Chuck was having a bit of a problem like that as well. He emailed me yesterday that he found the MAF connection loose (?) and that seems to have fixed it.

[nelly1]

The O2 sensor was in specifications, so I'm not sure replacing it will help.
Tom, the plugs do dry out after setting. I will check a few other connections to make sure something did not come loose. I will replace the FPR.

[Tom @ Fast Forward]

If they dry out, I think it might be more fuel than oil. Could be bad coils or a bad ground to the coils causing lack of spark. Stick a spare plug in one of the leads and hold it to the engine block and look at the color of the spark. Don't take the plug out of the engine. Too dangerous. Use a spare plug. If it is blue at idle, it may be the problem.

[chuckerants]

I've been having intermittent "misses" for a while and only now gotten around to address the issue since I've recently started driving the 99 as a DD.

Here are the symptoms:

Under 10~20" of vacuum, the car will "miss", or behave like it's misfiring. The tach, as I;m watching will "bounce" like the ignition or fuel is cutting out and being restored. This has not happened under load, only cruising.

POSSIBLE CAUSES:
- Fuel: I don't think it's fuel related as it's done it at least once while my foot was off the throttle.


- Ignition/Wiring/Electrical: I'm thinking it;s the wiring somewhere. I remember when it did this couple of years ago and it was the 3 wires going to the MAF (that area) that was rubbed through by one of the OEM ( power steering?) pulleys.

I think I may have fixed it. I've driven over 100 miles and no more "misses".

The last time I removed the K&N to clean and re-oil the filter, I installed the MAF clocked a bit away from the wires plugging into the MAF. This caused the MAF/plug/wires to be taut.

I simply loosened the MAF and clocked it back toward the wires and now the wires are loose as it plugs into the MAF. That was it. No more misses.

Also, as I mentioned above, I've had a problem with the same wires as they come up from the bottom of the car in the front that had been rubbed through by a pulley. In that instance, the 'miss" occurred both on and off the throttle.

[nelly1]

I put in a new O2 sensor in for the heck of it. No difference. One thing I forgot to mention is when all this started to happened the engine over heated and the radiator started to leak. I though it was coincidence.
Could it be a blown head gasket? I'm going to get a combustion leak tester this week and see if that is the problem.
I have another question. I found a 2001 1.8 engine with 5500 miles on it. It is for sale for $750. It has a turned cam bearing apparently caused by a improperly installed check valve. The guy told me it runs, not good but runs. My question...Will this bolt into a 1995 and or what other issues would I have other than having to possibly rebuild the engine before install.
Thanks, Alan

[bogey]

There is no such thing as coincidence. The assumption should be that the problem is caused by the last malfunction.

Your problems are most likely related to the overheating issue.

As far as a 96 engine in a 95, its a direct drop in.

[Gman7007]

Engine management and wiring harness would be your first big hurdles to installing an 01 into a 95.

[bogey]

My bad - thought it said a 96 engine into a 95!

The 01 engine should be fine if you transfer all the 95 sensors to the new engine. (unless this has the variable valve timing. Then I am not sure what is needed to properly control VVT).

[Tom @ Fast Forward]

Push comes to shove, if the old head is not too badly damaged, you could use it on the 01 block? You could always use the 01 engine and just ignore the VVT connecton. The default CAM setting is probably pretty close to the old engine?

[nelly1]

Today I did a compression check and found one cylinder quite low. They ran 145 lbs. in all except #3 which was 60 lbs. I assume I have a bad valve. That would explain the missing. When doing the compression check I noticed a far amount of fuel coming out of the cylinders as I cranked it over. I thought it was excessive. Still haven't figured out why it was running rich.

[Tom @ Fast Forward]

If you can do a leak down check, it will tell you immediately where the problem is. Rings, intake valves or exhaust valves.

[nelly1]

Ok here's what I did. I took the hose from the compression gage and spliced into an old compressor hose. Set the #3 cylinder to TDC turned up the air to 120 lbs. The pressure stayed at that level. Opened the radiator cap and saw no bubbles. Pulled the dip stick and did not hear any air coming out, went to the tail pipe and nothing there. Pressure still holding at 120 lbs. I opened the oil filler and heard a very faint hissing sound. That was it! Then I rotated the crank 180 degrees and while doing it I listened for any leakage. Still nothing, yet the cylinder puts out less than 60Lbs. pressure when cranked over.

[Tom @ Fast Forward]

One of those two TDC's should have leaked like a seive. One time the valves are closed, the other TDC one or both valves are open, at least a little.

Are you saying that you can rotate the engine OK and it cranks OK?

If you have 4 LONG screwdrivers, remove all four sparkplugs and gently drop one in each cylinder and rotate the crank by hand. See if all four go up and down. If you hydrolocked the piston and did the damage you think you did, I would think there is a broken piston/rod someplace.

[nelly1]

Dummy me! I can see your eyes rolling. The adapter I used was borrowed and I did not realize in the fitting there is a schrader valve. Worked much better after it was out.
Any way I had a lot of air escaping from the tail pipe and it seemed like some come out around the top of the head? I guess I will pull the head and check the valves.

[nelly1]

Head off
Not what I expected. A half quarter size piece off the top of the #3 piston. What possibly happened here?

[bogey]

Do you have pics of the gore...

[Tom @ Fast Forward]

Pictures please.

Middle of the piston or edge of the piston?

[nelly1]

edge of the intake valve relief , part of the ring is exposed

[Tom @ Fast Forward]

How do the other three pistons look around the same area and around the edge?

[nelly1]

They all look good, compression check was 145 lbs. each. I do have pic's how do I post them?

[Tom @ Fast Forward]

Knock typically shows up as marks around the rim of the pistons. It sounds like the other pistons are telling us you have no history of knock. Knock is usually what breaks/cracks pistons. Lean burns holes typically towards the center or, at least, away from the rim. Sounds like you don't have signs of that either. From this point, a pucture is worth at least 1000 words.

[nelly1]

Here I was able to do this. http://www.me.com/gallery/#home

[Tom @ Fast Forward]

That only works for you as it needs your name and password.

[nelly1]

492

493

494

495

496Let's try this

[Tom @ Fast Forward]

Well, that could be from some super lightning strike as in one bodacious knock but the rest of the edge doesn't seem to show smaller strikes. Not likely that everything was running along well and then boom. It will be interesting to know where the missing piece is? Too big to go along side the piston? Too big to vaporize?

For knock to do something that drastic, I would think it would have to be at or near TDC. If so, with that damage, I would expect to see a bent/broken rod. Are cylinder 2 and 3 about the same depth?

Almost looks like something stuck to the intake valve and the piston hit it???

[nelly1]

I measured the depth and they are the same. No sign of any metal deposits in the cylinder or in the valves. It's really odd.

Well, any way I'm also in need of a new engine. I can across a 95 long block with 22,000 actual miles for $1100 delivered to my door, I'm thinking I should pull the trigger and get it. I think it would be the most cost affective route.

[Tom @ Fast Forward]

Not a bad price. Just be sure to ask if it is a JDM engine. If so, run, don't walk to the nearest exit.

[nelly1]

Thanks' for the advice! When I get the old engine out I will pull the pan and let you know what I find.

[Tom @ Fast Forward]

That piece of piston just HAS to be somewhere.

[socal pat]

I measured the depth and they are the same. No sign of any metal deposits in the cylinder or in the valves. It's really odd.

Well, any way I'm also in need of a new engine. I can across a 95 long block with 22,000 actual miles for $1100 delivered to my door, I'm thinking I should pull the trigger and get it. I think it would be the most cost affective route.

My #1 piston looked like that. I found the chunk in the intake manifold :eek: .

[nelly1]

497 Take a look at this. It is #1, are the reliefs around the intakes normal, or are they abby normal? What have I done!

[chuckerants]

Asks for log in info.

Here I was able to do this. http://www.me.com/gallery/#home

[Gman7007]

Intake cam not timed properly after that last timing belt change??? Just a thought.