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).]

clogged cat

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

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).]

Thank you I will check and let you know what the out come is

Sounds like you have a vacuum leak.

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

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

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.

Is there a way for me to test or have the ecm tested to see if its bad before buying one

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.

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.

I'm a little bit late to the party, but second the broken EGR tube (most likely cause) or another vacuum leak.

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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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

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.

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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Arty: a.k.a. FestYboy or Fieroman87
'87 GT 5 spd. (soon to be 3.6L TT 6 spd.), '88 Festiva 5 spd. rockin' a high revin' 1.6, '87 Scirocco 5 spd. (VR6 swap?)
AIM: FestYboy88L

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

timing being advanced to much will cause both cherry red exhaust and stalling g/l

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

Use "Search" for "Glowing manifolds"

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.

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

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.