2002 Grand Cherokee Hard to Start

Take a closer look at the fuel pump relay and the crank position sensor. Codes won't always be set if these fail intermittently.

Over the last week, the dealer has:

- Tested the injection system.

- Tested a bunch of sensors.

- Checked all the grounds, battery, etc.

They suspected it could be carbon build up and suggested having the valves cleaned/replaced if necessary. A compression test showed 1 cylinder down in the 120 range, so the valve job is uderway. Ugh.

Sounds like an expensive guess to me.

There isn't any thing to break in the trottle body. It's just an air valve.

I'd be looking hard at the spark system.

When my Jeep gets hard to start, I clean the connection on the CPS with a spray contact cleaner or WD40 and am good to go again. I also clean the TPS which seems to help with cold starts too. When it's connection is clean it does idle up better cold.

I have an old beast but still....

Mike

No surprise there...

I'd agree with your flooding theory, but it's not caused by the T/Body, as it has nothing to do with fuel. It just regulates how much air is allowed into the engine. It is most likely an injector slowly dripping fuel into the intake, causing a pool of fuel and a mixture that is WAY too rich for starting. It will then take several revolutions before the engine will start. It may run a little rough for a few seconds after startup also.

It's a simple diagnosis, and you can even tell the idiots how it's done... Just run the engine until it's at operating temp. Shut it off, unbolt the fuel rail and pull the injectors out far enough to see the business end. The leaking injector will be obvious. Note that this is done with the injectors and fuel line still connected to the rail, as the system must be under pressure to see the leak.

Or, since these guys seem to prefer the shotgun approach over diagnosis, they could just replace all of the injectors.

In article , bllsht wrote: #this is done with the injectors and fuel line still connected to the #rail, as the system must be under pressure to see the leak. # #Or, since these guys seem to prefer the shotgun approach over #diagnosis, they could just replace all of the injectors. #

If it's still under warrenty, that might not be so bad...

/herb

Just for closure, in case anyone runs in to the same problem. It's finally fixed ... heh. I picked it up yesterday. There were two leaking injectors, one leaking outside (they mentioned replacing an o-ring), and one leaking into the intake. Hopefully this is *really* the end of it.

Thanks to the group for all your replies.

bllsht wrote:

Lots of expensive parts replaced for a simple problem. Did they finally figure it out, or did you have to tell them how to diagnose it?