95 Lumina Hesitation trouble- thought I had it fixed - Page 2

Shinobitoshi · 10-15-2009, 10:04 PM

Ok. I guess I'll try different plugs. After changing the one coil I thought might be bad I don't know what else to try. Especially since new plugs worked
last time, even though it was short lived.

manicmechanix · 10-15-2009, 10:26 PM

Quote:

Originally Posted by Shinobitoshi

Ok. I guess I'll try different plugs. After changing the one coil I thought might be bad I don't know what else to try. Especially since new plugs worked
last time, even though it was short lived.

You are better off with the AC plugs even if it doesn't solve your hesistation. Maybe you can return the other plugs. My suggestion is to check the resistance of the wires even if new, and the coil secondaries at least. That's easy to do.

Shinobitoshi · 10-15-2009, 10:38 PM

I'll have to pick up a multimeter and do that.

Any idea what proper readings would be?

manicmechanix · 10-15-2009, 11:15 PM

As a guide coil secondaries should 5-7K ohms. Wires less than 7K.

Shinobitoshi · 10-16-2009, 12:50 AM

OK. so I was looking for information on how to test the coil packs. I found a lot of stuff, but none of the information I found seemed relevant to the coil packs on this car. The only exposed metal to test is the terminals that the ignition wires connect to. On the bottom of the pack there are two slits that tabs go into. I'm honestly not sure what I'm even doing now.

manicmechanix · 10-16-2009, 01:13 AM

Measuring between the the terminals on each coil is the secondaries. The two slots or prongs on the bottom of the coils are the primaries. I wouldn't worry about the primaries for now.

Shinobitoshi · 10-16-2009, 10:33 AM

I haven't gotten to test the coils and wires yet. But just for the hell of it I did unplug the egr this morning and drove it a bit. I noticed no difference at all in the way it drove.

jd-autotech · 10-16-2009, 01:17 PM

did you do as i said?

Shinobitoshi · 10-16-2009, 01:44 PM

JD, no. Rather than taking a chance with tapping the injectors I had them cleaned instead. I hope that would be the same or better.

jd-autotech · 10-16-2009, 09:45 PM

do it i m tellin you, you wont regret it

Bearwulf · 10-17-2009, 01:23 AM

How did you check the coil that you changed? Did you use a spark tester or timing light to check for spark before replacing that coil? Did you use the di-electric grease between the coil & the ICM when installing the new one?
Have you had the ICM tested? How many miles on the engine?
Does it jerk really bad when starting out from a stop?

Shinobitoshi · 10-19-2009, 08:42 PM

Sorry it's been a few days since I posted, this weekend was hell with homework.

Bearwulf,
I checked the coil with a multimeter. But that was not until after I replaced it. Before I replaced it noticed a rusty terminal and decided to swap it out anyway. When I tested it with the multimeter it checked out fine, but I had a hell of a time finding a spot on the terminal that would read through all the rust. So I'm still glad I swapped it.

I did use dielectric grease between the coil and the module, but it really probably didn't need it, there is a spacer there and there is a rubber gasket type thing separating the plugs that insert into the bottom of the coil.

I have not had the ICM tested, I guess I probably should, but this is my only vehicle, so taking it out would leave me with no way to take it somewhere to have it tested.

The engine has 156,000+ miles on it.

It does not jerk really bad when starting from a stop. The hesitation usually happens in between shifting gears, but not at all like a slipping transmission. It will complete the gear change, but when the RPMs are low after the shift, it bucks and the RPMs drop, then it has to catch up. The same thing happens when I slow to a stop, without the bucking part.

So, I switched out the spark plugs like I was recommended to do. Crazy part is, immediately after changing the plugs, it ran like a champ again for about 35 miles, then it started doing the same thing again. I tested the wires, all check out at less than 4k ohms. The ignition coils were weird. The coil I replaced read at 8800 ohms, while the other two read at 5900 and 5800 respectively. The old coil that I replaced read at 5900 ohms once I was able to get a read on it through the rust. Maybe faulty new coil? or maybe all three were weak?

Anyway, because I ran into my uncle from PA this weekend, who is a mechanic, he told me I should swap out the PCV valve and check the EGR valve. I swapped the PCV yesterday and noticed that it had a cracked vacuum elbow boot attached to it, which I replaced hoping that might correct a vacuum leak. NO GO. I pulled off the EGR and it was pretty darn clean. A little bit of carbon build up, but all the valves moved freely and there were no clogs in the tube or the valves. I cleaned it all off anyway and replaced it, while changing the gasket. I drove around for a bit and it still has issues.

I decided to check my 02 sensor. My chilton manual tells me that I should use a test light, which I don't have currently, for the first part of the test, so I skipped that. The second part said I should use a multimeter to test the resistance between terminals A and B on the o2 sensor wiring harness. I tried for about 30 minutes, but I could not get any reading. Possible o2 sensor issue? or maybe I'm just doing something wrong.

At this point my only guesses are o2 sensor or MAP sensor, I suppose I could change out the manifold air temperature sensor also, but I tested that and the resistance readings seem to be within spec according to my chilton manual.

Any advice?

manicmechanix · 10-19-2009, 09:16 PM

Well usually if you had sensor that was off or maybe a lazy 02 sensor it would set a code but not always. What you described with the jerking when the engine slows sounds like it could be the torque converter. Have you checked the transmission fluid level and condition? It probably really needs a fluid and filter change anyway, but it might be too late to clear up a TQ/trans problem if it has one. It's hard to tell what's goping on from here but my guess is it it might the trans.

Shinobitoshi · 10-19-2009, 09:31 PM

i really thought that it might be too, but I really can't see how the problem would have been completely eliminated and the transmission would still shift fine immediately after changing the plugs twice now. I also just had the trans fluid checked, and was told it was fine, haven't looked myself though. I have no idea when the last filter/fluid change was though.

There is obviously a code being set, which is why I was trying to figure out if I could jumper this stupid OBD1.5. The light will come on, but it always resets after the car has been off. Once I turn the car on, the light is off and stays off for a few minutes, but then comes on. The light does not seem to affect the hesitation though, because it runs the same whether the light is on or off.

manicmechanix · 10-19-2009, 09:40 PM

Quote:

Originally Posted by Shinobitoshi

i really thought that it might be too, but I really can't see how the problem would have been completely eliminated and the transmission would still shift fine immediately after changing the plugs twice now. I also just had the trans fluid checked, and was told it was fine, haven't looked myself though. I have no idea when the last filter/fluid change was though.

It is probably coincidental that every time you work on the ignition it runs good for awhile. The thing about a torque converter acting up is it will run good untill engine warms up and lockup is activated then when you hit that speed around 35-45 mph it will show up. Does it jerk around this speed?

Quote:

There is obviously a code being set, which is why I was trying to figure out if I could jumper this stupid OBD1.5. The light will come on, but it always resets after the car has been off. Once I turn the car on, the light is off and stays off for a few minutes, but then comes on. The light does not seem to affect the hesitation though, because it runs the same whether the light is on or off.

Yeah I had forgotten that you have that obd 1.5 that you can't pull codes on. I didn't know or had forgotten that you were getting a check engine light. Sounds like you have an intermittent problem and it'd sure be nice to know what that code says. Heck, for all we know it might be a transmission related code lol. Instead of throwing parts at it, you might be ahead to find some place that can at least read the codes if not diagnosis the whole problem, or maybe you could buy a scanner that has the adapter and can read these '95 OBD 1.5 setups, then return the scanner.

POST REPLY TO THIS THREAD