Another day another problem

[1EVIL88VERT]

Well finished my motor install yesterday and now it runs like crap. when trying to go WOT or even half throttle from about 2000rpm and up it backfires like its going way lean and tries to kill itself. I have searched for similar problems for a while now and i just can't figure this one out. i have checked fuel pressure ( 44psi ), my EGR crap, timing, spark....i'm just at a loss on this one. Also it seem to do it more while under load...not so much while its just reving

 

[CrazyCobra]

I had a similar problem only it started a round 4000, turned out to be spark plug gap. Its seems simple but had me stumped for a little while .
Good luck.

 

[86bluecobra]

have you checked to make sure plug wiring order is right.? some twit wired mine like a regular 302 and i was experiencing kinda the same thing.

 

[Mike92GT]

mine did the same thing when I replaced my headgaskets. Turned out I had the distributor one tooth off.

 

[Mike92GT]

ditto on checking the firing order. roller and non-roller 302's have a different firing order I believe

 

[1EVIL88VERT]

i double checked the plug wires and they are set to the H.O. firing order, i'll double check to make sure its not off a tooth though... I set the timing at 16deg. if it's off a tooth will it still show 16deg on the timing gun?

 

[Mike92GT]

Just re-read your post. You might consider your mas air meter. My car ran great with a C&L 73mm when I had the stock heads and cam, but when I switched to my current combo in my sig, it wouldn't idle, it would lean-pop at times, stall, surge, etc... I switched to a Pro-M 80mm and it has driven nearly perfect ever since

 

[1EVIL88VERT]

My previous set-up was exactly the same but with 1.9 intake valves, a slightly less agressive cam, no porting,and a whole 4/10's of a point less compression and it ran like a champ before? nothing else was changed...

 

[jrichker]

Do the obvious...

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $35.