When I open the engine compartment when its dark, I can see the exhaust manifold glowing red. I've heard this could be caused by several things. I'm assuming this has happened to other Fiero owners?
My 87 GT does it (mine is more of an orange color). It could be a clogged cat, bad EGR Valve or tube, vacuum leak somewhere, ignition timming, cracked manifold...there are probably more that I either forgot or am unware of !
Mine does it only on the trunk side manifold and it has to be pitch black for me to see it glowing.
I have replaced the EGR Valve, didn't find any vacuum leak (this doesn't mean there isn't one...I just can't find it if there is), checked and reset my timming, checked the manifold for any cracks ect.... and it still glows slightly at night time (only patches glow orange...not the whole mainfiold) It seems to get worse (more orange) if I really abuse the throttle but there is even a hint of orange if driving normal. The only thing I think it could be is the CAT but then I would think they both would glow (not unless they are and I just can't see the other one well enough to see the glow)!
Heck if I replace the Cat and it still does it i'm gonna start thinking it is normal.
------------------ Keith
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12:06 AM
FieroMGDriver Member
Posts: 961 From: Concord, NC USA Registered: Nov 2001
Thanks Keith. I have an 87 GT also and I have a new EGR valve and a new CAT, so who knows. Maybe its not hurting anything, but it makes me uneasy with my plug wires so close. I think I might get some heat wrap tape to go over the manifold.
Just thought I would mention that it is not normal (I just said that). There are people that don't have the glowing problem but I have invested so much time in this little problem that I have all but given up.
My next step (ohh god I hate to do it) is to take it to a garage and have them trouble shoot it.
Is there anyway to check if the cat is bad (I don't have a rotten egg smell....that some say is evident when the cat goes). I do however have a very strong exhaulst odor that is almost overpowering when standing behind the car!
Edited in: I do think engine damage can result from running it like this to long.
------------------ Keith
[This message has been edited by camon (edited 11-14-2001).]
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12:52 AM
FieroMGDriver Member
Posts: 961 From: Concord, NC USA Registered: Nov 2001
The only reason I knew my CAT was bad is that it rattled like crazy and my car wouldn't pass emissions. After I got a new one, my car had much more power. My old one must have been clogged. I'm not sure about any smell. If you don't have emissions testing, I would just take it off. Also, if you are interested in getting more power, the stock CATs are very restrictive even when functioning properly.
If a cat is rattling, usually that means that it is partially burned out or on its way. The stuff that burns out usually blows through to the muffler and will either partially of fully plug the muffler thus moving the restriction from the cat to the muffler. Camon, if you are getting a strong exhaust smell with no hint of sulfer, then either you don't have a cat or it is totally burned out. If it is #2 then you will need to verify that your muffler is not plugged (even partially). The rotten eggs smell is a slightly to fully lean engine with a properly working cat. A stronger (non rotten egg) sulfer smell is an indication of a slightly to very rich engine with a working cat. There's a notable difference to exhaust with a non-working or missing cat. That smell will give you a headache or make you sick in a short time.
A restriction in either place will cause the pressure to increase in the manifolds and the heat build-up may even cause the manifolds to glow. Other things that can cause them to glow are: lean engine (either by vacuum leak or ecm/engine tuning, O2 sensor etc), overly rich engine whereby the exhaust is significantly still burning after it leaves the combustion chamber, slightly burned exhaust valve (causes a blow torch effect), thin exhaust manifolds, turbo and I'm sure there are a few more. GL
[This message has been edited by 87GTZ34 (edited 11-14-2001).]
I think I will just take it some where to get it looked at. I have invested like 3 weeks in this problem and have hardly made any progress. If it is a vacuum leak I can't locate it. If it is a CAT problem then it will need to go to the garage anyway to get a new one put on. Hopefully it isn't a burnt valve problem (don't feel like an engine overhaul). Will a compression testbe able to tell if this is the case. What should the compression read on my compression gauge?
My timming is to the best of my ability spot on. I set it by grounding the ACLC a & b pins and schecked wire #1 brought the timming mark to the 2nd hash mark (going clockwise) on the timming plate (I was told that is the 10 degree hash) then did the same for #4 wire. So I believe the timming is on (if the hash I was told is in fact the 10 degree mark).
I had the same problem in mine and it started overheating and fouling out the spark plugs. I dropped in a new engine and it had the same problem. I finally replaced the EGR valve, Cold start Switch, Coolant Temp. Switch and Throttle position Sensor all at once (I got tired of cleaning the plugs after every fix). Now it runs fine, no problems.
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03:12 PM
tesmith66 Member
Posts: 7355 From: Jerseyville, IL Registered: Sep 2001
Been there, done that. You probably have a cracked EGR tube (the tube that runs from the EGR valve to the underside of the intake plenum). It's a hard one to diagnose because the tube is wrapped in that heat blanket stuff.
You can get a replacement from several sources (Fiero Store or West Coast Fiero are all I can think of right now...), or (like I did) go to the boneyard and get one from a 2.8 liter Firebird or Camaro. All you have to do is elongate the bolt holes on one end and it will fit. Cost $1.00, plus the fun of junkyardin' for the day!
You might as well get an extra while you're there.
P.S. If you let this go too long, you could start a fire or burn some exhaust valves(like I did)
------------------ Timothy E. Smith 1986 SE V6 1984 Coupe
[This message has been edited by tesmith66 (edited 11-14-2001).]
[This message has been edited by tesmith66 (edited 11-14-2001).]
On the v-6 the tube runs from the egr valve to the underside of the intake plen. it is under the IAC and TPS and just to the left of the Dist. Cap. and travles up to the underside of the intake. Hard to miss..
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03:08 AM
RossT Member
Posts: 3038 From: Bismarck, North Dakota Registered: May 99
I just replaced mine. I took of the Dist, cap and rotar to get at it. I used one of those new 10mm sockets from sears. I think they call it a box wrench socket. Kind of like an open end wrench, but it ratches?? like a regular socket.
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03:11 AM
tgowens Member
Posts: 2496 From: Somewhere in my Fiero, of course! Registered: Apr 2000
FieroMGDriver, there are two things that could cause a glowing manifold - either a massive vacuum leak or a faulty fuel injector....... if you have checked all of the vacuum lines and the EGR system and all is well then I would suspect a faulty injector......
If you have a clogged cat you also usually have a loss of power -- you can tell when the cat clogs up!!
Personally, I wouldn't put heat wrap over the manifold...... moisture gets in and is trapped and will rust out the manifold quicker......
camon, your compression looks fine -- + or - 10% from cylinder to cylinder is within normal range.......
[QUOTE]Originally posted by camon: [B]Question.....
If the EGR tube is at fault would the EGR Valve still operate (diaphram move up) when the throttle is applied? Mine does!!!
Yes, the EGR valve will operate normally. A cracked tube will cause a massive vacuum leak, which will lean out the mixture and raise combustion temperatures dramatically. The results are unstable or erratic idle, high idle speed and glowing manifolds. Long term affects are burned exhaust valves (ask me how I know this) and frayed nerves.
------------------ Timothy E. Smith 1986 SE V6 1984 Coupe
Am interested in knowing how this turns out. The cracked EGR tube sounds like a real possibility. Please update if you identify and remedy the problem.
Well I will check the EGR tube on Saturday. This could very well be the problem then. I was thinking that if the EGR Diaphram worked then the EGR system was working properly. But seeing that a faulty tube will still allow the EGR to function then this just may be my problem.
Also thank for the compression response. I thought the numbers looked OK. I just wanted to verify it!
I will post after I check and/or replace the EGR tube on Saturday night after I get to check the manifold for glowing!
Thanks again!
------------------ Keith
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12:50 PM
tesmith66 Member
Posts: 7355 From: Jerseyville, IL Registered: Sep 2001
