93 Trans Sport Changing Plug wire basics??

I have found info on other Threads posted on simular problems.
I would really appreciate any furthure help you anyone can give.

I have a 93 TS with the same jerking sputtering problem.
An mechanic told me it was the torque converter clutch locking up, when you tap the brake of let of the gas you get your 500 rpms back and loose the jerk.

The trany guy told me this is the most misdiagnoised problem.

He said I had a bad plug wire, that sounded much cheaper to try to fix.

My problem is the first wire I went to wouldn't come off, desided to pull with a plyers ripped the boot apart but got the plug and wire off. I read this is a common problem.

What I don't understand is how to get the black wire protector off that is under the engine stabilizer or mount bracket and attached to the front of the valve cover???????

Second I know about the heat sheild boots on the rear bank of plugs.
What is the best way to get at them, the only place I can see them if from the underside?????

Is there also a wire shield on the backside of the engine and how do you handle it???

Thank you and I really appreciate any help you can give.

I have the rear bank of plugs and wires changed as well as the front plugs.

My only problem left is how to route the wires on the front bank through this black protective shield.

Can anyone that has change the wires before enlighten me on how to do this.

On the rear bank I had to loosen all the plugs from the top side (blind) and install them that way. I found that you can get to the first couple also by pulling the passenger side tire off and going through that way.

Can anyone help with this plastic protector?
"What I don't understand is how to get the black wire protector off that is under the engine stabilizer or mount bracket and attached to the front of the valve cover???????"

Thanks again to anyone that can help.

I have the rear bank of plugs and wires changed as well as the front plugs.

My only problem left is how to route the wires on the front bank through this black protective shield.

Can anyone that has change the wires before enlighten me on how to do this.

On the rear bank I had to loosen all the plugs from the top side (blind) and install them that way. I found that you can get to the first couple also by pulling the passenger side tire off and going through that way.

Can anyone help with this plastic protector?
"What I don't understand is how to get the black wire protector off that is under the engine stabilizer or mount bracket and attached to the front of the valve cover???????"

Thanks again to anyone that can help.

You have to loosen the engine stabilizer and take the bracket at the engine away. This is easy to do and the engine will stay in position without any support. Then you can pull the plastic protector right up. The protector itself is possibly to take apart to install new wires.

You have to loosen the engine stabilizer and take the bracket at the engine away. This is easy to do and the engine will stay in position without any support. Then you can pull the plastic protector right up. The protector itself is possibly to take apart to install new wires.

Thank you I wasn't sure if the engine would move or stay put.

I got my plugs and wires changed, one plug was black and wet, a second mostly black.

I still have my shaking problem, it seems to drop in rpms and then shake. I can feel that it isn't running smoothly at idle and can hear it in the exhaust like a miss? The 2 plugs that looked bad come from the same coil. I pulled the wires off this coil while it was running and it seems to be sparking regular. I don't know if that's a good test or not.
The plug wire that had the wet plug previously was really hot does this indicate something?

Anyone have any suggestions what I could try next?

Please help can't really get rid of the van they wouldn't give anything for it.

The 2 plugs that looked bad come from the same coil. I pulled the wires off this coil while it was running and it seems to be sparking regular. I don't know if that's a good test or not..

I hope I do not understand this rightly....disconnecting the wire FROM the coil while running forces the coil to generate extremely high voltages because of the extended spark path...it would certainly not be a good thing for the coil..., may break insulation definitively. however, if it was able to spark in this condition and survive , this could let believe it should do the job properly with a spark plug connected to it. But....
I think I would try to find one section of coil pack and swap it for a try...

IN fact...do you have a Check Engine Light ON? Pulling the codes is easy if needed check www.avigex.ca/xport/readingdiagnostics.jpg

The plug wire that had the wet plug previously was really hot does this indicate something? .. WOuld believe this is coincidental....

THe other thing is...do you need to add engine coolant from time to time?...this is a 3800, not prone to that kind of problem, but a blown head gasket might explain...I do not want that, but check for
symptoms: heating problems, bubbles from the radiator with cap opened.

I think I would try to find one section of coil pack and swap it for a try...

I will try a new coil in each place to find out if this is the problem. Even though the coils are numbered like the first is 1 & 4 it wouldn't matter which place they went in would it????
The coils all put out the same correct???

IN fact...do you have a Check Engine Light ON? Pulling the codes is easy if needed check www.avigex.ca/xport/readingdiagnostics.jpg

I do not have a Check Engine Light ON.

WOuld believe this is coincidental....

THe other thing is...do you need to add engine coolant from time to time?...this is a 3800, not prone to that kind of problem, but a blown head gasket might explain...I do not want that, but check for
symptoms: heating problems, bubbles from the radiator with cap opened.[/QUOTE]

Yes I do have to add coolant but have a leak at the top of the radiator.
Took it to a radiator guy he said it was common with the 3800 because they run hot. He said it would be OK as long as the level didn't go much below the cap which it doesn't but I check it often.

...common for the 3800 to loose coolant ....RUN hot.. ...I'm amazed, somewhat, but I'd rather like that as an explanation. just tell me no steam escapes from the radiator cap or the reserve tank...i do not like thinking of that,

Coils packs are identical, just marked as installed for convenience.
Something very common (would not explain the 2 dirty plugs though) is the EGR valve problem. Has this been totally ruled out yet? If one section is blocked partly open, stray exhaust invades the intake manifold and can cause rough idle.
ALso lately one or 2 members on this forum reporting rough idle or the like have found disconnected vacuum hoses and solved the problem by returning them to their due place..

...common for the 3800 to loose coolant ....RUN hot.. ...I'm amazed, somewhat, but I'd rather like that as an explanation. just tell me no steam escapes from the radiator cap or the reserve tank...i do not like thinking of that,

It appears that you have a different view point than this radiator shop did. He told me that these radiator can leak right up by the top.
I do not see steam leaking from the cap or reserve tank but it does leak.
They said if the fins are covered it would be OK????
I have never had an overheat issue nor do I have problems with heating like you asked before? I am just going by what I have been told on these problems.

I want to thank you for helping me out.

I have to ask again about the EGR valve? I am not sure what or where it is on this engine if so. I tried doing a search so I wouldn't have to ask but came up with that it might not have one on the 92/93.

http://groups.google.com/group/alt.autos.gm/browse_thread/thread/9d4b660ca2a890ac/de3617b700bf3b6f%23de3617b700bf3b6f?sa=X&oi=groupsr&start=0&num=3[/url]

If I have one how do you tell if it is blocked?

Coils packs are identical, just marked as installed for convenience.
Something very common (would not explain the 2 dirty plugs though) is the EGR valve problem. Has this been totally ruled out yet? If one section is blocked partly open, stray exhaust invades the intake manifold and can cause rough idle.
ALso lately one or 2 members on this forum reporting rough idle or the like have found disconnected vacuum hoses and solved the problem by returning them to their due place..

I didn't see any hose's hanging loose.

'94 has a linear valve like this www.avigex.ca/xport/egrlin ; 92 has no egr and '93 has a 3 section valve. Several simply remove the valve and block the ports but this would not pass an EPA test.
Easiest test is to electrically disconnect the valve. THis could stop the valve from opening and staying opened in case it grips opened. THis will trig a CEL however that will disappear once reconnected.
If valve is stuck partly opened, only way to find out is to remove valve and visually inspect it. I do not have that model ; nicke66 worked on his and could give better clues about what to look for.


I disconnected the electrical connector from the EGR valve it didn't change anything. CEL light came on like you said it would.
Will try the coil first and if needed pull the EGR valve to see if it is stuck, looks like I would need a new gasket for that?

I wrote my last post as if you had a '94.. sorry for the confusion; '93 3 section EGR valve
www.avigex.ca/xport/egr3.jpg seems to have more failure history than the linear '94...; I hope you have no problem taking it off for a test. Once it it removed, manage to block all ports in the adapter and go for a test ride.
At least the test you have done proved the CEL works.

Waiting for the results with the coil....that would be a simple solution..

I wrote my last post as if you had a '94.. sorry for the confusion; '93 3 section EGR valve
www.avigex.ca/xport/egr3.jpg seems to have more failure history than the linear '94...; I hope you have no problem taking it off for a test. Once it it removed, manage to block all ports in the adapter and go for a test ride.
At least the test you have done proved the CEL works.

Waiting for the results with the coil....that would be a simple solution..

Details on what I have done so far.
Changed Plugs and Wires no change.
Changed coils out individually and the entire bank, no change.
With instructions from Nicke66 I removed the EGR valve.
None of the valves where stuck or hanging up, I cleaned up all carbon the best I could. He suggested I do a ohm reading on the three EGR valves stating they should read between 10-20 ohms. I got 0 for a reading with the ignition off, key on, and engine running?
I also blocked the valve off with tin foil that I read about in another thread. The CEL did not come on, it did come on when I disconnected the EGR.

I still have what feels like a lack of power when accelerating and when I ease of the gas around 40 and above the RPM's will shift down about 500 RPMs and I have the shake, I can release it by taping the brake or letting off the gas and applying it again. Doing this I gain that 500 RPMs back but I can still tell the lack of power and a slight roughness.

Can anyone think of anything else I can try????

The trany guys mentioned that when the engine was missing it could plug the catalytic converter with fluorocarbons. Is this a possibility???

when I ease of the gas around 40 and above the RPM's will shift down about 500 RPMs and I have the shake, I can release it by taping the brake or letting off the gas and applying it again. Doing this I gain that 500 RPMs back but I can still tell the lack of power and a slight roughness..
WHat you describe here is the Torque COnverter Clutch applying - thus cutting converter slip , 500 rpm down - and then releasing - 500 rpm up. The "shake" ressembles the "TCC shudder" syndrome,
www.avigex.ca/xport/tccshudder.jpg that happens when the torque converter clutch is either worn out or lacking sufficient pressure preventing it from applying firmly, sadly, a transmision problem if there is no other explanation, but one can live with it by disabling TCC, costing 1 or 2 MPG on highway, but one have to consider that against the cost of repairing the transmission. ALso CV joints are often suggested in these conditions but rarely prove to be the culprit just on these symptoms: you would have other signs, like clunking noises when turning.
About "lack of power"...no real idea...the blocked catalytic is an option but I'd see that happening at high throttle and high rpm, cause in 4th, the engine runs so slow that a really serious blockage is needed to refrain exhaust from exiting...but I cannot totally rule out that explanation..in last resort.

Finally, can you say that blocking the EGR has somewhat improved the behaviour, specially since you had mentioned rough idle before...
ALso, blocked EGR WILL eventually light up the CEL, but it requires the vehicle to be driven steady at constant speed for a little while for computer to "execute" the EGR test.

www.avigex.ca/xport/tccshudder.jpg that happens when the torque converter clutch is either worn out or lacking sufficient pressure preventing it from applying firmly, sadly, a transmision problem if there is no other explanation, but one can live with it by disabling TCC, costing 1 or 2 MPG on highway, but one have to consider that against the cost of repairing the transmission.


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I don't know what the transmission repair cost would be but probably more than the van is worth??? Can the TCC be removed without pulling the works? Do you have any idea roughly what it would cost?

Could you please explain the procedure for disabling the TCC.
I have already lost the mileage as is we are getting about 100 miles less per tank full than before this problem began.

JUst have to disconnect one wire from the connector
www.avigex.ca/xport/tccloc.jpg
www.avigex.ca/xport/transaxleconnector.jpg
(it may be possible to extract it from the connector without damage with proper care) . As seen on diagram,
www.avigex.ca/xport/transaxle.jpg

it is either the PURPLE on the hot side (position A) or the TAN/BLACK (position D) on the ground side.
From then on, you will probably have the check engine light ON for detecting improper TCC operation...will have to live with it.
It shudder disappears, this will have proven this diagnostic; if not, you can always reconnect the TCC and keep searching...

Simply disconnecting the whole plug will disable TCC but would also impair proper shift control by disconnecting the solenoids too...but it can be tried for a test. (I,m not sure it will allow 4th gear though, since one of the solenoids goes ON for 4th (but none for 3rd).

JUst have to disconnect one wire from the connector
www.avigex.ca/xport/tccloc.jpg
www.avigex.ca/xport/transaxleconnector.jpg
(it may be possible to extract it from the connector without damage with proper care) . As seen on diagram,
www.avigex.ca/xport/transaxle.jpg

it is either the PURPLE on the hot side (position A) or the TAN/BLACK (position D) on the ground side.
From then on, you will probably have the check engine light ON for detecting improper TCC operation...will have to live with it.
It shudder disappears, this will have proven this diagnostic; if not, you can always reconnect the TCC and keep searching...

Simply disconnecting the whole plug will disable TCC but would also impair proper shift control by disconnecting the solenoids too...but it can be tried for a test. (I,m not sure it will allow 4th gear though, since one of the solenoids goes ON for 4th (but none for 3rd).

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With help from the schematic link you sent I opted to go with the tan/black wire first in position D (Transaxle Converter Clutch Control).
The wire can be pushed out with a little force with out ruining it.
First remove the red clip on the back of the plug, I did a combo of pushing with a small screw drive and pulling on the wire until the rubber sealant but freed.
This eliminated the shudder problem that I had.
The CEL comes and goes, mostly when it is needing to shift to 4th or OD which ever. I am running about 1000 RPMs higher so it obviously isn't shifting to 4th. It is still only running around 2500 RPM at HWY speed.
I will post later on mileage effect, but it looks about the same as what I had.

I can still feel the lack of power, sometimes it comes on like it used too.
This could be still something trany related, maybe fuel injectors I am not sure but there is a definite improvement in eliminating the TCC and the shudder. I don't know what to expect to get out of this van it has 181,000 mile on it now. It is not worth any major repairs I don't think.

Thank you very much to LMP and Nikke66 for your help.