2.5L Distributor Rotor alignment - Poor fuel economy 12mpg!

[victorgallas]

Hey everyone.

I need help with my Jeep from the gurus here.

Its a 1991 2.5L 4 cyl engine with the fuel injection system. It has the injector per cylinder setup on this. 

I have pretty much replaced all of the sensors on the engine, cleaned it all up inside and even added new main bearings and connecting rod bearings as they where shot when I bought the car.

Since doing all the work, the engine has been running smooth and the truck runs alright. But I do notice a lack of power; I know its the 4 cylinder, but I always have to give it good amount of gas to get it going.

My biggest headache is that I am getting about 12 to 13 MPG, which I think its insane!

I have no leaks on the intake, fuel pump, filter and all those maintenance items are new as well.

The only thing that I recall not checking before was the position of the rotor in the distributor when installing a new distributor I got.

 

I used the haynes manual and it stated that when installed, the rotor should be at the six o clock position when you are standing on the side of the engine. The front of the engine is to your right shoulder and the back to your left and you are staring right at the distributor in front of you. 

In this six oclock installation, I couldnt even get the engine to start. I could feel that the engine would try to start and it would stop the started right away. In a way I feel that it was too advanced.

 

I then began to look around and some other sites are listing that the rotor should be installed at the 3 o clock position, essentially poiting forwards.

 

My question here is. What is the correct rotor position for a 2.5L 1991 Engine with the port fuel injection electronic setup?

 

Any tips here?

 

What other areas could be causing my poor fuel economy? 

Crank sensor at the rear of the engine? That is pretty much the last sensor I havent touched...

 

Any ideas will be very welcome. At this point i want to drive this daily but with a 12 MPG thats a little absurd...

[Jeep Driver]

Your distributor is set correctly. 

 

I'd be looking at injectors or MAP or O2. 

 

 

 

 

Look up distributor indexing so you understand the process. 

 

Then take an old cap and cut the hole at #1. 

 

Just to see for yourself where you are in terms of timing.........I'm wondering of your timing is retarded. 

[HOrnbrod]

91 = OBD1 = Check for fault codes first.

 

http://comancheclub.com/topic/28111-reading-obdi-91-and-92-mj-fault-codes/

[victorgallas]

Hey,

 

So i did more digging here.

 

For the 87 up to 90, the distributor rotor is set at six oclock. 

From 91 to 95, distributor is set at 3 oclock.

http://www.autozone.com/repairinfo/repairguide/repairGuideMain.jsp?pageId=0900c1528008aa69

 

Did this and the engine started right up.

I also was concerned of being too retarded, but this seems to be the correct setting for fuel injected, later model ones.

 

I just installed a brand new MAP, O2, Air temp, Engine temp, TPS and Idle valve on the engine, all new. 

 

For the OBD codes, the light on the dash is not on. Does this mean that it does not have any stored codes?

I did just refresh the entire cluster during the rebuild and I know the bulb works. When you turn the car on, the light comes one for the ECu then goes off after the engine is running. 

Before when I had a bad TPS, since it got dunked in parts cleaner by accident, the CEL light was on. I put a new TPS and the lights went away and runs without any lights on the cluster.

 

I just ordered a new crank sensor, wondering if a failing one could cause any misses?

 

Thanks for the quick reply everyone.

Vh

[HOrnbrod]

You are not checking the fault codes correctly if the CEL doesn't flash after the initial ignition key sequence.