Questions for Joe 1320 or Anyone else....

[Jason97T/A]

Hey Joe, you gave me some advice awhile back about gettin a compression test done on my 97 ta because of a bad misfire that the dealership told me was internal. Turns out I took it to someplace else and the egr valve was stuck open. That seemed to take care of the really rough idle and sputtering under accleration after he put a new one on. Well my SES light is still on for I think a code maybe 0400?? Well anyway it is a random multiple misfire code. Here's the problem....When I come to a stop at a stop light or near a complete stop, the engine will give a couple jerks, shake a few times. It seems to do this after the car gets warmed up, but Does Not do it at every stop, most though. Also the Air conditioner will cut out a lil bit, loose power, and the Amp guage will fall below 13 for a sec. And I think even the oil pressure guage will bounce a little bit. What does this mean? Oh and by the way, did you ever dig up that SLP Cold Air Kit? Thanks
Jason

[Flash 97 WS/6]

Did you to a PCM reset after getting the EGR replaced? Might just need to pull the PCM fuse for a few min and force it to start over learning the fuel curves etc...

$0.02 -

[Jason97T/A]

Originally posted by Flash 97 WS/6
Did you to a PCM reset after getting the EGR replaced? Might just need to pull the PCM fuse for a few min and force it to start over learning the fuel curves etc...

$0.02 -

I took it to the autozone to have it scanned to see what set the SES light off, and it was the random mult misfire. They then cleared the code. And it came back the next day. Does that work the same?
Jason

[Joe 1320]

Pulling the fuse to the PCM does clear the codes, but if you have a consistant problem, the code will return. As far as the misfire, There are a few things that it could be. I really wish I could observe all the sensors in real time while it's running. Without that, we'll have to trace it down, step by step. The first thing I would check is all of your grounds. The gauges are electrical, so if there is an intermittant contact, everything electrical will fluctuate. When your rpms drop, so does your alternator output and your oil pressure. Do you have an automatic or manual trans?

After checking all the grounds, I really think you need to go over the ignition system. It doesn't take much for a plug wire to go bad. Open the hood while in the dark and see if there is any blue glow around any of the plugs/wires/coil and bracket. Any leakeage will show up in the dark. Make sure all wire boots are well seated on the plugs and in the optispark. Any of these may cause an intermittant miss.

Check all the harness connections going to the injectors as well as the main harness connector. When the engine drops to idle, there is less voltage and an intermittant contact may fail. As the rpms increase, more voltage is supplied and the contact may work.

You can also try the "tap" test. Take the handle of a large screwdriver and while the engine is at idle, tap the MAF, TPS and PCM. If you get a stumble when you tap any of these, you've found your cuplrit. Note: do not beat the heck out of them due to frustration. LOL!

I know you said that most of those componants were changed, I've seen almost new parts fail prematurely, so don't assume that because it's been replaced, it is still good. Let me know when you've checked those items, we'll dig into it further if needed.

As far as the SLP part, I sent you a private message, check there...... I can't remember when I did it, but it should be there.

[Jason97T/A]

Originally posted by Joe 1320
As far as the misfire, There are a few things that it could be. I really wish I could observe all the sensors in real time while it's running.

A friend of mine has autotap software. Any sensors we should check and if so what should we be looking for?

Without that, we'll have to trace it down, step by step. The first thing I would check is all of your grounds.

What should I be looking for at these grounds, and how many grounds are there?

The gauges are electrical, so if there is an intermittant contact, everything electrical will fluctuate. When your rpms drop, so does your alternator output and your oil pressure. Do you have an automatic or manual trans?

I have a automatic trans

After checking all the grounds, I really think you need to go over the ignition system. It doesn't take much for a plug wire to go bad. Open the hood while in the dark and see if there is any blue glow around any of the plugs/wires/coil and bracket. Any leakeage will show up in the dark.

Is it really easy to see in the dark, like a bright glow, or do you have to look really close and hardly noticeable? I have tried this before, and I thought I saw maybe a lil blue light around the opti? Could be my imagination? Or is the coil around there too?

Check all the harness connections going to the injectors as well as the main harness connector. When the engine drops to idle, there is less voltage and an intermittant contact may fail. As the rpms increase, more voltage is supplied and the contact may work.

What should I look for at the connections? A loose connection? Should I play with them a lil to see if it stumbles or what? Are the connections removeable?

You can also try the "tap" test. Take the handle of a large screwdriver and while the engine is at idle, tap the MAF, TPS and PCM. If you get a stumble when you tap any of these, you've found your cuplrit. Note: do not beat the heck out of them due to frustration. LOL!

Can I try this with a sledge hammer?

By the way Joe, I've been wanting to road trip sometime, maybe I can hit Florida in the future. haha.....Doubt the car would make it that far, especially with my luck.
Anyway, thanks
Jason

[Joe 1320]

When the engine stumbles, it would be helpful to read the 02 values and the injector pulse width. Any ignition problem would send unburned fuel and oxygen into the exhaust and the sensor would actually read it as being lean. The computer would then add fuel, based on what the 02 sensor reads and add more fuel. You may even see a puff of black smoke out the tailpipe.

When looking underhood for ignition leakeage, you 'll have to look closely, you won't see huge sparks, just a soft glow around any wires that are leaking. If you thought you saw a faint glow around the opti, you might have seen the culprit. It may be as simple as one of the boots not being completely seated. I even use a smear of clear dielectric grease on the inside of the boots to help seal them and make it a little easier to pull off when the time comes. Helps seal out water contamination to the terminals too. It would be a good idea to pull the boots to the opti and check for corrosion of the terminals. If you really look at the design, hit a few large puddles and the opti is gonna get wet.

The coil is located on the front of the driver's side head and there is a braided ground strap attached to one of the studs and goes to the unibody. Make sure all is tight. If the coil was replaced, there is supposed to be a heavy, white grease dielectric grease that is supposed to be smeared on the backside of the coil where it attaches to the bracket to eliminate any arcing from the coil body to the bracket. The coil driver module is located immediatly above the coil and is attached to the bracket as well. Make sure the flat connector is making good contact. I've had to "adjust" the pins before to make a good solid connection.

Each injector has it's own harness connection, held in place by a silver clip. Wiggle them all and make sure that each connector is firmly seated on the injector. The engine may stumble when you mess with the harness, indicating a poor connection. Trace the harness back to the main injector harness connector and make sure it's tight too. If I had a dime for every time I've systematically gone through each harness connection on various cars only to find a loose connection, I could buy headers on that alone. Seriously, you are looking for crimped wires, loose harness connections, blue glow around any plug wires, opti or coil.

One thought, which shouldn't throw a misfire code, is the torque converter. If it suddenly cycles between lock and unlock while stopped, the engine would shudder, almost stall then correct itself. The rpms would drop, then correct itself almost like a misfire. I've seen them do that, just not throw a random misfire code. In bad cases, the motor just dies. Keep us posted on what you find. I am putting my money on either corroded opti cap and/or plug wire connections, but without having hands on, it's just a best guess.

At least you didn't have the motor torn down again.

[Jason97T/A]

Yeah Joe, I really didnt want to have to motor torn down. This problem with the stumble has been there for a couple months now, way before the EGR Threw a code in the computer and caused a bad misfire and rough idle. But what I don't get, there was never a misfire code before the EGR was stuck open. The EGR is fixed and there is still a ran/mult miss code. That being the case, if it was causing the stumble, wouldn't it have done it before the EGR was stuck open? You see what I'm saying?
Is there anyway to test the torque converter.
Oh and today I was driving, paying close attention to the amp guage, and once the car was warmed up and driving, and i came to a stop at a light, it was under 13 almost in the orange, then eventually its back up? What could that be? Does that rule out torque converter?
I'm gonna go play with the injector connections now.......so let me know. Thanks
Jason

[Joe 1320]

Jason,

If it threw a P0400, that is still an EGR code. EGR flow to be exact... could be the egr tube going from the valve to the rear of the manifold may be plugged or partially plugged. You would need to remove the tube and flush it out using 02 sensor safe TB cleaner to remove the carbon build up then reinstall.

The low amps at idle is a typical condition with these cars. The situation gets worse with a crank underdrive pulley. I wouldn't worry about it.

If you aren't throwing a code for the converter clutch, doubtful that is a problem. Usually they will kill the motor at idle because the clutch won't unlock.

The EGR being stuck open still may have plugged up the EGR tube. It would be a good idea to pull it and flush it out.

[Jason97T/A]

Originally posted by Joe 1320
Jason,

If it threw a P0400, that is still an EGR code. EGR flow to be exact... could be the egr tube going from the valve to the rear of the manifold may be plugged or partially plugged. You would need to remove the tube and flush it out using 02 sensor safe TB cleaner to remove the carbon build up then reinstall.

My fault joe, P0300. Random/ Mult Misfire. Sorry bout that.