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3.0 rebuild

PostPosted: Fri Nov 05, 2010 5:44 pm
by DavetheDude
Anybody out there ever put a timing belt on a 3.0? The book told me to put the crank sprocket on the mark and then line up the cam sprocket marks. In parenthesis it says that when the crank sprocket is lined up, you are at top dead center. That is not the case. I am at least 30 degrees off of TDC. Here is the question. When putting a timing belt on this engine, should it be at top dead center or not? Thanks

Re: 3.0 rebuild

PostPosted: Fri Nov 05, 2010 5:56 pm
by Josh2g
I am not 100% sure on these trucks but when I did a timing belt on my 95 Mitsu Diamante 3.0L DOHC(same block) the #1 had to be at TDC. So I would assume that the SOHC counterpart would be the same.

Re: 3.0 rebuild

PostPosted: Sat Nov 06, 2010 7:49 am
by DavetheDude
I got up early this morning and reset the timing with the engine at TDC. It started right up.

Re: 3.0 rebuild

PostPosted: Sat Nov 06, 2010 7:50 pm
by camoit
All timing is set up at TDC. Always turn the crank 2 compleate revolutions BY HAND before using the starter. This ensures you did not screw up and the valve timing. If ti's off and you hit a valve when turning by hand you can't hurt anything.

Re: 3.0 rebuild

PostPosted: Sun Nov 07, 2010 7:06 am
by DavetheDude
I always turn it over many times by hand. Either the sprocket is not original or it came from the factory with the mark in the wrong place. I thought maybe I overlooked the right mark for a ding or something, but the mark is definetly wrong.

Re: 3.0 rebuild

PostPosted: Sat Dec 04, 2010 9:07 am
by DavetheDude
After getting everything done the thing started and ran like crap until it decided to not start at all. So I decided to start from the begining and have the computer rebuilt. After getting the computer in it started right up but still does not run well. It will idle smooth at about 2k for 20 sec and then fall down and stumble around 800 for 20 sec and then rev back up to 2k and back and forth until it gets warm. Then it stubbles as it revs and just runs generally crummy. I have converted this thing to 3.0 injected and have replaced wiring harness, engine and trans, gas tank, fuel pump, you get the picture. In looking through the books I realized that the oxygen sensor was missing from the donor truck and so I don't have one hooked into the system. The computer shows no codes and the check engine light is not on. Here is the question. Will no feedback from the ox sensor make this thing do what I am seeing? Will it run without one? Unfortunately the pipe that the sensor screwed into was missing on the donor. Converted a 89 2.6 4x4 into a 91 3.0

Re: 3.0 rebuild

PostPosted: Sat Dec 04, 2010 4:43 pm
by DavetheDude
More info. After it warms up it idles steadily. I checked the coolant temp sensor and it was bad so I'll replace that. I'm sure that is the idling problem. But after it warms up it still will not accelerate very well. Like not enough gas. So I clamped the return fuel line and it smoothed right out and ran good. Is my regulator bad or could it be the fuel pump? It has a new fuel pump in it but I didn't go top of the line. Bought a cheap one.

Re: 3.0 rebuild

PostPosted: Fri Dec 10, 2010 7:30 am
by lush90
What condition are your injectors in? I swapped a Diamante 3.0 into my '91, worked out the bugs but couldn't get smooth acceleration until I had the injectors professionally cleaned (Injector Dr.). The injectors looked perfect and I tried all the injector cleaners in a can stuff but their pre-cleaning test showed 2 were like 45% clogged the other 4 about 25%, after cleaning the truck runs like a top. Hope this helps!

Re: 3.0 rebuild

PostPosted: Fri Dec 10, 2010 6:56 pm
by DavetheDude
This engine was setting for several years and that sounds logical. I'll try that next. Thanks

Re: 3.0 rebuild

PostPosted: Tue Dec 21, 2010 7:39 pm
by DavetheDude
Got my injectors cleaned and that did the trick. Runs good with good acceleration.