Help! Can't start after rebuild.

Bob Avellar

May 25, 2001
Actually the only thing done to the motor was installation of new timing chain and gears. Intake manifold was taken off and that's about it. All the wiring was swapped into another Regal as a donor car so I may still have some electrical gremlins to eliminate but I don't know if that is the problem. Here is what I "think" I know.
1. I have spark to the plugs (actually only checked #1) on a spark tester. So I guess I have a crank signal and cam signal.
2. I have pulses to the injectors as I checked them with a test light.
3. I used the finger in 31 hole to determine the compression stroke and then continued to rotate the motor 1 7/16" past TDC to arrive at 25 degrees AFTD. The slot in the cam sensor faces aproximately toward the power steering pump when inserted into the cam gear and I aligned the plastic cap up to that same position so I should be fairly close to getting a cam pulse at that time. At least I should be within the window of timing to start the car.
4. As far as I know the grounds for firing things up should be clean and tight. I may have some other grounds inside the dash that need to be resolved but the ECM has ground- and like I stated I am getting spark and injector pulses.
5. Fuel pressure is there 45 ish.
6. All new plug wires and wired correctly to the apprpriate cylinders as shown on the coil pack.
7 Motor has not run in about a year but ran perfectly when taken out.
8. I think that we checked to see ithat the piston was at TDC and the timing mark on the balancer was at zero degrees so the cam timing seems to be OK.
Here's what is happening:
Car turns over but backfires through the intake and basically doesn't come close to starting. Just like ignition timing is off or spark plug wires are crossed.
Sometimes I can smell fuel on the plugs after cranking but they were not wet with fuel. I know the liftrs have probably bled down so I don't know if that might cause these symptoms.
The oill pump gears were packed with grease but during granking I did not build any pressure on the mechanical gauge. Before I attempt any more cranking I plan to use a drill to spin the oil pump gear to get some pressure built up.
I really am at a loss on this . My main impression is it is somehow related to ignition timing due to the backfire through the intake. My mechanic friend actually installed the timing chain/gears and he knows to align up the dots, etc and we can't see how that could be messed up. Steel gears were used and a stock chain was used.
Is there some way that we still have the cam sensor so far out of wack that it won't start? Everything seems to be set to the compression stroke (finger in hole) and position of cam window and cap seem correct.
I will be gone for most of the day but I hope you will post any and all suggestions to help me get my baby started again. I will probably try again on Sunday a.m.
BTW I have already done a search here related to cam sensor prblems but nothing seems to help.. Give me some ideas or other things that I can test.
Another vote for cam sensor. Had me stumped for a couple days after my rebuild, set it and it fired right up.

If I were you, I would remove the drivers side valve cover. Rotate the eng. by hand and watch the rockers to make CERTAIN that # 1 is up to fire, not exhaust.
Like the others have said ---Use 1- 5/8 for your 25 degrees.
Although if everything else were right 1-7/16 is close enough to start.
Pretty sure I used 1 7/16" for 25 deg but I wouldn't think it would backfire like it did if it were that close? Maybe the lifters are so bled down that IT could be the problem. I was thinking that if the valves weren't opening much because of it that we might still feel compression as the cylinder comes up on the beginning of the exhaust stroke???? Everything we did setting and checking the cam sensor sure seemed like it was correct. I will take off the valve cover if u think it will be worthwile. I guess I should to be sure. If its on the compression stroke how far off does it have to be to make it backfire and not start? I would think it would have to be way off to do that? Thanks guys and I'm still listening!!
like Lee said make sure #1 is up .... could you be 180* off ????? simple to check ....rotate the cam sensor 180* an see if it starts then
Grumpy, If I rotate the cam sensor 180 deg that would be like moving the cam signal 90 deg in relation to the pistons wouldn't it? Since the cam rotates at 1/2 the crank speed. So I think that would put me about 65 degrees before TDC on whatever stroke I might be on. At least that is what I understand. All I know is that I have set it to near 25 deg after TDC of either the exhaust or compression stroke since I am at 1 7/16" after the zero mark on the balancer. Like I said it is pushing my finger out of the hole just before I come up to the mark on the balancer and that is why I think it is the compression stroke (unless the lifters are so drained that they are not opening the valve on the exhaust stroke and that is making all the compression). I just can't see it being set wrong but I have been wrong before!
Even if the cam sensor is 180 out, the car will still start and run. But the way you set the cam sensor doesn't seem quite right to me. I agree, the 1-5/8" or 1-7/16" sounds close enough to fire the car up, but I would use a multimeter to set the cam sensor. The way you stated doesn't sounf 'good enough' to me. And the symptoms you stated sounds exactly like a cam sensor setting problem. I'm pretty sure the multimeter way of setting the cam sensor is on And with the exception of getting confused between clockwise and counter-clockwise, it has worked perfectly for me every time.

Just my 2 cents. Now to crawl back in my hole....

Used a drill and primed the oil pump. OK!
Reset the cam sensor (seemed to be where we had it before) but anyway-IT RUNS!!!!!!!!! Good oil pressure. Actually it never dropped below 38 lbs at hot idle with the fan running. I started it up with straight 50 wt oil so that may be where the extra pressure is from. I'll be changing it and the filter soon as soon as I figure out how to get my fuel pressure to come down. See the new post on that subject. Thanks for the help guys. I'm sure I'll be asking for more advice. YAHOOOOOO!!