JSe420

So I have tried to just ignore this problem that I have had for a while now. Ive just been throwing parts at it thinking that I would eventually get the right one and my problems would be solved. wrong. So she starts really rough on cold starts and idles pretty rough all the time. I have already wasted a starter because of all the cranking on cold starts Its pretty embarrassing to get into a nice car and have it start like crap and idle like crap. But anyway, so far I have done, new plugs, wires, caps, rotors, air mass meter, coolant temp sensor, and I just put a new wire harness in it tonight. Still no progress.

Heres a couple things I am still in question about:
-My ASR light fluctuates, but would that cause the problems I have?
-I haven't done o2 sensors yet but plan to eventually. Could bad o2 sensors be the culprit of my rough startups and bad a/f ratio?
-I also haven't done an injector service but plan to do that as well.

Anything else I should look out for? I was hoping that the wiring harness would solve all my woes but I was wrong. Not going to give up on this one so any suggestions are appreciated. Thanks

BJaltima

Sorry to hear about that. Mine seems to have a little of a rough idle when cold, but she only does it on a rare occasion. What do we have in our V-8's that would compare to the OVP relay that the I-6's have? It seems to be the same issues, except there's no OVP relay to check.....or so everyone keeps saying :p

ocpanther

So far to combat DIFFERENT rough idle issues I have:

1) replaced fuel pump relay
2) replaced fuel pump
3) fixed several vacuum leaks
4) replaced OVP
5) replaced the two vacuum lines to the ICV
6) replaced the throttle position wiper switch
7) adjusted the air/fuel mixture
8) replaced the ICV
9) Replaced the ECU
10) replaced the cold start injector valve
11) adjusted and lubricated the throttle linkage
12) replaced spark plugs
13) cleaned and reseated spark plug wires (had two totally corroded)

every one of these things had some effect all were at different times and fixed one thing or another. Now I finally have a one crank start whether hot, cold, just run, not run for a week. granted this is all on the I-6 3.0L from 89, so I am not sure how it translated to the V8s but the later cars seem to like airflow and to know how much plus have good vacuum.

Hope something in this information helps.

ps2cho

His is a completely different engine and fuel management, so you can't really give any thoughts from the M103.

The O2 sensor on yours is a 3 wire, but I believe the 3rd wire is only for the preheater. Probe the sensor wire to establish what the O2 sensor is reading. It ranges from 0-.9v so you want to "see" on the DMM about .5v otherwise you could be running very rich/lean. I would assume it is in the same place as the I6's under the passenger carpet?

ocpanther

I forgot, I did the O2 sensor too.

JSe420

Thanks for the responses. I can tell that I am definitely running rich just by the way it smells. I really cant imagine an o2 sensor would cause whats going on with my car though. It cranks for wayyy to long. I was told to probe the o2 sensor when it was hot and when it was cold and if the values were the same then the o2 sensor was bad. If they were different it was good. Does that sound right?

Edit:

I should also note that my auxiliary fans are acting up. Turning on and turning off at completely random times. I thought that the new coolant temp sensor would solve that problem..but again I was wrong.

ps2cho

Not really. The O2 sensor is used mainly in closed-loop, so I doubt the poor starting is O2 related, but if you have no history in the last 60k miles, just replace it. Splice in a 1990 Mustang GT's one for $35. It's cheap enough so justify just replacing it.

Have you checked fuel pressures? What about cold/warm starts? Could help point to possible accumulator issues...

JSe420

Havent checked fuel pressures. Will check as soon as possible.
Definitely plan on doing o2 sensors either way but I just really want to get it starting the way it should and what not. Sensors from a '90 mustang are plug n play?

ps2cho

Sorry, what am I saying, ignore that. Only applies to earlier models.

JSe420

Anyone else dealt with a problem like this before? I need to get this thing running right, its getting nice out!