'94 Condorde 3.5 Update

[ShelbyZD]

Well.. FINALLY.. got time/place to look into some of the Concordes problems. Its been crazy cold here lately (-0'ish F) so I havent had much incentive since the car has been working quite well.

Anways, Heres the problem:

1. Engine Fans are stuck on all the time (when started).

2. Poor Fuel milage. (About 18mpg city/highway combined)

3. Engine miss.

4. Idle speed is very low.. about 400

Stuff done:

1. New spark plugs.

2. Tested wires - no problems

3. Coil pack seems to be fine.. lots of voltage .. shocking me .. :( heh

4. Dumped a bucket of water on top of the engine (when it was cold of course).

5. Semi fuel injector test. Aka we unplugged it and it made virtually no difference in the idle.

6. No fault codes.

We did narrow it down to the very front left cylinder (no 1?)
and the spark plug is definately brown on the bottom, fuel injector ticking, but there is only a very subtle change in the idle speed when either the spark plug wire or fuel injector is disconnected. The water test - no change in idle note/speed.


Also, I should note that the A/C was disconnected. No Belt because the compressor is seized. There are however NO plugs disconnected anyware. Also Also..The car does not burn any oil, Mobile 1 5-w50 has about 1000 kms on it and is still very clean.

[moparman76_69]

do a compression test?

[ShelbyZD]

Tried.. couldnt find the guage. :(

[Vigo]

on my 97 intrepid, that cylinder has misfired since the day i got it ( put a timing belt on it to get it running). i have done every freaking test i could think of to it. at one point it was so bad it was undriveable, and messing with the pcm connector made it much more driveable. might have been bad connection or grit in there but the problem didnt entirely disappear.

i have heard some things about injector wiring harnesses going bad on those, and i think that is the next step for my intrepid. heres the tests ive done:

fuel pressure test
fuel injector signal test
fuel injector flow balance test
fuel injector cleaner (BG44 iirc)
fuel injector ohm check
replaced an injector
replaced fuel filter
Checked injector circuits continuity/resistance from injector to pcm connector
replace lower intake manifold gaskets
spark plug wire ohm test
watched spark tester (two kinds)
compression test
Block EGR and EVAP (ruling out variables out of frustration)
cylinder leakdown test
coil ohm test (pri and sec sides)
replace plugs
replace plug wires
swap coil pack with known good
Checked/cleaned pcm connectors and various others
swap pcm with known good (had extra, no $$$ thank goodness)
remove valve cover and inspect for flat cam lobes, broken valve springs, broken/unseated rocker arms, collapsed lifter/hlas.
inspect cam timing gear for sensor ring damage/interference.
rerouted plug wire to rule out ignition crossfire and inspected insulation for breaks
replace cam position sensor with known good.
reset cam timing.



its been a long frustrating journey of failure despite checking more things then most people would even think of.


also, i bought a 93 3.5 concorde for 550 bucks and im tearing into that motor right now because the bearings are crumbling to bits.

fun fun.

[Orangetona]

Replace your intake manifold gasket. Im willing to bet it will cure your engine miss problem. For both of you actually. The 3.5L is notorious for it. Also, DO NOT USE SILOCONE on the gasket. Same with the thermostat gasket etc.

I had this same problem on our 97 eagle vision with the 3.5L. It was sucking air through the intake gasket. Its relatively easy to do.

Im editing this for Vigo, I read you replaced the lower intake manifold gasket, but did you use rtv/silocone? If so, you need to change it again. For some reason the gasket doesnt accept it.

[Vigo]

no i didnt use silicone, and its not leaking. i've doused the whole area with all sorts of liquids repeatedly.

but i second changing it. i got the whole manifold gasket set (which has like 7 gaskets in it) for $5 at o'reillys. cant beat that!!

[shadow88]

I still think the fans are on all the time because the a/c pressure transducer is bummed. As long as you won't be using your a/c, unplug the connector. It's under the car on the aluminum a/c line from the condenser to the compressor (I think). It's towards the passenger side right by the bend of the "u"-frame.

[ShelbyZD]

Thanks guys.. I'll definately look into this stuff.. eventually. It's so blasted cold here now.. can't do too much. :(

[Vigo]

iirc the a/c will only turn on the low setting. go to your relay box in front of drivers strut tower, pull LOW fan relay. if they still run its on the high setting which is not triggered by the a/c system and the problem is elsewhere.

i think. :P

[moparman76_69]

on my 97 intrepid, that cylinder has misfired since the day i got it ( put a timing belt on it to get it running).

So no compression is leaking from that cylinder? You saying you had to do a timing belt was making me think bent valve.

[JDAWG]

a 3.5 WILL bend valves if it broke or skipped a tooth, do a timing belt NOW

[shadow88]

a 3.5 WILL bend valves if it broke or skipped a tooth, do a timing belt NOW


On a 94? I haven't seen one of those bend yet and I have seen many timing belt failures on those. From about 99ish to current- they bend.

[22mopar]

a 3.5 WILL bend valves if it broke or skipped a tooth, do a timing belt NOW

really???? I just did one that the waterpump locked up, took out the timing belt... replaced the belt and pump and NO bent valves. ShopKey says free sping engine, Chrysler says it's a free wheeling engine. I guess we all could be wrong.:D

[ShelbyZD]

On a 94? I haven't seen one of those bend yet and I have seen many timing belt failures on those. From about 99ish to current- they bend.

Why would they do that? As the saying goes.. if it aint broke dont fix it.


Anyways, had an opportunity and cleaned the electrical contacts on the pcm. No difference sadly. :(

...so the list will go on.

[shadow88]

Don't quote me on this, but I think it was a raise in compression that lost the free-wheeling feature.

Do you have compression test results for us?

[Tony Hanna]

I may be completely off-base here, but low idling, cooling fans running, engine running rich. Have you checked the coolant temperature sensor and associated wiring?
Might not have anything to do with the problem on something that new, but if it was an old TM that would be the first thing I'd check.

[Vigo]

the timing belt in my intrepid has broken twice with no valve contact. The ones i own are non interference. Also, a compression check would show a bent valve pretty quickly and i've done that test half a dozen times on the offending cylinders with 120 every time.