82 Spider not running well

[harvfiat1]

I have been working on my 82 Spider. After doing a transmission rebuild I installed a new timing belt,
water pump and bearing. I am in alignment with the crank notch (0 degrees), cam pointers all with the rotor pointing at #4. Replaced the #1 fuel injector.
The car starts right up and idles nicely but not
totally smooth. Fan turns on and off and cycles
properly. It is drivable but is not anywhere near
Proper power levels.
I feel good about the timing and tuning of the engine. The timing light has me at (10 degrees).
My thoughts are maybe I am dealing with a major
Air/vacuum leak.
When I picked up the car I drive it from Nc
To Ny 500 miles without any issues. I am sure
This is a case of shooting myself in the foot.
Any theories about solving this would be appreciated.
Harvey

[So Cal Mark]

if you had the cam sprockets off, are you sure you didn't swap them?

[harvfiat1]

Thanks for the response.
The sprockets were not removed.
Back to the drawing board?

[narfire]

Perhaps while idling, pull a spark plug lead off one at a time to see if an change. No change from that, perhaps try the same with the injector leads.

[harvfiat1]

I found a Possible reason for the roughness.
I was looking at wires under the coolant overflow
Tank and noticed a disconnected black wire
That is supposed to be connected to a green wire.
What is the effect of disconnecting the Lambda
Sensor on runability?

[RRoller123]

The sensor makes minor adjustments to the air/fuel mixture after it reaches operating temperature (400F I think it is), so it would be likely that you would notice a difference. The question I guess is why it would be disconnected, possibly a PO thought that the sensor was bad and rather than replace it just disconnected it? The sensor is not too expensive, and easy to replace. It can be tested easily too. It should produce an average of about 0.45VDC when the engine is fully warmed up. Can be checked with a voltmeter. The readings will jump all around like a puppy but the average should be around a half a volt.

[harvfiat1]

I did a compression test today.
The results show a reason for bad
Running as I am experiencing.

#1. 150
#2. 40
#3. 40
#4. 150

Blown head gasket?
Anything else to consider?

[jfrawley]

Same numbers on my '82 a couple of years ago. Blown headgasket between #2 and #3 was the cause.

JF

[spider2081]

A head gasket can fail at any time. So that is a possibility. I think improper valve timing can also cause a poor compression tests. You can easily recheck cam position by removing the rubber buttons from the thin metal cover behind the cam gears and timing belt. There is a raised line cast in the cam box looking through the hole where the rubber button was, that line should be inline with the hole in the cam gear. If it is the cam should be in the correct position.

Did you hand rotate the engine 3 or 4 t full rotations to be sure timing marks stayed as you set them???

[cyber104]

If you run a leakdown test on #2 and leave the sparkplug out of #3 you will be able to verify if it is a head gasket problem. Pumping air into #2 will cause air to come out of the sparkplug hole on #3 provided all valves in those 2 cylinders are closed.

If you can't get all the valves to close simultaneously, then a simple leakdown test on either #2 or #3 will also give you a pretty good idea.

The fact that #1 and #4 have good readings and #2 and #3 are very low leads me to believe that either your valves are hanging up in those 2 cylinders due to improper adjustment/shimming or you have a head gasket or ring problem. A previous poster mentioned mixing up the cam pulleys - that is a common problem that folks run into especially if they were trying to swap out an old plastic gear for a metal one. However, you state that those pulleys were not removed or replaced.

Out of curiosity - did you check the timing alignment marks before you changed the belt? I've seen folks use 2 intake or 2 exhaust pulleys and make it work - but the marks don't line up. Experienced mechanics can simply set the cam timing using other means other than the alignment marks.

Hope this helps

[So Cal Mark]

the fact that 2 cylinders show normal compression proves that the pulleys are correct

[harvfiat1]

Multiple hand rotations of the engine with new
belt applied. While at idle the timing light put the crank notch at 10 degrees. The cam marks
were right on the money as well as on the timing light strobe.
When I adjusted the valves I checked clearances
after adding appropriate shims many times.
The clearances were all in proper range. My next
step prior to head removal will be to,one more time,
verify the valve clearances.