I have a gutted '98 Prelude Base that is doing something really weird. I just got the motor back and have had it sleeved, 89mm wiseco pistons, new crankshaft, and crower billet steel rods installed. I installed the head, put the motor in the car, connectoed everything, and then set the cam timing. I have the crank at TDC. The Crower Rally/Road Race cams are at TDC as per Crowers instructions. When I hit the start button the motor is popping and backfiring through the intake manifold (Skunk2 Pro-Series).

Things that are known good are as follows:

1. Timing Belt and cam timing
2. Calibration in the AEM EMS is also known good.
3. injectors are obviously firing
4. spark is good
5. cams aren't ground incorrectly.
6. all mechanics of the engine are in good working order
7. CKP/TDC/CYP sensors and associated wiring are all good
8. Nothing is clogged in the turbo manifold or intake manifold.


If anyone on here has any ideas of where to look next, please let me know. I will try it all. I have a funny feeling that something is telling the coil to fire at the wrong time. I there some other sensor that I am forgeting about that handles something this drastic. The motor is literally firing like it is 180 degrees out of time. I don't get it.

Any help would be greatly appreciated.

-Chris

 

using the correct firing order? lol

 

Check -- double check -- and triple check all your ground wires even put a meter on them to make sure they're all sound. Those grounds have caught many competent people out.

 

hmmm..valve adjustment??fuel pressure??bad wiring??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">using the correct firing order? lol</TD></TR></TABLE>

 

i would throw a stock ecu on to make sure the car will start with that, it doesnt have to drive or idle.. at least to see if it will start fine.. the base timing on the AEM unit can be off... if it is it can usually do what you are explaining in your post.. ive had that happen to me before when I was making a map from scratch.

 

yeah ems timing could be off...did you run the initial setup???shoot a timing light at it and see if the readings correspond to the values in the ems... i wouldn't recommend running the stock ecu though without knowing how the car is modified (eg. big injectors will just flood it instantly)....

 

Yes, the firing order is correct. I spoke to RC Engineering and they assured me that the 1600cc/min injectors should spray a good pattern at 30psi of fuel pressure. I will check the engine grounds, then swap coil outputs on the EMS, and then recheck the base timing. I checked the base timing before, but whenever I hit it with the timing lighti can't even see any of the timing marks, but the EMS is loaded with a known good calibration. Maybe there is a bad engine ground, or maybe the coil output I am using is firing irratically, but I can't see any timing marks while spinning the motor over. Any ideas on why this is??

 

I will definitely try that tonight.

 

Ok, problem fixed. AEM messed up and sent an extra "D" plug instead of a "B" plug. I had to switch coil drivers a while back and the car WAS running fine. Then after the full on drag car conversion I must have inadvertently (sp?) miss pinned the coil driver. Well, I called AEM and they sent me the "B" plug for the EMS and I wired it to coil driver #2 and VOILA!!!! The car fired right up. It actually idles at 950 RPM with a 13.9-15.2 AFR while running 1600cc/min RC injectors. I am stoked and can't wait to lay down some 4 digit numbers on the dyno.

 

For a second there, I thought you were having cam clearance issues, which was a problem when I installed my Stage 2's a while back.

https://honda-tech.com/zerothread?id=593951

Anyways, at least you got it figured out.