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1990 Mustang 5.0 takes forever to start

1987 Views 15 Replies 5 Participants Last post by  MustangBradley
I got my 90 mustang GT in on a good trade. It has a BAD problem with starting. Almost like its got a VERY bad carb on it. BUT its all factory and fuel injected. Only thing thats been removed is the Smog Pump and EGR. problem is it literally takes almost 40 seconds of holding down the starter for it to FINALLY run, and when it does finally run it kinda backfires in the intake and and have to keep giving it gas to keep it running. But after it gets a little warm it idles and runs perfect. drive it 200 miles and runs great. stop at store to put gas in it and got to hold down starter for another 30 seconds before it finally cranks back up.

When i got it it had no O2 sensor harness on it. thought that was what was wrong with it. finally found one and bought it and hooked them up and still took forever to crank, but problems got even worse, after running for about 5 minutes it starts missing BAD from idle to about 2500 RPM then runs Like a new car. So i unplugged them for now. But i got to get those fixed also.
The car has a new Temp sensor on it, New IAC valve on it, Just tested the tps and it checked out perfect. Its got good fuel pressure to the Shredder valve. Spark plugs and wires and rotor button and cap all look good. Any one have any idea what could be going wrong? I would REALLY appreciate it if anyone could give me somewhere to look. I dont want to have to take it to a shop, but its not looking too good as of rite now.

PLS HELP!!!:?:
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The coil i have not replaced, but i did pull a random wire to check for fire and it was like lightning coming from it, as if it was like a new one, but i will buy a new one and try it.

I also did try to mess with the timing a little, i marked where it was set and loosened it and retarded and advanced the timing, both made it even worse.... so i set it back to where it originally was.....

I appreciate y'all trying to help me out,.... this is killing me. lol.
thanks for the advice. The only thing i did was loosen the distributor hold down bolt and periodically moved it further back then further forward. it just basically got worse, so i put it back exactly where it was in the first place. I was actually thinking of pulling the whole distributor out and completely resetting the timing the best i can by ear.... as i dont have a timing light, but i have noticed, on the harmonic balancer you can see where the factory line is for the timing and then about a half inch to the right of it someone has marked another line with some type of White paint.... Any idea what that could be for?
Bradley, I am going to try exactly what you just told me rite after i get off the computer. Now the person that posted last said my timing is to far retarded, so i am going to try to advance it and see what that does for me. I will take a picture of it also when i get out there... Do you have any clue about the problem im having after i plugged the O2 sensors up? the acting like its running on 4 cylinders until about 2500 to 3000 rpm? could that possibly be the timing? But it also does not do it all the time, just when it feels like it, sometimes for about the whole time im driving it and sometimes not at all?
+1 eagle

In case nobody has told you the spout connector "must be unplugged" to adjust your timing or your computer will do anything to try and get it back to normal. The spout connector is right in front of the distributor.. It is the only thing hanging there with a 2 prong connector and plug rammed in to complete the circuit.. Pull this with car off.. Then start and you could try to advance and retard to get it better.. But rent the gun and do it right.. Or you could blow a nice 1/4 hole through a piston :)

OMG. that would suck. How much is it to rent a timing light normally? Thanks for the info!
Of course, it is best to use a timing light, but with the info from your previous posts, I am merely trying to get you back to a known good baseline. You don't need a timing light to set the timing back to stock, since that is what the mark is for that I described above. Once you get the timing to stock, you'll be able to do more diagnosis.

You'll want to pull codes, then kill the memory and start it up again. Let it relearn for about 10 minutes of idling and then pull codes again. Compare the two lists. I expect the O2 sensors to be on the first list, but if you have them working properly, they should not be on the second list.

Once you get to this point, you should have an idea of what you need to investigate further.

Have you ever had the distributor out? Has the car ever run right for you? If I read your first post correctly, it has never run right. I wonder if you are one tooth off on the distributor. I was one tooth off, and had a similar set of symptoms to what you have. If you suspect the distributor has been out, it might be worth your time to find TDC and make sure the rotor is pointing at the Number 1 plug wire.
I got a code reader from autozone today. Have not had time to pull codes yet, I have to work 3 12 hour night shifts starting thursday night. But when im off monday im going to get further into it.
When you said kill the memory how am i supposed to do that? Pull the battery cable for a length of time?

And whoever had it before me had put a brand new ford motorsport Ignition control module and Distributor in it. Its brand new. and i tried the timing, it is cranking a little better, but i think it is one tooth off. i had to turn it as far to the left as it could go (Before the Ignition control module hit the Thermostat housing) and it started actually idling like it should when it first crunk up and i didnt have to keep giving it gas. and it did crank alot faster. so Im pretty sure i got to pull TDC and reset the timing.
Im so glad were actually onto something with it....
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