Compression test results and long start

[StealthyStu]

My car has developed a delayed start problem. It can take up to 10 seconds of cranking before firing. The problem developed over the course of about 2-4 weeks.

I have changed the spark plugs, inspected the wires, checked my fuel system, and lastly, done a compression test. The results were not good.

Cylinder 1: 95
Cylinder 2: 80
Cylinder 3: 95
Cylinder 4: 90
Cylinder 5: 95
Cylinder 6: 85

I have a '91 turbo. The service manual claims that ideal compression is 135 psi, and the lower limit is 115 psi.

Alex3000gt and I poured some oil into 2 of the cylinders to see if the compression numbers would go up. One had no response (remained at 85 psi) and the other jumped from 80 psi to 90 psi, indicating the piston rings were not creating a great seal, but that the valves could still be more of a problem. Surprisingly, the car still makes pretty decent power.

Are my compression numbers leading my car to take forever to fire up? (after these results I'm personally surprised that my car starts at all)
Any guess on how long I can continue to run before the compression numbers get so bad I can't start or my starter needs to be replaced?

Thanks for the feedback.

[stealthee]

10 seconds of cranking before firing sounds fuel related. I had horrid compression on my TSI after leaning out. About 60psi per cylinder, yet it fired almost immediately. You need to check your fuel pressure for your starting problem. For the compression, its odd that every cylinder is so consistently low. You may want to do further testing before concluding you have internal problems.

[StealthyStu]

Thanks for the response stealthee. Here's some more info:

I have a a fuel pressure gauge mounted in my engine bay and it sees plenty of pressure. We even went so far as to clamp the return line which caused the fuel pressure to rise to about 90 psi and it still didn't help the delayed start. Also checked for leaky fuel injectors by removing the plenum and priming the pump. No leaks.

As for the low compression, we checked the results with another gauge and found they were consistent. I don't know how to justify the consistency other than it's old lol

Thoughts?

[anyonebutme]

check time?

[StealthyStu]

Good thought anyonebutme. We checked that as well and the 4 cam gears on top are all on time. We assumed the crank was in the right spot too

[anyonebutme]

I wouldn't assume....you don't have to pull the covers to check.

[Chris@Rvengeperformance]

why don't you try another tester. It is weird for the numbers to be low, but so consistent.

[StealthyStu]

I'm putting a new Walboro 255 in tomorrow. The check valve in the current pump may have broken which is why the rail loses pressure immediately after the pump finishes priming.

[sublime_whatigo]

When it does start how does it run immediately? Not sure what you were looking for when you said "leaky injectors" but if they are leaking fuel into the lower intake and cylinder it can cause longs starts because of flooding.

But ya you definitely need to check the timing!!

[Primus101]

When your cams are on their marks, the balancer should show TDC-