View Full Version : fuel injectors and the IAC

07-15-2002, 10:09 PM
I think mine are bad or installed wrong or something. Is there some special way of putting them in or something? My car acts a lot like it did the day it broke down on me and these are the same injectors in my new motor and it runs the same as then for the most part. Actually worse; it wont idle or run unless I play with the pedal and the tach is just going all over the place while the whole car is shaking and sounding like chit. If I take my foot of the gas the RPM slows then dies.

Could faulty injectors cause it to act like this? This is the only thing I can think of that could be causing it to run like this. Everything else appears to be fine. Can't find any vacuum leaks either. I just don't know what could be causing it to run so lean. I must have re-checked my plug wires a dozen times but it runs as if they are crossed. That is the best way to describe the situation.

Also, someone told me my IAC could be the root of the problem. The IAC is also from the old motor. I took it off and inspected it and the top hole looked nasty and dirty. The bottom hole wasn't pretty but wasn't too bad. I was going to clean it but then I read my service manual and it says to not clean it, only replace it. Is this true?

07-15-2002, 10:25 PM
I'm not familiar with your situation, but have you checked replaced any of those since rebuilding the motor? The way it is running sounds like it may be one of those problems.

07-16-2002, 08:51 PM
anybody else have any suggestions?

07-16-2002, 09:24 PM
I am in the same boat as you right now. As soon as my mechaninc gets this problem figured out, I will be sure to tell you what the deal is.

I have so far replaced these components:

Cam sensor (CID sensor)
Crank sensor
O2 sensor
MAF sensor cleaned
ECT sensor (of no relevance, but still replaced)
Plugs & wires

If you get it figured out before I do, let me know and maybe it will help me, and vice versa.

07-16-2002, 09:36 PM
To add to what I said earlier, the IAC only affects idle. If it is running like crap above idle then it isn't the IAC for sure. Injectors usually go bad by clogging up a little at a time. Your symptoms are too severe for it to be the injectors, unless someone put sugar in your gas or something. Make sure your harmonic balancer hasn't "spun," or the bolt hasn't sheared off.

Don't forget the simple things, like fuel filter, vacuum lines, etc.

Good luck.

07-17-2002, 01:43 AM
I think im going to bite the bullet and just take it to the dealer. $75 an hour is going to hurt. I am tired of playing with the car. I think I am just going to mess up my new motor if I keep on running it lean. I am going to find out soon if my insurance will cover towing it to the dealer.

07-17-2002, 02:47 AM
Check every connection after the MAF. How were the IC tubes sealed?

07-18-2002, 01:22 AM
tubes were sealed with ultra-copper high temp RTV. I did this twice, so the second time I took extra care at making sure I had plenty of goop on there to seal them up. I heard them whistling the first time and after I resealed them, the whistling stoped but it didn't run any better.

One strange thing I found out though: If I keep my foot on the brake pedal and give it gas in Park, my brake pedal gets closer and closer to the floor.....like there is a vacuum leak or something. I tried doing this on my Mustang and on my girlfriends car and neither one of them did it. Could that mean anything or am I just looking too far into it?

I am going to have the car towed either tomorrow or friday. I have given up on it. One last thing I wanted to check were the fuses. I guess its a long shot that the ECM fuse is blown or something, but I would hate to have to pay the dealer lots of cash for diagnosing a blown fuse.

07-18-2002, 03:05 AM
Listening is not the way to check for air leaks and adding more RTV is not the way to seal the connections.
You need propane or intake cleaner and you spray it at each connection while the car is at idle. When you notice a change in the idle, it means that connection has a leak. You only need a very small even coating of RTV on 1 side of the joint. 22 lb ft of torque is all you need and make sure the flanges are equal or square.

Rob Noth
07-18-2002, 11:52 AM
How about starting with the easiest test - check for codes. If you haven't already done this, it might give some clues as to the problem. If you take it to the Ford dealer, all they will probably do is check for codes, then replace anything that has a code, or if there are no codes, they'll just start replacing everything...


07-18-2002, 04:57 PM
About your brakes going to the floor, this is normal. Your mustang and your girlfriends car probably have a vaccum brake booster. Ours is the accumulator filled with pressure. Therefore while you press the brake, the pressure releases causing your pedal to get closer to the floor. I beleive the term for that is called "pedal creep".