John S
07-27-2009, 08:05 AM
I'm posting this here because the ignition thread does not seem to get much traffic I'd like to help others avoid the problems I just experienced.
If you look at my post history you'll find that I have been fighting a timing problem with my XFI and Dual Sync Dist for well over a year now. Last week with the aid of Scott at SDCE in Warwick RI and about 6 hours of dyno time my car is finally running correctly. I want to share this with other Dual Sync users in case they ever experience the same problems that I did and possibly help them to avoid hours of frustration and the cost of well over $1000 needlessly.
On the way to a cruise one night I jumped on the accelerator pretty hard for a quick blast and let off. When I let off the engine was running like crap and I had to call to have the car towed home.
Here is my original post from then, https://www.pro-touring.com/forum/showthread.php?t=44270
After getting things back together I ended up with this problem https://www.pro-touring.com/forum/showthread.php?t=46942 and due to some work commitments and health problems I was not able to get back to working on the car until this past June. I was still being plagued with the timing issue and could find no mechanical or electrical problem.
I sent the ECU and the distributor back to FAST to be tested, They returned both to me claiming that they were in perfect working order, ran their test engine fine and I should start loking for problems in the engine internally.
I pulled the top end down, replaced the hex adjust timing set with a standard double roller, degreed the cam, adjusted the valves, spent hours checking and rechecking everything, got 2nd and 3rd opinions, spent time on the phone with MSD, FAST, AFR and Lunati and was finally convinced that everything was correct mechanically and prepared to fire the engine.
After firing the engine I still had some backfiring but adjusting the timing a bit got the engine to a steady idle. Great, I thought I was home free.
While apart I changed the intake and exhaust so I knew some tuning would be in order. I mad an appointment to have the car on the Dyno at SDCE which would mean a 4.5 hour drive there, a night in a hotel and a 6.5 hour return trip.
After arriving at SDCE and getting the car on the dyno several quick checks were made then the tuning began. After working with the base maps for the cold start and Idle Scott began the first dyno pull but shut down right away.
There was still a problem with the timing as RPM increased and he wanted to correct it before proceeding. After over an hour of testing Scott was convinced that the problem was with the distributor and had something to do with the relationship between the rotor position and the magnets.
We removed and disassembled the distributor and Scott was thinking of ways to modify the breaker plate to get the magnets in better position. It was then that we noticed that the rotor that holds the magnets was able to spin on the distributor shaft with a lille effort.
THE ROOT CAUSE:
The rotor holding the magnets is indexed by a plastic sleeve that slides over the dist shaft and rests under the rotor mounting plate. The shaft has a small ( approx .050") keyway cut in it and the plastic piece has a matching key cast into it. The small plastic key was gone allowing the magnet housing to rotate and change positions on the shaft.
I consider myself very lucky that I did not grenade the engine.
I'm very disappointed with FAST at this point for several reasons, namely that I've spent hours on the phone with them, sent them log files and sent them the distributor to be tested all to no avail! Also placing the durability of expensive engines on the shoulders of such a small plastic part in an expensive distributor does not seem right. But that is just MHO.
If you look at my post history you'll find that I have been fighting a timing problem with my XFI and Dual Sync Dist for well over a year now. Last week with the aid of Scott at SDCE in Warwick RI and about 6 hours of dyno time my car is finally running correctly. I want to share this with other Dual Sync users in case they ever experience the same problems that I did and possibly help them to avoid hours of frustration and the cost of well over $1000 needlessly.
On the way to a cruise one night I jumped on the accelerator pretty hard for a quick blast and let off. When I let off the engine was running like crap and I had to call to have the car towed home.
Here is my original post from then, https://www.pro-touring.com/forum/showthread.php?t=44270
After getting things back together I ended up with this problem https://www.pro-touring.com/forum/showthread.php?t=46942 and due to some work commitments and health problems I was not able to get back to working on the car until this past June. I was still being plagued with the timing issue and could find no mechanical or electrical problem.
I sent the ECU and the distributor back to FAST to be tested, They returned both to me claiming that they were in perfect working order, ran their test engine fine and I should start loking for problems in the engine internally.
I pulled the top end down, replaced the hex adjust timing set with a standard double roller, degreed the cam, adjusted the valves, spent hours checking and rechecking everything, got 2nd and 3rd opinions, spent time on the phone with MSD, FAST, AFR and Lunati and was finally convinced that everything was correct mechanically and prepared to fire the engine.
After firing the engine I still had some backfiring but adjusting the timing a bit got the engine to a steady idle. Great, I thought I was home free.
While apart I changed the intake and exhaust so I knew some tuning would be in order. I mad an appointment to have the car on the Dyno at SDCE which would mean a 4.5 hour drive there, a night in a hotel and a 6.5 hour return trip.
After arriving at SDCE and getting the car on the dyno several quick checks were made then the tuning began. After working with the base maps for the cold start and Idle Scott began the first dyno pull but shut down right away.
There was still a problem with the timing as RPM increased and he wanted to correct it before proceeding. After over an hour of testing Scott was convinced that the problem was with the distributor and had something to do with the relationship between the rotor position and the magnets.
We removed and disassembled the distributor and Scott was thinking of ways to modify the breaker plate to get the magnets in better position. It was then that we noticed that the rotor that holds the magnets was able to spin on the distributor shaft with a lille effort.
THE ROOT CAUSE:
The rotor holding the magnets is indexed by a plastic sleeve that slides over the dist shaft and rests under the rotor mounting plate. The shaft has a small ( approx .050") keyway cut in it and the plastic piece has a matching key cast into it. The small plastic key was gone allowing the magnet housing to rotate and change positions on the shaft.
I consider myself very lucky that I did not grenade the engine.
I'm very disappointed with FAST at this point for several reasons, namely that I've spent hours on the phone with them, sent them log files and sent them the distributor to be tested all to no avail! Also placing the durability of expensive engines on the shoulders of such a small plastic part in an expensive distributor does not seem right. But that is just MHO.