Hello,

Is there an easy way of disabling ignition before turning over the engine for cylinder compression test? 1997 xj6 .....or, is the only way to disconnect the fuel line?

 

I would just remove the fuse for the fuel pump or the injectors if there is one.

 

Thanks Scarecrow. I removed the fuse and it just turns over now. One observation is that the turn over lasts for about three seconds. I probably can get a final pressure reading in one session or, might have to do a couple of them.

 

Thanks.
Measurement method worked.

 

How'd the test come out?

 

You don't need to disconnect ANYTHING. Don't turn the key ON and it won't try to start.

There is a starter wire at the back of the engine. Unplug it and use a starter button/wire with clips or a large gauge wire to energize the starter solenoid.

With the other hand you should hold the throttle OPEN during cranking.

bob gauff

 

Scarecrow, I measured 150 psi on both cylinders that are misfiring and also on a good one.

A little background, I currently get misfire on 3 and 4. This happened after I replaced spark plugs and their gaskets (due to oil in the spark plug wells). Swapping ignition coils did not resolve the issue (i.e. the problem stayed with 3 & 4). The next step I would like to do is to make sure there is voltage coming to the coils.

Bob, thank you for the information/tip on the starter wire at the back of the engine.

 

CLOGGED fuel injectors can cause misfire problems.
The fuel rail can be removed and the individual injectors can be held open with a small 9V battery and wires to blow it from the pintle side to clear the inlet screen.

Flush the rail is debris is found inside.

bob gauff

 

Bob, thanks.

Just to confirm, to clean the injectors, I would remove them and blow through them at my workbench? (Or blow through them through the supply line while installed)

Also, are there air psi considerations when blowing through them?

 

You can also send them to someone like "Mr. Injector": Mr Injector - Home

His prices are very reasonable, and turnaround is very fast. The GM3800 crowd uses him quite a bit.

.

 

Al, thanks for the info.
I will eventually send them in for cleaning.
For now, I would like to explore injectior cleaners/additives.

Any good ones out there?

 

I'm no expert, but the only one that you can pour into your tank out of a bottle that I've read is not "snake oil" and can make an actual difference is the Chevron Techron.

Others also swear by Seafoam.

However, of course no liquid pour in cleaner will unblock injectors blocked by debris that isn't soluble.


.

 

I've let a set of gummed up injectors soak in jars of GM top engine cleaner overnight with good results. These injectors were so gummed by bad fuel they wouldn't pulse. I filled a small jar about a quarter way and let the injectors sit standing up in the fluid and poured some fluid through the top of each injector and let sit overnight. Went from no crank to running fine.

 

Thanks Al and Scarecrow. I am in the process of removing the fuel injectors.

 

I bought a cheap ultrasonic cleaner from Harbour Freight and that seems to do a decent job of cleaning some injectors I had.

 

I have a small wire harness with a 9V battery clip and a fuel injector harness connector to energize the injector so it can be 'blown-out' backwards to clean the inlet screen of debris.

The battery holds it open for cleaning.

bob gauff

 

Thank you Jagboi64 and Bob for your comments.
I will post an update once I get them cleaned through one or a combination of the methods suggested so far.

 

Hi ocean_view,

Below are links to photos showing how I cleaned our injectors at home, based on various methods I found online. I was concerned that just soaking them in cleaner would not be effective enough due to a lack of manipulation of the internal solenoid valves. Even ultrasonic cleaning may be less effective in that regard. I think my total cost was about $50.00, including the new filters and O-rings, a couple of bottles of Techron, the PVC pipe & fittings, the rubber hose and valve, and the Bosch EV-1 connector:

Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Cheers,

Don

 

Don, thank you for the information and links.