: New '81 Major Tune Up Issues



Angry Matt
08-08-09, 09:42 PM
I wanted to freshen up my new brougham ('81 v6) with some new plugs and wires. I bought factory replacement AC Delco plugs. Put them on and the car ran like crap. Thought maybe I did damage to a wire in the process, so I bought new wires. No improvement. Went back and exchanged the plugs for another set incase of a bad one. No improvement. By crap I mean heavy sputtering during excelleration, extreme loss of power, and a light thump once every two seconds or so at idle in drive. So bad I don't even want to look at this car right now, it's embarrassing to drive. I remembered bumping the EGR vacuum solenoid when doing the plugs and notice the nipple going to the EGR valve was broke and the whole thing feels loose. I bent the rubber connector to the side and slipped a line on what was left of it the broken nipple. Seems to have a good connection now. I disconnected the EFE because the line was broke when I got the car and it ran good then. The EGR valve seems ok when I push it in from underneath. The car ran awesome until I read the tune up thread and decided to change the plugs. They're gapped properly and I've tried adjusting the timing. What could I have done wrong? I just bought the greatest car I've ever owned and I don't want to see it in my driveway when I wake up. Not to mention I have no money, so putting it in the shop is out of the question.

sven914
08-09-09, 02:56 AM
Did you make absolutely sure that the fire order is right (one wire off at a time)? Is it possible that you moved the distributor? Check the electrodes on the cap for looseness (I've seen some caps where the electrodes have broken off because the wires were stuck to them. The plugs themselves could be bad (dropped during shipment), or the wrong plugs for your engine (they should have 2s stamped on them, according AC Delco's official site). I would also retrace the service, not removing anything, but move you hands around the wires to see everything you touched and moved that could be causing your problem.

Angry Matt
08-09-09, 09:51 AM
I checked the wires according to the fsm several times. Crossed the ones that I thought could have been switched and it ran horrible. This is the second set of plugs that's doing this, actually different brand and type, not Bosch. They are gapped at .080 where the first set was .060. The fsm calls for .060 but the plugs I pulled from the car were .080 and it ran great and got great gas mileage. I'm confident it's not in the plugs at this point with two sets, brands, and gaps and no difference whatsoever. It has to be something that I did during the new plug switch because it happened immediately. I can't even try the old plugs because the ahole that put them in had them so tight I broke two getting them out. Could a vacuum leak cause this lack of performance? Or the ignition module going since I changed plugs? I have a spare that I think is good. Maybe I'll get a new cap and rotor anyway just so I know it's new. Anybody know anything about the EGR solenoid? Mine has 6 vacumm lines and the ones I find only have 4. I can see how to wire them minus the two, but I don't know if this will work.


Did you make absolutely sure that the fire order is right (one wire off at a time)?

What do you mean by one off at a time?

jayoldschool
08-09-09, 10:04 AM
They are gapped at .080 where the first set was .060. The fsm calls for .060 but the plugs I pulled from the car were .080

Re-gap the plugs at FSM spec .060. Replace the EGR (check rockauto.com to see if you can get a part number for the correct one). Change the cap and rotor. Re-check the firing order and make sure that you have the wiring right. Check all vacuum lines for breaks.

Angry Matt
08-09-09, 10:54 AM
I'm going to the junk yard tomorrow. Is it a bad idea to pull an egr from there? I'm really short on cash and I need this car to get to work. I can't gap these plugs at .060 can I? They're made to be at .080. I don't understand why different plugs for the same motor are made with different gaps.

jayoldschool
08-09-09, 11:07 AM
You need one of these to set the gap, and they are dirt cheap at the parts places:

http://www.oneprojectcloser.com/wp-content/uploads/2008/08/spark-plug-gap-tool.jpg

Not a great idea to go with a used EGR...

Angry Matt
08-09-09, 11:45 AM
I have a gapper. My uncle (whose been a mechanic for 40+ years and is a wiz with the electronics) said not to gap plugs different then what they were made for as you will stretch the whatever its called and it won't be flat causing uneven wear on them. I check all my gaps before I put the plugs in and set them to what the plug manufacturer calls for. Again, I don't know much about this area. I'm probably going to go get a new egr and cap and rotor from advance since they have it in stock and aren't much more than rockauto. Tomorrow is my only day to focus on the cars all day.

sven914
08-09-09, 03:55 PM
What do you mean by one off at a time?

When ever I do something where routing is critical, I remove one wire or hose and replace it before moving to the next one. This way I don't have a bunch of loose ends and no idea of where they go.

What part number was stamped on the AC Delco plugs you put in? The wrong plugs might be too short or too long or have the wrong electrical properties to properly ignite the air fuel ratio.

brougham
08-09-09, 04:08 PM
Just because the new plugs are gapped at .08 doesn't mean its right for your car. Go by whatever the sticker under the hood says. Since the ones you took out were gapped that way too the last person didn't do it right either.

jayoldschool
08-09-09, 05:36 PM
My uncle (whose been a mechanic for 40+ years and is a wiz with the electronics) said not to gap plugs different then what they were made for as you will stretch the whatever its called and it won't be flat causing uneven wear on them

With all respect to your uncle, there is no problem to gapping plugs correctly. You do not stretch the electrode. It certainly won't cause "uneven wear"...

Angry Matt
08-09-09, 06:45 PM
But what about when the electrode is on an angle? His point was that it should be flat as it was designed to be. I know he could be wrong. It all came up after I gapped plugs that were .035 to .060 (completely different application). The electrode was almost diagonal to where it should have been and it just didn't look right. When you look at the cross references of other plugs, some call for larger gaps and he said that's what the plug was designed to fire at. So basically I need to get the plugs I had in it before when the problem started? That's when I thought this was a plug issue. I got a new cap, rotor, and egr valve, and am going to the yard to find a vacuum solenoid tomorrow. The more I mess with the vacuum solenoid the more it changes the way it runs.


What part number was stamped on the AC Delco plugs you put in? The wrong plugs might be too short or too long or have the wrong electrical properties to properly ignite the air fuel ratio.

I think it was the R45TSX. R45TS8 was in the car when I got it and these are the replacements according to autozone. One of the 6 was longer and much older, but the same part #. It was stamped "made in USA" where the others weren't. I thought that had something to do with it, so I traded them all for a different set to be sure. (yeah I know I'm going to get blasted for this) Autolite platinums with an .080 gap. But it runs exactly the same as it did with the AC's (bad). From what I can see AC aren't stamped with USA anymore anyway.

jayoldschool
08-09-09, 08:44 PM
Matt, it is just in how you use the tool. You don't grab the very end of the electrode and bend, you place the tool close to the bend and gently open or close the gap. The end of the electrode will stay parallel to the center electrode if you do it right.


o I traded them all for Autolite platinums

No wonder it's running like a Ford! lol

Get those Autolites out of there, and get a matched set of original spec AC Delco plugs (properly gapped) back in!

According to rockauto.com, the AC Delco application for your car is R45TSX. Gapped at .060. I do see that other plugs call for .080 for your car, so this is obviously where the confusion is coming from...

Angry Matt
08-09-09, 09:27 PM
Why would two AC Delco's with the same part number be of different size? I understand they were obviously from two different time periods, but would this make a difference?

jayoldschool
08-09-09, 09:38 PM
If you look at the plugs on rockauto, you will see that Delco number replaces lots of older numbers. That's what happens: old designs get superseeded by new ones.

Angry Matt
08-09-09, 10:21 PM
I understand that, I'm wondering if having one longer plug and five shorter will make it run goofy. That's what they sold me. I didn't notice because I took them out of the boxes as I was putting them in the car.

sven914
08-09-09, 10:24 PM
According to AC Delco's web site (http://parts-catalog.acdelco.com/catalog/catalog_search.php) your Buick 6 takes #2 or #41-826 plugs.The R45TSX is also listed, but there is no vehicle list, so I think that is just the universal plug.

Angry Matt
08-09-09, 10:31 PM
It also says R45TSX with the .060 gap. The motor calls for an .060 gap. What's the difference from the #2? I really getting confused.

Angry Matt
08-09-09, 10:39 PM
I found this site somehow. I don't know much about it but it's got some interesting info.

http://www.motorera.com/Cadillac/cad1980/CAD81.HTM

It's got the tune up specs and it calls for the R45TSX.

Could this even be my problem? I was thinking it was a vacuum leak.

jayoldschool
08-09-09, 10:40 PM
You're really over-thinking this. Get 6 matched AC Delcos in there with the correct gap.

Angry Matt
08-09-09, 10:51 PM
Thanks for calling me on that. I do this all the time. I'm going to do a bunch of stuff to it tomorrow, I'll let you know if it fixes it.

sven914
08-09-09, 10:56 PM
Having that one plug that was wrong could have been your source problem (who knows that one could have been right and the other 5 wrong); like I said before, spark plugs that are too long or too short cannot ignite the air fuel mixture properly.

And motorera is wrong about my plugs (R44LTS6 according to them, but 41-630 according to AC DELCO).

Bro-Ham
08-09-09, 10:56 PM
I'm saying a prayer for your car tonight Matt - - it will be OK! Dave :)

Angry Matt
08-10-09, 08:17 PM
Thanks Dave, it seems to have worked. I changed the cap, rotor, egr, and plugs today. I disconnected the vacuum solenoid to the egr and ran a straight line to it. It ran ok, no sputtering, but didn't feel right. I got home and went to back in and the idle started surging like crazy and stalled twice. I started it and let it surge, pinched the line to the egr and it stopped. So I plugged the egr and it runs great. Will not having an egr have any negative effects other than emissions? And where is the vacuum for the egr supposed to come from? It's from the booster, but obviously doesn't function right without the solenoid. Maybe I can tie it to a manifold line where it would get less vacuum? The solenoid I think isn't going to be easy to find and I'd just as well not use one.


And motorera is wrong about my plugs (R44LTS6 according to them, but 41-630 according to AC DELCO).

Thanks I'll keep that in mind before I refer to that page for anything.

sven914
08-11-09, 02:38 AM
If the EGR is routed through a solenoid, then it is semi computer controlled. Routing it to another source probability wont help because it will still be getting vacuum at the wrong time. The way it sound is that your EGR opens with vacuum, which is highest at idle (deacceleration actually but who cares), which is the worst time to have EGR flow. EGR flow is supposed to happen at cruising speeds.

I can't really see anything too bad happening from disconnecting the EGR valve, until you get the solenoid.