Need help with 3.2 startup after rebuild

bdonally · 08-24-2006, 05:41 PM

Just finished work on my 3.2 - replaced 3 pistons, new rings, did the heads, had the injectors rebuilt. Didn't split the case.
It fired on the first try, but there was a lot of backfiring and it ran rough. It seemed to clear if I rev'd it a bit.
It repeatably backfires when I start it, then it idles OK but it doesn't sound right, like the timing is off.

I have checked the plug wires - they are OK, and the rotor lines up with the notch when the Z1 mark is lined up with the case split.
I triple checked the cam timing before I closed up the engine.
I did make a mistake that required that I remove the left heads after I timed the cams, and I was very careful when I reset the left cam timing, although I did not re-check the right side because I didn't open that side of the motor.

I cannot see any possible wiring errors that would lead to such a problem.
Any ideas about what can cause fairly severe backfiring will be appreciated - I really don't want to pull it out and start over.

Eagledriver · 08-24-2006, 08:16 PM

I'd check the cam timing again first. You can do that by taking off the intake valve covers and rotating the engine like when you first timed the cams. Things to check in this process are:

When the rotor is pointed at #1 TDC (the notch) is the number 1 intake valve fully closed (not starting down). You can turn the engine furthur (like 20 degrees or so) and the valve should still be closed. At this time the intake valve on number 4 should be opening just like when you time the cams. If number 1 intake is opening then you have the cam or the dizzy 180 degrees off. If number 4 is not opening then you have that cam or the dizzy 180 degrees off.

You can also check the lift at TDC like when you timed the cams.

If the cams are correct and the dizzy is correct then I'd triple check the plug wire firing order. I think your dizzy turns clockwise but double check.

Other possibilities are the sensors for the computer such as the flywheel sensors and the cylinder temp sensor.

-Andy

bdonally · 08-26-2006, 06:46 AM

Ok I have determined that i made a stupid error and installed the right cam 180 degrees off. I can fix that easily enough.
What damage might this have caused, given that I started the engine?
I need to decide whether to pull the motor and tear it down or just reset the cam timing.
Thanks

hcoles · 08-26-2006, 08:18 AM

I did the same embarrasing mistake. 180 out no damage. Retime it and fire it up. 180 means all the relationships for top of piston and valves were the same but spark was going off on the exhaust stroke so no go. I think that's correct... in any case I have about 10k miles on it without issues.

bdonally · 08-26-2006, 09:45 AM

That's great to hear, and thanks
I have it retimed - it is actually not that difficult in the car, although you have to think through piston positions so you can get the cam turned 180.
Should be on the road tonight.

Determined · Determined's Garage

Hi there,

May I ask who rebuilt your fuel injectors and what it costed.

Regards,

Alex
orozcoa@earthlink.net

hcoles · 08-27-2006, 08:31 AM

FYI I sent my injectors (3.2 type) to WitchHunter - ~ $15/ea. clean and test...they give you the before and after flow rates/etc.

Very nice people...I sent the new O rings/etc. they told be what I sent was not correct and put on the proper ones for me...

engine idles smoother for sure

there are a lot of places that clean and test injectors...many use the same machine

-h

bdonally · 08-27-2006, 10:23 AM

I had mine done at a local place - Rovan - but that is only of use if you are in the Toronto area.
They checked them, replaced the screens and o-rings, and did a final test. In my case all they found was that two of them were not shutting off completely. After cleaning all was well and they all flowed the same rate. Altogether it cost me c$200, including taxes - about US$22 each before taxes.