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Manifolds are cherry red by michael910
Started on: 04-13-2008 07:26 PM
Replies: 22
Last post by: svocal on 04-15-2008 04:15 AM
michael910
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Report this Post04-13-2008 07:26 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
I have a 1987 fiero 2.8 liter and was wondering what would cause the manifolds to be cherry red after only running less then a minute? I replace the egr valve cause it was broken and sprayed carb cleaner in the egr tubeand I also cut off the cat converter and ran a flex pipe until i get it welded back on still it idles around 2000 rpm and manifolds and cherry red. looking for help

[This message has been edited by michael910 (edited 04-13-2008).]

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fierogt3800
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Report this Post04-13-2008 07:27 PM Click Here to See the Profile for fierogt3800Click Here to visit fierogt3800's HomePageClick Here to Email fierogt3800Send a Private Message to fierogt3800Direct Link to This Post
clogged cat
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michael910
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Report this Post04-13-2008 07:43 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
Thanks but I forgot to mention that I cut off the cat and ran a flex pipe until i get it back on still having the same problem
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jimbolaya
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Report this Post04-13-2008 07:46 PM Click Here to See the Profile for jimbolayaClick Here to Email jimbolayaSend a Private Message to jimbolayaDirect Link to This Post
If the cat is removed, then I guess it can't be clogged so that means you are running lean. Too much air and not enough fuel. Possible culprits are clogged or leaking injectors (this should be accompanied by a rough idle because one cylinder is not firing equal to the others) clogged fuel filter, weak fuel pump or some clog in fuel lines. there are other causes I'm sure but I can't think of any at the present time. Good Luck and Welcome.

Jim

[This message has been edited by jimbolaya (edited 04-13-2008).]

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michael910
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Report this Post04-13-2008 07:50 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
Thank you I will check and let you know what the out come is
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pswayne
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Report this Post04-13-2008 08:06 PM Click Here to See the Profile for pswayneClick Here to Email pswayneSend a Private Message to pswayneDirect Link to This Post
Sounds like you have a vacuum leak.
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michael910
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Report this Post04-13-2008 08:08 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
how can I check to see if it is a vacuum leak or do I have to take it to the shop
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jimbolaya
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Report this Post04-13-2008 08:11 PM Click Here to See the Profile for jimbolayaClick Here to Email jimbolayaSend a Private Message to jimbolayaDirect Link to This Post
 
quote
Originally posted by michael910:

how can I check to see if it is a vacuum leak or do I have to take it to the shop


I don't have a V6 but I read here that most often a leak is in the vacuum lines that run under the Plenum (that red thing that says Fiero on the top of your engine) The lines are made of some type of plastic that can become brittle and break after 20 years.

Jim
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terr5178
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Report this Post04-13-2008 08:56 PM Click Here to See the Profile for terr5178Click Here to Email terr5178Send a Private Message to terr5178Direct Link to This Post
I had this problem on another car, I later found out that it was the ecm. It controls the fuel mixture and was dumping too much fuel into the engine. I had to replace the ecm computer. Don't try to drive the car like this the excess heat will ruin your headers/ exhaust manifold and gaskets and can warp the heads and burn up your head gasket. To check for vacuum leaks i uses a !/4 inch copper tube about 2 feet long and listen to the engine through the tube. It works like a doctors stethiscope. You can pinpoint a leak over the sound of a loud engine. Although I don't think that is you problem.
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michael910
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Report this Post04-13-2008 09:05 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
Is there a way for me to test or have the ecm tested to see if its bad before buying one
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Jefrysuko
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Report this Post04-13-2008 09:37 PM Click Here to See the Profile for JefrysukoSend a Private Message to JefrysukoDirect Link to This Post
 
quote
Originally posted by michael910:

how can I check to see if it is a vacuum leak or do I have to take it to the shop


Check the EGR line between the Plenum and EGR valve. That is the most common cause and is also commonly misdiagnosed by shops and those who choose to do the work themselves. Usually the break is hidden by the heat wrap that is arround it.

If it needs replaced the braided one from Fiero Store is probably the best replacement currently on the market.
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pswayne
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Report this Post04-13-2008 09:43 PM Click Here to See the Profile for pswayneClick Here to Email pswayneSend a Private Message to pswayneDirect Link to This Post
With the engine running, but not warmed up (you don't want to burn yourself), grab the EGR tube and try to move it. If you hear a hissing sound that changes as you move the tube, it's bad and must be replaced.
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Raydar
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Report this Post04-13-2008 09:49 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarDirect Link to This Post
I'm a little bit late to the party, but second the broken EGR tube (most likely cause) or another vacuum leak.
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Dennis LaGrua
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Report this Post04-13-2008 10:30 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaDirect Link to This Post
Is your engine idling higher than it should? A sure sign of a vacuum leak. To find a leak use a spray bottle and spray water around all the vacuum lines. If it slows then you've found the leak. If it is idling normally then a clogged injector or two could be the culprit

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buddycraigg
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Report this Post04-13-2008 10:35 PM Click Here to See the Profile for buddycraiggClick Here to Email buddycraiggSend a Private Message to buddycraiggDirect Link to This Post
he has a 2000+ idle, the exhaust manifolds are glowing.
the EGR pipe has been blocked off at the plenum.

i have suggest that he try to stall the engine by putting his finger over the hole in the throttle body for the IAC.

let's see what his response is.
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fieroman87
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Report this Post04-14-2008 12:07 AM Click Here to See the Profile for fieroman87Click Here to Email fieroman87Send a Private Message to fieroman87Direct Link to This Post
i'm betting on impropper timing... i say this because this is the same symptom my 2.8 exhibited when the timing was off/out

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michael910
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Report this Post04-14-2008 07:26 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
I had one or two cracked lines that i repaired now the idle is low but it wont stay running. I cant tell if the manifolds are still cherry red or not but i'm guessing now the timing is off
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rcp builders
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Report this Post04-14-2008 09:00 PM Click Here to See the Profile for rcp buildersSend a Private Message to rcp buildersDirect Link to This Post
timing being advanced to much will cause both cherry red exhaust and stalling g/l
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michael910
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Report this Post04-14-2008 09:02 PM Click Here to See the Profile for michael910Click Here to Email michael910Send a Private Message to michael910Direct Link to This Post
ok so it might have jumped timing then and now thats causing the problem cause before it was idling around 2000 rpm
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30+mpg
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Report this Post04-14-2008 09:29 PM Click Here to See the Profile for 30+mpgClick Here to Email 30+mpgSend a Private Message to 30+mpgDirect Link to This Post
Use "Search" for "Glowing manifolds"
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Jefrysuko
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Report this Post04-14-2008 11:26 PM Click Here to See the Profile for JefrysukoSend a Private Message to JefrysukoDirect Link to This Post
 
quote
Originally posted by michael910:

ok so it might have jumped timing then and now thats causing the problem cause before it was idling around 2000 rpm


If your idle dropped you most likely fixed your vacuum leak or enough of it to drop the temps in your exhaust and eliminate the red hot manifolds. Now you should worry about setting the timing. Do a search or refer to a service manual to find the correct procedure.

One thing to note about the procedure for setting the timing is that the car should be up to full operating procedure which might be hard for you since the car won't stay running. Grounding the connector changes the timing to a set value which might help the car to stay running if so just let it sit there and warm up and then set the base timing. If the car won't stay running with the ALDL connector grounded do your best to get the timing close even though it isn't up to temp such that it will stay running long enough for it to come up to temp.

Once I realized that the car needed to be up to temp while setting the base timing I noticed a big difference in both fuel mileage and simply the way the car ran.
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Report this Post04-15-2008 02:39 AM Click Here to See the Profile for FI3RO85GTClick Here to Email FI3RO85GTSend a Private Message to FI3RO85GTDirect Link to This Post
I had that EXACT same problem on my v6. It was a cracked lower intake. If if gets that hot that fast id start looking there
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svocal
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Report this Post04-15-2008 04:15 AM Click Here to See the Profile for svocalClick Here to Email svocalSend a Private Message to svocalDirect Link to This Post
I had the same problem on my 86 Fiero after it was rebuilt. It turned out to be one of the cylinders wasn;t firing and fuel was dunping down the exhaust. It actually melted the cat. Replaced the spark plugs and had fuel mixture rechecked.

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