Need help with a 1991 caravan

[AzNJ808]

First I'd like to say that i'm new to this forums, so hello to everyone here! I
hope by coming here I can resolve my problems with my van. I have tried
searching on-line for answers with no luck or solution in sight. Maybe by
some chance, the people here might be very helpful in my situation.
I usually don't ask for help on forums, but this is my only hope to solve this
gremlin.

ok I have a 1991 dodge caravan 3.3 v6 auto, and since a week ago i've
been having problems. At times (mainly in the afternoon) i would try to
start it and it would crank but backfire. It sometimes would start no
problems, then die out completely after 2, 5, mins..but sometimes it would
start, run fine..then as i try to start it the next day (10 hours later, after
sitting in driveway..overnight or day) it would do the same thing, crank and
backfire..after i do get it started and run it for about 30 mins, i turn it off
then start it again immediately..no problems..only after letting it sit over a
period of time is when the problem stated really starts.

I have changed so far:

TPS sensor
02 oxygen sensor
air charge temp sensor
spark plugs
spark plug wires
ignition coil (no distributor)
two black connected relays

I have researched on-line and found out that it also could be crank and cam sensors...
and the asd relay...i have a hayne's manual for my van..but it also shows 1984-1991
and the pictures/illustrations shown are different than the ones on my van. Example is
the relays..it shows 5 relays on the inner fender, under the hood by the battery..
mines show three above the battery and 4 on the opposite side by the jack..the 4
relays by the jack has two that are connected to the same relay. I have no idea
or where to find the asd relay..someone told me it was black..but there is one gray,
white, and black on the inner fender above the battery..and the one on the other
side is one black and white..with two black ones connected together with i have
changed. My van doesn't have an egr module..I don't know if the asd relay could
be the problem..but it's worth a shot..if someone could help me with the location
of the relay or solve my problem..I'd be very grateful. I will post pics if needed
and keep y'all updated as i wrench to find the problem. Help me solve my gremiln..
Thanks in advance

[tempfixit]

Take a look at this site it may help you:
http://www.autozone.com/az/cds/en_us...rInfoPages.htm

Look at figure 2

Hope this helps

[AzNJ808]

I have recently changed the in tank fuel pump and fuel filter..it started up
after a few cranks with no problem..after 8 hours, I tried to start it again.
it is still the same..it wont start..it cranks still, but at times would backfire
from exhaust and sometimes out through the air filter box..My van is
becoming a money pit, please advise what to do next...i am at my wits end
with no solution in sight.

tempfixit>> thanks for the link, now I know which relay is what..

http://www.tomco-inc.com/Catalog/cam...%20sensors.pdf

after reading this...
I will now change the cam and crank sensors..over the weekend..and post my results..

[RIP]

Yup, that would be my choice. Cam/crank sensors are infamous for causing what you're seeing without throwing a code as they should. I'd recommend OEM sensors.

[AzNJ808]

ok so now I have finished changing the sensors...the van starts right up..no backfiring..
but it dies out after letting it run for about 15 mins...I haven't done the overnight test yet..
since i had just finished with the change. but what would be my next part to check/change..

I was thinking IACM (idle air control motor) aka AIS (automatic Idle speed motor)

also while changing the sensors, the paperspacers was removed from both sensors..
and the car would start but would have this ginding noise..so I went back and pulled it
out a little, and problem solved (would the spacing of the paper needed to be exact??
or can i get away with this) also, would this be the cause of the engine dying out??
if so, then i will go back and put them paper spacers where it is needed. please confirm
for me and thanks for your help.

[RIP]

Ouch! Spacing between the sensors and it's reference point is critical. The paper on the tips of the sensors provide that spacing. If you heard grinding then you may have trashed one or both sensors. Tough to say without seeing them. I would try reapplying the spacers and reinstall before forking out more cash on something else. Which sensor did you pull back to cure the noise. Might try it on that one first then crank it up and see if it cured the stalling.

Sounds like you're on the right track. Just need to tweak it a bit. When it stalls do you get a check engine light?

[AzNJ808]

thanks RIP for the quick reply..

there is no CEL thrown, when the engine stalls..and the condition of the sensor is slightly abrazed, but not to the point where the sensor magnet is exposed or cracked..I will try to go back and replace the spacers and see if that works..if not then, maybe I will change both..

After the 8 hour wait..car cranks, but no start..although the backfiring has been solved..

[AzNJ808]

UPDATE: so I have bought new crank/cam sensors..because i didn't want
to take the chance of running damaged parts/sensors. I tried to buy some
paper spacers but it wasn't in stock where I lived and if i purchased it
online, it would've taken a week. But this time the New set of sensors came
with a paper note saying: That the paper is not to be removed and to install
as is..if no paper is present, you have to glue a paper spacer to the tip (.30)
prior to install..The first set, didn't have this note..thats why it was removed..
Thats why I asked on here how important it was to have it there..

So after switching them out with brand new ones (with the paper spacers)
it started right up again..also with a grinding noise. I was worried that i would
be ruining them again..but i remembered that the paper has to sheer off on its
own..and within a minute the noise was gone.

All i have to do now is do my overnight time tests and we'll see whats the result..

As for the old sensors here is how the old (the oem) sensors that came off my van looked.

crank on the left..and cam on the right





Heres the one that had the paper spacers removed..and installed without paper spacers...how it looks after removing it to install a 2nd set.

Cam sensor


Hardly any damage

Crank sensor


Slightly abrazed

Are these sensors in good condition and still can be used?? If i just order
some paper spacers??

[AzNJ808]

congrats RIP......cam and crank sensors with paper spacers did the trick..
you have solved the gremlin..My van works normal for NOW and I have you
mostly to thank..cheers!! It was your advice that I trusted and now
you have helped me in a big way, and I am very grateful for your time and
understanding. If you haven't pointed me in the right direction, I would've
changed alot of things that wouldn't have to be changed. And spended
alot of money.

Thanks to the 2 people who responded and replied..This is the place to find
help if you have a issue with your dodge caravan..

Let it be known..RIP's advice can definitely be a solution to your problem. Thanks again!!