I've been reading this board for a long time and have learned a ton from it. I just finished up a cam swap with new K-Motion springs, Edelbrok true roller timimg chain and new plugs (wires are on their way). I can get the car to start but it runs very rough (timing is at 7 degrees advanced) and will not go over 2000 rpm. When you try to go past 2000 RPM, it spits fuel back through the TBI unit and sputters horribly. I did the AFPR mod outlined in the tech pages and as of yet have not bumped fuel pressure from the stock setting. Anyone ever seen this problem? I tried to do a search but didn't come up with much.

BTW....car is an 88 Formula 305 auto all stock except above mentioned mods.....

Thanks for any help.

 

well first i would move the timing back a bit.. and second find out what psi your fuel pressure is running at.. what chip is in the ecm??

 

A. Are you sure that you installed the timing chain with the cam and c5rank oriented in the correct way?

B. Doublecheck your spark plug wires and then check them again.
(ask Pablo why you should always do that )


C. Make sure that you installed your distirbtor correctly with the rotor facing the #1 terminal when that cylinder is a TDC. Easy way is to bring it up to TDC , mark the position of the #1 terminal on the distributor body , remove the cap and see if it is close to it.

But since you are getting a reading of 7 degrees advanced then I dont think that this is your problem.


It is mostl likley your wires because backfirne through the intake is a sign of retarded timing , or the wrong plug wire on a cylinder.

 

Well......new plug wires last night and it's still having the same problem. Time to start pulling things back apart.....

 

check and make sure you didnt damage the igintion module. i hear bad ignition modules in camaros cause backfiring and it would keep it from revving. they test them for free at auto parts places.

 

Thanks TBI305Camaro, I hadn't thought of that. Hopefully this is it and I won't have to tear the thing back apart....

 

Did you double check your rocker arm adjustment to make sure the your intake valves aren't hanging open. Which would allow compression to push the fuel backwards through the throttle body. Also, did you disconnect that brown wire before setting the timing.

 

You didn't install your distributor properly. I did the same thing when I did my cam swap. The car would barely run and would back-fire badly out of the TB. Make sure you are at TDC on the compression stroke, pull the distributor and re-install it with the rotor pointing at (or to be a bit more precise, just a bit ahead of) the number one cylinder. It took me three tries but when I got it correct it ran really smooth. This is easy to screw up. If the car isn't on the compression stroke or you just missed the right tooth...

Good luck..I hope that's it and you don't have to pull it apart!

 

My305Camaro is right.
When a engine spits fuel/backfires through the carb/TB, it's almost always incorrect ignition timing.
Could be that the timing chain was installed incorrectly, too.

 

Well, we took the timing chain cover back off last night and discovered the problem. I installed the timing chain wrong and I had WAAAY to much advance (I'm a computer guy, not a mechanic).
The mechanic was surprised I could even get the thing to run! Thanks for the help, you guys nailed it.......

 

 

Big Evil is correct once again

 

:hail: