86 fiero 2.5 engine compression issue?
I have a 86 Pontiac fiero I bought after it set for 10 years I've been trying to get to start at first I had no spark so I replaced distrubutor and finally got spark.:). But still no start... So I checked compression the first cylinder has 135 pounds the second has 65 the third has 115 and the fourth has 105... So what should my next step be?
More Questions From This User See All
Answers & Comments
Verified answer
As far as the low compression issue, the next step would be a cylinder leak down test.
http://www.carcraft.com/techarticles/116_0406_cyli...
Although, since the engine hasn't been running, you may want to squirt a little oil in the cylinders, and do the compression test again. And if the numbers get better, try starting it again. If it does start, check and clean the plugs afterward.
The Iron Duke is a good little engine, and usually very reliable, comparatively speaking.
As best as I can recall, they did occasionally have a problem with cylinder head bolt breakage (I remember finding that myself, at least once), so check if any are loose, and/or show signs of coolant leakage around the bolt head. Could be a blown head gasket caused by that.
Also a good bet if the leak down test doesn't point to the rings or valves being the problem.
_______________________________________________________
As for the head bolts, my memory would seem to be intact.
"The old Iron Duke is notorious for breaking head bolts. Not a hard job. Pop the head off, get an Easy-Out. Grab a headset and a fresh set of head bolts. Done literally hundreds in the last 20 years."
http://67-72chevytrucks.com/vboard/showpost.php?s=...
http://67-72chevytrucks.com/vboard/showthread.php?...
Wow. the fact that it hadn't run in ten years didn't discourage you, huh? Good man! There is a real good chance that all of the gaskets are rotten, and the fuel mix is not getting near the combustion chamber. Plus the fact that the 2.5's were infamous for catching on fire. So some of the wiring or ancillary systems may be toast. I think you probably have throttle body injection. if it's not working, there is a separate fuse or relay for this system. Might be in the engine compartment, or under the dash. There is a lot of FIERO info available on line, but I haven't been on those sites for a while. Jeez good luck man. I hope you get her runnin'. Oh and don't forget to check the crank position sensor, if so equipped.
I believe you should have more than that on all cylinders. More like 150+
Also, look at your lowest compression and the highest, it's almost 2X less.
I think a complete engine rebuil is called for, especially if you tried to turn the engine over without first squirting a tablespoon of oil or even LiquidWrench in each cylinder before cranking.
You might have a couple of busted rings or at least some healthy chips taken out of them.
Sounds like a bad valve in cyl. 2 But you need to check and see if you timing is right and fuel is flowing. With 3 cylinders you should get a start, even if doesn't run good.
Real Fiero Tech