nichzimmerman

I tried blowing compressed air into the spark plug hole on cylinder 1 at TDC (the zero on the ignition timing scale), then rotated the crank 360 degrees and did it again. in both cases my wife told me she felt air out the exhaust. I put a bunch of oil in the cylinder and did another compression check and still got the needle barely off zero. are these tests generally adequate to diagnose a stuck exhaust valve? I would just like to be as sure as possible before committing to more disassembly. cylinders 2, 3, and 4 have compression in the 150s. thanks!

Hi folks, I'm the guy that started the topic called "1990 loyale engine problem" and since the scope of the problem has evolved so much I figured a new thread is in order. Before the timing belt change, compression on cylinders 1 and 3 was normal. After the t-belt swap everything was back to normal except cylinder 1 was reading 20 psi. Obviously the engine was running a bit rough.I checked and rechecked the timing belt configuration and even adjusted the right cam sprocket a tooth or two in each direction and switched the crank sprockets just in case I had them backwards. In every case, the engine ran the same and compression was just 20psi (needle just barely off the stop.) What next? I tightened the compression tester fairly tight to ensure air wasn't leaking past. Valves maybe? Thanks.

This group has been extremely helpful through my first timing belt change. Yet another update: everything is back together and the engine started and ran, but not quite like it should. The starters speed seemed to oscillate as if I had a couple spark plugs missing, and the engine had a lot of vibration at idle. It largely went away at higher rpm but it clearly isn't running quite right. I double checked the timing belt and all the marks lined up as they should. I followed the procedure in the haynes manual, which is the same as in the YouTube video series (line up all marks, rotate crank 360 deg between belt installs). I tested compression on the two cylinders that were previously in the 80s and they are now both in the 150s. What to do? Oh, and about 1/4 cup blackish water dripped out the exhaust during and after I ran the engine.

Update: the driver side timing belt had bad wear on the side facing the engine and lots of belt fibers were inside the cover. I found that the oil pump sprocket (seee pic of part and diagram) had lost the inside ring which apparently keeps the belt on the sprocket. The ring had cracked, come off, got mangled up, then started eating away at the belt. Im relieved to figure out why my belt failed so soon, but I cant seem to find a replacement part anywhere online. Is this the sort of thing a dealer can get for me or where else can I look? Thanks.

I see a large variety of timing belt kits for sale...the only thing they have in common is they each come with two belts. advance auto sells a kit that includes belts, idler pulley, tensioners, and seals for the crank, cams, and balance shaft. anything else I should be replacing while I am in there? thanks.

Thanks for the help guys. I wish I could provide friendlier editing but I'm using a smartphone and it defaults to a single paragraph when I post. I did not have time to take the center cover of this morning but I took the left and right off. both belts were still attached but the driver side belt had damage. see the attached picture. could something like this cause the belt to jump a tooth and throw off the timing? These belts were replaced 40,000 miles ago does this mean I probably need to replace some of the gears? ive never worked with timing belts before. This is an SPF I engine and my Haynes manual says 17 to 24 psi is normal. mine was 24. the compression on the good cylinders was 165 and the Haynes manual suggested low compression on 2 cylinders of the same side is indicative of a head gasket leak and there's oil on the bottom side of those cylinders. that's all that went into my diagnosis. Thanks again for the help!

Hi, new guy here. I was happily driving my Loyale down the highway when the engine just quit. no stumble or misfiring, just completely quit, and it wont even think about starting. so far I have checked the fuel pressure just after the fuel filter, checked that all plugs were getting a spark, and checked compression. so far all is normal except the compression on the left two cylinders (from the drivers seat) are 80 - 90 psi. I figured a head gasket problem, but would that cause the engine to quit like that? what else should I look at? thanks. nic