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Engine ran rough just after starting


Matt

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Just thought I would run this by you guys. My didtributor was not on the UPS truck today. It was lunch time so I went to car and started it up. The temp was 77 and as I watched it climb before driving away it reached about 100 and it had been running only a few min when it started to what seemed like load up. It was very rough and I was trying to clear it out by giving it a little gas but it felt like it was on only a few cylinders. With foot off gas the rpm was up and down and almost shutting down. I shut the engine off and immidately restarted it and it was all fine again and smooth. I drove away and it was fine, went to store and back to work and it was great. I checked the computer wires and taped it to check it out the other day, nothing happened. What else could it be? Does any one have any ideas???

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Just thought I would run this by you guys. My didtributor was not on the UPS truck today. It was lunch time so I went to car and started it up. The temp was 77 and as I watched it climb before driving away it reached about 100 and it had been running only a few min when it started to what seemed like load up. It was very rough and I was trying to clear it out by giving it a little gas but it felt like it was on only a few cylinders. With foot off gas the rpm was up and down and almost shutting down. I shut the engine off and immidately restarted it and it was all fine again and smooth. I drove away and it was fine, went to store and back to work and it was great. I checked the computer wires and taped it to check it out the other day, nothing happened. What else could it be? Does any one have any ideas???

Lets wait till you get that distributor swapped, impossible to diagnose anything now given that the SHAKING distributor could be the problem, this is an example of mental masturbation until we eliminate the obvious problem.

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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One more thing, read this thread, its important that the new distributor be installed in the correct orientation. If you look at this post you will see a recent post where the distributor is installed at about 90 degrees to the centerline, not good in terms of CAM position, I believe. He even notes that he thinks that the distributor is off a tooth to compensate. However, the CAM position sensor is off if I am reading the manual and information correct. I just don't know if "close enough" is OK in this case he is experiencing detonation or spark knock as he says..

http://caddyinfo.ipbhost.com/index.php?sho...l=to%20tdc&st=0

Toward the end, the discussion surrounds distributor installation. I have posted many pictures detailing the physical positioning of the distributor showing that the centerline of the distributor socket area has to be installed at a 45 degree angle to the centerline of the engine.

Note this statement>>> "the HEI on the 4100s serves two purposes. Spark, and to tell the PCM what the cam position is. The 4100 HEIs are unique because they have a pickup coil for the ignition module AND a hall effect sensor to tell the car what position the camshaft is at."

Mike

post-3-1114550977_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Mike,

I guess that the hall effect cam position sensor carried over from the 4100 thru the 4.5 to the 4.9. Would that be correct?

I'm assuming that Matt will take the cap off, mark the position of the rotor, pull the distributor clear of the cam gear, mark the rotor a second time, position the replacement rotor in an identical position to the second mark, install the distributor, and allow the rotor to turn (as it is being installed). The rotor should line up with the first mark on the distributor. When finished with the install, the replacement distributor will be oriented the same as the original one was before it was loosened for removal.

All of this is on the assumption that the original distributor is installed correctly now.

That is an interesting bit of information on the distributor having a cam position sensor as part of it's functions.

Britt

Britt
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Mike,

I guess that the hall effect cam position sensor carried over from the 4100 thru the 4.5 to the 4.9. Would that be correct?

Yes its the same on the 4.9 Britt, sorry for the confusion with the 4100 statement, the photo above is from a 91 4.9, here is the 4.9 HEI distributor description from the manual, Mike

post-3-1114566181_thumb.jpg

Early on sailors navigated by the stars at night and the North star became the symbol for finding ones way home. Once you know where the Northstar is you can point your ship in the right direction to get home. So the star became a symbol for finding ones way home or more symbolically even finding ones path in life.

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Hi All. We were out all night and thought I would check in before we hit the hay. I'm glad I did to see the additional info. The only thing is now I will not sleep. Is there nothing simple about this freeking engine. I must just be tired I guess because I'm truely up set at how much BS there is just to swap a distributor. You guys are great for making sure everyone gets all the info they need. I do not know what I wouold do with out ya all. I hope I do not mess this up,it sounds like I can. I think I'm getting tired of this engine. Now that I'm good and mad, good night.

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Am on road all week and next week with company car. Returning to late at night to work on Seville. Will get to distributor soon and give an up date then. Take care all. Hope this goes through this time, am useing cell phone modem. Take care

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