hey guys I am in need of help.
my car wont even attempt to fire and it backfires threw the throttle body. plus the car run fine the other day, it had a looping idle but it fired.

 

I think backfiring is a sign of timing problems. Bad timing chain perhaps? Is this a daily driver that recently started doing this? Has it been sitting for a bit? Did you do any changes or mods recently. Crossed plug wires can also cause this. Anyways, give us more info and back story to better help you.

 

I figured it was a timing problem but wasn't fully sure that the computer didn't have a role in it.

the back story: I bought the car back in June. ever since the car has been going south despite my efforts. but anyway no the car is not my daily driver I bought it to restore. but it was a daily driver before me. it startied a looping idle like three months ago and never figured it out. then this passed weekend in was fine one day (stilling hunting for an idle) and wouldn't run the next day and had to get dragged out of the garage.

 

Fouled plugs.

After you un-foul the plugs, you need to figure out why they fouled in the first place.

 

How old is rotor and cap?

 

the cap and rotor plugs and wires were done in November when I did the valve seals.

I tried to un-foul the plugs they just get flooded with in two stall outs.

 

Have you checked the CTS and MAP sensor?

 

I have checked the map but not the cts. Although either of those would still allow the car to start it would just run like crap

 

check/clean the EGR valve.

 

That might take care of the idle hunting. I dont know , would that effect the back fire though the throttle body?

 

I've seen bad ICM's make them pop back too.

 

Yea I dont know thats what my concern is.

 

so I checked the timing. with the 1st cylinder at TDC the rotor points to number 3 on the cap. so I'm guessing the timing chain jumped. does any one know if these cars still use a fiber toothed gear on the cam?

 

Fiber gear or not, the timing is off. You might as well bite the bullet and put a new chain in.

 

I think the 91's came with all steel gears. At least, the replacement timing kit is all steal. I haven't cracked open mine yet to confirm. Although, after searching TGO archives, most said the 87 and newer "roller" motors had all metal timing sets. Please someone correct me if I am wrong.

Did you rock the crank back and forth and check for slack? If the chain is original then might as well replace it and not worry about it. I'm going to change out mine soon.

 

I didn't check for slack but if my timing is off then its mostly likely there. the only reason I asked about the fiber gears is that would be the reason that the timing became of, because my 305 has relatively low miles (126,xxx). but anyways yes I have ordered a timing gear and chain set. haven't cracked open the case to look yet though.

 

Check compression first.
Maybe your dist. hold down clamp was loose, I'd reset the timing, unhook the timing connector when you do.

 

does your aldl work? thowing any codes if its not working its not grounded right and likely your computer isnt either. i chased mine down for months, turns out my computer and nothing was properly grounded and was shorting all my sensors.

 

Thanks ill have to check when all this snow melt. Theres like 2ft up here and another storm on the way. So as soon as I can get the hood and doors open ill check.

 

thats what happened to me, i thought it was timing for the longest time, and it could be. but mechanically everything on mine checked out right, timing was right with the esc wire disconnected. mine idled fine sometimes but would stall out and under load it didnt want to move except at high rpms. eventually it friend my computer, and every sensor as well as part of my wiring harness.

 

Yea my timing was off though I tried changing my switching my plug wires around to see if it would fire but run crappy. But no luck.

 

did you disconnect the esc wire? otherise one shop that ill never go to again set my timing 180 off or something before because that wire wasnt disconnected so it idled but it barely moved in any gear.

 

no I wasn't aware I had to. where is that located?

 

Its a tan wire with a black stripe.

 

chances ar if you havent disconnected that wire then your timing isnt right.

 

My wire is right under where that gauge is .. disconnect the wire crank the car set our timing where u want it .. then tighten dizzy check timing again cut the car off and reconnect the wire .. done

Sent from my XT907 using IB AutoGroup

 

ok ill have to check when most of the snow disappears. and yes the last I new of my Aldl did work and its throwing a code but I think its because I don't a have cat at the moment.

 

i dont have a cat and my truck doesnt throw a code. id check it and see what it pulls

 

Unless they changed it from 90-91 lack of cat should not throw codes. I don't think there were after cat O2 sensors until OBD-2. Should be able to pull the cat & the computer be none the wiser.

What's the code?

 

i was gonna say mines a 93 and i barely pull any codes even with a cam, heads, intake exhaust and multiple other mods. only one i pulled was egr but i tuned that out after retune

 

Not saying this is your issue just a FYI I have had a bad CTS not let my vehicle start. It was a 4cyl ford but sensor still serves the same purpose...

 

Does anyone know if the cts would do that on our cars? Would be a nice easy fix. I know Chad 85t/a said about that being it before.

 

it didnt on mine, i removed mine for awhile on my old one before i could replace it. i know fords have alot of cts issues. the sensor shouldnt be all that expensive does it run richer or leaner than usual?

 

Its been running rich for a while. Which maybe a new one wouldnt hurt.

 

id adjust timing while its running

 

yea but my whole problem is getting the car to run.

 

coolant temp sensor generally fails producinng a false very cold coolant temp. filthy rich.

 

so I just tired getting the codes off the car. nothing came up.

 

did you plug that wire back in?

 

the esc wire?

 

yea

 

Yes it was plugged in

 

so I got the timing checked today and it was perfect. although there is a lot of oil in my cylinder. so could it be the icm or a faulty computer?

 

Sure. It could be. Doesn't have to be, though. REAL diagnosis needs to be performed. A scan tool would be helpful, so you can see the live sensor data that the computer is using to calculate fuel and spark.

 

"although there is a lot of oil in my cylinder" ... did you ever run a compression test on it, i dont know much about injected cars yet, but i wouldnt think the computer would be the cause of oil in the cylinders, bad valve seal or bad rings most likely, could also be a bad piston

 

I just did the valve seals in November so it would be in the bottom end. but the oil shouldn't have anything to do with the backfire.

 

I replaced the icm and it made no change.

 

turns out that the rocker arm nuts on number one cylinder and junk. they tightened up and held the valves open. I backed them off and no more back fire. although now for some reason my head gaskets decided to fail. so still no starting.