mrpoopie

iTrader: (1)

Hey guys, I have a 91 NA, and the problems I am having are:

- I have to crank the car a couple times to keep the engine running cold.
- Once it warms up, it doesn't keep a constant idle. RPMs fluctuate approximately 100 RPMs up and down.
- I am having hot start issues. Most recently, I warmed up the car, made a short stop, and had to crank the engine multiple times within a 15-20 minute period to get it started again to drive home.

Last night, I ran a compression test, as you can see below. Is the engine's compression too low ? If so, is that the likely cause of the issues I am having?

The first two videos are for the front rotor, and the last video is for the rear rotor.

http://s7.photobucket.com/albums/y27...t=IMG_0181.mp4

http://s7.photobucket.com/albums/y27...t=IMG_0182.mp4

http://s7.photobucket.com/albums/y27...t=IMG_0183.mp4

jjcobm

iTrader: (18)

It has compression of a tired engine but still good enough to run fine. 100 RPM fluctuation is ok, but this and the other issues tell me you have possible leaky injectors. Not too sure by what you mean cranking the engine a few times to keep it running cold? It sounds like the same "hot start" issue, only when cold starting correct? If so, leaky injectors.

SirCygnus

iTrader: (1)

what part of atlanta do you live?

mrpoopie

iTrader: (1)

So leaky injectors can cause this ? How would I go about finding out which injector is leaky?

What I mean is, if I crank the engine the first time on a cold start, it will stay on for about 7-8 seconds to die. I then have to crank the engine again, and then it will usually stay running.

Is it a possibility that when I try and hot start, that I am not getting enough pressure in the fuel lines, maybe caused by a failing fuel pump?

mrpoopie

iTrader: (1)

Smyrna, not too far away from Cumberland Mall.

mrpoopie

iTrader: (1)

Bump

SirCygnus

iTrader: (1)

test things before you figure out what you need to do. leaky injectors? test. fuel pressure issue? test that.

mrpoopie

iTrader: (1)

How do I test for leaky injectors?

I'm guessing for both a fuel pressure gauge would do the trick? For leaky injectors, see if there's a loss in pressure and for testing fuel pressure test and see if there is proper pressure going through the fuel lines?

SirCygnus

iTrader: (1)

yup. simplest way to test is to tap into the fuel line coming out of the fuel filter and put a gauge right there. crank the car. it should have pressure, and hold it. not for ever, but if it says 35 psi or something arbitrary, and you walk away for 5 minutes, it should still be at the same psi.


also, your compression is fine.

just do a general tune up and send the injectors out to be cleaned.

SpikeDerailed

iTrader: (7)

Just out of my own curiosity how many miles are on that engine?

mrpoopie

iTrader: (1)

Around 135,000 miles.

mrpoopie

iTrader: (1)

Cool. I will give that a shot when I pick up a fuel pressure tester from Harbor Freight.

I've already replaced the spark plugs, spark plug wires, coolant flush, and oil change. Hopefully that should be enough.

One other thing I noticed is when I fill my radiator overflow tank, after I drive the car around, the coolant in the overflow tank disappears. Should I be worried about this?

SirCygnus

iTrader: (1)

i would check all the sensors to make sure they are in spec, and i would go ahead and send off the injectors to get cleaned. replace all the hoses and gaskets.

everything down to the engine block that can be replaced, will be.

also, i would run premix. i have a weird thing about me that says engine oil should not be burned in a combustion chamber.

mrpoopie

iTrader: (1)

Sensors have been checked, and all hoses, and lower and middle intake gasket has been changed.

I am premixing for this tank, since I had to replace the ECU and MOP since the MOP fried the ECU.

I will have the injectors cleaned when I find some time.