I really, really thought I had it fixed. Need Help Please!!!

Topic: I really, really thought I had it fixed. Need Help Please!!! (Read 4603 times) previous topic - next topic

I really, really thought I had it fixed. Need Help Please!!!

May 21, 2016, 10:47:22 PM

Hi,

It's been a little while since I've been on here (I've been busy with end of the school year stuff and graduation!). In my last engine related post I think I noted that my rough running/sputtering problems had been solved with the replacement of the fuel injectors. That helped tremendously for about a month and a half. I have put about 600 miles on my '85 since the new injectors and it has been running great! However, just two days ago I started it up for the first time in about a week and a half, and it was doing its same old things. It was coughing, sputtering, and surging while I was driving it around town. I would greatly appreciate any suggestions on what I could try next.

Thanks!

I really, really thought I had it fixed. Need Help Please!!!

Reply #1 – May 21, 2016, 11:07:35 PM

Can you test fuel pressure? Pumps ever been replaced?

I really, really thought I had it fixed. Need Help Please!!!

Reply #2 – May 21, 2016, 11:28:42 PM

I've never tried testing the fuel pressure. I would doubt that with 86,000 miles the fuel pump has ever been replaced.

I really, really thought I had it fixed. Need Help Please!!!

Reply #3 – May 22, 2016, 07:35:31 PM

I've never seen a weak pump cause a idle or even cruse problem, they will cause lazy performance on acceleration and in case of Turbo Coupes completely stop pulling... I'm not saying don't check pressure but my bet is your problem is elsewhere...

I really, really thought I had it fixed. Need Help Please!!!

Reply #4 – May 23, 2016, 12:07:39 AM

Thank you. Given that I've changed the injectors and the O2 sensors, and that it doesn't change if I adjust the timing (advanced and retarded the timing, and it ran the same), what else might I check? I mean, when I drove it on Thursday it was almost stalling at stop signs. It's sputtering and surging when driving down the street. What's maddening is that it's intermittent. It will sputter and cough for a few seconds and then run ok for a minute or two, then it will repeat the same thing.

I really, really thought I had it fixed. Need Help Please!!!

Reply #5 – May 23, 2016, 03:53:06 AM

Check the MAP sensor, check for vacuum leaks, especially at either end of the MAP sensor hose. I've seen a MAP intermittently register no vacuum, since a speed density car calculates load by the MAP, that can be a huge problem. At zero registered vacuum, you'll get a massively over-rich mixture, and since you're load is screwed up, you may also get incorrect timing advance. I don't know how deep that rabbit hole goes on an 85 CFI car, byt my 88 SFI car did all these things before my MAF conversion. I ran it down to a MAP with the help of a couple senior techs at the Ford shop I was working at.

I really, really thought I had it fixed. Need Help Please!!!

Reply #6 – May 23, 2016, 08:19:55 AM

Have you replaced the EGR at all? How about the catalytic converters--any black smoke coming from the tailpipe?

If all else fails...you need a new EEC-IV processor. The 1984-85 V6 processors are notorious for acting up, and a lot of them were bad from the start. I've unfortunately experienced that a few times, once with my current '84 V6 and once back in 1988 when my first 3.8L car was just 4 years old. My folks thankfully purchased the extended warranty for it...the mechanics changed all kinds of stuff, including the EGR, and it didn't help at all, or like you it would help for a bit then the surging/bucking would come back. They finally threw a new processor at it, and the car ran like new ever since. They told me at the time that since the EEC-IV was new they were seeing higher failure rates than normal on 1984-85 vehicles. So...that should be the last resort for you but it would likely solve your issue. I'd recommend a 1986 processor if you can find one (technically you can run any 1984-87 3.8L V6 T-Bird/Cougar processor in your car).

I really, really thought I had it fixed. Need Help Please!!!

Reply #7 – May 23, 2016, 11:56:31 AM

Thanks! Guys!
EricCoolCats, when you say processor, are you meaning the computer that's located behind the passenger side kick panel? Are these still available new?
Also, I've run it up on a diagnostic code reader and everything checks out fine.

I really, really thought I had it fixed. Need Help Please!!!

Reply #8 – May 23, 2016, 01:06:40 PM

Yes, that's the processor. I don't think they're available new but I find them on eBay every now and then. Personally I would avoid any 1984 and 1985 V6 EEC processors just to avoid the risk of having the same issue. I am also leery of remanufactured EEC processors; try to find an OEM Ford one if possible.

Also, I was thinking about your issue and it's possible that the timing chain is stretched. That would lead to more interference, what with the engine timing being off, and would cause the issues you describe. But I'm still leaning toward an electrical (computer) issue. Even a bad EEC sometimes will throw no codes because it doesn't know it's broken.

I really, really thought I had it fixed. Need Help Please!!!

Reply #9 – May 23, 2016, 04:03:05 PM

Ok cool! Thanks!
At what point should timing chains be replaced? The car only has 86,000 miles.

I really, really thought I had it fixed. Need Help Please!!!

Reply #10 – May 23, 2016, 04:28:01 PM

It's a shoot...technically your mileage isn't that high BUT your car is 30+ years old. I'm at 108K on my current '84 and it's still pretty good (had my mechanic go over that when I got the car). On my first '84, the timing chain went bad at around 140K miles. You're probably okay but with the tendency of those motors to have stretched timing chains as they age, I just thought it was prudent to let you know. IIRC it's a single chain.

I really, really thought I had it fixed. Need Help Please!!!

Reply #11 – May 23, 2016, 08:18:37 PM

Thanks! I will check into getting a new processor.

I really, really thought I had it fixed. Need Help Please!!!

Reply #12 – May 23, 2016, 09:59:23 PM

Its not the timing chain. A stretched chain wouldnt cause a intermittent problem.

Again I will say test the fuel pressure. I have seen many pumps cause the exact problem your having. Im not sure if a v6 car uses two pumps like a 2.3 car but if so it could very well have one of the two going bad but still provide enough pressure to keep it running half ass.

I really, really thought I had it fixed. Need Help Please!!!

Reply #13 – May 23, 2016, 10:29:41 PM

I agree...which is why I stated that processor replacement should be a last resort. There are a lot of other things to check first, including the EGR and fuel pressure/pump.

I really, really thought I had it fixed. Need Help Please!!!

Reply #14 – May 24, 2016, 08:17:31 AM

Thanks again guys!