1 gen 2.8 mpfi rants & questions

[X11_STE]

Kinda got a few things going on w/ my '87 Celebrity VR. First about a month ago was having problems with stalling and jerking. My mech. tells me its a bad EGR valve thats causing the MAP sensor to read off. OK, I went ahead and bought a new valve ($200) but didnt have the money to have him put it on (I could do it myself, just dont *want* to). Then one night in a po'd mood on the side of the road, I disconnected the the MAP sensor (EGR was previously disconnected). Since then the car has been running GREAT! (I hope this doesnt jinx me). So I'm wondering if I really should have the valve & sensor r&r'd. Im pretty sure the gas mileage might suffer a little & the SES light stays on, but big whoop.

The other big issue(s) I'm having is the motor started making really bad growling sounds. Then the temp gauge started acting weird pegging out to max then going to the 220 mark going around a corner then back again. But the car never drove like it was overheated. After much diagnosing (including a rubber hose!) I determined that the a/c compressor clutch/ pulley was failing. What little driving I did after that, I kept the a/c on (though the rest of the system doesnt work). Kept the growling down while I waited for the a/c bypass pulley to come from Tn. Today I pulled the compressor off & found the pulley had 1/2" of slap in it!!!! As I was installing the bypass pulley I found they forgot to include washers & nuts!!

Afterwards, I decided to check out the cooling system. Found the rad. to be weeping a little. Dang! Does anyone know where I can get a new HD rad. with the brass tanks? All I can find is plastic and for me that just wont do. After pouring 1.5 gallons of coolant into the rad, I went for a drive. Drove like a brand new car!! I mean, you couldnt hear anything from the engine until 2500rpm. Then it just purred. But the temp. gauge is still reading way high. Any ideas?

OK, off my soap box and getting back to overhualing the brakes (another long story I dont want to get into).
Jeremiah

[armos]

The MAP sensor is definitely either faulty or confused, as indicated by the fact that it runs better when you unplug it. When you unplug it the ECM will ignore the sensor completely. When it's in that mode, it uses rough plugged in values to take the place of the sensor, and it will run rich this way. This will hurt your gas mileage and over the long term could hurt the catalytic converter.
However, a MAP sensor that reads incorrectly can have that same effect of running rich, so if it runs better unplugged I'd leave it that way until you find the solution.

The MAP problem could be caused by a vacuum leak in one or more of the plastic hoses. The MAP sensor needs to read air pressure in the intake and a vacuum leak in the system will mess that up. Especially make sure the vacuum hoses that lead to the MAP sensor are in good shape, but others also matter.
I'm not sure how a bad EGR valve could be confusing the MAP sensor, unless it's leaking to the outside air somehow.
You might have a vacuum leak in the hose leading from the EGR valve to the underside of the neck of the intake manifold. That hose very often cracks open, so that might be what the mechanic was talking about. This is a common failure and can cause a significant vacuum leak.

If you can't find a vacuum leak, then I'd try a new MAP sensor. I don't remember exact prices but they aren't real expensive, something like $40 at RockAuto I think. I haven't worked on a Celebrity but it should be easy to replace, I have the same engine (L44 2.8 ) in a Fiero and the MAP sensor is just sitting there easy to get to.
The factory service manual doesn't offer much tips about diagnosing the sensor itself, it just says to replace it if it appears faulty.

I'm a bit worried the mechanic might have seen an EGR error code from the ECM and just assumed that had something to do with the MAP problem. If so, it's unlikely they're related, and usually an EGR error on this engine setup is caused by the EGR solenoid which controls the EGR valve, not the valve itself.


Wild swings of the coolant temperature are normally caused by lack of flow or low coolant, so it makes sense with the radiator leak you found. I'd probably remove the thermostat for now if it's easy to reach. That way an air pocket won't cause it to close, and since it will be open constantly you'll have more time before it gets hot. Be careful not to let it get too hot or much more difficult problems will bite you.

I don't know much about the supply of radiators, I bought one for my car a couple years ago but it had the plastic tanks.
There is an all-aluminum Champion radiator on eBay that some people have been putting into Fieros. But it requires some slight hacking to make it fit. I don't know if they have one for the Celebrity or not, but maybe you'd want to look into it. Who knows, it might even fit your car without needing to hack stuff up.
Here's a discussion about the Fiero one:

http://www.fiero.nl/forum/Forum2/HTML/124495.html

[X11_STE]

Cool, thanks, I will check into those areas.