1989 Rough Idle
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1989 Rough Idle
3.0 Eddie Bauer with rear air runs rough at idle and smooths out with higher rpm. Problem started several months ago and ran fine when cold but rough when starting from a hot condition. Problem was intermitent for a while and cleared up for several weeks, became intermitent for several weeks and is now a permanent problem. I have installed new plugs, plug wires, distributor cap and rotor, pcv valve and checked and replaced leaking vacuum hoses. Any suggestions? Thanks, Louie in FL.
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Joined: Dec 2006
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From: Kitchener,Ontario,Canada
Sounds fuel system related.
Air cleaner, fuel filter is cheapest, when was last changed?
Fuel pump regulator (check pressure)
IAC & ECT, ACT could be your problem (are they fitted) , whats fuel consumption like ?
Could also be an air leak somewhere or EGR valve stuck.
ATB Aeroman.
Air cleaner, fuel filter is cheapest, when was last changed?
Fuel pump regulator (check pressure)
IAC & ECT, ACT could be your problem (are they fitted) , whats fuel consumption like ?
Could also be an air leak somewhere or EGR valve stuck.
ATB Aeroman.
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Joined: Apr 2005
Posts: 5,720
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From: Washington state
read codes and please post here
many codes will not set CEL
http://fordfuelinjection.com/?p=13
likely suspects, ECT or wiring plug, engine thinks its still cold when hot=over rich air/fuel mix. or O2 sensor which is not in the fuel control loop when engine cold.
can also get codes read at many local auto parts stores
we'll start with codes and save some throw parts at problem money.
also give us a list of work done in last year on Aero
many codes will not set CEL
http://fordfuelinjection.com/?p=13
likely suspects, ECT or wiring plug, engine thinks its still cold when hot=over rich air/fuel mix. or O2 sensor which is not in the fuel control loop when engine cold.
can also get codes read at many local auto parts stores
we'll start with codes and save some throw parts at problem money.
also give us a list of work done in last year on Aero
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Re: 1989 Rough Idle
I forgot to mention that my mechanic has checked the system twice and there are no error codes. In august he replaced the air conditioning compressor, condenser, accumulator and several ac hoses. He also installed a new fuel filter, hego sensor, and air filter. The run rough problem was intermitent before and after this work and has become continuous in the last two weeks. He unfortunately died of a heart attack on Oct 26 and I have since then checked all vacuum hoses and cleaned the idle bypass valve, the ACT, and verified the correct ohm and voltage readings on the TPS. The van has 165,000 miles and the only serious problems I have ever had were with the AC system and the power windows. Louie
Post Fiend
Joined: Apr 2005
Posts: 5,720
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From: Washington state
i would start with measuring the resistance of the ECT both cold and hot plus check it's connector and wiring for corrosion, insulation scraps and wire breaks
if the ECT is original 165k miles, time to replace, cheap DIYer 10 minute repair
http://fordfuelinjection.com/?p=28
use teflon tape on threads, this is a 2 wire device that does not rely on electrical contact with the engine. will prevent corrosion lock into alum. intake manifold
the cold start>cold drive away strategies are pertinent for your Aero problem
http://fordfuelinjection.com/index.php?p=64
if the ECT is original 165k miles, time to replace, cheap DIYer 10 minute repair
http://fordfuelinjection.com/?p=28
use teflon tape on threads, this is a 2 wire device that does not rely on electrical contact with the engine. will prevent corrosion lock into alum. intake manifold
the cold start>cold drive away strategies are pertinent for your Aero problem
http://fordfuelinjection.com/index.php?p=64
Last edited by 96_4wdr; Nov 3, 2007 at 09:39 AM.
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1989 Rough Idle Update 2
I replaced the ECT. Plastic portion of the old one came apart when I unplugged it but the new one did not correct the problem. Because the Idle Bypass Valve was pretty dirty when I inspected it I also replaced it with a new one. Upon cranking cold it still idles rough and cruises rough but seems to be okay under hard acceleration. I drove it about six miles and shut it off for about 2 hours. After cranking it for the return trip home it ran much worse than it ever has at idle, moderate acceleration and at cruising speed. Consistent with past experience the problem seems to be temperature related.
The original 165,000 mile sensors remaining are the ACT, MAP, and TPS. Any suggestions? Louie
The original 165,000 mile sensors remaining are the ACT, MAP, and TPS. Any suggestions? Louie
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Post Fiend
Joined: Apr 2005
Posts: 5,720
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From: Washington state
pull off the IAC and watch it open fully when cold. if not then wiring has failed. also pulling off electrical plug while running cold=engine die
spray carb cleaner with spray tube around each vacuum fitting and vacuum tree on back of intake manifold, also intake manifold
use short small squirts
temp can affect a seal vacuum leak
idle smooths out=vacuum leak found
also check vac. line to tranny vac. modulator
measure ACT resistance per link, they only have a mild effect on air/fuel mix
check TPS for resistance change smoothness per link above
most wear out before 165k
with no codes, you are now hunting in the dark
spray carb cleaner with spray tube around each vacuum fitting and vacuum tree on back of intake manifold, also intake manifold
use short small squirts
temp can affect a seal vacuum leak
idle smooths out=vacuum leak found
also check vac. line to tranny vac. modulator
measure ACT resistance per link, they only have a mild effect on air/fuel mix
check TPS for resistance change smoothness per link above
most wear out before 165k
with no codes, you are now hunting in the dark
Last edited by 96_4wdr; Nov 7, 2007 at 09:26 PM.
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