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No start after timing chain replacement

3647 Views 16 Replies 6 Participants Last post by  CMax03
Any ideas on what I may have overlooked while replacing timing chain on 1990 D20 2 wheel drive pickup? Engine rotates but will not run. I followed directions closely and I'm sure chain links matched marks on sprockets and was on TDC compression stroke for #1 cylinder when I installed. It ran for a few moments when I first completed the job and started the motor but it died after about 15 seconds. I replaced the battery tonight and it ran again but only for a few seconds on my first attempt. After thoughts began to creep in my head I thought maybe somehow I put the distributor in on the wrong stroke (exhaust stroke) so I removed the distributor and turned the crank one full revolution, lined the timing marks and reinstalled. To my amazement it ran again but only for a few seconds before it cut off. It will not start and I am scratching my head. I removed the oil pump again to make sure marks on the shaft and notch were lined up and everything looks good.
I checked compression and looks good just under 180 psi in each cylinder after few cranks with throttle body wide open and fuel pump disabled. I am getting spark confirmed with spark tester.
I am stumped and would love any feedback offered.
Thanks in advance.
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It was not running before this job. When I pulled the valve cover off I discovered the chain guide on driver's side was broken. From what I have read this is common on these older trucks. I did notice that the cam and crank spocked did not look like they were exactly in the 12 o'clock position. Both had their keys at the top but I remember them looking like they were just to the left of 12 o'clock. Maybe more like 11:55. Close but not 12 o'clock. I'm thinking as much as I hate it I'm going to have to pull it all apart again. The cam sprocket that came with my kit from NAPA didn't have holes in it to wedge something through it which made torquing to specs a complete guessing game. It is impossible to hold the cam still and apply enough force to be sure. While I did this I had an assistant monitor the crank to be sure that as I torqued the cam bolt the chain didn't move on the crank. Since I'm going to have to do another tear down I'll purchase another cam sprocket with the holes drilled in it.
Also, it isn't easy getting that oil pump back in without slighlty bumping the shaft which turns the distributor. I know it would take quite a blow to move the crank. However, I'm wondering if while reinstalling the oil pump I could be allowing the shaft to turn slightly causing me to be off by say one tooth on the gear which drives the disributor?
Anyone have any links to pics showing what the distributor drive gear should look like once the oil pump has been installed with engine's #1 cylinder at TDC?
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It's also worth noting that this vehicle sat for about 4-5 months without running prior to this job. I would think that is not long enough to lead to bad fuel but if someone else feels differently I'm open to suggestions.
I appreciate all the feedback so far. I've been out of town and then sick but this afternoon I decided to take another crack at this truck. Following Zanegray's advice as well as what many others have posted in the past I thought it must be the oil pump/dizzy that is creating my headache. I put the engine at TDC #1 cylinder by removing spark plug and rotating engine until I could feel pressure and then located timing marks on pully. Removed the dizzy and oil pump. Practiced reinstalling the pump a few times before adding oil and tightening. Afterwards, I looked through the dizzy hole on the timing cover and it looked like I've managed to position the shaft so that it is at the 11 and 5 o'clock position as described by everyone. Upon starting the engine it again ran for a few seconds (maybe 8-10) before shutting off. It will not start afterwards. I wondering if this truck has a shut off switch so that if there is low oil pressure it will not allow the engine to run? If so do I need to reset something?
I hate to go this route but it looks like I'm going to have to take it all apart again. I'm not happy about it but I'm also not one to just give up. Maybe, I missed a tooth or something when installing. It's amazing that you can be so sure about everything but when the problems show up you start to second guess yourself. Another question, what would happen if it where somehow installed on the exhaust stroke? My assumption is that it would run extremely rough if at all.
Again, I find your tips to be vdery helpful and appreciate any help you may offer. This will probably take me some time to complete due to a busy schedule but I will let everyone know the outcome/progress.
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Too late as I have already pulled everything apart again. After removing the valve cover and finding TDC I noticed that the camshaft's key is not quite at the 12 o'clock position. Very close but not exactly. A little past the position. The crank's key is dead on the 12 o'clock spot but if the cam's key is at 12 even the crank is a few marks off on the pulley. In other words, with cam at 12 o'clock the crank looks to be about 15 degrees advance if that makes sense. So I am thinking that it must have been reassmbled incorrectly. Do you think it would hurt anything if once I remove the chain I bump the cam gently so that it is at a true 12 o'clock position before a assemble everything?
I feel like I am overanalyzing this but when it comes to timing it has to be right or as I am finding it will not run.
I am now looking for a new cam sprocket and would even consider using the old one. I know this is not adviseable but I cannot believe all the aftermarket camsprockets that do not have the holes drilled in them. The one with my kit is useless for anyone without access to air tools in my opinion. It is even difficult to get back off because of no way to hold the cam still while removing.
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do not go by the cam shaft key way ..

check to make sure no. 1 cylinder valves are closed and then on following turn of crank that no.3 closes..

the f.o. is 1342...
Valves are closed and in the order stated above. My only concern is that the key on the camshaft is just beyond the 12 o'clock position. It looks like maybe by only one tooth. Could it be that this one tooth is why I could not get it to run the last time? I guessing that during the last installation trying to torque those garbage sprockets could have caused me to jump a tooth. Again, I didn't have any way to hold still enough to get to the proper torque.

I'll follow your advice. My assumption is that if the marked chain links match the indication marks on each sprocket this should be resolved.

I ordered a new cam sprocket from Advance Auto this morning which will be in tomorrow. Should have an update in a few days.

Finally had time over the weekend to finish up this project. I completely did the job over again. In the process I went with a new camshaft with theholes in it to allow for easier torque to specs. Truck is running great but I think I did a lot of work that was not necessary. I think my problem was in the dizzy. When I went to reinstall the last time I rotated the lower shaft and noticed the rotor on top was not turning with the shaft. Then I remembered my assistant playing with the dizzy while it was removed and as it turns out it was put together incorrectly. A lot of work but I am happy it runs now.

Thanks for all the feedback earlier and for anyone considering attempting replacement my only advice would be to be patient and give yourself plenty of time. I think for the average home mechanic this is a good 7-10 hour job.

I am happy the truck runs great.
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