tried to start engine but had the loudest backfire. Just finished repainting intake and valve covers. replaced all vac lines with rodney dickman's, had throttlebody cleaned and bored out, replaced iac and tps. I have spark from the coil and from any sparkplug wire. Had a fuel leak at schrader valve but fixed that, so fuel is making it to block, also can hear pump when key is turned on. Battery is brand new. took everything off and checked all connections, i am not sure if it matters when plugging in the fuel injectors, had them marked but cleaned the marks off . engine was running before i had the great idea.
check the timing to be sure northing has changed while working near the distributer and around the engine. Also check the spark plug wires to make sure you put them on the right plugs. Backfire usually happens when the spark and fuel ignites while the valve is still open which leads me to believe the timing is off or the plug wires are crossed. ##### I have a question for you. What type of TPS did you use, where did you buy it and what part # was it. I have been trying to get one but the only one I found didn't work.#### Thanks Email me at firstname.lastname@example.org
I ll check them one more time but you never know. i usually buy all my parts from The Fiero Store they have always been reliable. The parts where made by standard. I hate going to anyone to anyone that does not know Fiero's they always give bad advice and parts that do not work. The timing never checked without engine running but will find out. thanks for the reply
If you put everything back correctly, it could be possible a backfire jumped your timing chain a tooth or two. When you crank it over, does it sound the same as when it ran ok, or sound different. Jumped chain can make it crank faster/smoother or like the battery is dead.
[This message has been edited by rogergarrison (edited 04-14-2008).]
Posts: 4692 From: Howell, NJ USA Registered: Sep 2006
I had the same issue on my Fiero. I took the wires off without looking at the location and put them back on according to the book. Well, someone previously put the distributor in wrong making the wires one plug off. I just moved the wires one plug over on the cap and it was fine. Dave
1987 GT (my toy-see above), 1987 GT (wife's toy), 1986 SE soon to be VR6, certified master technician/shop owner www.njautobahn.com
taking the cap off and checking to see where the rotor stopped it was a little off from the #1 . thinking back when i first started over a month ago i was thinking of checking the vavle lash but decided not to because did not have long enough wrench and trying with a regular ratchet was a little hard after turning it about a quarter turn. plus was not comfortably with doing the procedure. what is the best way to fix.
Posts: 7889 From: Shanghai, China Registered: Feb 2006
You need to verify all your spark plug wires are on correctly? You never removed the dist? The easiest way is to mark the number 1 spark plug position on the cap and then transfer the mark to the dist base. You do this because you have to remove the cap to check the rotor. Now turn the engine clockwise (18mm socket on crank pulley bolt) so that the harmonic balancer fat timing mark lines up with the 10* mark on the timing scale. Now check your rotor. If it's pointed 180* out, then rotate the engine one full turn. Is it pointing at the #1 spark plug position on the dist base? If not then either move the wires to what you have as #1 or move the dist to make it line up.
well checked plug wires too many times and the timing everything looks pretty damn close. still does not want to start. had a smaller backfire still. I am just going to test everything. Would the pickup coil cause this? That would be the only thing left on the dist. that is not new. The dist is actually about 8 yrs old. what about bad gas? or vaccuum leak, or bad map? this the caziest thing did not do anything cazy but know this, thank for the help everyone.
Just put a meter to the pickup coil and is bad. Had a bad one along time ago but it just did not start with no backfiring. Does anyone know of a better distributor, one that you can change the pickup coil without taking it out.