93 Dodge Caravan Stalling Problems

I bet both computers (assuming that he gets the original back) work fine.
The prior code - 77 - was
read wrong, so it could have been part of the following code meaning the
following code was bogus
also. It could be that instead of a 77 and 53 that there's actually 3
separate codes in there.

The sad thing is that the original poster could probably have gone to one of
many auto parts
places (Autozone, etc.) and they would have a scanner behind the counter
that they could have
plugged into the vehicle and told him the exact codes.

Ted

 

I can't say that for sure. I'm saying that an unknown used computer is
more likely to have trouble than a known computer that you had been
using every day. Personally, I prefer the devil I know over the one
that I don't.

Yes, I doubt your computer was ever the problem. It was trying to tell
you the problem and you instead swapped it out.


Matt

 

I haven't checked my service manual lately. Does it identify which
codes cause MIL illumination and which don't? I don't remember seeing
that in the list when I've visited it in the past.


Matt

 

And the sad part is that it usually isn't the computer per se that is
the problem, it is the I/O section. In my past life designing and
installation industrial control systems, the I/O gear failed at least 10
times as often as the CPU, memory or other parts of the control
computer. Good thing for us that the I/O was part of a subsystem and we
could replace individual I/O cards. The integrated units in cars don't
allow that flexibility as near as I can tell ... I've never tried to
open one up. In my case, I'm about 80% sure that the failure is just
the one I/O point that switches the rear washer pump to ground. The
pump stays on constantly. I unplugged the connector from the computer
and could short the appropriate pin with a paper clip and control the
pump just fine, so it appears that pin is being held to ground constantly.

Given the interface between the AC control module and the BCM, there is
come chance that the BCM is being constantly commanded to provide rear
wash, but I think that is less likely than a shorted output on the BCM,
however, it appears from the manual that the interface between these two
modules is a bus, not discrete wires and I have no means to monitor the
bus to read the commands being sent. However, I unplugged the module in
the dash that contains the rear washer switch and the BCM still kept pin
held to ground.


Matt

 

Isn't the output circuit integral with the computer?

Matt

 

Yes, it is. Read the whole post. In order.

 

That's part cost only. Replaced it myself.

 

I did. Your post wasn't clear that you understood that these were not
separate components. You discussed computer in one paragraph and
"output circuit" in another and though they were separate items.

Matt

 

Yes. Both my '87 and my '95 manuals say which does what.

 

Thanks for everybody's help.
To sum things up:
I should assume that the computer was not the problem?

The real problem is that the EGR Valve Assembly
should be replaced?

Am I correct in this assumption.

I am going to have the thing looked at again tomorrow, and will post
the results tomorrow night.

 

Yeah, I was at CTC playing games with computer to find correct parts
for my 1987 2.2L 'van, parts (some of them are there). For example
coolant sensor (round 3 pin style), wasn't listed for 1987, had to try
eariler years 86, 85 bingo, ditto to early distributor (1985 again), I
guess chrysler was trying to clean out all the remaining stocks on the
production floor. So on.

My 'van was a change-over year in engines, computer, emissions & fuel
system.

BTW, get your 'puter back. In meantime, try the codes again and watch
the light carefully. Blinks starts right away when finished toggling
that key.

Computer ever rarely fail. Smack the young guy, this guy needs to do
a troubleshooting steps carefully, with experience will only take
moments. Buy your own real service manual not hayes or chiltons! The
real thing will pay off in no time. These books has excellent
diagnostic throubleshooting charts, texts. Ebay or dealer's. It is 3
book set, sometimes four.

Always get the real service manuals for vehicles first thing if you
like to maintain them and here is good too.

Cheers,

Wizard

 

Assume nothing, please. Do the trouble shooting yourself with basic
info you learned to confirm which is the faulty part and use their
suggestions or find another decent mechanic and throubleshoot.

Cheers,

Wizard

 

It is *likely* the original computer was fine. The replacement computer is
faulty.

That may be, but it is by no means clear. What is needed is proper
*diagnosis* of the EGR system and all its components.

DS

 

It is "Computer memory power lost within last <50-75, per spec> engine
start events" *WHEN READ WITH A DRB OR OTHER DIAGNOSTIC COMPUTER*.

When it is read via the flash code method:

If any fault codes are stored, the flash sequence *will* start with 12.

If no fault codes are stored *and* the SMEC/SBEC has lost power feed
within the last 50 to 70 (per spec) engine start events, the flash
sequence *will* be "12, 55".

If no fault codes are stored *and* the SMEC/SBEC has *not* lost power feed
within the last 50 to 70 (per spec) engine start events, the flash
sequence *may* (per spec) consist only of "55".

See above.

That is not accurate thinking on your part.

DS

 

Well, I take it back -- just tried it by disconnecting the intake air
temp sensor, and got a 12, 23, 55. But where is this documented?
There may well be an EGR fault, but if the module reporting faults is

 

Documented? Dunno.

It's one of the things covered in Chrysler factory technician
training.

 

I am bringing the van into another mechanic Thursday moring.
Will give the final verdict then, hopefully!
Funny but the van has run better the past few days as the weather has
warmed up, but the popping or sputtering sound, and hesitation, are
still there.

 

DID YOU EVEN TRY TO DICONNECT THE VACUUM LINE TO THE EGR TO SEE IF THE
ENGINE RAN SMOOTH.

Warren

 

DID YOU EVEN TRY TO DICONNECT THE VACUUM LINE TO THE EGR TO SEE IF THE
ENGINE RAN SMOOTH.

Warren