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Old 04-06-2002, 18:53   #1 (permalink)
K RO
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Idle misfiring/surging

I have an 89 EA GL with the single-point 3.9 and a dual petrol / LPG conversion.

When I bought it, a faulty relay meant the petrol system had been unused for a couple of years. The relay cost $25 to replace, but the fuel had badly corroded the system. A new tank and fuel pump, new fuel lines and a rebuild of the injection mechanism were necessitated, and the car was then run on petrol a-ok for about 6 weeks.

About that point, I tried to run it on gas again: fine, but the engine stalled when the gas/petrol switch was made. A $200 fade-out system fixed that (kept small quantities of the just-turned-off fuel flowing while the other one was starting to be delivered). Again, another 6 weeks of fine running on both fuels.

At this point, the car began to idle roughly, and that progressed within a week to surging and stalling at idle or moving away from idle. The longer it idled, the worse it was. I took it back to the mechanic who did the LPG work, who checked and decided it was neither the brand new injectors, nor the new relays, causing the problems. He suggested a plug change - which didn't help - and pressure-tested to rule out any head problems.

The problem persisted. Thinking electric, I took it to an auto electrician: nothing wrong with anything. They fitted a new set of leads: no change.

At this point I gave up and took it to Ford, who suggested all of the things I'd tried, replaced the engine control chip, and fitted a $200 set of Bosch race-standard leads: no fix. Finally they decided (after 3 days with the car) the problem was irrepairable and recommended a replacement engine.

I'm interested to know what could possibly be causing the problem. The car involved was recently written off in an accident, but I bought the wreck from my insurer and am contemplating repairing it (in which case, I need to decide what to do about the damn engine).

Can anyone give me any ideas?
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Old 04-06-2002, 19:20   #2 (permalink)
Ebeast
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Idle

I seem to have a problem with my eb cfi, idles poorly and just started stalling when going slow. I dont know whats wrong either, hope i dont need an engine swap.
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Old 04-07-2002, 07:37   #3 (permalink)
Brent79
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Re: Idle

Does it idle poorly on both gas and petrol? Have you checked for ECU error codes??

Brent
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Old 04-07-2002, 20:19   #4 (permalink)
K RO
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re

Brent:

Yes, it idles poorly on both fuels, and will stall almost immediately on gas. I personally haven't checked the ECU codes but I assume the Ford mechanics did... they charged me enough to replace the whole damn engine twice... they also replaced the chip, so I imagine the whole control system came under examination. They reported they were unable to find anything not working as it should.

I work shifts, mainly nights, so I don't have a whole heap of time to check it myself :(
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Old 04-08-2002, 06:30   #5 (permalink)
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Re: re

try the map sensor?
if you hold your foot down a little can you get a decent idle at low revs?
if so it could just be the idle control solenoid...
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Old 04-08-2002, 21:53   #6 (permalink)
ben
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Re: re

dude you sound like you have done a head gasket, ford certainly wouldnt tell you as they make $80/hour on engine replacements. check your coolant level

If its electrical:

ok they may not have picked this up if the sensor isnt actually out of range (the ECU codes test reports a sensor that is currently, or has ever been (until last reset) out of range), but it could still be faulty..........check your throttle position sensor, these are often internally fraid and cause jolts and rapid random rev changes, sometimes stalling at lights and hard breakings, also rough idle, also surging at a constant speed.

if this isnt the sensor, the only other one that could cause this is coolant temp sensor, so check the operation of that......but generally these just go out of range when they're ****ed.

If its been ok for 6 weeks after getting it back from them then its probably just electrical, the smallest things can cause big problems, and ford dont often have the answer.......take it into ultratune for a free quote or something if you cant figure it out.

ben
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Old 04-08-2002, 21:58   #7 (permalink)
Brent79
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Re: re

What about the TFI module? a ****ed one would cause those symtoms wouldnt it?

Brent
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Old 04-08-2002, 22:07   #8 (permalink)
ben
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Re: re

sure would brent but as far as i know if it was ****ed it would come up in the memory codes test.....or even the instantaneous codes...which really makes me stumped whether ford did the test properly or whether they are conning an engine swap.....afterall they probably think he's gullible enough after having 2 done ? (is this right??)

ben
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Old 04-08-2002, 22:14   #9 (permalink)
Brent79
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Re: re

Ben, an interesting bit of info for ya... When i had my CFI converted, the computer wasnt receiving a secondary waveform from the distributer coz of bad wiring yet it didnt spit out any ignition error codes! All i got was a TPS and ISC error code...

Brent
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Old 04-09-2002, 09:41   #10 (permalink)
ben
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Re: re

that is interesting......but the TFI wasnt functional when it gave no error code right ? Its obvious a dead ignition system can do this....and the best way i can suggest to test it is take each lead off one by one and test for a consistant spark...this tells you the whole electronic ignition is working, if the sparks arent consistant, its probably the TFI module, or if just one isnt working or is inconsistant check the distributor cap, or dizzy for that matter.....

ben
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