Explorer 4.0, crank problems, misfire and loss of power.

[Vikane]

My ‘96 Explorer 4.0 have given me a few worries lately, hope someone can recognise this and suggest possible solutions.

The engine is difficult to start, I have to crank the engine at least 10-20 second, worse when the engine is hot.
Sometimes, after start, it sounds like it’s not running on all cylinders, and when I am driving it has no power at all. It also misfires a lot.

There is no DTC present, other than one I have had for a while, P1151. I belive that code is present because I possibly have a cracked cylinder head, and this affects the emission.

I have measured the TPS and MAF, without finding anything.

Any suggestions to what might cause these problems ?

 

[MrShorty]

You might want to have your question moved to the EEC-V forum, where those more familiar with the '96+ engine management system can help.

first thing I'd probably check would be the fuel system. One of the first things I usually suggest with a hard warm start is to check the diaphragm in the fuel pressure regulator (FPR). (I'm pretty sure your '96 still has the continuously recirculating fuel system) Pressurize the system/start the engine, then pull the vacuum line to the FPR. If there's obvious gasoline in that vacuum line, the FPR needs to be replaced. Then I'd put a fuel pressure gauge on it and see what pressure the fuel system is generating.

 

[Vikane]

Thanks for your reply MrShorty.
I was supposed to put the thread in the EEC-V forum, but it seems like I messed that up. Maybe admin can move it ?

I must admit that I have been thinking about the fuel system, because I replaced the original fuel pump a while ago with a walbro pump, could this affect the FPR ?

I will look into the fuel pressure and measure it.

 

[MrShorty]

The FPR is a basic mechanical back pressure regulator. As long as the pump is putting out the right pressure/volume, the brand of the pump shouldn't affect the FPR.

 

[Vikane]

This is the puel pump I installed http://cgi.ebay.com/ebaymotors/REAL...ories&fits=Model:Explorer&hash=item4aa9284fa2