Odd cold starts

[Nixon1]

Just curious what might cause this.. When I start the car on a cold engine, right after it starts, the rpms immediately drop down to around 600 and the car gets REALLY lopey....like it has a huge cam, or it's about to stall. Stays there for around 2 or 3 seconds, then the rpms kick up to around 1600 and sit there.....beyond that, everything is completely normal besides a few minor operating demons I've been trying to exorcise since I got the car. That sounds like a slightly malfunctioning sensor or something to me..what could be the causes? TPS is brand new, and so is the IAC valve assembly. I have no clue about the EGR though. Thanks everyone.

[PKRWUD]

Just out of curiosity, did you reset your ECM after installing the IAC?

[Nixon1]

ALWAYS. After EVERY sensor I change out. ECM's been reset SEVERAL times after the IAC installation...most recently for two brand new O2 sensors.

[PKRWUD]

Get a hand vacuum pump, and when the engine is cold, attach it to the EGR valve (plug the EGR vacuum hose), and apply and release vacuum to it several times. Make sure it moves when you do, and make sure it holds vacuum at the same time. After doing this a few times, start it and see if there's a difference. After the idle settles, try applying slight vacuum to the EGR until it starts to stumble. Is this the same stumble it has at cold start-up?

[Nixon1]

I'll pick up the vacuum pump as soon as my broke @ss can afford to buy one. I just bought a fuel pressure gauge.....decided to forego the compression gauge because I already know which cylinder is down and I know exactly why (exhaust valve sticking open on cyl 8...exhaust on driver's side, from muffler, reaks to holy hell of unspent gas)...

I'll make sure to make another post with results if I get the vacuum pump. Thanks man...that's a useful tip there!

For future reference, are there any steps to disabling the EGR on these cars besides buying the EGR blocker plate, removing the valve assembly, and plugging the vacuum lines? On GM cars, the computer throws check engine lights constantly for the EGR if you do that and in some cases, the computer throws a complete fit and the car acts up real bad. I definitely don't want that!

[PKRWUD]

A functioning EGR system won't rob a single hp from you, so fix it and leave it. IMO.

I answered several posts in here last night, including one about a bad header gasket. If that was you, did the gasket go bad on cylinder #8? It sounds to me like you have a burned exhaust valve.

[PKRWUD]

Okay, nevermind, it wasn't you. It still sounds like a burnt exhaust valve. lol. you didn't happen to have a blown header gasket for a while, did you?

[Nixon1]

All of my header bolts on both sides were loose for a while. I got most of them tightened, but there are a few that I cannot tighten because, as far as I can see, it's physically impossible. A ratchet is far too big to fit on there, and a wrench won't clear the header tubes.

The valve is ticking, so I'm basically positive that there's SOMETHING wrong with the valve. In addition to the nasty exhaust smell on the driver's side exhaust pipe only, the compression on cylinder 8 is only 125 psi.

[PKRWUD]

Okay, Nixon, I'm going to share with you one of my favorite little tid-bits. Go to Sears and buy, or, if you already own a Craftsman 200 piece tool set, you've already got... A set of Ignition Wrenches. They are small, and fit into a little plastic pouch. There are two kinds; one set is nothing more than very thin and short combination wrenches. The other set is also thin and short, but both ends are open end wrenches. One, however, is cockeyed. Find the one that has a cockeyed 3/8" end, if your header bolts are typical. You will then have the one tool, on Earth, that beats all header bolts into submission. It gets them all, and it makes it a snap. You want the one in the middle in each of these pics. The second pic shows how thin these are, but they are TOUGH!

[PKRWUD]

Go get a set.

[Nixon1]

So I need the crooked-end 3/8ths huh? I'm not sure if my bolts are standard-size, but I assume they are... I know an 11mm wrench does the trick..I forget what that converts to in standard. The headers are the only bolts on any car I've worked on so far that I've used a standard wrench on... Everything I've dealt with has ALWAYS been metric, and USUALLY 10 or 12mm.

And THANKS dude! Seriously.. I've been trying to dream up ways that the people who installed those could have possibly tightened them at all for weeks now and I haven't come up with anything... Time to haul butt over to Sears now! My gramps gave me a set of ignition wrenches, but there's nothing special about them...they're just a bunch of wrenches in really, really, really small sizes.

[PKRWUD]

Traditional header bolts are what would normally have a 7/16" head on them, but for clearance, have 3/8" heads on them. However, if you are using an 11 mm, then you have a 7/16" head on your header bolts. That's gonna make accessing them a pain, too, although the 7/16" ignition wrench makes it easier. You might want to break down and spend $15 and get a set of ARP header bolts.

Either way, buy the set of ignition wrenches. What's funny is that they have added those to their 200 piece tool sets forever, and hardly anyone ever uses them. Almost every time I turn someone on to this little header bolt tool trick, the other person slaps their forehead and tells me they've had a set of those wrenches for years, and never knew what to use them for. lol.

There are very few things in this world that are as rewarding as the feeling you get when you suddenly discover the "right tool" for a PITA job.



Take care,
~Chris

[Nixon1]

Oh yeah. I'd believe you there, man. Now, here's another question-how do they expect me to get a torque wrench on those header bolts to torque them to specs when the tubes practically wrap loops around any points of access? I'm just going to do what I did before...which is tighten it until I feel it's tight enough that it won't easily loosen but where it's not going to freeze up and cause me to strip the bolt or anything trying to remove it. Works for me.

[PKRWUD]

Set up another bolt the same size somewhere else, and use your torque wrench on it. Then try to tighten it further with the ignition wrench, and pay attention to how much effort it takes you to get it to move. That's about how tight you have to tighten them.



Take care,
~Chris

[Nixon1]

How very scientific of you. I think a guesstimate will work here for now... Screw the valves anyways...the heads are already toast! ALTHOUGH, the car ran good again tonight....was slow at first then the ticking stopped. I took her down my street without it ticking. Ok...first gear was lightning. I hit 2nd gear and I swear to god the kick was STRONG.....put me back in my seat. Felt like I had been in a slingshot...the damn thing ROCKETED. ::Sigh:: Too bad it doesn't run like this all the time.