Help on MPI stalling
 

Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but I
do have one small(ish) thing I just can't figure out. whenever I start it
from cold (sat for more than 6 hours) I'll get a stumble followed by the
engine quitting. This happens within 2 minutes of starting and then I can
fire it up without incident afterwards. I'd say this happens 70% of the
time. I've checked vacuum lines, retightened the intake and exhaust
manifolds, and re-seated electrical plugs. Also, there have been no faults
displayed by the check engine light....... I'm running stock champion plugs
for an 86 CJ-7.


Anyone have any insight?

Thanks in advance.
Rich Harris

Re: Help on MPI stalling
 

Mine will often die within seconds of starting. I did notice that if I was
still in the habit of giving it a little gas before turning the key that it
was more likely to die. It seems a little annoying, but overall the fuel
injection is an incredible mod.

Jim

--
'86 CJ-7
D30 D44 D300 4:1 T-5
SOA ARB 4.56 Mopar MPI
Fresno, CA USA
http://home.comcast.net/~cj.7/



"Richard Harris" <SHARRIS11@san.rr.com> wrote in message
news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
I
> do have one small(ish) thing I just can't figure out. whenever I start it
> from cold (sat for more than 6 hours) I'll get a stumble followed by the
> engine quitting. This happens within 2 minutes of starting and then I can
> fire it up without incident afterwards. I'd say this happens 70% of the
> time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
plugs
> for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris
>
>

Re: Help on MPI stalling
 

Mine will often die within seconds of starting. I did notice that if I was
still in the habit of giving it a little gas before turning the key that it
was more likely to die. It seems a little annoying, but overall the fuel
injection is an incredible mod.

Jim

--
'86 CJ-7
D30 D44 D300 4:1 T-5
SOA ARB 4.56 Mopar MPI
Fresno, CA USA
http://home.comcast.net/~cj.7/



"Richard Harris" <SHARRIS11@san.rr.com> wrote in message
news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
I
> do have one small(ish) thing I just can't figure out. whenever I start it
> from cold (sat for more than 6 hours) I'll get a stumble followed by the
> engine quitting. This happens within 2 minutes of starting and then I can
> fire it up without incident afterwards. I'd say this happens 70% of the
> time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
plugs
> for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris
>
>

Re: Help on MPI stalling
 

Richard Harris (SHARRIS11@san.rr.com) wrote on Saturday 23 August 2003 02:36
pm:

> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
> I do have one small(ish) thing I just can't figure out. whenever I start
> it from cold (sat for more than 6 hours) I'll get a stumble followed by
> the engine quitting. This happens within 2 minutes of starting and then I
> can fire it up without incident afterwards. I'd say this happens 70% of
> the time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
> plugs for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris

Rich,

I've got the same problem, and have been bugging Hesco about it off and on.
He's given me a few hints.

The first one is on their hint page, and that's to drill a 1/16" hole near
the center of the air intake flap (go to Hesco's web site for details).

The second was to make sure my distributor was centered. Turn the
distributor left and right, marking the points at which idle becomes rough.
Center the distributor between those marks. This didn't do me any good,
and I put it back into its original position.

Check for blocked exhaust. I had a bad catalytic converter, but replacing
that only fixed some horsepower issues during normal running temperatures.

His last suggestion was the adjustable fuel pressure regulator. That's
probably what I'm going to end up going with.

I'm not blaming the MPI design for this, though. I had an issue with a bad
rebuilt engine, and although it had a bad cylinder, it never died on
startup. The second rebuilt I put in also did not have this problem. The
third (and current) rebuilt I put in was the first to exhibit this problem.
It's probably an issues of tolerances, not an issue with the MPI. BTW, the
engines that had no problems were 84s. The one with the problem is an 81.

Good luck!
--
Michael White "To protect people from the effects of folly is to
fill the world with fools." -Herbert Spencer, 1891

Re: Help on MPI stalling
 

Richard Harris (SHARRIS11@san.rr.com) wrote on Saturday 23 August 2003 02:36
pm:

> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
> I do have one small(ish) thing I just can't figure out. whenever I start
> it from cold (sat for more than 6 hours) I'll get a stumble followed by
> the engine quitting. This happens within 2 minutes of starting and then I
> can fire it up without incident afterwards. I'd say this happens 70% of
> the time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
> plugs for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris

Rich,

I've got the same problem, and have been bugging Hesco about it off and on.
He's given me a few hints.

The first one is on their hint page, and that's to drill a 1/16" hole near
the center of the air intake flap (go to Hesco's web site for details).

The second was to make sure my distributor was centered. Turn the
distributor left and right, marking the points at which idle becomes rough.
Center the distributor between those marks. This didn't do me any good,
and I put it back into its original position.

Check for blocked exhaust. I had a bad catalytic converter, but replacing
that only fixed some horsepower issues during normal running temperatures.

His last suggestion was the adjustable fuel pressure regulator. That's
probably what I'm going to end up going with.

I'm not blaming the MPI design for this, though. I had an issue with a bad
rebuilt engine, and although it had a bad cylinder, it never died on
startup. The second rebuilt I put in also did not have this problem. The
third (and current) rebuilt I put in was the first to exhibit this problem.
It's probably an issues of tolerances, not an issue with the MPI. BTW, the
engines that had no problems were 84s. The one with the problem is an 81.

Good luck!
--
Michael White "To protect people from the effects of folly is to
fill the world with fools." -Herbert Spencer, 1891

Re: Help on MPI stalling
 

Mine does the same thing. It will start when cold and run for a few minutes,
then the motor will speed up and die. The restart is smooth and problem
free. It only behaves like this when I let it idle, if I drive away, it is
fine. It is also fine if I wedge my rubber stopper under the gas pedal it
run the idle speed up so I can use my compressor.




"Richard Harris" <SHARRIS11@san.rr.com> wrote in message
news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
I
> do have one small(ish) thing I just can't figure out. whenever I start it
> from cold (sat for more than 6 hours) I'll get a stumble followed by the
> engine quitting. This happens within 2 minutes of starting and then I can
> fire it up without incident afterwards. I'd say this happens 70% of the
> time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
plugs
> for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris
>
>

Re: Help on MPI stalling
 

Mine does the same thing. It will start when cold and run for a few minutes,
then the motor will speed up and die. The restart is smooth and problem
free. It only behaves like this when I let it idle, if I drive away, it is
fine. It is also fine if I wedge my rubber stopper under the gas pedal it
run the idle speed up so I can use my compressor.




"Richard Harris" <SHARRIS11@san.rr.com> wrote in message
news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
I
> do have one small(ish) thing I just can't figure out. whenever I start it
> from cold (sat for more than 6 hours) I'll get a stumble followed by the
> engine quitting. This happens within 2 minutes of starting and then I can
> fire it up without incident afterwards. I'd say this happens 70% of the
> time. I've checked vacuum lines, retightened the intake and exhaust
> manifolds, and re-seated electrical plugs. Also, there have been no faults
> displayed by the check engine light....... I'm running stock champion
plugs
> for an 86 CJ-7.
>
>
> Anyone have any insight?
>
> Thanks in advance.
> Rich Harris
>
>

Re: Help on MPI stalling
 

Not that it solves the problem, but that sounds like it's happening
about the time the O2 sensor should be reaching a temp where the
system goes closed loop. AIR, the MOPAR unit uses a heater on the
sensor controlled by a relay and it determines the cold start
switchover based on the output of the sensor OR a fixed time,
whichever comes first. What you describe would be consistent with
timing out before the O2 sensor reaches operating temp on the first
pass, then actually reaching the proper temp and giving an output
before it times out on the second pass. Other than a voltage drop in
the wiring that keeps the heater from reaching the right temp, the
only other answer would be a different sensor - a little expensive to
try "just to see if it works" and it should set a code.

That's just some musings after watching my son struggle with his '91
XJ when he forgot to plug the relay back in when he was cleaning
connectors a while back.

On Mon, 25 Aug 2003 16:21:41 UTC "Jeff Strickland" <beerman@yahoo.com>
wrote:

> Mine does the same thing. It will start when cold and run for a few minutes,
> then the motor will speed up and die. The restart is smooth and problem
> free. It only behaves like this when I let it idle, if I drive away, it is
> fine. It is also fine if I wedge my rubber stopper under the gas pedal it
> run the idle speed up so I can use my compressor.
>
>
>
>
> "Richard Harris" <SHARRIS11@san.rr.com> wrote in message
> news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> > Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
> I
> > do have one small(ish) thing I just can't figure out. whenever I start it
> > from cold (sat for more than 6 hours) I'll get a stumble followed by the
> > engine quitting. This happens within 2 minutes of starting and then I can
> > fire it up without incident afterwards. I'd say this happens 70% of the
> > time. I've checked vacuum lines, retightened the intake and exhaust
> > manifolds, and re-seated electrical plugs. Also, there have been no faults
> > displayed by the check engine light....... I'm running stock champion
> plugs
> > for an 86 CJ-7.
> >
> >
> > Anyone have any insight?
> >
> > Thanks in advance.
> > Rich Harris
> >
> >
>
>


--
Will Honea <whonea@codenet.net>

Re: Help on MPI stalling
 

Not that it solves the problem, but that sounds like it's happening
about the time the O2 sensor should be reaching a temp where the
system goes closed loop. AIR, the MOPAR unit uses a heater on the
sensor controlled by a relay and it determines the cold start
switchover based on the output of the sensor OR a fixed time,
whichever comes first. What you describe would be consistent with
timing out before the O2 sensor reaches operating temp on the first
pass, then actually reaching the proper temp and giving an output
before it times out on the second pass. Other than a voltage drop in
the wiring that keeps the heater from reaching the right temp, the
only other answer would be a different sensor - a little expensive to
try "just to see if it works" and it should set a code.

That's just some musings after watching my son struggle with his '91
XJ when he forgot to plug the relay back in when he was cleaning
connectors a while back.

On Mon, 25 Aug 2003 16:21:41 UTC "Jeff Strickland" <beerman@yahoo.com>
wrote:

> Mine does the same thing. It will start when cold and run for a few minutes,
> then the motor will speed up and die. The restart is smooth and problem
> free. It only behaves like this when I let it idle, if I drive away, it is
> fine. It is also fine if I wedge my rubber stopper under the gas pedal it
> run the idle speed up so I can use my compressor.
>
>
>
>
> "Richard Harris" <SHARRIS11@san.rr.com> wrote in message
> news:ZmP1b.2356$Pd3.124372@twister.socal.rr.com...
> > Got the MOPAR FI kit on my CJ. I'm really pleased with the whole thing but
> I
> > do have one small(ish) thing I just can't figure out. whenever I start it
> > from cold (sat for more than 6 hours) I'll get a stumble followed by the
> > engine quitting. This happens within 2 minutes of starting and then I can
> > fire it up without incident afterwards. I'd say this happens 70% of the
> > time. I've checked vacuum lines, retightened the intake and exhaust
> > manifolds, and re-seated electrical plugs. Also, there have been no faults
> > displayed by the check engine light....... I'm running stock champion
> plugs
> > for an 86 CJ-7.
> >
> >
> > Anyone have any insight?
> >
> > Thanks in advance.
> > Rich Harris
> >
> >
>
>


--
Will Honea <whonea@codenet.net>

Re: Help on MPI stalling
 

"Will Honea" <whonea@codenet.net> wrote in message
news:JxX2tWiP5BNp-pn2-NHdNIYSfw7TB@anon.none.net...
> Not that it solves the problem, but that sounds like it's happening
> about the time the O2 sensor should be reaching a temp where the
> system goes closed loop. AIR, the MOPAR unit uses a heater on the
> sensor controlled by a relay and it determines the cold start
> switchover based on the output of the sensor OR a fixed time,
> whichever comes first. What you describe would be consistent with
> timing out before the O2 sensor reaches operating temp on the first
> pass, then actually reaching the proper temp and giving an output
> before it times out on the second pass. Other than a voltage drop in
> the wiring that keeps the heater from reaching the right temp, the
> only other answer would be a different sensor - a little expensive to
> try "just to see if it works" and it should set a code.
>
> That's just some musings after watching my son struggle with his '91
> XJ when he forgot to plug the relay back in when he was cleaning
> connectors a while back.
>


I think I'll spend the money on more important stuff, and occasionally start
my CJ twice. Thanks for the explanation though. Do you suppose my header
could be playing a part in this? The O2 sensor should be installed in a
collector where all of the tubes come together, but my senior-moment-plagued
mind's eye says the sensor is in a collector that only looks at one set of
tubes. My header is a 3 into 2 into 1 design, and logic says the sensor
should be in the 2 into 1 collector, but I think it is in one of the 3 into
2 collectors. I don't really care if the sensor looks at all of the exhaust
gas or not, but I wonder if the header could actually be cooler than the
standard manifold, and keeping the O2 sensor from getting hot in time. You
did mention the manifold heater, but that is contained in the carburator
manifold, not the fuel injection manifold. Hmmm ...