1998 Explorer SOHC Fuel pressure spec

[CDW6212R]

I don't know about stretch doing that(that's a lot of vacuum and compression loss), but valve timing is very important. That you have both a low vacuum and low compression suggests something more than just a leaking gasket or other part.

Has any of the valvetrain work been done before on the engine? The SOHC has specific issues that need to be corrected in pre-2002 engines. Some people manage to get 150k miles out of them, some engines have gone south at 20k. If any of that had done before, they may have not set the cam timing properly. There are no timing marks, it is done entirely with special tools that locate the parts before tightening a bolt.

If you don't have any of that done yet then you might be wise to begin doing that. It would correct and verify the cam timing. Check out the other threads here about the SOHC "cam cassettes", it isn't a simple job.

 

[JohnJ]

You said the spark plugs are whitish on one cylinder bank and not the other? I'm curious to know what your O2 sensors look like. If the one on that same side looks whiter than on the other side try running the engine with just that one spark plug completely removed (unplugged and unscrewed.) Results may be useful.

 

[fastkurve]

Thanks for answering Don,

Is cam timing verification/adjustment something being done with engine in the truck?

I bought that truck used at 18,000 miles in 1999. Never had any kind of work done on the internals. Just did the 00m12 stuff, that's all.

Do I understand correctly when I say that the timing chain tensioners only take up chain slack but does not correct the stretch (means offsetting the cam timing with crankshaft) ?

The way I understand or could explain the hypothesis here is the degreeing of the cam is slowly being offset by the chain stretch, the tensioners being there just to take up slack and avoid the chain to jump a gearteeth at the sproket...

Sorry for my poor english, this is not my native language.

Robert

 

[CDW6212R]

The cam chains are not really very long, I doubt that you have enough stretch to affect your compression and vacuum that much. Being out of time would be a whole different matter. I might suspect that if you just got it with a lot of miles on it.

I don't know how possible it is that you have had a chain jump a tooth on a gear, or how much affect it would have. I'd think that you would have had a bigger negative symptom if that had happened. Have you had any other real odd symptoms along the way?

Doing that 00M12 kit takes care of two things, the front cam chain tensioner, and the check valve to it. Evidently there was no check valve on the first engines, oil would not reach that tensioner for a second on startup. That creates the noise then, from lack of chain tensioning. There is a mechanical spring in those tensioners, and they use oil pressure to supplement that.

The rear tensioner is just as likely to have lost spring pressure, which also causes chain slop and noise. The rear tensioner is cheaper than the front, and relatively easy to change. By removing the right inner fender, that can be changed in five minutes, with the right socket extensions. The torque is 42lbs.ft. on those as I recall.

I don't know why you have a loss of compression and vacuum, those would not be related by a simple vacuum leak. I'd plan to do the rear tensioner also as you go along, the part is about $25 here.

 

[fastkurve]

Thanks for your feedback Don

 

[lilrebel]

fuel line preasure

i believe 35psi is correct. I had a gauge on my Mustang that constantly read 35 and went up as i have accelerated. Also, your fuel pump may be running out of steam. In time, Fuel pumps dont pump as much fuel and when they were new.

can the steel braided line that runs up to the fuel rail be spliced..i have just a pin hole easy to get to rather than changing out the whole line?